Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Home
My WebLink
About
161205 MAD (Storm Drainage Report).pdf
Madrona School Edmonds, Washington • .•- '-•• December 2016 1 Site Permit • .•Am Wes•• December 2016 Prepared for: Edmonds School District 20420 68th Avenue West Lynnwood, WA 98036-7400 Prepared by: KPFF Consulting Engineers 1601 Fifth Avenue, Suite 1600 Seattle, WA 98101 (206) 622-5822 KPFF Job No. 1500129 Principal in Charge: Thaddeus J. Egging, PE Project Manager: Joss Gramstad, PE PRELIMINARY Madrona School — Edmonds School District I KPFF Consulting Engineers Table of Contents 1 . Project Description...........................................................................................................z 2. Stormwater Systems Overview.........................................................................................2 ExistingConditions..................................................................................................................... 2 developedconditions.................................................................................................................. 2 3. Minimum Requirements...................................................................................................3 Minimum Requirement No.1: Preparation of Stormwater Site Plan ........................................... 3 Minimum Requirement No. 2: Construction Stormwater Pollution Prevention (SWPP) .............. 3 Minimum Requirement No. 3: Source Control of Pollution.......................................................... 4 Minimum Requirement No. 4: Preservation of Natural Drainage Systems and Outfalls............... 4 Minimum Requirement No. 5: On -site Stormwater Management ............................................... 4 Minimum Requirement No. 6: Runoff Treatment........................................................................4 Minimum Requirement No. 7: Flow Control................................................................................ 4 Minimum Requirement No. 8: Wetlands Protection.................................................................... 4 Minimum Requirement No. 9: Basin/watershed planning........................................................... 4 Minimum Requirement No. so: Operation and Maintenance...................................................... 5 4. Stormwater Design Requirements....................................................................................5 CodeCompliance....................................................................................................................... 5 FlowControl............................................................................................................................... 6 WaterQuality............................................................................................................................. 6 Conveyance................................................................................................................................ 6 5. Stormwater Pollution Prevention..................................................................................... 8 List of Figures Figure1-1: Vicinity Map....................................................................................................................1 List of Tables Table 2-1: Existing TDAS............................................................................................... 2 Table 3-1: Wetland B (North Basin) Land Cover.............................................................5 Table 3-2: Wetland B (South Basin) Land Cover............................................................5 Table 4-1: UIC Well Design.............................................................................................6 Table 4-2: Bioretention Cells with Underdrains Summary...............................................7 Madrona School — Edmonds School District 111 Appendices Appendix A — Site Maps Appendix B — Calculations and Program Output Appendix C — Geotechnical Engineering Report Appendix D - Hydrogeologic Report Appendix E - Wetland and Stream Delineation Report Appendix F — Wetland Hydroperiod Analysis Appendix G — Stormwater Pollution Prevention Plan Appendix H — Operations and Maintenance Manual KPFF Consulting Engineers Iv 1. Project Description The project is located at 9300 236th ST SW in Edmonds, Washington. The existing Madrona Elementary School will be demolished and replaced with a new school. The proposed school consists of a larger gymnasium and administration unit and five smaller classroom units. Other site improvements include new sports fields, play equipment, a bus drop-off loop, and parking lots. The new school will be situated in the field south of the existing school to enable phased construction while the existing school is in session. The project is disturbing the eastern 15 acres of a larger 40 acre parcel owned by the Edmonds School District. The site generally slopes from east to west with the lower southeast quarter of the site situated on a bench approximately 12 feet higher than the southwest quarter. The site is bound to the north by 236th St SW, to the east by a depressed wetland, to the south by 240th St SW, and to the west by a steep slope down to the former Woodway Elementary School. Water quality will be achieved through underdrained bioretention planters serving all of the pollution generating impervious surfaces. These planters are engineered to infiltrate at least 91 % of the total runoff volume through the underdain. For flow control, the project is proposing a series of deep injection control wells. Storm drainage pipes and well fields have been analyzed to convey and infiltrate return events up to and including the 100-year event. The wetland to the east is largely dependent on the project site for its hydrology. A wetland analysis has been included to demonstrate how the project maintains the wetland function. SITE I' Figure 1: Vicinity Map (NTS) Madrona School — Edmonds School District 1 This report is written according to the 2010 City of Edmonds Stormwater Code Supplement (Edmonds Supplement) and the 2005 Stormwater Management Manual for Western Washington (DOE Manual). 2. Stormwater Systems Overview EXISTING CONDITIONS The existing site is part of the larger Edmonds Way Watershed as defined on figure B — 1 in the Edmonds Supplement. The site is comprised of three Threshold Discharge Areas (TDA). TDA 1 includes the eastern half of 236th st and adjacent forested area as well as the eastern half of the staff parking lot and east driveway. TDA 1 drains through catch basins and pipes to the piped system in 236th St SW heading East to Edmonds Way. TDA 2 includes the eastern half of the site including half of the existing school, the southeastern field, and the large wetland. This Wetland is also known as Wetland B in the Wetland and Stream Delineation Report (See appendix E). Some offsite area from the neighboring residences also is included in TDA 2. Surface runoff either sheet flows directly to the wetland or is discharged via open pipe ends or dispersion trenches. Runoff in the wetland pools at the south end against the 240th St SW embankment until reaching the 18" culvert crossing the road. Downstream of the culvert, runoff is directed to the Edmonds Way system via open ditches and pipes. TDA 3 includes the western half of the site including the remaining half of 236th st and the existing school, parent parking lot, track, and south western field. TDA 3 either sheet flows or discharges via open pipe ends or dispersion trenches to the steep slope west of the site. Edmonds School District Maintenance staff has noted that during heavy rain, flowing water originating from the steep slope encroaches on the former Woodway Elementary school. Table 2-1: Existing TDAS See Figure Al in Appendix A for a map showing each of these areas. DEVELOPED CONDITIONS The proposed development includes approximately 6.72 acres of impervious area including parking lots, maintenance drives, building roof, and pedestrian courtyards. The proposed condition discharges runoff either to the existing system in 236th St SW, the groundwater table, or the wetland east of the site. UIC WellSub-Basins There are three UIC well sub -basins that discharge runoff to the groundwater table. KPFF Consulting Engineers 2 UIC Well Basin #1 contains five wells and is 3.239 acres of mostly impervious surfaces receiving runoff from the bus loop and parking lot areas. This UIC well field contains the majority of the pollution generating impervious surfaces. Bioretention and an oil water separator are proposed to provide water quality for 91 % of the total runoff volume prior to discharging to the UIC wells. UIC Well Basin #2 contains five wells and is 3.083 acres receiving runoff from the track and interior play spaces. This sub basin is mostly pervious; however, the underdrained play field is modeled as impervious as runoff will enter the underdrains quickly. Water quality is not proposed for this basin as none of the surfaces are considered pollution generating. UIC Well Basin #3 contains three wells and is 1.324 acres of mostly impervious surfaces receiving runoff from building, lawn, the emergency access drive, and pedestrian courtyards. Water quality is not proposed for this basin as none of the surfaces are considered pollution generating. UIC Well Basin #4 contains three wells and is 1.936 acres of an almost equal amount of pervious and impervious surfaces receiving runoff from building, lawn, the emergency access drive, forest, and pedestrian courtyards. Water quality is not proposed for this basin as none of the surfaces are considered pollution generating. See Figure A3 in Appendix A for a map showing each of these areas. WetlandSub-Basin The wetland sub -basin was designed to preserve the existing wetland hydrology in order to meet minimum requirement number 8. As the proposed development impacts the runoff pattern, a detailed analysis is included in section 3. All runoff from pollution generating impervious surfaces tributary to the wetland sub - basin are treated for water quality via bioretention. Non -pollution generating surfaces discharge directly through stabilized pipe outfalls or existing subsurface the drains. See Figures F1 and F2 in Appendix F for maps of this area. 3. Minimum Requirements The project includes more than 5,000 square feet of new plus replaced impervious surfaces; therefore, all 10 of the Ecology Minimum Requirements are to be met. The following outlines project compliance: MINIMUM REQUIREMENT NO. 1: PREPARATION OF STORMWATER SITE PLAN This storm drainage report, the appendices, and the submitted plans represent the Stormwater Site Plan as outlined in the Ecology Manual. MINIMUM REQUIREMENT NO. 2: CONSTRUCTION STORMWATER POLLUTION PREVENTION (SWPP) See Section 5, below. As the new plus replaced impervious surface is greater than 2,000 square feet, all 12 SWPP elements are to be met. See appendix G for the SWPP Plan. Madrona School — Edmonds School District 3 MINIMUM REQUIREMENT NO. 3: SOURCE CONTROL OF POLLUTION The proposed development does not contain pollution sources. As such, no source control BMPs have been proposed. The SWPP does include source control BMPs to be used during project construction. MINIMUM REQUIREMENT NO. 4: PRESERVATION OF NATURAL DRAINAGE SYSTEMS AND OUTFALLS The proposed drainage system will generally preserve the natural drainage patterns with the exception of discharge to the western steep slope. Most runoff from the developed site will infiltrate via the Underground Injection Control (UIC) wells. Runoff from 236th St SW will continue to drain to the existing roadway drainage system. The runoff patterns to the wetland east of the site will also be preserved. MINIMUM REQUIREMENT NO. 5: ON -SITE STORMWATER MANAGEMENT All of the stormwater from the project area will be infiltrated on site via the UIC wells or discharged directly to the wetland east of the site. See Section 4, below. MINIMUM REQUIREMENT NO. 6: RUNOFF TREATMENT Runoff treatment has been provided for 91 % of the runoff volume from pollution generating impervious surfaces. See the "Runoff Treatment" portion of Section 4 below. MINIMUM REQUIREMENT NO. 7: FLOW CONTROL Flow control has been designed to meet this requirement through the use of infiltration through the UIC wells. See the "Flow Control" portion of Section 4, below. MINIMUM REQUIREMENT NO. 8: WETLAND PROTECTION The stormwater system has been designed to maintain the hydrologic conditions of the existing wetland. MGS Flood was utilized to model the existing land cover to determine the existing baseline hydrologic conditions, and a wetland hydroperiod analysis was conducted to compare the hydroperiod under the proposed conditions to that of the existing. Existing tl Conditions The existing conditions for Wetland B were modeled using a combination of contours from the project survey and the Edmonds GIS Map as well as the geotechnical engineer's recommended infiltration rates. Due to the topography of the wetland, the wetland was modeled as two structures in MGS Flood to account for the north and south portions of the wetland: Wetland B-North and Wetland B-South. The north subbasin receives runoff from the surrounding area including residential area to the north and east and a portion of the Madrona School site to the west. Likewise, the south subbasin receives runoff from the surrounding area including the southeast portion of the site, as well as the outflow from Wetland B-North via a trapezoidal broad -crested weir. Wetland B-South discharges via an 18-inch culvert under 240th Street to the south. Wetland i er Proposed Conditions Similar to the existing condition, stormwater from the eastern portion of the proposed Madrona School site drains to the wetland basin. The following tables (Table 3-1 and Table 3-2) compare existing surface areas to proposed surface areas for Wetland B's north and south basins. KPFF Consulting Engineers 4 Table 3-1: Wetland B (North Basin) Land Cover Table 3-2: Wetland B (South Basin) Land Cover The proposed site land cover decreases the amount of impervious area in the Wetland B-North basin and increases the impervious area in the Wetland B-South basin. Since impervious surfaces produce proportionally more runoff, the total area that discharges to Wetland B-North increased and the area that discharges to Wetland B-South decreased in order to maintain the hydrologic conditions of the existing wetland basins. Using the wetland hydroperiod analysis tool in MGS Flood, the hydroperiod for the proposed conditions are compared to the existing condition for both the north and south portions of Wetland B. The MGS Flood report with the wetland hydroperiod analysis (Appendix F) demonstrates that the Stage Excursions Threshold (0.5 ft) and Amphibian Stage Excursions Threshold (0.25 ft from Feb 1 to May 31) are not exceeded in the proposed condition. MINIMUM REQUIREMENT NO. 9: BASIN/WATERSHED PLANNING No basin management is planned for this area. No additional requirements, beyond those listed above, are applicable to this project. ►ri11,41 M ►r/:1*01111:1=11ril211,11i ,11[01iVIKil:721-,%d �I_1�1�7►r►_�I��i �►_l�[a Refer to Appendix H for the Operation and Maintenance Manual. 4. Stormwater Design Requirements CODE COMPLIANCE This project has been designed to meet the requirements of the Stormwater Code Supplement to Edmonds Community Development Code Chapter 18.30 and the 2005 Department of Ecology Stormwater Management Manual for Western Washington. Madrona School — Edmonds School District 4i FLOW CONTROL Since the project is creating more than 10,000 square feet of effective impervious area, the Ecology Manual requires the implementation of flow control facilities and on -site stormwater management BMPs. Furthermore, stormwater discharges shall match pre -developed forested discharge rates and flow durations from 50 percent of the 2-year peak flow up to the full 50-year peak flow. The proposed flow control design meets or exceeds these requirements for sub -basins discharging to the water table. As the existing site does not include any flow control facilities and Minimum Requirement #8 requires wetland protection, predevelopment runoff peaks and durations were not maintained for sub -basins tributary to the eastern wetland. Reducing flows to the wetland through flow control would degrade the wetland's function. UIC Well Design Through pilot test and full scale UIC well installations, the geotechnical engineer's recommended long term UIC well infiltration rate is 3.3 gallons -per -minute per foot of screen. See the Hydrogeologic Report included in Appendix D. As the UIC wells each contain 50 feet of screen, the individual infiltrative capacity of each well is 165 GPM or 0.368 CFS. The table below shows the UIC well capacities compared to the 100 year peak flow using MGS Flood with one hour time steps. Design of the UIC wells is based on the "Hydrogeologic Report" prepared by the project geotechnical engineer, Shannon and Wilson, Inc. and the "Guidance for UIC Wells that Manage Stormwater" as published by the Washington State Department of Ecology (Ecology), December 2006. Well design complies with the Ecology guidance for rule -authorized wells using the presumptive approach, and the UIC wells will be registered as Class V UIC wells with Ecology. Each UIC well will function as a deep dry well comprised, generally, of a borehole filled with gravel. Wells will be bored to approximately 120 feet below grade so as to access the deep advance outwash receptor horizon. Each well will have the upper 60-70 feet cased with 36-inch-diameter steel casing and will include a vertical conveyance pipe to allow high -flow infiltration and a separate piezometer tube to allow for testing and monitoring. Per the geotechnical investigations, the Qva aquifer is approximately at elevation 278 feet. The wells will be bored to approximately elevation 325; therefore, the bottom of each well will be approximately 47 feet above groundwater. WATER QUALITY Per the redevelopment requirements of Western Washington Ecology Manual, since the development includes more than 5,000 square feet of new plus replaced hard surfaces and the proposed improvements exceeds 50% of the assessed existing site improvement value, water quality treatment is required for pollution generating surfaces. Additionally, since the treatment facilities are designed using an approved KPFF Consulting Engineers 6 continuous runoff model (MGS Flood), the water quality design storm volume shall be equal to the simulated daily volume that represents the upper limit of the range of daily volumes that accounts for 91 % of the entire runoff volume over a multi -decade period of record. Water quality treatment to meet the above requirements will be provided via bioretention cells with underdrains. Table 4-2 summarizes the design for each bioretention cell. The bioretention cells are sized to treat site stormwater based on expected pollutant loads in accordance with local stormwater code (City of Edmonds 2010). Due to the low infiltration capacity of the native soil on site, each cell will implement a layer of bioretention soil that removes pollutants by percolation through this layer, but do not rely on infiltration into the subgrade for drainage. An underdrain is included to convey water after it percolates through the treatment layer and routes the flow to the discharge point. Per the recommendation in the Hydrogeologic Report, bioretention cells are designed with only mature, stable compost without biosolids and employ elevated underdrains in order to minimize biofouling of the UIC wells downstream. Table 4-2: Bioretention Cells with Underdrains Summary Sub -Basin Inflow Volume Treatment % Total Runoff (ac-ft) Volume (ac-ft) Treated 1 563.97 549.05 97.35 2 430.56 394.76 91.68 3 51.93 48.41 93.21 4 47.21 45.02 95.37 5A 37.80 37.80 100.00 5B 60.65 58.71 96.81 6 78.51 77.78 99.07 7 96.39 89.23 92.58 8 93.52 85.48 91.41 9 55.64 55.33 99.43 See Appendix A Figure A2: Bioretention Drainage Basins Refer to Appendix B for MGS Flood design calculations. CONVEYANCE Runoff is conveyed by a network of swales, gutters, catch basins, manholes, and pipes to the discharge point. Pipes are sized using the Rational Method to convey runoff from the 100-yr event as the site is not designed with overflow connections to city systems. It is the intent that all runoff from the developed area, excluding runoff from 236t" St SW, is captured and conveyed to either the groundwater table or the wetland east of the site. Conveyance to each of the UIC wells is designed to encourage sedimentation upstream of the UIC wells. The conveyance network is designed with dead storage in the manifold pipes upstream of the UIC wells to encourage sedimentation prior to discharge to the wells. The pipes connecting the individual UIC wells to the manifold pipes have a negative slope, further encouraging sedimentation in the manifold pipes. This system will ensure that runoff enters the UIC wells in each field uniformly and with the lowest velocity possible (full pipe barrel area utilized). Regular maintenance of the manifold pipes is required to ensure the system Madrona School - Edmonds School District rl performs as intended. See Appendix B for conveyance calculations and Appendix H for maintenance recommendations. 5. Stormwater Pollution Prevention As the proposed development encompasses more than 1-acre, erosion control measures will comply with the requirements of the National Pollution Discharge Elimination System (NPDES) permit administered by the Department of Ecology (DOE). All 12 Stormwater Pollution Prevention (SWPP) elements are to be met. Construction site stormwater best management practices (BMPs) will be implemented as necessary to control erosion and to prevent sediment and other pollutants from leaving the site during construction activities. The SWPP plan demonstrate compliance with these measures and can be found in Appendix G. KPFF Consulting Engineers 8 Site Maps Y Al: Existing Threshold Discharge Areas Y A2: Bioretention Drainage Basins Y A3: UIC Well Tributary Areas Madrona School — Edmonds School District Appendix A 9'L 93RD X • rQ .. ..... ... 1A me :--- ....... . .............. DOWNSTREAM SYSTEM .......... ... ... 'A --- -------- '5' 'r EDMONDS� WAY 1 9, . . . ..... . .. . ..... . 41� I - N, """'J v. t 3 1 ti Project Title MADRONA K-8 Client MAHLUM ARCHITECTS Drawing Title EXISTING THRESHOLD DISCHARGE AREAS 1601 5th Avenue, Suite 1600 Seattle, WA 98101 206.62 .5822 .ww.kpff.co. Al Drawing Reference Scale ill = 60' Date Dram/Ck'd By 12/05/2016 CB/JCG A 139W,�JAMMMI BIORETENTION 8It "' 2`1 vil, Project Title MADRONA K-8 Client MAHLUM ARCHITECTS BASIN TOTAL AREA (AC) PERVIOUS AREA (AC) IMPERVIOUS AREA (AC) BIORETENTION 1 2.462 1.747 0.715 BIORETENTION 2 1.644 0.574 1.070 BIORETENTION 3 0.151 0.021 0.130 BIORETENTION 4 0.141 0.023 0.118 BIORETENTION 5A 0.105 0.013 0.092 BIORETENTION 5B 0.169 0.028 0.141 BIORETENTION 6 0.224 0.028 0.196 BIORETENTION 7 0.260 0.020 0.240 BIORETENTION 8 0.254 0.021 0.233 BIORETENTION 9 1 0.155 0.027 0.128 1 Drawing Title BIORETENTION DRAINAGE BASINS 1601 Sin Avenue, Suite 1600 Seattle, WA98101 ww.kpff.co. —i-, -.- 1, 1 60' ,a Drawn/CWd By 11/28/2016 CC/CB b", 'z ...... . ... . .... ... ... v.. . .... ........ .. ... . . - - - — --- ----- -------- ..... . .. ` .. . ...... f"- -A s. . .... . .. ..... .... V"} . . .. . mot,.. 'i . . .... . i0411 A- . .... �"! I N Di . ..... ..... . "a I g if R! 4 ....... . . . .. r i* i�! W-, A "Q, 77,,77777 3-4dty �5. CA . . ... ........ If ...... . . ... . . . ....... :: ....... ... 711 .... . ..... s. 4. ...... .. .. rr. ..... . . .. .. .... A . . . . ...... , ka . ..... ... . 1 . .... .. .. . 5(", o' "i, A uo z" tit s A wvr"me, aw, BASIN TOTAL AREA (AC) PERVIOUS AREA (AC) IMPERVIOUS AREA (AC) UIC WELL FIELD #1 3.239 0.876 2.363 UIC WELL FIELD #2 3.083 0.914 2.169 UIC WELLFIELD #3 1.324 0.244 1.080 UIC WELL FIELD #4 1.936 1 1.014 0.922 0 75 150 Now• Project Title MADRONA K-8 Client MAHLUM ARCHITECTS UIC WELL FIELD TRIBUTARY AREA UIC WELL FIELD #1 PERVIOUS AREA .............. UIC WELL FIELD #2 ........... PERVIOUS AREA .............. .............. ............. UIC WELL FIELD #3 .............. ............ ** .............. PERVIOUS AREA ............. UIC WELL FIELD #4 PERVIOUS AREA Drawing Title Figure Number UIC WELL TRIBUTARY AREAS A3 ------ Drawing Reference F 1" = 150' 1601 5th Avenue, Suite 1600 Seattle, WA 98101 Date Drawn/CWd By 206.622M22 w.w. kinff.— 12/05/2016 CB/JCG V'• i •• Calculations Y B1 - Stormwater Runoff and Pipe Conveyance Calculation Y B2 — Flow Splitter Calculation Y B3 — Biorention Calculations Y B4 — UIC Well Calculations Madrona School — Edmonds School District Appendix B Storm Drain Profile #1 - SDMH #10 RUNOFF CALCULATIONS (RATIONAL Alt€AG................... METED ,......................... ,,,,,,,,, �� * ,,,,�.,,,, rea (AC)(Area (ACC) TotalArea (AC)Co po�site 'C a' 0'03 388 m Po"x4, RAS� E ........ ........... -- ------------- Tc _ 5 (MIN) Hyd. Man. (2-11) 100 WlYear Storm m = 8,7 5 Hyd. Man. (2-5.4A) Seattle n = 545 Hyd. Man. (2-5.4A) Seattle I = 3,64 (IN/HR) Hyd. Man. (2-4) Flow (Rational) _ �8,97 (CFS) \\kpff.com\Civil\1500001-1500400\1500129 (Madrona)\PROJECT DOCUMENTS\Storm Drainage\Calculations\2016-08-22 (CD)\Conveyance\SDPF - 100 - SDMH #103.xlsx Appendix i31 Worksheet for SDPF 100 - SDAD #103 (18") Friction Method Manning Formula Solve For Full Flow Capacity Roughness Coefficient 0.010 Channel Slope 0.00500 ft/ft Normal Depth 1.50 ft Diameter 1.50 ft Discharge 9.66 ft3/s > 8.97 CFS v/ Discharge 9.66 ft3/s Normal Depth 1.50 ft Flow Area 1.77 ft2 Wetted Perimeter 4.71 ft Hydraulic Radius 0.38 ft Top Width 0.00 ft Critical Depth 1.20 ft Percent Full 100.0 % Critical Slope 0.00524 ft/ft Velocity 5.46 ft/s Velocity Head 0.46 ft Specific Energy 1.96 ft Froude Number 0.00 Maximum Discharge 10.39 ft3/s Discharge Full 9.66 ft3/s Slope Full 0.00500 ft/ft Flow Type SubCritical Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:15:58 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 *� Worksheet for SDPF 100 - SDAD #103 (18") Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.50 ft Critical Depth 1.20 ft Channel Slope 0.00500 ft/ft Critical Slope 0.00524 ft/ft Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:15:58 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Appendix 131 Storm Drain Profile #10 - S AD #1 4 RUNOFF CALCULATIONS (RATIONALMETHOD) —,„e ��,,,�,��,a ... .... N .,. AREA C AREA (SF} Area (A ,...., (Area (AC)*C) 'Total Area (AC) . Composite C GRASS i 1 7,884 �i�l1�1 _ J .� � _ 8 � PAVEMENT 0 95 55 670 1,278 1.21 ................... .............. .. .. ............ Tc _ (MIN) Hyd. Man. (2-11) 100 77]Year Storm m = Hyd. Man. (2-5.4A) Seattle n = 2 Hyd. Man. (2-5.4A) Seattle I = ,; (IN/HR) Hyd. Man. (2-4) Flow (Rational) _ (CFS) \\kpff.com\Civil\1500001-1500400\1500129 (Madrona)\PROJECT DOCUMENTS\Storm Drainage\Calculations\2016-08-22 (CD)\Conveyance\SDPF - 100 - SDAD #104.xlsx Appendix B1 Solve For Discharge ConunidBevaUon Tai|waterBevaUon Discharge Coefficient Diameter Headwater Elevation Headwater Height Above Conmzd Tai|waterHeight Above Centroid Flow Area Velocity Headwater Elevation SHORT SEGMENT [F12"omPIPE WILL BEHAVE SIMILAR TOA 1oromORIFICE. 1.40 K 1.4o'BACKVVAJERATTHE 1onYR 0.00 ft EVENT ATanxo#1o4DOES NOT OVERTOP THE RIM. 0.79 fP 5.88 ft/s Bentley Systems, Inc. *uestauMvmvus SoIBkJ1otId&vFftwMaster vm(SELEorsvwv 1} [08.11z1.03] 1214120163:17:14nw ovnwmonaCompany Drive Suite mmwWatertown, crowrooUSA +1-2oo-7nn1mm poo° 1 of 1 Z�� Storm Drain Profile #1 - S AD #1 5 RUNOFF CALCULATIONS (RATIONAL METHOD) —11-11-1,11111111 Ai3EA C AREA (SF} Area (A ,...., (Area (AC Cj ..1 otal.Area (AC) Composite�C GRASS i 3 006 ��1061�� �� I�� � ����� �_��� a PAVEMENT 019 29,142 ' &:. x 0,641 Tc = 5(MIN) Hyd. Man. (2-11) too 77]Year Storm m = Hyd. Man. (2-5.4A) Seattle n = 2 Hyd. Man. (2-5.4A) Seattle I = ,; (IN/HR) Hyd. Man. (2-4) Flow (Rational) _(CFS) \\kpff.com\Civil\1500001-1500400\1500129 (Madrona)\PROJECT DOCUMENTS\Storm Drainage\Calculations\2016-08-22 (CD)\Conveyance\SDPF - 100 - SDAD #105.xlsx Appendix 131 Friction Method Manning Formula Solve For Full Flow Capacity Roughness Coefficient 0.010 Channel Slope 0.01140 ft/ft Normal Depth 1.00 K Diameter 1.00 ft Discharge 14.4W/s]> 2o9CpS,/ Discharge 4.94 ftl/s Normal Depth 1.00 K Flow Area 0.79 fP Wetted Perimeter 3.14 K Hydraulic Radius 025 K Top Width 0.00 ft Critical Depth 0£1 ft Percent Full 100.0 Y6 Critical Slope 0.00993 ft/ft Velocity 630 ft/s Velocity Head 0.62 K Specific Energy 1.62 K FmudoNumber 0.00 Maximum Discharge 532 Kl/s Discharge Full 4.94 ftl/s Slope Full 0.01140 ft/ft Flow Type SubCritical Downstream Depth 0.00 0 Length 0.00 k Number [fSteps » Upstream Depth 0.00 0 Profile Description Pm5|aHaad|oss 0.00 ft Average End Depth Over Rise 0.00 Y6 Bentley Systems, Inc. *uestauMethods oo/mwnuu&vNk*wMusm,vm(nELEorsvr/vs1) [08.11.01.03] 1214120163:15:34pM uvn/emonaCompany Drive Suite unowWatertown, crommoUSA +1-uoo-7n5-1000 poo° 1 of u Z�� Worksheet for SDPF 100 - SDAD #105 Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.91 ft Channel Slope 0.01140 ft/ft Critical Slope 0.00993 ft/ft Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:15:34 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Appendix 131 1 RUNOFF CALCULATIONS (RATIONALMETHOD) AREA C AREA (56 ',.< Area (AC) (Area (AC)*C) Total Area (AC) Composite C GRASS 8 25,0fl8 11,644 O b��;� PAVEMENT a I? 6 609 - t :_ In n� _ Tc _ 5 (MIN) Hyd. Man. (2-11) 100 Year Storm m = T,t„r Hyd. Man. (2-5.4A) Seattle n = ' 3 Hyd. Man. (2-5.4A) Seattle I = 3,6 (IN/HR) Hyd. Man. (2-4) Flow (Rational) _ �a (CFS) \\kpff.com\Civil\1500001-1500400\1500129 (Madrona)\PROJECT DOCUMENTS\Storm Drainage\Calculations\2016-08-22 (CD)\Conveyance\SDPF - 110 - SDAD #111.xlsx Appendix B1 Worksheet for SDPF 110 - SDAD #111 Friction Method Manning Formula Solve For Full Flow Capacity Roughness Coefficient 0.010 Channel Slope 0.01140 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Discharge 14.94 W/s I > 4.35 CFS Discharge 4.94 ft3/s Normal Depth 1.00 ft Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.91 fit Percent Full 100.0 % Critical Slope 0.00993 ft/ft Velocity 6.30 ft/s Velocity Head 0.62 ft Specific Energy 1.62 ft Froude Number 0.00 Maximum Discharge 5.32 ft3/s Discharge Full 4.94 ft3/s Slope Full 0.01140 ft/ft Flow Type SubCritical Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:14:57 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 Worksheet for SDPF 110 - SDAD #111 Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.91 ft Channel Slope 0.01140 ft/ft Critical Slope 0.00993 ft/ft Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:14:57 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Appendix 131 AREA C AREA (SF) Area (AC) (Area (AC)*C) Total Area (AC) Composite C 0,05 6 R, SSF ................ . ........ .......... . .. . ......... iF .... .. .. .... .......... ...... ......... ... ....... . .... . ...... N f 0,24 Tc= (K8|N) Hyd.Man. (2-11) 100 Yea,3uxm M &75 Hyd.Man. <2-S.4A Seattle n 0,545 Hyd.Man. <2'5.4V Seattle 1 3,64 (|N/HK) Hyd.Man. <2-4> \\kpff.com\OvK1500001-1500400\1500129<madnmpKpn0JscTnOCUrwcmTS\Stormnminage\[e|cu|minns\2016-08-22 Worksheet for SDPF 610 - SDCB #612 Friction Method Manning Formula Solve For Full Flow Capacity Roughness Coefficient 0.010 Channel Slope 0.00500 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Discharge 13,27 ft3/s > 1.05 CFS Discharge 3.27 ft3/s Normal Depth 1.00 ft Flow Area 0.79 ft2 Wetted Perimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.77 fit Percent Full 100.0 % Critical Slope 0.00559 ft/ft Velocity 4.17 ft/s Velocity Head 0.27 ft Specific Energy 1.27 ft Froude Number 0.00 Maximum Discharge 3.52 ft3/s Discharge Full 3.27 ft3/s Slope Full 0.00500 ft/ft Flow Type SubCritical Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:16:51 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 '� Worksheet for SDPF 610 - SDCB #612 Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.77 ft Channel Slope 0.00500 ft/ft Critical Slope 0.00559 ft/ft Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:16:51 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Appendix 131 Storm Drain Profile #7 - SDCO #701 RUNOFF CALCULATIONS (RATIONALMETHOD) . € C AREA ( F} Area (AC)� (Area (AC)*C) Total Area (AC) Composite C GRASS 0J 0 �S I r (�; m_ a PAVEMENT 742 0,22 � ��� � ti. .._ _.....,...�.. __ P _ ._ Tc =(MIN) Hyd. Man. (2-11) 100 Year Storm m = 81,,7 IS Hyd. Man. (2-5.4A) Seattle n = Hyd. Man. (2-5.4A) Seattle I = i + (IN/HR) Hyd. Man. (2-4) Flow (Rational) _ 1,7 (CFS) \\kpff.com\Civil\1500001-1500400\1500129 (Madrona)\PROJECT DOCUMENTS\Storm Drainage\Calculations\2016-08-22 (CD)\Conveyance\SDPF - 700 - SDCO #701.xlsx Appendix 131 Worksheet for SDPF 700 Friction Method Manning Formula Solve For Full Flow Capacity Roughness Coefficient 0.010 Channel Slope 0.00500 ft/ft Normal Depth 0.67 ft Diameter 0.67 ft Discharge 1.13 ft3/s I > 0.77 CFS V Discharge 1.13 ft3/s Normal Depth 0.67 ft Flow Area 0.35 ft2 Wetted Perimeter 2.10 ft Hydraulic Radius 0.17 ft Top Width 0.00 ft Critical Depth 0.50 ft Percent Full 100.0 % Critical Slope 0.00601 ft/ft Velocity 3.19 ft/s Velocity Head 0.16 ft Specific Energy 0.83 ft Froude Number 0.00 Maximum Discharge 1.21 ft3/s Discharge Full 1.13 ft3/s Slope Full 0.00500 ft/ft Flow Type SubCritical Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:16:25 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 1 of 2 t� Worksheet for SDPF 700 Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s Upstream Velocity Infinity ft/s Normal Depth 0.67 ft Critical Depth 0.50 ft Channel Slope 0.00500 ft/ft Critical Slope 0.00601 ft/ft Bentley Systems, Inc. Haestad Methods SolBk1otiMaster V8i (SELECTseries 1) [08.11.01.03] 12/4/2016 3:16:25 PM 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 Page 2 of 2 Appendix 131 Water Quality Flow Rate Orifice Calculations Head Diameter of orifice = 2.19 IN Q = 0.180 CFS Head above bottom orifice = 1,92 FT Orifices Flow dirougli cyrifice plates in tfic standard tee scctionorturn-down clbow muiy be aparoximated, by the general, equation: CA -�12 g h (5-4) Micro Q — flow (Cfs) C c twffj ei ent of did charggc (1) e (-,,2 For platc ori Fi cc) A = area of ori ri cc f zf) h hydraulic head (11) gravity (32,2 fl/scc ZSZMM NZ44MWOR4 i • " Program Version: MGSFlood 4.38 Program License Number: 200410007 Project Simulation Performed on: 11/28/2016 6:19 PM Report Generation Date: 11/28/2016 6:19 PM Input File Name: Project Name: Analysis Title: Comments: 2016-11-02 Bioretention Cells.fld Madrona K-8 Sicrotenfion Cells Computational Time Step (Minutes): PRECIPITATION INPUT 15 Extended Precipitation Time Series Selected Climatic Region Number: 12 Full Period of Record Available used for Routing Precipitation Station : 96003605 Puget East 36 in_5min 10/01/1939-10/01/2097 Evaporation Station 961036 Puget East 36 in MAP Evaporation Scale Factor 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 1.000 5.565 Area of Links that Include Precip/Evap (acres) 0.000 0.047 Total (acres) 1.000 5.612 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Subbasin Till Forest Till Pasture Till Grass Outwash Forest : Subbasin 1 ----- -------Area(Acres) 0.000 0.000 0.000 0.000 z3ZEM Outwash Pasture 0.000 Outwash Grass 0.000 Wetland 0.000 Green Roof 0.000 User 1 0.000 Impervious 1.000 Subbasin Total 1.000 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 10 Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 : BASIN 1--------- -------Area(Acres) 0.000 0.000 1.747 0.000 0.000 0.000 0.000 0.000 0.000 0.715 2.462 : BASIN 2--------- -------Area(Acres) 0.000 0.000 0.574 0.000 0.000 0.000 0.000 0.000 0.000 1.070 1.644 : BASIN 4--------- -------Area(Acres) 0.000 0.000 0.023 0.000 0.000 0.000 0.000 0.000 0.000 Impervious ------------------------- Subbasin Total ---------- Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total 0.118 0.141 : BASIN 3--------- -------Area(Acres) 0.000 0.000 0.021 0.000 0.000 0.000 0.000 0.000 0.000 0.130 0.151 : BASIN 5A------- -------Area(Acres) 0.000 0.000 0.013 0.000 0.000 0.000 0.000 0.000 0.000 0.092 M M : BASIN 6--------- -------Area(Acres) 0.000 0.000 0.028 0.000 0.000 0.000 0.000 0.000 0.000 0.196 0.224 ---------- Subbasin: BASIN 7--------- -------Area(Acres) Till Forest 0.000 Appendix B3 Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 1 : BASIN 8--------- -------Area(Acres) 0.000 0.000 0.021 0.000 0.000 0.000 0.000 0.000 0.000 0.233 0.254 : BASIN 9--------- -------Area(Acres) 0.000 0.000 0.027 0.000 0.000 0.000 0.000 0.000 0.000 0.128 0.155 : BASIN 5B------- -------Area(Acres) 0.000 0.000 0.028 0.000 0.000 0.000 0.000 0.000 0.000 Appendix B3 Impervious 0.141 Subbasin Total 0.169 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 10 Link Name: BioRetCell 1 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) 445.76 Riser Crest Elevation (ft) 446.76 Storage Depth (ft) 1.00 Bottom Length (ft) 232.5 Bottom Width (ft) 2.0 Side Slopes (ft/ft) : L1= 3.00 L2= 3.00 W1= 3.00 W2= 3.00 Bottom Area (sq-ft) 465. Area at Riser Crest El (sq-ft) 1,908. (acres) 0.044 Volume at Riser Crest (cu-ft) 1,459. (ac-ft) 0.033 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 1.50 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.000 Riser Crest Elevation : 446.76 ft Hydraulic Structure Geometry Number of Devices: 0 z3ZEM Link Name: BioRetCell 2 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) 443.02 443.69 L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 1.50 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 3 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Circular 12.00 0.000 443.69 ft 443.39 0.27 53.3 1.0 L1= 3.00 53. 144. 0.003 443.66 L2= 3.00 W 1= 3.00 W 2= 3.00 Appendix B3 Volume at Riser Crest (cu-ft) 58. (ac-ft) 0.001 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 4 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) Circular 12.00 0.000 443.66 ft 443.38 0.28 55.8 1.0 L1= 3.00 56. 154. 0.004 63. 0.001 443.66 L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Appendix B3 Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 5A Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) Circular 12.00 0.000 443.66 ft 442.95 0.71 55.4 3.0 L1= 3.00 166. 433. 0.010 310. 0.007 443.66 L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.000 Riser Crest Elevation : 443.66 ft Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 6 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) 442.03 Riser Crest Elevation (ft) 442.52 Storage Depth (ft) 0.49 Bottom Length (ft) 96.4 Bottom Width (ft) 1.0 Side Slopes (ft/ft) : L1= 3.00 L2= 3.00 W1= 3.00 W2= 3.00 Bottom Area (sq-ft) 96. Area at Riser Crest El (sq-ft) 391. (acres) : 0.009 Volume at Riser Crest (cu-ft) 176. (ac-ft) 0.004 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 7 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) Circular 12.00 0.000 442.52 ft 442.02 0.50 99.5 1.0 L1= 3.00 100. 410. 0.009 186. 0.004 442.52 L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 1.50 z3ZEM Biosoil Porosity (Percent) Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 8 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) Circular 12.00 0.000 442.52 ft 442.03 0.49 91.9 1.0 L1= 3.00 92. 374. 0.009 168. 0.004 442.52 1 ii L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 1.50 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.000 Riser Crest Elevation : 442.52 ft Hydraulic Structure Geometry Number of Devices: 0 z3ZEM Link Name: BioRetCell 9 Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Volume at Riser Crest (cu-ft) (ac-ft) 441.70 0.86 20.0 4.9 L1= 3.00 98. 252. 0.006 205. 0.005 442.56 L2= 3.00 W 1= 3.00 W 2= 3.00 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: 0 Link Name: BioRetCell 5B Link Type: Bioretention Facility Downstream Link: None Base Elevation (ft) Riser Crest Elevation (ft) Storage Depth (ft) Bottom Length (ft) Bottom Width (ft) Side Slopes (ft/ft) Bottom Area (sq-ft) Area at Riser Crest El (sq-ft) (acres) Circular 12.00 0.000 442.56 ft 441.73 0.88 14.6 3.5 L1= 3.00 51. 174. 0.004 442.61 L2= 3.00 W 1= 3.00 W 2= 3.00 Appendix B3 Volume at Riser Crest (cu-ft) 125. (ac-ft) 0.003 Infiltration on Bottom and Sideslopes Selected Soil Properties Biosoil Thickness (ft) 1.50 Biosoil Saturated Hydraulic Conductivity (in/hr) 3.00 Biosoil Porosity (Percent) 40.00 Maximum Elevation of Bioretention Soil : 450.00 Native Soil Hydraulic Conductivity (in/hr) 0.00 Underdrain Present Orifice NOT Present in Under Drain Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 12.00 Common Length (ft) : 0.000 Riser Crest Elevation : 442.61 ft Hydraulic Structure Geometry Number of Devices: 0 **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 10 Number of Links: 10 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perind Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: Subbasin 1 0.000 Total: Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: BASIN 1 201.151 Subbasin: BASIN 2 66.091 Subbasin: BASIN 4 2.648 Subbasin: BASIN 3 2.418 Subbasin: BASIN 5A 1.497 z3ZEM Subbasin: BASIN 6 3.224 Subbasin: BASIN 7 2.303 Subbasin: BASIN 8 2.418 Subbasin: BASIN 9 3.109 Subbasin: BASIN 5B Link: BioRetCell1 0.000 Link: BioRetCell2 0.000 Link: BioRetCell3 0.000 Link: BioRetCell4 0.000 Link: BioRetCell5A 0.000 Link: BioRetCell6 0.000 Link: BioRetCell? 0.000 Link: BioRetCell8 0.000 Link: BioRetCell9 0.000 Link: BioRetCell5B 0.000 Total: 3.224 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.000 ac-ft/year, Post Developed: 1.823 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 10 ********** Link: BioRetCell 1 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 557.35 Inflow Volume Including PPT-Evap (ac-ft): 563.97 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 549.05, 97.35% Primary Outflow To Downstream System (ac-ft): 564.35 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 97.35% >91 % ********** Link: BioRetCell 2 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 421.87 Inflow Volume Including PPT-Evap (ac-ft): 430.56 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 394.76, 91.68% Primary Outflow To Downstream System (ac-ft): 430.98 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 91.68% >91 % ********** ********** ********** Link: BioRetCell 3 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 51.25 Inflow Volume Including PPT-Evap (ac-ft): 51.93 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 48.41, 93.21 % Primary Outflow To Downstream System (ac-ft): 52.00 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 93.21 % > 9"1 % ********** Link: BioRetCell 4 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 46.52 Inflow Volume Including PPT-Evap (ac-ft): 47.21 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 45.02, 95.37% Primary Outflow To Downstream System (ac-ft): 47.27 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 95.37% >91 % ********** Link: BioRetCell 5A Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 36.27 Inflow Volume Including PPT-Evap (ac-ft): 37.80 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 37.80, 100.00% Primary Outflow To Downstream System (ac-ft): 37.87 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 100.00% >91 / ********** Link: BioRetCell 6 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 77.28 Inflow Volume Including PPT-Evap (ac-ft): 78.51 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 77.78, 99.07% Primary Outflow To Downstream System (ac-ft): 78.60 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 99.07% >91 % ********** Link: BioRetCell 7 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 94.62 Inflow Volume Including PPT-Evap (ac-ft): 96.39 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 89.23, 92.58% Primary Outflow To Downstream System (ac-ft): 96.65 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 92.58% >91 % ********** ********** ********** ********** ********** ********** Link: BioRetCell 8 ********** Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 91.86 Inflow Volume Including PPT-Evap (ac-ft): 93.52 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 85.48, 91.41 % Primary Outflow To Downstream System (ac-ft): 93.74 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 91.41 % >91 % ********** Link: BioRetCell 9 ********** Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 54.72 Inflow Volume Including PPT-Evap (ac-ft): 55.64 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 55.33, 99.43% Primary Outflow To Downstream System (ac-ft): 55.66 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 99.43% >91 % ********** Link: BioRetCell 5B Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 60.01 Inflow Volume Including PPT-Evap (ac-ft): 60.65 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 58.71, 96.81 % Primary Outflow To Downstream System (ac-ft): 60.68 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 96.81 % >91 % ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Subbasin 1 Scenario Postdeveloped Compliance Link: BioRetCell 9 *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ------------------------------------------------------------------------------------------------------------ 2-Year 0.354 2-Year 2.757E-02 5-Year 0.471 5-Year 4.930E-02 10-Year 0.557 10-Year 5.884E-02 25-Year 0.668 25-Year 7.324E-02 50-Year 0.857 50-Year 9.416E-02 100-Year 1.021 100-Year 0.107 200-Year 1.097 200-Year 0.141 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals 3 NZ44MWOR4 i • " Program Version: MGSFlood 4.40 Program License Number: 200410007 Project Simulation Performed on: 11/30/2016 4:05 PM Report Generation Date: 11/30/2016 4:06 PM Input File Name: UIC FIELDS.fld Project Name: MADRONA SCHOOL Analysis Title: UIC WELL SIZING Comments: ANALY&S TO DETERMINE PEAK FLOWS TO UIC WELL FIELDS 1-FIR Tone Stop, Puget East 3 PRECIPITATION INPUT Computational Time Step (Minutes): 60 Extended Precipitation Time Series Selected Climatic Region Number: 0 Full Period of Record Available used for Routing Precipitation Station : 96003605 Puget East 36 in_5min 10/01/1939-10/01/2097 Evaporation Station 961036 Puget East 36 in MAP Evaporation Scale Factor 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 1.000 9.582 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 1.000 9.582 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin : NULL ---------- ------- Area (Acres) Impervious 1.000 Subbasin Total 1.000 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 4 ---------- Subbasin: UIC WELL FIELD #2---------- ------- Area (Acres) -------- Till Grass 0.914 Impervious 2.169 ---------------------------------------------- Subbasin Total 3.083 ---------- Subbasin: UIC WELL FIELD #3---------- UIC 'XELL FIELD #1 UIC VVELL FIELD #.2 -------Area (Acres) -------- Till Grass 0.244 Impervious ------------- - 80 ----- ---- ---- Subbasin Total 1.324 UIC VYELLFIELD # COIL %-VATER 'SEPARATOR LJliv rYEFF FIELD #4 ---------- Subbasin: UIC WELL FIELD #4---------- ------- Area (Acres) -------- Till Grass 1.014 Impervious 0.922 ---------------------------------------------- Subbasin Total 1.936 ---------- Subbasin: UIC WELL FIELD #1 -------Area (Acres) -- Till Grass 0.876 Impervious 2.363 Subbasin Total 3.239 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 Link Name: OIL WATER SEPARATOR Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 4 Number of Links: 1 ********** Subbasin: UIC WELL FIELD #3 ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.302 5-Year 0.382 10-Year 0.447 25-Year 0.514 50-Year 0.601 100-Year 0680 200-Year 0.740 ********** Subbasin: UIC WELL FIELD #4 ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.288 5-Year 0.378 10-Year 0.457 25-Year 0.605 50-Year 0.662 1'00-Year 0728 200-Year 0.883 ********** Subbasin: UIC WELL FIELD #1 ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.680 5-Year 0.855 10-Year 1.014 25-Year 1.178 50-Year 1.361 100-Year 1.550 200-Year 1.727 3 ********** Link: OIL WATER SEPARATOR Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.680 5-Year 0.855 10-Year 1.014 25-Year 1.178 50-Year 1.361 100-Year 1.550 200-Year 1.727 ********** Link: OIL WATER SEPARATOR Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.680 5-Year 0.855 10-Year 1.014 25-Year 1.178 50-Year 1.361 100-Year 1.550 200-Year 1.727 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perind Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ��. t ► 1 111 Total: Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: UIC WELL FIELD #2 105.715 Subbasin: UIC WELL FIELD #3 28.222 Subbasin: UIC WELL FIELD #4 117.281 Subbasin: UIC WELL FIELD #1 101.320 Link: OIL WATER SEPARATOR 0.000 Total: 352.537 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) ********** ********** wo 210 Predeveloped: 0.000 ac-ft/year, Post Developed: 2.231 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: OIL WATER SEPARATOR 15-Minute Timestep, Water Quality Treatment Design Discharge On-line Design Discharge Rate (91 % Exceedance): 0.33 cfs Off' -line Design Discharge Rate (91 % Exceedance): 0.18 cfs Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 1057.15 Inflow Volume Including PPT-Evap (ac-ft): 1057.15 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 1057.15 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: NULL Scenario Postdeveloped Compliance Subbasin: UIC WELL FIELD #2 *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) ------------------------------------------------------------------------------------------------------------ Discharge (cfs) Tr (Years) Discharge (cfs) 2-Year 0.268 2-Year 0.625 5-Year 0.340 5-Year 0.790 10-Year 0.398 10-Year 0.944 25-Year 0.447 25-Year 1.106 50-Year 0.526 50-Year 1.265 100-Year 0.589 100=Year 1.443 200-Year 0.615 200-Year 1.619 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ********** EPASWMM Time Series Data MGSFIood Output, Subbasin Outflow: UIC WELL FIELD ##3 - Target Tr= 100 Years, (Actual Plotting Position Tr= 101.4 Years) 5 UIC WELLS INDIVIDUAL UIC WELL DAY TIME CFS CFS GPM 6/10/2010 10:00 0.0038 0.00076 0.34 6/10/2010 11:00 0.0028 0.00056 0.25 6/10/2010 12:00 0.0022 0.00044 0.20 6/10/2010 13:00 0.0018 0.00036 0.16 6/10/2010 14:00 0.0015 0.0003 0.13 6/10/2010 15:00 0.0012 0.00024 0.11 6/10/2010 16:00 0.0067 0.00134 0.60 6/10/2010 17:00 1.5536 0.31072 139.46 6/10/2010 18:00 1.0035 0.2007 90.08 6/10/2010 19:00 0.3157 0.063141 28.34 6/10/2010 20:00 0.1302 0.02604 11.69 6/10/2010 21:00 0.0669 0.01338 6.01 6/10/2010 22:00 0.0404 0.00808 3.63 6/10/2010 23:00 0.0276 0.00552 2.48 6/11/2010 0:00 0.0206 0.00412 1.85 6/11/2010 1:00 0.0164 0.00328 1.47 6/11/2010 2:00 0.0138 0.00276 1.24 6/11/2010 3:00 0.012 0.0024 1.08 6/11/2010 4:00 0.0107 0.00214 0.96 6/11/2010 5:00 0.0098 0.00196 0.88 6/11/2010 6:00 0.009 0.0018 0.81 6/11/2010 7:00 0.00841 0.00168 0.75 6/11/2010 8:00 0.0079 0.00158 0.71 6/11/2010 9:00 0.0075 0.00151 0.67 Appendix B4 EPASWMM Time Series Data MGSFIood Output, Subbasin Outflow: UIC WELL FIELD #2 - Target Tr= 100 Years, (Actual Plotting Position Tr= 101.4 Years) 5 UIC WELLS INDIVIDUAL UIC WELL DAY TIME CFS CFS GPM 6/10/2010 10:00 0.0035 0.0007 0.31 6/10/2010 11:00 0.0026 0.00052 0.23 6/10/2010 12:00 0.0021 0.00042 0.19 6/10/2010 13:00 0.0017 0.00034 0.15 6/10/2010 14:00 0.0014 0.00028 0.13 6/10/2010 15:00 0.0011 0.00022 0.10 6/10/2010 16:00 0.0061 0.00122 0.55 6/10/2010 17:00 1.4462 0.28924 129.82 6/10/2010 18:00 0.931 0.1862 83.57 6/10/2010 19:00 0.291 0.0582 26.12 6/10/2010 20:00 0.1207 0.02414 10.83 6/10/2010 21:00 0.0626 0.01252 5.62 6/10/2010 22:00 0.0382 0.00764 3.43 6/10/2010 23:00 0.0264 0.00528 2.37 6/11/2010 0:00 0.0199 0.00398 1.79 6/11/2010 1:00 0.0161 0.00322 1.45 6/11/2010 2:00 0.0136 0.00272 1.22 6/11/2010 3:00 0.012 0.0024 1.08 6/11/2010 4:00 0.0108 0.00216 0.97 6/11/2010 5:00 0.0098 0.00196 0.88 6/11/2010 6:00 0.0091 0.00182 0.82 6/11/2010 7:00 0.0086 0.00172 0.77 6/11/2010 8:00 0.00811 0.00162 0.73 6/11/2010 9:001 0.00771 0.001541 0.69 EPASWMM Time Series Data MGSFIood Output, Subbasin Outflow: UIC WELL FIELD #3 - Target Tr= 100 Years, (Actual Plotting Position Tr= 101.4 Years) 3 UIC WELLS INDIVIDUAL UIC WELL DAY TIME CFS CFS GPM 6/10/2010 10:00 0.0018 0.0006 0.27 6/10/2010 11:00 0.0013 0.000433 0.19 6/10/2010 12:00 0.001 0.000333 0.15 6/10/2010 13:00 0.0008 0.000267 0.12 6/10/2010 14:00 0.0007 0.000233 0.10 6/10/2010 15:00 0.0006 0.0002 0.09 6/10/2010 16:00 0.003 0.001 0.45 6/10/2010 17:00 0.6815 0.227167 101.96 6/10/2010 18:00 0.4445 0.148167 66.50 6/10/2010 19:00 0.1426 0.047533 21.33 6/10/2010 20:00 0.0579 0.0193 8.66 6/10/2010 21:00 0.029 0.009667 4.34 6/10/2010 22:00 0.0169 0.005633 2.53 6/10/2010 23:00 0.0111 0.0037 1.66 6/11/2010 0:00 0.0079 0.002633 1.18 6/11/2010 1:00 0.0061 0.002033 0.91 6/11/2010 2:00 0.0049 0.001633 0.73 6/11/2010 3:00 0.0041 0.001367 0.61 6/11/2010 4:00 0.0036 0.0012 0.54 6/11/2010 5:00 0.0032 0.001067 0.48 6/11/2010 6:00 0.0029 0.000967 0.43 6/11/2010 7:00 0.0026 0.000867 0.39 6/11/2010 8:00 0.00251 0.000833 0.37 6/11/2010 9:00 0.00231 0.000767 0.34 EPASWMM Time Series Data MGSFIood Output, Subbasin Outflow: UIC WELL HELD #- Target Tr= 100 Years, (Actual Plotting Position Tr= 101.4 Years) 3 UIC WELLS INDIVIDUAL UIC WELL DAY TIME CFS CFS GPM 6/10/2010 10:00 0.0015 0.0005 0.22 6/10/2010 11:00 0.0011 0.000367 0.16 6/10/2010 12:00 0.0009 0.0003 0.13 6/10/2010 13:00 0.0007 0.000233 0.10 6/10/2010 14:00 0.0006 0.0002 0.09 6/10/2010 15:00 0.0005 0.000167 0.07 6/10/2010 16:00 0.0026 0.000867 0.39 6/10/2010 17:00 0.7292 0.243067 109.10 6/10/2010 18:00 0.4522 0.150733 67.65 6/10/2010 19:00 0.1307 0.043567 19.55 6/10/2010 20:00 0.0579 0.0193 8.66 6/10/2010 21:00 0.033 0.011 4.94 6/10/2010 22:00 0.0225 0.0075 3.37 6/10/2010 23:00 0.0172 0.005733 2.57 6/11/2010 0:00 0.0143 0.004767 2.14 6/11/2010 1:00 0.0125 0.004167 1.87 6/11/2010 2:00 0.0113 0.003767 1.69 6/11/2010 3:00 0.0105 0.0035 1.57 6/11/2010 4:00 0.0098 0.003267 1.47 6/11/2010 5:00 0.0093 0.0031 1.39 6/11/2010 6:00 0.0088 0.002933 1.32 6/11/2010 7:00 0.0084 0.0028 1.26 6/11/2010 8:00 0.0081 0.0027 1.21 6/11/2010 9:00 0.0078 0.0026 1.17 Appendix C Geotechnical Engineering Report By: Shannon & Wilson, Inc. Date: October 31, 2016 Madrona School — Edmonds School District Appendix C Geotechnical Engineering Report New Madrona K-8 Project 9300 2361h Street SW Edmonds, Washington Excellence, Innovation. Service. Value. offlVIRM October 31, 2016 Submitted To: Ms. Taine Wilton Edmonds School District #15 20420 68th Avenue West Lynnwood, Washington 98036 By: Shannon & Wilson, Inc. 400 N 34th Street, Suite 100 Seattle, Washington 98103 21-1-22082-004 SHANNON ILA TABLE OF CONTENTS Page 1.0 SITE AND PROJECT DESCRIPTION.................................................................................I 2.0 SITE CONDITIONS..............................................................................................................2 2.1 Regional Geology.......................................................................................................2 2.2 Regional Seismicity....................................................................................................2 3.0 SUBSURFACE EXPLORATION.........................................................................................3 ' 5.0 LABORATORY TESTING...................................................................................................5 6.0 SUBSURFACE CONDITIONS.............................................................................................5 6.1 Site Geology and Subsurface Conditions...................................................................5 6.1.1 Subsurface Conditions at Proposed Building..............................................5 6.1.2 Subsurface Conditions at Proposed Parking Lots and Driveways...............6 6.2 Hydrogeologic Conditions.........................................................................................6 7.0 ENGINEERING STUDIES AND RECOMMENDATIONS................................................6 7.1 General.......................................................................................................................6 7.2 Foundation Design.....................................................................................................7 7.3 Seismic Design...........................................................................................................7 7.4 Lateral Earth Pressures and Retaining Walls.............................................................8 7.5 Lateral Resistance......................................................................................................9 7.6 Slope Stability............................................................................................................9 7.7 Pavement Design......................................................................................................10 7.7.1 Traffic Load...............................................................................................10 7.7.2 Subgrade Conditions..................................................................................10 7.8 Non -Porous Pavement Section Recommendations..................................................10 7.9 Porous Pavement Section Recommendations..........................................................11 7.9.1 Grass Grid Pavers......................................................................................11 7.9.2 Pervious Hot Mix Asphalt (HMA) and Concrete......................................11 7.10 Pavement Sections Near Steep Slopes.....................................................................12 7.11 Frost Susceptibility...................................................................................................12 8.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS.....................................13 8.1 Earthwork and Use of On -site Soils.........................................................................13 8.2 Pervious Pavement Materials...................................................................................14 8.3 Construction and Maintenance Considerations for Pervious Pavement ..................14 8.4 Temporary and Permanent Excavation Slopes.........................................................15 8.5 Erosion Control........................................................................................................16 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 1 TABLE OF CONTENTS (cont.) Page 8.6 Construction Drainage..............................................................................................16 8.7 Subsurface Drainage................................................................................................16 8.8 Utilities.....................................................................................................................16 8.9 Wet Weather Earthwork...........................................................................................1.7 8.10 Plans Review and Construction Observation...........................................................18 9.0 LIMITATIONS....................................................................................................................18 10.0 REFERENCES.....................................................................................................................20 TABLES 1 Recommended Minimum Parking Lot and Driveway Section Thicknesses .........1.1. 2 Recommended Minimum Porous Pavement Section Thicknesses ........................11 3 Imported Backfill Specifications Based on 2016 Washington. State Department of Transportation Standard Specifications.........................................13 FIGURES 1 Vicinity Map 2 Site and Exploration Plan 3 Typical Rockery Detail 4 Measured Water Level, Pilot Infiltration Test, Test Pit PIT-1 5 Measured Water Level, Pilot Infiltration Test, Test Pit PIT-2 6 Measured Water Level, Pilot Infiltration Test, Test Pit PIT-3 APPENDICES A Subsurface Explorations B Laboratory Test Results C Analytical Laboratory Test Results D Important Information About Your Geotechnical/Environmental Report 21-1-22082-004-R1 f.aocx/wp/1kn 21-1-22082-004 11 SHANNON 6WILSON, ING GEOTECHNICAL ENGINEERING REPORT NEW MADRONA K-8 PROJECT 9300 236TH STREET SW EDMONDS, WASHINGTON 1.0 SITE AND PROJECT DESCRIPTION The Edmonds School District No. 15 plans to construct a new Madrona K-8 School on the south side of the property at 9300 236th Street SW in Edmonds, Washington, as shown in the Vicinity Map (Figure 1). The property contains the existing Madrona K-8 School and is bounded by 236th Street to the north, residential developments on the east and south sides, and the former Woodway Elementary School on the west. The site has a number of distinct surface features including a parking lot on the northwest side, track and large open field area on the southwest side, and a baseball field on the southeast side. There is a densely wooded ravine area along the east side of the property and a densely wooded slope on the west side of the property that slopes down to the former Woodway Elementary School. The purpose of this study is to finalize our geotechnical recommendations with data from additional subsurface explorations and testing to aid in the final design of the proposed structure. Geotechnical recommendations were provided previously in a preliminary geotechnical engineering report submitted on August 6, 2015. Our scope of services for the design phase included drilling and sampling 12 geotechnical borings and excavating 5 test pits. However, one of the proposed drilling locations was changed to a test pit exploration for a total of 11 geotechnical borings and 6 test pits. The proposed drilling location was changed to a test pit due to the close proximity to subsurface utilities and access issues. Locations of the subsurface explorations were selected to coincide with the planned location of the proposed building and associated facilities. Descriptions of the subsurface exploration activities are discussed further in Section 3.0. The results of our pilot infiltration testing (PIT) are discussed in Section 4.0. This report presents updated geotechnical engineering recommendations to incorporate the additional subsurface information gathered from the new explorations and information provided by the design team. We have included recommendations for pavement design and a discussion of buffer and setback distances when adjacent to steep slopes and other geologic hazard areas. The results of the soil fertility testing are also provided to aid the design team in evaluating the suitability of on -site topsoil for use in landscaping. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 2.0 SITE CONDITIONS 2.1 Regional Geology SHANNON ING , The site is located in Edmonds, Washington, which is within a region known as the Puget Lowland. The Puget Lowland is a structural depression bordered by the Olympic and Cascade Mountain ranges that is generally within about 500 feet of sea level. The geology of the area has been influenced by repeated cycles of glaciation, which worked to fill the lowland to significant depths with a complex sequence of glacial and nonglacial deposits. The most recent glacier to impact the area, the Vashon Stade of the Fraser Glaciation, overrode the area with up to 3,000 feet of ice in some locations. Following the last glaciations, the erosion of some of the glacially overridden soil deposits, as well as local deposition and human placement of additional soil deposits, have further complicated the local geology (Troost and Booth, 2008). The project site itself is situated on a ridge underlain by Quaternary Vashon till (Qvt) that was observed at relatively shallow depths during the current subsurface investigation. This geologic unit was found to be a very dense, gray to gray -brown deposit consisting of silty sand with variable gravel, cobble, and some boulder content. Other explorations performed on the site (Shannon & Wilson, Inc. [Shannon & Wilson], 2016) encountered deposits of Quaternary Vashon advanced glacial outwash (Qva) at depths of approximately 40 to 50 feet below ground surface (bgs). This geologic unit is characterized by dense to very dense sands and gravels with variable amounts of silt. Qva is typically less compact and more pervious than Qvt. Geologic maps of the Snohomish County region indicate that the contact between the glacial till and advanced outwash material is on the slope on the west side of the property. The Qva at the site may be underlain by pre-Vashon interglacial and glacial soils, predominantly fluvial. 2.2 Regional Seismicity The Puget Sound Lowland is located in the fore arc of the Cascadia Subduction Zone. The seismicity of the region is largely derived from the subduction of the Juan de Fuca Plate beneath the North American Plate. The convergence of these two plates results in a number of generally east -west -trending faults, as well as basin and uplift regions (Troost and Booth, 2008). The seismic hazard of the region comes from three major sources, a major subduction type events, deep intraplate events (such as the 2001 Nisqually earthquake), and earthquakes due to rupture of shallow crustal faults. The site itself is located a reasonable distance from subduction and intraslab sources, and as a result, the more local, crustal faults are believed to drive the seismic hazard for the site. The closest known potentially active fault to the site is the South Whidbey Island Fault (SWIF). The 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 2 SHANNON ING , SWI.F is a shallow, strike -slip fault that is believed to be capable of producing a magnitude 7.5 event, which could impose significant seismic demands on structures at the site. 3.0 SUBSURFACE EXPLORATION Previously, we completed subsurface explorations as a part of a preliminary geotechnical engineering study to aid in the selection of the proposed building location. Previous explorations consisting of 16 test pits on the southern half of the property were completed on June 24, 2015. Logs of the previous subsurface explorations are included in Appendix A. Recent subsurface explorations consisted of test pits and geotechnical borings completed between Monday, July 25, 2016, and Friday, July 29, 2016. Holocene Drilling (Holocene), under subcontract to Shannon & Wilson, completed a total of 11 geotechnical borings with the use of a track -mounted Diedrich D-50 drill rig. Holocene used the hollow -stem auger drilling method to complete the borings to depths ranging from 15.5 to 16.5 feet bgs. Holocene collected samples on approximate 2.5-foot intervals with the use of the Standard Penetration Test. Once the geotechnical borings were completed, Holocene backfilled the holes with bentonite to within approximately 1 to 2 feet bgs. Borings that were drilled in the asphalt parking area were patched with concrete. Clearcreek Contractors (Clearcreek), under subcontract to Shannon & Wilson, completed a total of six test pits to depths ranging from 4 to 10 feet with the use of a rubber -tired John Deere 310SJ backhoe. Three of the test pits were used to characterize infiltration within the near - surface soils. Infiltration testing within the near -surface soils is discussed below in Section 4.0. Following the excavations and testing, Clearcreek backfilled the test pits with the excavated material and tamped the material down using the excavator bucket in approximately 1-foot-thick lifts. Once Clearcreek had completed backfilling the test pits, they rolled the surface for further compaction and replaced the grass layer where it was possible to salvage. The explorations were located throughout the site as shown in the Site and Exploration Plan, Figure 2. Test pits designated with a PIT were the ones in which we performed the in situ infiltration testing/PITs, while the test pits designated with a TP were not used for in situ infiltration testing. During the exploration process, the soil and groundwater conditions were observed by an engineer or a geologist from our office. Soil samples were collected and transported to our Seattle laboratory for analysis and testing. Logs of the explorations are presented in Appendix A. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 SHANNON ING , The geotechnical boring and test pit locations provided in Figure 2 are approximate, being based on hand measurements from site features, and surface elevations shown in the logs are estimated from a topographic survey of the site prepared by PACE Engineers, Inc. 4.0 FIELD INFILTRATION TESTING We performed small-scale PITs within three of the six test pits excavated during the current subsurface explorations. The PIT test pits were designated as PIT-1 through PIT-3, and the locations are shown in the Site and Exploration Plan, Figure 2. All three of the infiltration tests were performed on July 28, 2016. These test pits were over excavated following the PITs on July 29, 2016. Details of the three tests are presented below and are summarized in the PIT data plots (Figures 4 through 6). The PIT-1 test pit bottom during the PIT was approximately 3.8 feet bgs, or about Elevation 440.7 feet. The tested soil unit was fill, consisting of reworked glacial till. After the water flow was terminated, the test pit drained completely overnight. No free water was present below the PIT test depth when we overexcavated it on July 29, 2016. A plot of the PIT-1 test data is presented as Figure 4. The observed (short-term) infiltration rate was approximately 0.80 inch per hour, based on the last hour of the constant head period. If these soils represented the subgrade beneath a bioretention feature constructed with imported bioretention soil, the City of Edmonds (City) will require the application of a correction factor of 2 due to the test being performed during the dry season. This would result in a design (long-term) infiltration rate of 0.4 inch per hour. The PIT-2 test pit bottom during the PIT was approximately 3.3 feet bgs, or about Elevation 452.7 feet. The tested soil unit was glacial till, with a short-term infiltration rate of 0.13 inch per hour, based on the falling head data collected after the water flow into the test pit was terminated. Applying the correction factor would result in a design infiltration of 0.06 inch per hour. The test pit failed to drain completely overnight and this soil is considered to be a hydraulic restriction to infiltration, due to its low infiltration rate. A plot of the PIT-2 test data is presented as Figure 5. The PIT-3 test pit bottom during the PIT was approximately 2.9 feet bgs, or about Elevation 447.1 feet. The tested soil unit was glacial till, with a short-term infiltration rate of 0.07 inch per hour based on the falling head data collected after the water flow into the test pit was terminated. Applying the correction factor would result in a design infiltration rate of 0.03 inch per hour. The test pit failed to drain completely overnight and this soil is considered to be a hydraulic 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 4 SHANNON ING , restriction to infiltration due to its low infiltration rate. A plot of the PIT-3 test data is presented as Figure 6. If a shallow well were installed in the vicinity and read during the wet season, no correction. factor would be required, provided groundwater is at least 3 feet below the bottom of the facility. 5.0 LABORATORY TESTING Laboratory testing was conducted on several soil samples collected from the test pit explorations to assist in classification and characterization of the subsurface soils. The laboratory tests included natural moisture content determination and grain size analysis. The natural moisture contents are indicated on the test pit logs in Appendix A. The results of the grain size analyses are presented in Appendix B. Most of the grain size tests were sieve analyses. Combined sieve and hydrometer tests were performed on two samples (from B-4 at 5 feet deep [about Elevation 440 feet] and from B-5 at 7.5 feet deep [about Elevation 439.5 feet]) so that the U.S. Department of Agriculture (USDA) texture could be identified. Both samples are considered to be "sandy loam," based on the USDA textural system. Based on our discussions with the City, the short-term infiltration rate for these soils is 1 inch per hour. Since the explorations were completed during the dry season, a seasonal correction factor of 2 is required, resulting in a design infiltration rate of 0.5 inch per hour. This assumes that these soils represent the subgrade beneath bioretention features with imported bioretention soil. In order to characterize the existing topsoil within the upper and lower field, we submitted two samples to Spectra Laboratories (Spectra) in Poulsbo, Washington. The samples were tested for soil fertility and the results with recommendations from Spectra are included in Appendix C. 6.0 SUBSURFACE CONDITIONS 6.1 Site Geology and Subsurface Conditions Intact glacial till soils were encountered in all but one of the explorations performed under the current scope of work. The test pit PIT-1 did not encounter intact glacial till, but did encounter weathered till at a depth of approximately 7 feet bgs. 6.1.1 Subsurface Conditions at Proposed Building Explorations performed within or near the proposed building footprint on the existing upper play field in the southeast corner of the site indicate that this area is underlain by a thin layer of topsoil followed by layers of fill, weathered or reworked glacial till, and intact glacial 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 5 SHANNON ING , till. Borings B-7, B-9, B-10, and B-1.2 indicate that there is a layer of fill soils at depths ranging from 4.5 to 7 feet bgs. Fill soils consisted of medium dense to very dense, silty sand to silty sand with gravel. Intact very dense glacial till underlying the building footprint was encountered at depths ranging from approximately 1 to 7 feet bgs. 6.1.2 Subsurface Conditions at Proposed Parking Lots and Driveways Explorations performed within the parking areas west of the existing school building and north of the track indicated that fill soils overlying the glacial till are present at depths ranging from 7 to 9.5 feet bgs. Borings and test pits on the north and east sides of the existing building also encountered fill soils at depths ranging from 4.5 to 6 feet bgs. Intact, very dense glacial till was found to underlie the fill soils. 6.2 Hydrogeologic Conditions Groundwater was not encountered in the recent shallow soil borings and test pits, all of which were performed during the dry season. Moist to wet layers were observed below about 15 feet in. borings B-2, B-3, and B-5, and below about 1.2 feet in boring B-9, which may indicate the presence of perched groundwater. Subsurface explorations performed previously onsite as part of our hydrogeologic study (Shannon & Wilson, 2016) identified a regional groundwater aquifer at the site at about 180 feet deep and between approximate Elevations 276.3 to 277.2 feet. Perched groundwater zones were also encountered during the previous hydrogeologic explorations at depths ranging from 8.5 to 11 feet bgs (Shannon & Wilson, 2016). Note that groundwater is not expected to be encountered during excavations for the new school building. We understand that the project stormwater management system will consist of a series of shallow bioretention swales combined with underground injection control (UIC) wells. The results of our recent hydrogeological testing and analysis are presented in a separate report (Shannon & Wilson, 2016). Please refer to this report for design recommendations regarding UIC construction and infiltration rates. 7.0 ENGINEERING STUDIES AND RECOMMENDATIONS 7.1 General Based on the observations made during the subsurface exploration program and information reviewed for the project, we expect the glacial till material will provide good support for conventional spread footing foundations with minimal settlements. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 6 SHANNON ING , The following subsections provide detailed recommendations on the following topics: ■ Foundation design • Seismic design ■ Lateral earth pressures ■ Lateral resistance ■ Slope stability ■ Pavement design 7.2 Foundation Design The subsurface explorations encountered undisturbed, very dense, native glacial till soils across the entire site. Spread footings founded in the dense, native till material may be designed with an allowable bearing pressure of 10,000 pounds per square foot (psf). Spread footings that are founded in compacted structural backfill placed above the glacial till may be designed for an allowable bearing capacity of 4,000 psf. These allowable bearing values may be increased by one-third for transient seismic loading. Any fill material that is to be reused should be evaluated by a geotechnical engineer to see if they are suitable for use. Use of on -site fill material is discussed in Section 8.1. Based on the subsurface conditions, isolated overexcavation could be required due to the presence of some existing fill within the building footprints. As an alternative to overexcavation of fill material encountered at footing subgrade elevations, in situ densification of the fill could be accomplished with the use of heavy vibratory compaction equipment (i.e., excavator -mounted "ho-pac"). Footing subgrades should be observed by a qualified geotechnical engineer or geologist. If the native glacial till material or compacted structural backfill is used as the foundation bearing soils, it is anticipated that any settlement that occurs will be essentially instantaneous as the load is applied during construction. If the footings are designed for the bearing pressures noted above, then the total footing settlements will be less than '/z inch. Differential settlements would be about one-half of the total settlement. However, if the entire structure is founded on the glacial till, then differential settlements would be insignificant. 7.3 Seismic Design The seismic design of the structure should be in accordance with the International Code Council, Inc. 2015 International Building Code (IBC) (International Code Council, Inc., 2014). The IBC design criteria are based on a target risk of structural collapse of 1 percent in 50 years. The soil 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 7 SHANNON ING , profile is assessed by assigning a site class definition. It is our opinion that based on the soil classification, i.e., very dense, the site can be classified as Site Class C. Seismic inputs are the short -period maximum spectra acceleration, Ss, and spectral acceleration at a period of one second, Si. Using the map provided in the IBC, which corresponds to Site Class B sites, the mapped values of Ss and Si are approximately 1.262 and 0.493g, respectively. The site coefficients for the given spectral acceleration values and site class C are 1.0 and 1.31 for Fa and F, respectively. Seismic hazards such as liquefaction and fault rupture are not present at the project site. 7.4 Lateral Earth Pressures and Retaining Walls Lateral earth pressures will act on portions of the building as well as on retaining walls. The magnitude and distribution of these lateral pressures will depend on many factors, including, but not limited to, the type of backfill, the method of backfill placement, level of backfill compaction, slope of backfill, drainage, and characteristics of the wall itself. If the wall is allowed to move at least 0.001 times the wall height, the wall is considered flexible and active earth pressures can be used. If the wall is considered to be inflexible then at -rest earth pressures must be used. The active and at -rest earth pressures, evaluated using an equivalent fluid unit weight, are estimated to be on the order of 30 and 50 pounds per cubic feet (pcf), respectively. The values given above assume a permanent wall structure, the ground surface behind the wall is level, and that proper drainage is installed to prevent the buildup of pore water pressure behind the wall. The total earth pressures should be analyzed for seismic loading conditions using a dynamic load increment equal to a percentage of the static earth force. The percentage load increase for seismic condition was developed to be consistent with a pseudo -static analysis using the Mononobe-Okabe equation for lateral earth pressures (Kramer, 1996) and a horizontal seismic coefficient of 0.2. The load increase for seismic conditions is recommended to be a uniformly distributed load equal to 8H, where H is the height of the wall. Note the seismic coefficient is not equal to the peak ground acceleration (PGA) expected to be encountered at the site in a design event. The PGA is experienced only a few times within the record of earthquake shaking, and the actual earthquake ground motion is cyclic in nature, not static. Values of the seismic coefficient are thus typically one-third to one-half the value of the PGA that may be experienced at the site during a design level event. We understand that rockery walls may be installed. Rock walls have been used in numerous locations around Puget Sound area primarily to provide erosion protection to cuts in stable 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 8 SHANNON ING , materials. Rockeries have also been used to retain fill slopes; however, this practice is not as prevalent. In our opinion, rockeries could be used to retain cut slopes made in dense to very dense native soil that are less than 6 feet high. Rockeries should be constructed in accordance with the recommendations shown in Figure 3. Rockeries could be used to retain fill slopes provided they are 5 feet high or less, or if they are reinforced. If used with a reinforced slope, the rockery would form a fagade or erosion protection facing on an otherwise stable slope. Rockeries that are used to retain fill slopes that are 5 feet high or less should be built in accordance with the recommendations shown in Figure 3. We recommend that the fill be built out beyond the planned wall location and then cut back. With this procedure, the fill can be fully compacted, as compared with the difficulty of compacting the edge of a fill slope. 7.5 Lateral Resistance Footings may resist lateral loads using a combination of base friction and passive pressure against the buried or embedded portion of the footings and buried wall. We recommend that base sliding resistance be determined using an allowable coefficient of friction of 0.7 for a concrete foundation founded on on -site glacial till or compacted structural fill. Passive earth pressures can be evaluated using an equivalent unit weight of 400 pcf. This value includes a factor of safety of 1.5. 7.6 Slope Stability The slope along the eastern perimeter of the property is mapped as a critical area by the City due to the steepness of the slope and the presence of wetlands. We recommend that the Madrona K-8 school footprint be set back at least 1.0 feet from the top of slope. While we did not observe active landsliding on this slope, the Edmonds Community Development Code requires that buildings or other structures constructed near an environmentally critical area maintain a setback of 15 feet from the edge of the critical area which in this case is the top of the slope (Edmonds, Wash., 2016). However, the code also allows for setbacks to be determined by a Geotechnical Engineering Report. In our opinion, after review of the subsurface conditions and the current condition of the slope, a setback of 10 feet would not cause an increased potential for landslides or surficial soil instability on the steep slope. In our opinion, buried utilities within this setback distance are acceptable and will not be at risk due to slope instability. We understand that dead or diseased tree removal is planned along the east, west, and south perimeter of the property near the top of the slopes. We made a site visit on September 20, 2016, 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 9 SHANNON ING , to observe the slope areas where tree removal is planned. In our opinion, the planned tree removal will not cause instability of the slope and the trees may be felled and chipped in -place. 7.7 Pavement Design Pavement analyses were conducted using the American Association of State Highway and Transportation Officials (AASHTO) method for flexible and rigid pavement design (AASHTO, 1993). The AASHTO method is a widely used empirical design procedure for the design of flexible and rigid pavement structures. It considers strength of the base course materials, traffic stresses, and the strength of the pavement subgrade. The pavement design life is assumed to be 20 years. 7.7.1 Traffic Load Average daily traffic counts, including delivery trucks, school buses, and occasional heavy vehicles such as fire trucks, were based on assumed conditions for similar projects. Assumed traffic volumes were then converted into equivalent single -axle loads by using equivalent load factors. We assume that there will not be a significant increase in traffic at this location, but did include a 1 percent growth factor in the design life traffic counts for our analysis. 7.7.2 Subgrade Conditions The subgrade conditions at the proposed pavement locations are medium dense, silty sand to silty sand with gravel fill suitable for pavement support. If loose or soft subgrade is observed during construction, we recommend that it be removed and replaced with at least 1 foot of compacted structural fill. A Resilient Modulus, MR, of 15,000 pounds per square inch is recommended for pavement design where existing medium dense fill and newly placed compacted structural fill are present. 7.8 Non -Porous Pavement Section Recommendations For support of the proposed parking and driveway areas we propose pavement section thicknesses shown in Table 1 below. Recommendations have been separated into lightly loaded and heavily loaded pavement sections. Lightly loaded pavement sections are assumed to be those that are utilized primarily by car and other passenger vehicle traffic. Heavily loaded pavement sections are assumed to be those that are utilized by heavy vehicles such as buses, delivery, and fire trucks. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 10 SHANNON ING , TABLE 1 RECOMMENDED MINIMUM PARKING LOT AND DRIVEWAY SECTION THICKNESSES ?" rnteut Jght -!:"Heavy' +- Pavement I,a er. ; Lodi I .trsdih " Asphalt 3 inches 4 inches Flexible Base Course 4 inches 6 inches Concrete 4 inches 6 inches Rigid Base Course 4 inches 4 inches Base course should correspond to crushed surfacing in accordance with the Washington State Department of Transportation (WSDOT) Standard Specifications (WSDOT, 2016). Placement, compaction, and material specification for crushed surfacing is discussed in Section 8.1 of this report. 7.9 Porous Pavement Section Recommendations 7.9.1 Grass Grid Pavers Grass grid pavers will be a proprietary product and should be designed in accordance with the manufacturer's recommendations. For design of the porous pavement sections, we recommend that the compacted subgrade be assumed to have a California Bearing Ratio of approximately 20. 7.9.2 Pervious Hot Mix Asphalt (HMA) and Concrete As we understand, porous pavement sections consisting of pervious HMA or concrete underlain by an underdrain are being considered within the fire lane to collect surface drainage. Pervious pavement consists of porous asphalt or concrete overlying a stone bed. For support of the proposed fire lane areas, we propose porous pavement section thicknesses shown in Table 2 below. TABLE 2 RECOMMENDED MINIMUM POROUS PAVEMENT SECTION THICKNESSES Pavement T Pmeiita `r Th>i Pervious HMA Porous Asphalt 5 inches Stone Bed 10 inches Rigid Porous Concrete 9 inches Stone Bed 12 inches 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 11 SHANNON ING , Please note that porous asphalt is susceptible to considerable wear due to heavy vehicle loading especially in vehicle turning areas. Rutting due to surface abrasion is known to occur between the wheel and the pavement during breaking and turning. Also note that pervious concrete pavement is sensitive to the means and methods used in. mix design and placement. We recommend following the American Concrete Institute (ACI) Specification for Pervious Concrete Pavement, ACI 522.1-13 for design and installation practices of porous concrete pavement systems (ACI, 2013). This specification covers materials, preparation, forming, placing, finishing, jointing, curing, and quality control of pervious concrete pavement. Provisions governing testing, evaluation, and acceptance of pervious concrete pavement are included. Pervious concrete pavement will require annual cleaning to maintain its infiltration function. We recommend vacuum cleaning once or twice a year (depending on conditions) with a regenerative sweeper and pressure washing as needed. 7.10 Pavement Sections Near Steep Slopes Pavements constructed near the steep slopes on the east and west perimeters of the property should have the same minimum pavement sections shown above in Table 1. Subsurface conditions encountered in the explorations indicate that the site is underlain by glacial till at relatively shallow depths, so slope stability is not an issue with regard to pavement construction. 7.11 Frost Susceptibility Frost -susceptible soil is regarded as having greater than 3 percent finer that 0.02 millimeter (mm). Soil with a fines content not exceeding 7 percent passing the No. 200 sieve, based on the minus 3/4-inch fraction, can normally be expected to have 3 percent or less finer than 0.02 turn. The current subsurface explorations indicate the subgrade soil has an average fines content of about 30 percent, which should be considered frost -susceptible. The measured frost depth during cold winters of 1949 and 1950 was about 15 inches near Edmonds, Washington. In accordance with the WSDOT Pavement Policy (WSDOT, 2015), pavement can be designed for frost protection by providing a pavement section that is equal to or thicker than half of the anticipated frost depth. The pavement section includes pavement and non -frost susceptible base course. In our opinion, the minimum recommended pavement sections presented in Table 1 above should provide adequate frost protection. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 12 SHANNON ING , 8.0 GEOTECHNICAL CONSTRUCTION RECOMMENDATIONS 8.1 Earthwork and Use of On -site Soils Fill placed beneath structures such as floor slabs, pavements, sidewalks, or backfill against footings should be structural fill. Structural fill should be placed and compacted upon native soil surfaces observed during construction by a geotechnical engineer or the engineer's representative. The fill soils encountered onsite generally contain sufficient fines to make them moisture -sensitive. In our opinion, on -site soils may be difficult to place and compact to adequate relative compaction levels, particularly during wet weather or in wet conditions. The on -site glacial till soils may be used as structural fill material provided the following conditions are met: ■ The soil is free from organics, debris, or other deleterious material. ■ The water content of the on -site soil at the time of compaction is close to its optimum as determined by a Modified Proctor Test (ASTM International [ASTM], 2012). ■ On -site soils used for fills and backfills that become wet and unstable after placement should be removed and replaced with suitable material. ■ Stockpiled on -site soils are protected when rainfall is anticipated in accordance with Section 2-09.3(1)E (WSDOT, 2016). If on -site soil becomes too difficult to compact or construction site space limitations prevent stockpiling, we recommend using imported, granular, structural backfill. Imported backfill should meet gradation requirements of the WSDOT Standard Specifications (WSDOT, 2016). Table 3 provides material specifications for various backfill applications. On -site soil not suitable for structural backfill could be used as backfill within landscaped areas. TABLE 3 IMPORTED BACKFILL SPECIFICATIONS BASED ON 2016 WASHINGTON STATE DEPARTMENT OF TRANSPORTATION STANDARD SPECIFICATIONS A ' lic�ti©n Maternal eifictt®n Structural Fill 9-03.14(1) Gravel Backfill for Walls 9-03.12(2) Gravel Backfill for Pipe Zone Bedding 9-03.12(3) Crushed Surfacing Base Course 9-03.9(3) Structural fill should be placed in horizontal, uniform lifts and compacted to a dense and unyielding condition, and to at least 95 percent of the Modified Proctor maximum dry density (ASTM D155'7 [ASTM, 2012]). Subgrades to receive structural fill should be dense and unyielding and should be evaluated by the geotechnical engineer prior to the placement of fill. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 13 SHANNON ING , Preparation of subgrades should be in accordance with Section 2-06 of the WSDOT Standard Specifications (WSDOT, 2016). In general, the thickness of soil layers before compaction should not exceed 1.0 inches for heavy equipment compactors or 6 inches for hand -operated mechanical compactors. The most appropriate lift thickness should be determined in the field using the Contractor's selected equipment and fill, and verified with in situ soil density testing (nuclear gauge methods). All compacted surfaces should be sloped to drain to prevent ponding. Structural fill placement operations should be observed and evaluated by an experienced geotechnical engineer or technician. 8.2 Pervious Pavement Materials We recommend the following material specifications for pervious pavement: Porous Bituminous Asphalt. The bituminous surface course shall be a bituminous mix of 6 percent by weight dry aggregate. Porous asphalt uses the same mixing and application equipment as for conventional asphalt. A neat asphalt binder modified with an elastomeric polymer is recommended. The polymer modified asphalt binder shall be heat and storage stable. Aggregate shall be minimum 90 percent crushed material and have a recommended gradation of: U.S. Standard Sieve Size Percent Passing 1/2 (12.5 millimeter [mm]) 100 % (9.5 mm) 92 to 98 4 (4.75 mm) 34 to 40 8 (2.36 mm) 14 to 20 16(1.18mm) 7to13 30 (0.60 mm) 0 to 4 200 (0.075 mm) 0 to 2 ■ Stone Bed. Stone bed course aggregate shall be a crushed, %- to 1-inch uniformly graded coarse aggregate conforming to AASHTO size number 67 (or equivalent). Stone bed aggregate shall be placed immediately after approval of subgrade preparation. Clean (washed) stone bed aggregate should be in maximum 8-inch lifts. Each layer shall be compacted to a dense condition with a smooth drum roller. 8.3 Construction and Maintenance Considerations for Pervious Pavement Pervious pavement is susceptible to damage and clogging during construction and afterward. We recommend that the construction be undertaken in such a way as to prevent: 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 14 SHANNON ING , • Compaction of Subgrade: If the existing subgrade under the stone bed is to be used for infiltration, then the subgrade shall not be compacted or subject to excessive construction equipment traffic prior to stone bed placement. Contamination of Stone Bed and Pervious Pavement with Sediment and Fines: Control of sediment is critical and rigorous installation and maintenance of erosion and sediment control measures is required to prevent sediment deposition on the pavement surface or within the stone bed. Staging, construction practices, and erosion and sediment control must all be taken into consideration when using pervious pavements. Due to the nature of construction sites, pervious pavement and other infiltration measures should be installed at the end of the construction period. All pervious pavement installations must have a backup method for water to enter the stone storage bed in the event that the pavement fails or is altered. In uncurbed lots, this backup drainage may consist of an unpaved 2-foot-wide stone edge drain connected directly to the bed between the wheel stop. In curbed lots, inlets with 12-inch sediment traps may be required at low spots. Backup drainage elements will ensure the functionality of the infiltration system if the pervious pavement is compromised. These systems should be designed by the project civil engineer. 8.4 Temporary and Permanent Excavation Slopes Safe temporary excavations are the responsibility of the Contractor and depend on the actual site conditions at the time of construction. Temporary cuts are the responsibility of the Contractor and should comply with applicable Occupational Safety and Health Administration (OSHA) and Washington Industrial Safety and Health Administration Standards. For trench safety purposes, the fill material at the site should be considered as OSHA "Class U material, which requires side slopes no steeper than 1.5 Horizontal to 1 Vertical (1.5H:1V). Cut slopes during construction, particularly during wet weather, should be compacted to achieve a dense surface and covered with plastic sheeting to reduce erosion. All traffic and/or construction equipment loads should be set back from the edge of the cut slopes a minimum of 5 feet. Excavated material, stockpiles of construction materials, and equipment should not be placed closer to the edge of any excavation than the depth of the excavation, unless the excavation is shored and such materials are accounted for as a surcharge load on the shoring system. Permanent slopes excavated in dense native soils should be no steeper than 1.5H:IV. We recommend that permanent slopes in on -site fill materials be no steeper than 2H:IV. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 15 SHANNON ING , 8.5 Erosion Control Erosion control for the site will include the Best Management Practices incorporated in the civil design drawings and may incorporate the following recommendations: ■ Limit exposed cut slopes. ■ Route surface water through temporary drainage channels around and away from exposed slopes. ■ Use silt fences, straw, and temporary sedimentation ponds to collect and hold eroded material on the site. ■ Seed or plant vegetation on exposed areas where work is completed and no buildings are proposed. ■ Retain existing vegetation to the greatest possible extent. 8.6 Construction Drainage Even during dry weather, we recommend that site drainage measures be incorporated into the project construction. Perched water in the excavations (if present) and surface runoff can be controlled during construction by careful grading practices. Typically, these include the construction of shallow perimeter ditches or low earthen berms, and the use of temporary sumps to collect runoff and prevent water from damaging slopes and exposed subgrades. All collected water should be directed, under control, to a positive and permanent discharge system. The site will need to be graded at all times to facilitate drainage and minimize the ponding of water. 8.7 Subsurface Drainage We recommend installing a subdrain system along the outside of the perimeter footings to prevent pooling of stormwater against the building foundations. The subdrain system should consist of a perforated or slotted, 4-inch (minimum) -diameter plastic pipe bedded in %-inch to No. 8 size washed pea gravel. Where a perforated or slotted drain pipe from a subdrain system connects into a tightline, we recommend that a low permeability concrete collar or dam be placed along the first 2 feet of the tightline to force all water into the tightline. Cleanouts should be provided at convenient locations along all drain lines, such as at the building corners. 8.8 Utilities In general, utilities at the site can be installed within the existing site soils, provided they are not underlain by extremely loose, soft, or organic materials. Maintaining safe utility excavations is 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 16 SHANNON ING , the responsibility of the Contractor. Conventional excavation equipment can be used to excavate the soils. The utility trenches should be backfilled as noted in Section 8.1. We recommend utilities placed under the roadway have a minimum cover of 2 feet from the crown of the pipes or conduits to the top of the pavement subgrade. Catch basins, utility vaults, and other structures installed flush with the pavement should be designed and constructed to transfer wheel loads to the base of the structure. 8.9 Wet Weather Earthwork In the project area, wet weather generally begins about mid -October and continues through about May, although rainy periods may occur at any time of the year. Therefore, it would be advisable to schedule earthwork during the dry weather months of June through mid -October. Most of the soils at the site contain sufficient fines to produce an unstable mixture when wet. Such soils are highly susceptible to changes in water content, and may become muddy, unstable, and difficult to compact if their moisture content significantly exceeds the optimum. Performing earthwork during dry weather would reduce these problems and costs associated with rainwater, trafficability, and handling of wet soil. However, should wet weather/wet condition earthwork be unavoidable, the following recommendations are provided: Earthwork should be accomplished in small sections to minimize exposure to wet conditions. That is, each section should be small enough such that the removal of unsuitable soils and the placement and compaction of clean structural fill can be accomplished on the same day. If there is to be traffic over the exposed subgrade, the subgrade should be protected with a compacted layer (generally 8 inches or more) of clean crushed rock. ■ Fill material should consist of clean, well -graded granular soil, of which not more than 5 percent by dry weight passes the No. 200 mesh sieve, based on wet sieving the fraction passing the 3/4-inch mesh sieve. The fines should be non -plastic. ■ The ground surface in the construction area should be sloped and sealed with a smooth -drum roller to promote the rapid runoff of precipitation, to prevent surface water from flowing into excavations, and to prevent ponding of water. ■ No soil should be left uncompacted and exposed to moisture. A smooth -drum vibratory roller, or equivalent, should be used to seal the ground surface. Soils which become too wet for compaction should be removed and replaced with clean granular soil. ■ Excavation and placement of structural fill material should be observed on a full-time basis by a geotechnical engineer or his/her representative, experienced in wet -weather earthwork, to determine that all work is being accomplished in accordance with the project plans and specifications, and our recommendations. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 17 SHANNON ING , • Covering of work areas, soil stockpiles, or slopes with plastic; sloping, ditching, and installing sumps; dewatering; and other measures should be employed, as necessary, to permit proper completion of the work. Bales of straw and/or geotextile silt fences should be aptly located to control soil movement and erosion. Grading and earthwork should not be accomplished during periods of heavy, continuous rainfall. 8.10 Plans Review and Construction Observation We recommend that Shannon & Wilson be retained to review those portions of the plans and specifications that pertain to the geotechnical aspects of the project to determine if they are consistent with our recommendations. We also recommend that we be retained to observe the geotechnical aspects of construction, particularly the pavement and shallow footing subgrade preparation, drainage installation, and earthwork (structural fill placement and compaction). This observation would allow us to witness the subsurface conditions as they are exposed during construction and to determine that the work is accomplished in accordance with our recommendations. 9.0 LIMITATIONS This report was prepared for the exclusive use of the Edmonds School District No. 15 for specific application to the design of the Madrona K-8 School project at this site as it relates to the geotechnical aspects discussed in this report. The data and report should be provided to prospective contractors and/or the Contractor for factual information only. Our judgments, conclusions, and interpretations presented in the report should not be construed as a warranty of subsurface conditions and should not be relied upon by prospective contractors. Construction period observation by our firm is necessary to confirm recommendations and interpretations made in this report. The analyses, conclusions, and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical engineering principles and practice in this area at this time. No other warranty, either express or implied, is made. The analyses, conclusions, and recommendations contained in this report are based on site conditions as they existed during our site visits and explorations, and further assume that the explorations are representative of the subsurface conditions throughout the site; i.e., the subsurface conditions everywhere are not significantly different from those disclosed by the explorations. If subsurface conditions different from those described in this report are observed 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 18 SHANNON 6WILSON, or appear to be present during construction, we should be advised at once so that we can review these conditions and reconsider our recommendations, where necessary. If there is a substantial lapse of time between the submission of this report and the start of work at the site, or if conditions have changed because of natural causes or construction operations at or adjacent to the site, we recommend that this report be reviewed to determine the applicability of the conclusions and recommendations, considering the changed conditions and time lapse. Unanticipated soil conditions are commonly encountered and cannot be fully determined by merely taking soil samples or completing test pits. Such unexpected conditions frequently require that additional expenditures be made to attain a properly constructed project. Therefore, some contingency fund is recommended to accommodate such potential extra costs. Shannon & Wilson has prepared the enclosed Appendix D, "Important Information About Your Geotechnical/Environmental Proposal," to assist you and others in understanding the use and limitations of our proposals. Kevin Wood Geotechnical Staff Martin W. Page, PE, LEG Vice President Geotechnical Engineer, LEED AP, DBIATM KJW:MWP/kjw 21-1-22082-004-R 1 f/tvp/tkn 21-1-220 82-004 19 SHANNON ING , 10.0 REFERENCES American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO guide for design of pavement structures, Washington, D.C., AASHTO, 2 v. American Concrete Institute (ACI), 2013, Specification for pervious concrete pavement (ACI 522.1): Farmington Hills, Mich., American Concrete Institute, ACI 522.1-13, 7 p. ASTM International (ASTM), 2012,.Standard test methods for laboratory compaction characteristics of soil using modified effort (56,000 ft-lbf/ft3 (2,700 kN-m/m3)), D1557- 1.2e1: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 14 p., available: www.astm.org. Edmonds, Wash., 2016, Natural resources: Edmonds, Wash., Edmonds City Code and Development Code Title 23, available: htt1�://wwwacode�ulishin.com1WA/Edmonds/. International Code Council, Inc., 2014,.International building code 2015: Country Club Hills, Ill., International Code Council, Inc., 700 p. Kramer, S.L., 1996, Geotechnical earthquake engineering: Upper Saddle River, N.J., Prentice Hall, 653 p. Shannon & Wilson, Inc. (Shannon & Wilson), 2016, Hydrogeologic report, new Madrona K-8 project, Edmonds, Washington: Report prepared by Shannon & Wilson, Inc., Seattle, Wash., 21-1-22082-003, for Edmonds School District No. 15, Edmonds, Wash., November. Troost, K.G., and Booth, D.B., 2008, Geology of Seattle and the Seattle area, Washington, in Baum, R.L., Godt, J.W. and Highland, L.M., eds., Landslides and Engineering Geology of the Seattle, Washington, Area: Geologic Society of America Reviews in Engineering Geology XX, p. 1-35. Washington State Department of Transportation (WSDOT), 2015, WSDOT Pavement Policy: Olympia, Washington, WSDOT, 131 p., available: ham://www.wsdot,wao gov/NRlydonl�res/EF9AAC9E-6323-4B09-A3D 1- DD2E2C905D02/0/WSDOTPave entPolicyJune20l5.p f Washington Department of Transportation (WSDOT), 2016, Standard specifications for road, bridge, and municipal construction: Olympia, Wash., WSDOT, Manual M 41-10, 1 v., January, available: http:/Iwww.wsdot.wa.govlPublicationslManualslM4I-l0.htm. 21-1-22082-004-R1 f.docx/wp/lkn 21-1-22082-004 20 Filename: J:\211\22082-004\2-1-22084-004 Fig 2 - Site Plan.dwg Layout: Layout Date: 10-04-2016 Login: SAC co 0 0 0 H = 6 Ft. Max. 4 Medium 12" Min. dense to Very Dense Native Soil 6" Min. 16" Min. Width for Top Rock —� H/3 Min. Width for Base Rock All loose soil at rockery foundation subgrade should be overexcavated down to medium dense to very dense soil and replaced with compacted backfill as described above. The excavation shall be kept free of water. The prepared foundation subgrade shall be evaluated by a soils engineer prior to placement of rock. If•IILIII►U[II]JimingEel -kIma 10141 / Rock shall be sound and have a minimum density of 160 pounds per cubic foot. Not to Scale Ditch Drain to Appropriate Outlets 8" Compacted Native or Imported Soil (Impervious Surface Layer) Stable Excavation Slope in Very Dense Native Soil (Contractor's Responsibility) Opening Chinked with 2 to 4-inch Quarry Spalls Very Dense Undisturbed Native Soil Backfill Clean, well -graded sand and gravel or crushed rock, 2-inch maximum size, 40 to 60% gravel, less than 5% fines (passing #200 sieve). Fines shall be non -plastic. Compact in 4" lifts with minimum of 4 coverages by hand -operated tamper. Compact to at least 92% of Modified Proctor maximum dry density (ASTM D-1557). Backfill and rock placement should be built up together. 6" Diameter Slotted Pipe Bedded in washed 3/8" to No.8 sieve size pea gravel (6" cover around pipe), sloped to drain and connected by tightline to storm drain outfall or other appropriate outlets. No fabric around pipe. Maximum slot width is 1/8". 1.6 0.8 Transducer 1.4 __ Reading (Feet) _ -0.7 -tt�,ot} tf tqr, - Manual Reading - 1.2 Oil �sn��,� � _ (Feet) 0.6 0 .... _ .... 10 Inflow Rate (GPM) ._. �3 - LL 0 1 "}tfr 0.5 Residual water -'ifir=t t,t . .. perched on silt o muck at test 0 0'8 (` ��{`' pit bottom. Soils 0.4 0 m - -�, - immediately below jr,, -, - {p tx{ were moist. c,> 0.6 0.3 CU Q 41 .. .... _0.4Transducer #4 was inside a stilling tube. 4i ytt}i r, Approx. 5" mud accumulated and t hetube bottomby end of to test. ,t 0.2 Water level in tube fell below 0.1 .. - - - surroundin ding mud level. it { _ O4-0 0 200 400 600 800 1000 1200 1400 Time Since Start of Saturation (Minutes) ► W 1. This small-scale pilot infiltration test (PIT) was performed on 7/28/16. Water was added from 10:31 to 19:28. Approximate grade elevation 444.5 feet (NAVD88). Test pit floor depth 3.8 feet deep. A flow rate of 0.75 to 0.12 gallons per minute (gpm) was maintained for the initial saturation period. During the last hour of saturation, the flow rate was 0.11 gpm, with a water level of 14.25 inches above the test pit bottom. Test test pit drained from 19:28 on 7/28/16 to about 6:00 on 7/29/16. Test pit dimensions during the PIT were approximately 2.4 feet (north -south) by 5.5 feet (east - west), or 13.2 square feet. The test pit was over -excavated on 7/29/16 (starting at 8:30) to 10 feet deep. No sign of water was observed during over -excavation. PIT Results -Figure 4 PIT-1 Plot-9/28/2016-pvh Time Since Start of Saturation (Minutes) ►9W 1. This small-scale pilot infiltration test (PIT) was performed on 7/28/16. Water was added from 11:28 to 18:53. Approximate grade elevation 456 feet (NAVD88). Test pit floor depth 3.3 feet deep. A flow rate of 3.75 to 0.04 gallons per minute (gpm) was maintained for the initial saturation period. During the last hour of saturation, the flow rate was 0.04 gpm, with a water level of 15.75 inches above the test pit bottom. Test test pit drained from 18:53 on 7/28/16 to about 11:50 on 7/29/16. Test pit dimensions during the PIT were approximately 2.1 feet (north -south) by 6.3 feet (east - west), or 13.2 square feet. The test pit was over -excavated on 7/29/16 to 4.5 feet deep. The back hoe scooped out the residual PIT water and found that it had been perched on moist till. PIT Results -Figure 5 PIT-2 Plot-9/28/2016-pvh 1.6 0.8 1.4 - _ _ ___ 0.7 ' Rir s, iFt tii i}#}d} 2i! FF iP2Y .-.. Stt'4L ... _ .._ . .... 5+<F.,, 314))Y. Y, t{ cS(,{#,;lft r }tf +Yf}f}ft,.liitti,l $lis -- tr 1„{r(ttt#,risiP3�{tji()tft+`.`#ttt7ititritlt t2l;F��ti3 ri.,?�tiiiF# (3) .. iSi�i,Y}„ f . 1.2 0.6 o Cn r,; TTransduuc(er a� o Reading (Feet) E 0.8 0.4 0 o y Y� Manual h Reat'ng C m + (Feet) -, �. 0.3 Q �. + -. - - - Inflow Rate (GPM) - Residual water CU remaining in test pit z 0.4 over 16 hours after- 0.2 - 1 T 1 T - -. __ ow. fl . ceasing infl � _ T -. 0 2 0.1 - 4, - OL-------------- 1 U J I I_—i J i J ._ 0 0 200 400 600 800 1000 1200 1400 Time Since Start of Saturation (Minutes) ► W 1. This small-scale pilot infiltration test (PIT) was performed on 7/28/16. Water was added from 13:07 to 20:38. Approximate grade elevation 450 feet (NAVD88). Test pit floor depth 2.9 feet deep. A flow rate of 3.33 to 0.06 gallons per minute (gpm) was maintained for the initial saturation period. During the last hour of saturation, the flow rate was 0.06 gpm, with a water level of 16.2 inches above the test pit bottom. Test test pit drained from 20:38 on 7/28/16 to about 12:36 on 7/29/16 when we removed the transducer. Inital ponded area dimensions during the PIT were approximately 2.2 feet (east -west) by 8 feet (north -south), or 17.6 square feet. Due to sidewall slumping during the falling head test period, the final ponded dimensions were approximate 2.5 feet by 8.2 feet (20.5 square feet). The test pit was over -excavated on 7/29/16 to 3.4 feet deep. The back hoe scooped out the residual PIT water and found that it had been perched on moist till. PIT Results -Figure 6 PIT-3 Plot-9/28/2016-pvh SUBSURFACE EXPLORATIONS 21-1-22082-004 PARTICLE SIZE DEFINITIONS Shannon & Wilson, Inc. (S&W), uses a soil identification system modified from the Unified Soil Classification System (USCS). Elements of the USCS and other definitions are provided on this and the following pages. Soil descriptions are based on visual -manual procedures (ASTM D2488) and laboratory testing procedures (ASTM D2487), if performed. S&W INORGANIC SOIL CONSTITUENT DEFINITIONS CONSTITUENT s -------------- Major FINE-GRAINED SOILS (50% or more fines)' __ __ -- Silt, Lean Clay, Elastic Silt, or Fat Clay COARSE -GRAINED SOILS (less than 50%fines' _ - Sand or Gravely Modifying (Secondary) 30% or more More than 12% Precedes major coarse -grained: fine-grained: constituent Sandy or Gravelly' Silty or Clayey3 15% to 30% 5% to 12% coarse -grained: fine-grained: Minor with Sand or with Silt or With Gravel ° with Clay Follows major 30 or more total /o constituent coarse -grained and 15% or more of a lesser coarse- second coarse - grained constituent grained constituent: is 15% or more: with Sand or with Sand or with Gravels with Gravels 'All percentages are by weight of total specimen passing a 3-inch sieve 2The order of terms is: Modifying Major with Minor. 'Determined based on behavior. °Determined based on which constituent comprises a larger percentage 'Whichever is the lesser constituent. MOISTURE CONTENT TERMS Dry Absence of moisture, dusty, dry to the touch Moist Damp but no visible water Wet Visible free water, from below water table STANDARD PENETRATION TEST (SPT) SPECIFICATIONS 140 pounds with a 30-inch free fall. Rope on 6- to 10-inch-diam. cathead 2-1/4 rope turns, > 100 rpm NOTE: If automatic hammers are used, blow counts shown on boring logs should be adjusted to account for efficiency of hammer. Sampler: 10 to 30 inches long Shoe I.D. = 1.375 inches Barrel I.D. = 1.5 inches Barrel O.D. = 2 inches N-Value: Sum blow counts for second and third 6-inch increments. Refusal: 50 blows for 6 inches or less; 10 blows for 0 inches. NOTE. Penetration resistances (N-values) shown on', boring logs are as recorded in the field and have not been corrected for hammer efficiency, overburden, or other factors. DESCRIPTION SIEVE NUMBER AND/OR APPROXIMATE SIZE FINES < #200 (0.075 mm = 0.003 in.) SAND Fine #200 to #40 (0.075 to 0.4 mm; 0.003 to 0.02 in.) Medium #40 to #10 (0.4 to 2 mm; 0.02 to 0.08 in.) Coarse #10 to #4 (2 to 4.75 mm; 0.08 to 0.187 in.) GRAVEL Fine #4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.) Coarse 3/4 to 3 in. (19 to 76 mm) COBBLES 3 to 12 in. (76 to 305 mm) BOULDERS > 12 in. (305 mm) RELATIVE DENSITY / CONSISTENCY COHESIONLESS SOILS COHESIVE SOILS N, SPT, RELATIVE N, SPT, RELATIVE BLOWS/FT. DENSITY BLOWS/FT. CONSISTENCY < 2 Very soft < 4 Very loose 4-10 Loose 2-4 Soft 10-30 Medium dense 4-8 Medium stiff 30-50 Dense 8 - 15 Stiff > 50 Very dense 15 - 30 Very stiff > 30 Hard MBentonite Cement Grout FM Bentonite Grout Bentonite Chips Silica Sand E] Perforated or Screened Casing %o a" Surface Cement Seal Asphalt or Cap - Slough Inclinometer or Non -perforated Casing mVibrating Wire Piezometer PERCENTAGES TERMS'' z Trace < 5% Few 5 to 10% Little -------------- _ Some 15 to 25% -- - 30 to 45% Mostly 50 to 100% 'Gravel, sand, and fines estimated by mass. Other constituents, such as organics, cobbles, and boulders, estimated by volume. 2Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org. MAJOR DIVISIONS GROUP/GRAPHIC TYPICAL IDENTIFICATIONS SYMBOL GW .'• Well -Graded Gravel; Well -Graded Gravel with Sand Gravel GP Poorly Graded Gravel; Poorly Graded Gravels (less than 5% fines) (more than 50% o Gravel with Sand of coarse fraction retained on No. 4 sieve) Silty or Clayey GM Silty Gravel; Silty Gravel with Sand Gravel GC i Clayey Gravel; Clayey Gravel with COARSE- (more than 12% fines) GRAINED Sand SOILS SW Well -Graded Sand; Well -Graded Sand (more than 50% retained on No. 200 sieve) Sand with Gravel (less than 5% fines) Sp Poorly Graded Sand; Poorly Graded Sands Sand with Gravel (50% or more of coarse fraction passes the No. 4 Silty or SM Silty Sand; Silty Sand with Gravel sieve Clayey Sand (more than 12% fines) SC ✓ Clayey Sand; Clayey Sand with Gravel ML Silt; Silt with Sand or Gravel; Sandy or Gravelly Silt Inorganic CL 0010/11/ Lean Clay; Lean Clay with Sand or Silts and Clays (liquid limit less Gravel; Sandy or Gravelly Lean Clay than 50) Organic OL — — Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or FINE-GRAINED SOILS — — Gravelly Organic Silt or Clay (50% or more MH Elastic Silt; Elastic Silt with Sand or passes the 200 sieve)) Gravel; Sandy or Gravelly Elastic Silt Inorganic CH Fat Clay; Fat Clay with Sand or Silts and Clays (liquid limit 50 or Gravel; Sandy or Gravelly Fat Clay more) Organic Silt or Clay; Organic Silt or Organic OH Clay with Sand or Gravel; Sandy or / Gravelly Organic Silt or Clay HIGHLY- Primarily organic matter, dark in PT Peat or other highly organic soils (see ORGANIC SOILS color, and organic odor ASTM D4427) NOTE: No. 4 size = 4.75 mm = 0.187 in.; No. 200 size = 0.075 mm = 0.003 in. NOTES Dual symbols (symbols separated by a hyphen, i.e., SP-SM, Sand with Silt) are used for soils with between 5% and 12% fines or when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart. Graphics shown on the logs for these soil types are a combination of the two graphic symbols (e.g., SP and SM). Borderline symbols (symbols separated by a slash, i.e., CL/ML, Lean Clay to Silt, SP-SM/SM, Sand with Silt to Silty Sand) indicate that the soil properties are close to the defining boundary between two groups. Poorly Graded Narrow range of grain sizes present or, within the range of grain sizes present, one or more sizes are missing (Gap Graded). Meets criteria in ASTM D2487, if tested. Well -Graded Full range and even distribution of grain sizes present. Meets criteria in ASTM D2487, if tested. CEMENTATION TERMS' Weak Crumbles or breaks with handling or slight finger pressure. Moderate Crumbles or breaks with considerable finger pressure. Strong Will not crumble or break with finger pressure. DESCRIPTION APPROX. PLASITICITY VISUAL -MANUAL CRITERIA INDEX RANGE Nonplastic A 1/8-in. thread cannot be rolled < 4 at any water content. Low A thread can barely be rolled and 4 to 10 a lump cannot be formed when drier than the plastic limit. Medium A thread is easy to roll and not 10 to 20 much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. A lump crumbles when drier than the plastic limit. High It takes considerable time rolling > 20 and kneading to reach the plastic limit. A thread can be rerolled several times after reaching the plastic limit. A lump can be formed without crumbling when drier than the plastic limit. Mottled Irregular patches of different colors. Bioturbated Soil disturbance or mixing by plants or animals. Diamict Nonsorted sediment; sand and gravel in silt and/or clay matrix. Cuttings Material brought to surface by drilling. Slough Material that caved from sides of borehole. Sheared Disturbed texture, mix of strengths. Angular Sharp edges and unpolished planar surfaces. Subangular Similar to angular, but with rounded edges. Subrounded Nearly planar sides with well-rounded edges. Rounded Smoothly curved sides with no edges. Flat Width/thickness ratio > 3. Elongated Length/width ratio > 3. ATD At Time of Drilling Diam. Diameter Elev. Elevation ft. Feet FeO Iron Oxide gal. Gallons Horiz. Horizontal HSA Hollow Stem Auger I.D. Inside Diameter in. Inches lbs. Pounds MgO Magnesium Oxide mm Millimeter MnO Manganese Oxide NA Not Applicable or Not Available NP Nonplastic O.D. Outside Diameter OW Observation Well pcf Pounds per Cubic Foot PID Photo -Ionization Detector PMT Pressuremeter Test ppm Parts per Million psi Pounds per Square Inch PVC Polyvinyl Chloride rpm Rotations per Minute SPT Standard Penetration Test USCS Unified Soil Classification System qu Unconfined Compressive Strength VWP Vibrating Wire Piezometer Vert. Vertical WOH Weight of Hammer WOR Weight of Rods Wt. Weight Interbedded Alternating layers of varying material or color with layers at least 1/4-inch thick; singular: bed. Laminated Alternating layers of varying material or color with layers less than 1/4-inch thick; singular: lamination. Fissured Breaks along definite planes or fractures with little resistance. Slickensided Fracture planes appear polished or glossy; sometimes striated. Blocky Cohesive soil that can be broken down into small angular lumps that resist further breakdown. Lensed Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay. Homogeneous Same color and appearance throughout. 'Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org. 2Adapted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A Geotechnical Report New Madrona K-8 Project Edmonds, Washington October 2016 21-1-22082-004 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants www.astm.org. Total Depth: 16.5 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: - 449 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Asphalt_ ............................................................... 0.4 Dense, red -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; 2 few organics. Topsoil/Weathered Glacial Till :.: % 4 4.5 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to T angular gravel; fine to coarse sand; nonplastic 21 6 94/9`" fines; diamict. Glacial Till 3 m 8 L 0 90/10" 0 10 z a 088/10" O c 0 z 12 5� 50/4^ 14 - Moist to wet below about 15 feet. 6 :. 16 16.5 BOTTOM OF BORING COMPLETED 7/26/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-2 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-2 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.9 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 447.5 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Asphalt_ ............................................................... 0.4 Dense, gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; 2 nonplastic fines; diamict. Weathered Glacial Till 4 4.5 Very dense, gray -brown, Silty Sand (SM) to Silty Sand with Gravel (SM); moist; fine, z� 50/6" subrounded to subangular gravel; fine to 6 coarse sand; nonplastic fines; diamict. Glacial Till - Diamict pockets from 7.5 to 9 feet. 8 s c c O 10 a1 N 50/6" O 0 z 12 T 51 50/5" 14 - Moist to wet below about 15 feet. 6� 50/5" 15.9 16 BOTTOM OF BORING COMPLETED 7/26/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-3 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-3 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.8 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: - 445 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Asphalt_ ___ ________ _________ _________ _________________ 0.4 Medium dense, brown, Silty Sand (SM) to Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to angular gravel; fine to coarse 2 sand; nonplastic fines; trace to few organics; trace diamict pockets below about 7 feet. Fill 4 v` ' 2 6 8 _ s c 9'5 Very dense, gray -brown, Silty Sand (SM) to Silty Sand with Gravel (SM); moist; fine, z 10 subrounded to subangular gravel; fine to 4 a 90 0 coarse sand; nonplastic fines; diamict. O Glacial Till Z 12 5 78 14 a. s� 50/3" 15 8 16 BOTTOM OF BORING COMPLETED 7/26/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-4 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-4 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 16 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 447 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Topsoil. 0.5 Medium dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to angular gravel; fine to coarse sand; nonplastic 2 fines; trace organics. Fill 4 4.5 Loose, red -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; 2 6 trace organics. Topsoil/Weathered Glacial Till 7.0 Dense to very dense, gray brown, Silty Sand • (SM) to Silty Sand with Gravel (SM); moist; 3 m 8 fine, subrounded to subangular gravel; fine to 0 coarse sand; nonplastic fines; diamict. Glacial Till o - Slight iron oxide staining from 7 to 9 feet. 10 41 50/5° 0 0 z 12 s� 83/9" 14 - Moist to wet below about 15 feet. 061 50/6" 16.0 16 BOTTOM OF BORING COMPLETED 7/26/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-5 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-5 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.9 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 455 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Medium dense to very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict. 2 Weathered Glacial Till of 4 2 6 8 3 c 9'0 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to 10 angular gravel; fine to coarse sand; nonplastic z fines; diamict. a a 68l11" 0 Glacial Till 0 z 12 51 84/10" 14 6� 50/5" 15.9 16 BOTTOM OF BORING COMPLETED 7/25/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-6 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-6 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.9 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 454 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Asphalt. 0•2 Medium dense, brown, Silty Sand (SM); moist; few fine, subrounded to subangular gravel; fine to coarse sand; nonplastic to low plasticity 2 fines; diamict; trace organics. Topsoil/Weathered Glacial Till 4 4.5 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded 2 50/3" to subangular gravel; fine to coarse sand; 6 nonplastic fines. Glacial Till 3_ 50/5^ 8 0 0 a 10 a. 4 � 50I4`" 0 0 z 12 T s1 50/5" 14 - Trace pockets of poorly graded sand with silt s� 50/5" below about-1 5 feet --- --------- - 15.9 16 BOTTOM OF BORING COMPLETED 7/26/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-7 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-7 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.8 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: - 456 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Asphalt. 0•2 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to angular gravel; fine to coarse sand; 2 nonplastic fines; diamict. Glacial Till 50/3„ 4 2� 50/5" 6 3� $ c c O 10 L 4]:a 50I3" a 0 0 z 12 - Gray below about 12 feet. 5I 50/2" 14 6� 50/4" 15 8 16 BOTTOM OF BORING COMPLETED 7/25/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-8 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-8 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.5 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: - 456 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Topsoil. 0.5 Dense to very dense, brown and gray, Silty Sand with Gravel (SM); dry to moist; fine to coarse, subrounded to angular gravel; fine to 2 coarse sand; nonplastic fines; trace organics; diamict pockets. Fill/Weathered Glacial Till 4 2 6 78 7'0 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded $ 91/11" to subangular gravel; fine to coarse sand; 3 m c nonplastic fines; diamict. Glacial Till `- 0 10 z 41 2 62 0 0 z 12 - Few pockets of poorly graded, fine to medium sand with silt pockets below about 5� 50/4" 12 feet; moist to wet from about 12 to 14 feet. 14 15.5 ° s= 50/6" BOTTOM OF BORING COMPLETED 7/25/2016 16 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-9 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-9 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 15.8 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 454.5 ft, Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Topsoil. 0.5 Medium dense, brown, Silty Sand (SM); dry to moist; few fine, subrounded to subangular gravel; fine to medium sand; nonplastic fines; 2 diamict pockets; trace organics. Fill 4 - Roots at about 5 feet. 2 6 7'0 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded $ to angular gravel; fine to coarse sand; . .e 3T nonplastic fines; diamict. Glacial Till `- - Mottled orange and gray -brown with pockets a 10 of iron oxide staining from 7 to 9 feet. 41 N 50/51, 0 0 z 12 5T 50/3" 14 a. 6T 50/4" 15.8 16 BOTTOM OF BORING COMPLETED 7/25/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-10 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-10 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 16.4 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 456 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Topsoil. 0.5 Dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; 2 diamict. Weathered Glacial Till 4 4.5 Very dense, gray -brown, Silty Sand (SM) to Silty Sand with Gravel (SM); moist; fine, subrounded to subangular gravel; fine to 2 6 $4l11" coarse sand; nonplastic fines; diamict. Glacial Till 3 m 8 62 0 c 10 a1 N 50/6tt O 0 z 12 T 51 50/5" 14 s 85/5" 16 16.4 BOTTOM OF BORING COMPLETED 7/25/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-11 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-11 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal Total Depth: 16.3 ft. Northing: Drilling Method: Hollow Stem Auger Hole Diam.: 6 in. Top Elevation: — 456 ft. Easting: Drilling Company: Holocene Drilling Rod Diam.: 2-inch Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Diedrich D-50 Hammer Type: Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION 4� o -a 4� PENETRATION RESISTANCE (blows/foot) Refer to the report text for a proper understanding of the Q E Q t cz A Hammer Wt. & Drop: 140 Ibs / 30 inches subsurface materials and drilling methods. The stratification Q E o 5- lines indicated below represent the approximate boundaries � U (D between material types, and the transition may be gradual. 0 20 40 60 Topsoil. 0.5 Medium dense, brown, Silty Sand with Gravel (SM); dry to moist; fine, subrounded to subangular gravel; fine to medium sand; 2 nonplastic fines; trace organics. Fill 4 4.5 Very dense, gray -brown, Silty Sand with Gravel (SM); moist; fine, subrounded to J. subangular gravel; fine to coarse sand; :. 2 6 nonplastic fines; diamict. Glacial Till - Trace organics from about 4.5 to 8.5 feet. TT 31 m $ c c O 10 e 41 L 50/51. 0 o z 12 A. sI 50/2° 14 '. s� 90/9° 16.3 16 BOTTOM OF BORING COMPLETED 7/25/2016 18 0 20 40 60 LEGEND * Sample Not Recovered O % Fines (<0.075mm) Z 2.0" O.D. Split Spoon Sample • % Water Content Geotechnical Report New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING B-12 September 2016 21-1-22082-004 SHANNON & WILSON, INC. FIG. A-12 Geotechnical and Environmental Consultants REV 3 - Approved for Submittal 22 r 22 ,_ 3',4 2 1 22. . 00 4 T"Ps . "ev,, ,�., tKl: 0 ., 2 . i3 Aulhor a"aG =111SHANNON&WILSONTAL N.INC JOB NO: 21-1-22082-004 DATE: 7-28-16 to LOCATION: See Site and Exploration Plan GEOTEC-LOG OF TEST PIT PIT-1 PROJECT: Madrona K-8 7-29-16 _0c a u Sketch of North Pit Side Surface Elevation: Approx. 445 Ft. SOIL DESCRIPTION 0 m `� o Q E Horizontal Distance in Feet (D o U U) 0 0 2 4 6 8 10 12 OTopsoil and - 0 , 1 1 grass. 0 Dense, brown, Silty Sand with Gravel (SM); moist. ; 0 Fill (Reworked Till) 0) c 2 Fine Roots_- O Very loose to dense, brown -gray, O Z ` Silty Sand with Gravel and Cobbles .; (SM); moist; few cobbles, fine to coarse subrounded to subangular gravel; fine to coarse sand; S-1 I , .... "00 3 non -plastic fines; minor iron -oxide 47 % . m -- �" T-Probe 1" Penetration (before PIT) T-Probe 17" Penetration (after PIT) staining at 3.8 feet; diamict pockets. Test Pit Floor During Fill S-2 Pilot Infiltration Test (PIT) 4 Medium dense to dense, brown to S-3 red -brown, Silty Sand with Gravel 1 (SM); moist; fine to coarse S-4= 4 L T-Probe 2.5" Penetration (after PIT) O subrounded to angular gravel; fine S-5I 6 •�_T-Probe 1.5" Penetration (after PIT) to coarse sand; non -plastic fines. Roots and Conifer L T-Probe 0.5" Penetration (after PIT) Fill Duff/Needles 05 Medium dense to dense, red -brown to brown, Silty Sand with Gravel S-6 and Cobbles (SM); moist; few rounded cobbles; fine to coarse subrounded to subangular gravel; 8 05 fine to coarse sand; non -plastic fines; roots and conifer duff at top. Weathered Till S-7 10 NOTES -n 1. Small-scale PIT performed Test Pit Floor After PIT at 3.8 feet on 7-28/7-29-16. D W2. PIT ponded area 2.4' x 5.5'. 12 22 r 22 ,_ 3',4 2 1 22. . 00 4 T"Ps . "ev,, ,�., tKl: 0 ., 2 . i3 Aulhor a"aG =111SHANNON&WILSONTAL N.INC JOB NO: 21-1-22082-004 DATE: 7-28-16 to LOCATION: See Site and Exploration Plan GEOTEC-LOG OF TEST PIT PIT-2 PROJECT: Madrona K-8 7-29-16 _0c a u Sketch of North Pit Side Surface Elevation: Approx. 456 Ft. SOIL DESCRIPTION 0 m `� o Q E Horizontal Distance in Feet (D o U U) 0 0 2 4 6 8 10 12 O Topsoil. 0 / ,� 0Very dense, brown to gray-brown,Silty Sand with Gravel and Cobbles -0 O� / 2 (SM); dry to moist; few cobbles; fine to Y coarse subrounded to subangular o2 gravel; fine to medium sand; Z 1 Test Pit Floor During non -plastic fines; diamict. Pilot Infiltration Test (PIT) Till S-ij\.yy ♦� S-2I T-Probe 0.5" Penetration (after PIT) L T-Probe 0" Penetration (after PIT) 4 Test Pit Floor After PIT 6 8 10 -n NOTES 1. Small-scale PIT performed ' at 3.3 feet on 7-28/7-29-16. 2. PIT ponded area 2.1' x 6.3'. 12 ` , : J s2 r 22 ,_ 3',4 2 1 22. . 00 4 T"Ps . "ev,, ,�., tKl: 0 ., 2 . i3 Aulhor a"aG =111SHANNON&WILSONTAL N.INC JOB NO: 21-1-22082-004 DATE: 7-28-16 to LOCATION: See Site and Exploration Plan GEOTEC-LOG OF TEST PIT PIT-3 PROJECT: Madrona K-8 7-29-16 _0c a u Sketch of West Pit Side Surface Elevation: Approx. 450 Ft. SOIL DESCRIPTION 0 m `� m o Q E Horizontal Distance in Feet (D o U o) 0 0 2 4 6 8 10 12 O Topsoil. 0 Medium dense to dense, brown, Silty 02 Sand with Gravel (SM); dry to moist; -0 scattered cobbles and boulders. Test Pit Floor During Fill (Reworked Till) 0 2 - Pilot Infiltration Test (PIT)Je Z O Very dense, gray -brown, Silty Sand S-1TTest Pit Floor After PIT with Gravel and Cobbles and 1 Boulders (SM); dry to moist; few S-2I cobbles and boulders; fine to coarse subrounded to subangular gravel; 4 __ __ _ T-Probe 0" Penetration (after PIT) L fine to coarse sand; non -plastic fines; T-Probe 0.5" Penetration (after PIT) diamict. Weathered Till to Till 6 NOTES 8 1. Small-scale PIT performed at 2.9 feet on 7-28/7-29-16. 2. PIT ponded area 2.2' x 8.0' on 7-28-16. PIT ponded area 2.5' x 8.2' on 7-29-16. 10 .n 25 12 R.., 22 r 229,_ 3,4 T Us r16-09- G 5 _^20_ 4 004 P FF r6wg Da,",_,, 09 C 016 LAU! !,tE.wnp =111SHANNON&WILSOTAL N.INC JOB NO: 21-1-22082-004 DATE: 7-28-16 LOCATION: Edmonds, WA GEOTEC-LOG OF TEST PIT TP-1 F PROJECT: Madrona K-8 _0c a u Sketch of East Pit Side Surface Elevation: Approx. SOIL DESCRIPTION 0 o E Horizontal Distance in Feet (D o U o) 0 0 2 4 6 8 to 12 O Topsoil 0 Loose to medium dense, brown a� Silty Sand with Gravel (SM); moist. o Fill W Broke/Repaired 2 Storm Drain Pipe OVery dense, gray to gray -brown, Z Silty Sand with Gravel, Cobbles, and Boulders (SM); moist; fine to 02 coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict. 4 Till 6 C� S-1 8 NOTES 1. 9 feet long and 4'-6" wide. 2. 6-inch diameter concrete storm drain encountered 3 feet below 10 "7 ground surface. Repaired with SDR 35 pipe and rubber coupling. D 12 R.., 22 r 229,_ 3',4 T Us r16-09- G 5 _^20_ 4 004 P FF r6wg Da,",_,, 09 C 016 LAU! !,tE.wnp =111SHANNON&WILSOTAL N.INC JOB NO: 21-1-22082-004 DATE: 7-28-16 LOCATION: Edmonds, WA GEOTEC-LOG OF TEST PIT TP-2F PROJECT: Madrona K-8 _0c a u Sketch of East Pit Side Surface Elevation: Approx. SOIL DESCRIPTION 0 o E Horizontal Distance in Feet (D o U o) 0 0 2 4 6 8 10 12 O Topsoil 0 Loose to medium dense, brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse 2 sand; nonplastic fines. Fill Very dense, gray to gray -brown, O Silty Sand with Gravel (SM); moist; diamict. 4 Till Cobbles present. c 0 Z S-1 6 O 8 NOTES 1. 9 Feet long and 4'-6" wide. 10 "n_ t7 D y 12 R: J s2 r 2298_ 3,4 T U-s s rIs-09- G 5 _^20_ 4 004 P FF r6wg Da,",_,, 09 C 016 LAU!s !,tE.wnp =111SHANNON&WILSOTAL N.INC JOB NO: 21-1-22082-004 DATE: 8-25-16 LOCATION: Edmonds, WA GEOTEC-LOG OF TEST PIT TP-3F PROJECT: Madrona K-8 _0c a u Sketch of South Pit Side Surface Elevation: Approx. SOIL DESCRIPTION 0 : cm o E Horizontal Distance in Feet (D o U o) 0 0 2 4 6 8 10 12 Loose to medium dense, brown, 1 J Poorly Graded Sand with Silt and --- 0 . Roofs Gravel (SP-SM); dry to moist, few roots. o O Fill W W S-1 2 02 Very dense, gray -brown; Silty Sand Z with Gravel (SM); moist; diamict. Till S-2 C2 4 6 8 NOTES 10 "n_ D 00 12 -111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-1 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 454 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant plant roots. 7.0 S-0 Topsoil to 2 Very dense, gray brown, Silty O Sand with Gravel (SM); moist. c Till z 4 6 8 10 -n_ D co 12 IAffim SHANNON & WILSON, INC. JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan =I11 MF Geotechnical and Environmental Consultants LOG OF TEST PIT TP-2 PROJECT: Madrona Elementary School, Edmonds, Washington U- Sketch of East Pit Side Surface Elevation: 451 Ft. SOIL DESCRIPTION 0 M (D —C= 0- E Horizontal Distance in Feet 0 can o 0 2 4 6 8 10 12 Loose, brown to gray brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant tree a) and plant roots. Topsoil a) 5.3 S-0 2 Medium dense to dense, brown, 0 Poorly Graded Sand with Silt and a) C: (_1 � Gravel (SP-SM); dry to moist. 0 Z Fill Very dense, gray brown, Silty 4 Sand with Gravel (SM); moist. Till 6 8 10 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-3 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of West Pit Side Surface Elevation: 445 Ft. SOIL DESCRIPTION o co M a) � � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant tree and plant roots. Topsoil 2 Medium dense to dense, brown, O Poorly Graded Sand with Silt and Gravel (SP-SM); dry to moist. z Fill Very dense, gray brown, Silty 4 �> Sand with Gravel (SM); moist. 9.7 S-0 Till 6 8 NOTE 1. Boulder encountered at 1.5 10 feet below ground surface. D N 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-4 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of East Pit Side Surface Elevation: 452 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant tree and plant roots. Topsoil 2 Dense, light brown, Silty Sand O with Gravel (SM); dry to moist. 0 4.0 S-0 3 Fill z Very dense, dark brown, Silty Sand with Gravel (SM); moist. 4 Till 6 8 10 D N N 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-5 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 454 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant plant roots. Topsoil 5.2 S-0 2 Very dense, gray brown, Silty O Sand with Gravel (SM); moist. c Till z 4 6 8 10 -n_ D N w 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-6 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of West Pit Side Surface Elevation: 450 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel 2 (SP); dry to moist; abundant tree and plant roots. Topsoil 2 Medium dense to dense, light Zn O 7.7 S-0 �g brown, Poorly Graded Sand with c Silt and Gravel (SP-SM); dry to z moist. Fill 4 Very dense, dark brown to brown, Silty Sand with Gravel (SM); moist. Till 6 8 10 'rI 17 D N 46 12 IAffim SHANNON & WILSON, INC. JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan =I11 MF Geotechnical and Environmental Consultants LOG OF TEST PIT TP-7 PROJECT: Madrona Elementary School, Edmonds, Washington Sketch of West Pit Side Surface Elevation: 445 Ft. SOIL DESCRIPTION 0 M a) —C= 0- E Horizontal Distance in Feet 0 can o 0 2 4 6 8 10 12 0 Cl) Loose, gray brown, Poorly Graded Sand (SP); trace gravel; dry to moist; abundant tree and plant roots. a) Topsoil a) 2 Medium dense to dense, brown, 0 Poorly Graded Sand with Silt a) C 7.7 S-0 and Gravel (SP-SM); trace 0 Z cobbles; moist. Fill 4 Very dense, brown, Silty Sand with Gravel (SM); trace cobbles; moist. Till 6 8 NOTE 1. Boulder encountered at 2 10 feet below the ground surface. au cri 1 1 121 -111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-8 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of East Pit Side Surface Elevation: 452 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to 5.2 S-0 moist; abundant tree and plant roots. Topsoil 2 Very dense, gray brown, Silty O Sand with Gravel (SM); moist. c Till z 4 6 8 10 D N ca 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-9 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 454 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel 5.5 S-0 O (SP); dry to moist; abundant plant roots. Topsoil 2 OVery dense, gray brown, Silty O Sand with Gravel (SM); moist. Till z 4 6 8 10 -n_ D N V 12 -111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-10 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 446 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel 2 O (SP); dry to moist; abundant tree and plant roots. Topsoil 10.8 S-0 2 Medium dense to dense, brown, O Poorly Graded Sand with Silt and Gravel (SP-SM); dry to moist. z Fill Very dense, gray brown, Silty 4 Sand with Gravel (SM); abundant cobbles; moist. Till 6 8 10 -n_ D N 00 12 -111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-11 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of East Pit Side Surface Elevation: 452 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant tree and plant roots. 5.0 S-0 Topsoil 2 Very dense, gray brown, Silty Zn O Sand with Gravel (SM); moist. c Till z 4 6 8 10 -n_ D N co 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-12 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of West Pit Side Surface Elevation: 446 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel (SP); dry to moist; abundant tree and plant roots. \ Topsoil 2 Medium dense to dense, brown, O 6.1 S-0 Poorly Graded Sand with Silt and o Gravel (SP-SM); dry to moist. z Fill Very dense, gray brown, Silty 4 Sand with Gravel (SM); moist. Till 6 8 10 D w 0 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-13 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 454 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 1 ('1J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to 5.4 S-0 moist; abundant plant roots. Topsoil 2 Very dense, gray brown, Silty O Sand with Gravel (SM); moist. c Till z 4 6 8 10 -n_ D w 12 IAffim SHANNON & WILSON, INC. JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan =I11 MF Geotechnical and Environmental Consultants LOG OF TEST PIT TP-14 PROJECT: Madrona Elementary School, Edmonds, Washington Sketch of North Pit Side Surface Elevation: 448 Ft. SOIL DESCRIPTION 0 M a) —C= 0- E Horizontal Distance in Feet 0 can o 0 2 4 6 8 10 12 0 1 (1) Loose, gray brown, Poorly Graded Sand (SP); trace gravel,- dry to moist; abundant plant roots. Topsoil a) a 16.8 S-0 2 Medium dense to dense, brown, 0 Poorly Graded Sand with Silt and 21) Gravel (SP); trace cobbles; moist. Zo Fill Very dense, dark brown, Silty 4 Sand with Gravel (SM); trace cobbles; dry to moist. Till 6 8 10 tV 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-15 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 454 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown, Poorly Graded Sand with Gravel (SP); dry to 6.5 S-0 moist; abundant plant roots. Topsoil 2 Very dense, gray brown, Silty O Sand with Gravel (SM); moist. c Till z 4 6 8 10 -n_ D w w 12 �111 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants LOG OF TEST PIT TP-16 JOB NO: 21-1-22082-001 DATE: 6-24-2015 LOCATION: See Site and Exploration Plan PROJECT: Madrona Elementary School, Edmonds, Washington u Sketch of North Pit Side Surface Elevation: 448 Ft. SOIL DESCRIPTION o co M a) � a- E Q Horizontal Distance in Feet O o U co 0 0 2 4 6 8 10 12 0 �11 J Loose, brown to gray brown, Poorly Graded Sand with Gravel 2 O (SP); dry to moist; abundant tree and plant roots. Topsoil 5.2 S-0 2 Medium dense to dense, brown, O Silty Sand with Gravel (SM); dry 3 to moist. o z Fill Very dense, gray brown, Silty 4 Sand with Gravel (SM); abundant cobbles; moist. Till 6 8 10 'rI 17 D w 4h 12 21-1-22082-004 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project BORING B-3 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV �a ti �ro o 0 0 0 00 00 0° oa o' o� o oo� o00 00° ooM oory Q M O' O' O' O' O' O' 100 0 95 5 90 ......... .... ...... ........... ......... .. .......... .... ....... ........ ... ........ .. ......... ............10 85 .... .... ..... ... .... , ...... ._ 15 80, ... .. .... ...... ......... .... ... ........... ....... ....................... ...... ......... ....,.... ........ ., ..,,,,,,,,. ..20 75 ..... �� . ... .. ..... ... -_ . ... -25 65 ... .... ... ... ,. ... .. , .... " "" 35 co 60 _ .. -. N ' 40 CD Z3 55 . ... ... ... ... .... .... ... - ..48 n = 80 .. ........ ......... .. ..... ...... ..... ........ ... ..,...... _. .,, 50 N IL N G 45 �� . ... .. ... ... ... " "" 55 (D 40 .......... ...... .. .. ....., .. .. ............................... ............ . .................. . . ... . , .. ------ .. ......... .... 60 � N 35 . _ ...._. . _._65 N 25 _.. 75 20 ......... ..... ..... ............ . .. ._ ,. .. ..... ........ .......... .......... ... ...... , <......., . ... ... 80 15 10 ..... ... ..... ... """""""" ." 90 5 _.. 95 0100 ry o 0 0 0 o ro <o h a M N �° �` M ry p v co a M ry O Q, O O O O y ¢i O^ o a M ry ro o a ry 0 0 ^0• o o 11 o Z) o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. B-3, S-3' 7.5 SM Silty Sand 11 55 34 8.7 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project BORING B-4 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters �b ti �ro o 0 0 0 00 00 0° oa o' o� o oo' o00 00° ooM oory Q ^� ti M M P ti b ro �. O' O' O' O' O' O' O' O' O' O' O' 100 0 95 5 90 ......... ........... ...... .. ................ ..................... ................. . . ........ ... ........ .......................... ......... ............10 85 ..._. ......... ..... ... .... , ...... ._ 15 80 ........ ......... ................. ......... ....... ......... ....... .........-- .. ...... ......... ....,.... ........ . , .,,,,,,,,,. ..20 75 ._ .... ......... _,25 70, ...... ........ .......... ......... ........... .... ......... ......... ....... .. '. .... ,,,,,,,,,,,,,,,,,,,,, ... ........... -" 30 65 ,...... ..... ..... ... .. ........ "" 35 to..... co 60 ........ ._.... ..... -.. (p 40 2 CD 55 . ... ... .... ... ... .... ... - ..48 n c80, .. ........ ....... .. ........... ............ ... ............... .. .... ... ...... ..... ........ ... ......... ........ ..,....... ....... .. _. .,, 50 N IL N G 45 ... ... �� ..... ... N40 .......... ...... .. .. ....., .. ..... ............................. .................... .......... ... ......... .. ........--- .. ......... .... 60 � 25 _.. 75 20 ......... ..... ..... ........... . .. .. ................ ... ... ...... ........ ......... ......... ... ...... , <......., . ... ... 80 15 ..... ..... ......... ._ .. ..._ ..... ..... _ 85 10 .. .... -. ... .. _ 90 5 .. _.. 95 0 N O O O O O N <p h b ^b R. o b M ry ^ a 1 0 0 o 0 b M N 0 0 0 0 0'` o b 0 0 0 o Oo Oo Oo Oo 0o Oo 100 ^o• o� o� � o• o' o� o� o Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (ft) Symbol Group Name % % % % % % By By Std. 0 B-4, S-2' 5.0 SM Silty Sand 8 64 29 15 4 10.2 AKV JFL D422 rn ■ B-4, S-4' 10.0 SM Silty Sand 10 50 40 9.7 AKV JFL C136 Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project BORING B-5 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV �b ti �ro o 0 0 0 00 00 0° oa o' o� o oo� o00 00° ooM oory Q ^� qvM M O' O' O' O' O' 100 0 90 ........ .... .. ........... ......... .. .......... .... ....... ........ ... ........ .. ......... .......... .. 10 85 .. ..... .... .... ..... ... .... , ...... ._ 15 80 ,....... .. ..... ...... ..... .. ....... ....................... ...... ....................... ........ , ., ..,,,,,,,,. ,20 75 .-. .-. ... -_ . ... -25 70, ........ , ....... ...... ............ ........... .......... ....... .. '. .... ,,,,,,,,,,,,,,,,,,,,, ... ........... -. 30 65 ... ... .. ... ,. ... .. , .... " "" 35 co 60 _ .. -. N ' 40 CD Z3 55 . ... ... ... ._ .... .... ... - ..48 n = 80, .. ........ ......... .... .. .. .. ..... ...... ..... ........ ... ..,...... _. .,, 50 N IL N G 45 �� ... �. ... ... ... ... """55 (D 40 .......... ...... .. .. ....., .. .. ......... ........... .. ........--- .. ......... .... 60 � 35 . ..... ..... _ . _ . . _ _ 65 N 25 _.. 75 20 ......... ..... ..... ........... . .. .. ................ ... .. ..... ...... ...,....... ,... ..... ... ...... , <......., . ... ... 80 15 ..... ..._ ...... ..... ......... .... .._ .-. •... .... ..... ....... ..... ..... ........ -85 10, 5 - - 95 p N O O O O O N <p h b ^b R. 1 0 0 o b M ry ^ a o 0 b M N 0 0 0 0 0'` o N 0 0 0 o Oo Oo Oo Oo 0o Oo 100 ^o• o o o o Z) o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. 0 B-5, S-3' 7.5 SM Silty Sand 14 54 32 22 8 15.0 AKV JFL D422 rn ■ B-5, S-6' 15.0 SM Silty Sand with Gravel 15 52 33 10.0 AKV JFL C136 Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project BORING B-11 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV �a ti �ro o 0 0 0 00 00 0° oa o' o� o oo� o00 00° ooM oory Q M O' O' O' 100 0 90 ......... .... .... ........... ......... .. .......... .... ....... ........ ... ........ .. ......... ............10 85 -. ... --15 80,,...... ..... ..... ......... .,,,., ....... ....................... ...... ......... ......... ........ ., .......... ..20 75 ...... ......... _ , 25 70 ....... ..... .. ............ ............ .. ............ .. „ ......... ....... .. '. .... ,,,,,,,,,,,,,,,,,,,,, ... .. . -" 30 ... 35 U co 60- ......... ... ��, ... -.. N '40 CD 55 .... ... .... ... ... .... ... -..48 IL N G 45 • .... .... .... ... ... N U `G N40 ......... .. ... ...... ........................ ......... ... ..... ..... .............. .. ......... .... 60 N ....... ......... . .. ........ ........ ...._ ........................ .. e. .:.... ......... .. ......... .... 25 ...... _.. 75 20 .... ..... ..... ..... .......... ..........., .. .. ................ ... .. ..... .... ,.... "... ....... .. ......... ... ......, <.......,. ... . .. 80 15 ..... ...._ ...... ..... ......... .... .... ..._ ...... ....... ..... 10 .. .... -. ._. ..... .. 90 ry o 0 0 0 o ro <o h a M N �° �` M ry p v co a M ry O Q, O O O O y 11 ". o a M ry ro o a ry 0 0 0 o O- O- o- o- * 100 ^0• o o o o Z)o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. B-11, S-11' 5.0 SM Silty Sand 13 53 34 8.1 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project TEST PIT PITA Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV M� \11,MO W ro ' ' '. O O O O O O O O� 100 0 90 85,„ ..... . .A�S�.. ........... ......... .. ......... .... ....... ........ ... ......... .. ......... .......... ... --15 .. 10 80„ ........ ..... ..... ...... ..., ........................... ....... ....................... ...... ....................... ........ . , ..,,,,,,,, 75 ....... .... ..._ ......... 25 65 .... .. .. ..... ...... .. ........ "" 35 co 60 ........ ... -.. N ' 40 CD Z3 55 . ... ... ... ... .... ... -..48 . ` p IL N G 45 ��............�. ... .. ... ... 55 (D 40 .......... ...... .. .. ....., .. ........... ....................... ...... ..,,,,,,. .. ------ .. ......... .... 60 � 35 . .._ . ... _ . _. . _'65 N 25 75 20 ......... ..... ..... ........... . .. .. ................ ... ... .... ...... ........ ,.... .......... .......... ... ...... , <......... ... ... 80 15 ..... ..._ ...... .. ..... ......... ..._ ........ ----. ......_. tl.. .... ...._ ...... ....... _ . ..... ........ -85 10 .. .... -. ........ .. _ 90 5 _.. 95 0 ry o 0 0 0 o ro 1. h a M N 1 v <o a M ry �° �` M ry p O O O O O O y ¢i O^ o a M ry ro o a ry 0 0 0 0 100 ^0• o o o o Z)o• o' Grain Size (mm) Sample Depth USCSp USCS Cobbles Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % % By By Std. PIT-1, S-1' 3.0 SM Silty Sand with Gravel 15 56 29 5.7 AKV JFL C136 rn ■ PIT-1, S-6' 7.0 SM Silty Sand with Gravel and Cobbles 13 28 51 21 13.9 AKV JFL C136 Test specimen did not meet minimum mass recommendations. 2 Cobble percentages are calculated using the pre -removal, oven -dried mass of the total specimen. USCS Group Symbol, Soil Classification Group Name, Gravel %, Sand %, Fines %, <0.02mm %, <2um%, Cu, and Cc values are calculated from particles smaller than 76.2mm (3 inches) only, per ASTM D248T Z a x a N O O N N N Z < U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project TEST PIT PIT-2 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV �a ti �ro o 0 0 0 00 00 0° oa o' o� o oo� o00 00° ooM oory Q M O' O' O' O' O' O' O' 100 0 90 ........ ....... ........ .. ........... ......... .. .......... .... ....... ........ ... ........ .. ......... .......... .. 10 85 ,...... .... .... ..... ... ...., ...... ._.15 80 .. .... ........... , ........... ........... ....... ....................... ...... ......... ......... ........ . , .......... ..20 75 ....... ..... ......... _ , 25 70 ........... .... ..... .... ............ ............ ,,,,,,,,,,,,,,,,, ......... .......... ....... .. '. .... ,,,,,,,,,,,,,,,,,,,,, ... .. . -" 30 65 �.. .. ... ... ,. ... .. , .... " "" 35 co 60 ' 40 2 CD 55 . ... ... .... ... ... .... ... - ..48 = 80 ........ ....... .. ........... ............ ... ............... .. .. ..... ....... ..... ........ ... ......... ........ ..,....... ....... .. _. ..50 � IL N G 45 �� . ... .... .. .. ... ... " "" 55 (D 40 , .. ... ...... .. .. ...., .. ..... ............................. ................ ............... .... . ..... .............. ......... .... 60 � d y 35 . ... _ ...._. . .. _._65 N 25 _.. 75 20 .... ..... ..... ..... ............ .. .. ................ ... .. ..... .... ,.... "... ....... .. ......... ... ......, <.......,. ... . .. 80 15 ..... ..._ ...... ..... ......... .... .... ..._ ...... ....... ..... 10 .. .... -. ._. ..... .. _ 90 5 _.. 95 0 ry o 0 0 0 o ro <o h a M N �° �` M ry p 1 v co a M ry O O O O O O y 11 O^ o a M ry ro o a ry 0 0 0 0 100 ^0• o? o o o Z)o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. PIT-2, S-2' 3.5 SM Silty Sand 12 55 33 8.7 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project TEST PIT PIT-3 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV \\O O O O O 00 W ro D M 00 00 Ob O� Ory O 00 00 00 00 00 Q qvM M O' O' O' O' 100 0 90 ..... .... ......... ........... ......... .. .......... .... ....... ........ ... ........ .. ......... .......... .. 10 85 -... ..... ..... .... .... ..... ... ...., ...... ._.15 80„ ,...... .... .,...... ........... ........... ............................... ....... ....................... ...... ......... ........ ........ . , ..,,,,,,,, 75 ..._ ......... _,25 65 .. .. .... ........ .. ........ "" 35 co 60 ' 40 0 Z3 55 . ... ... ... ... ... .... ... - ..48 n = 80, .. ........ ........ .......... ......... ........ ........ ... ... ..... .... ....... ..... ........ ....... .......... ........ ... ..,...... _. .,, 50 N IL N G 45 �� . ... .. ... .. ... ... " "" 55 N40 .......... ...... .. .. ....., .. ........... .. ,,,,,,.,,, ............ ........................ ........--- .. ......... .... 60 � 35 . ..... .... ..... _ . _ . . _ _ 65 (n 30 .. ... ........ .. _,. 70 25 _.. 75 20 ......... ..... ..... ............ . .. ... .......... ......... ........... ....... ...... ....;. .......... ......... ... ...... , <......., . ... ... 80 15 ..... .... .._ ............................... ..._ ..... ..... _ 85 10 .. ... ......... -- ... ..... .. _ 90 5 _.. 95 0 _ N O O O O O N <o h b ^b o b M ry ^ a R. 10 0 o 0 b M N 0 0 0 0 0 <o 0'` o b M 0 0 0 o Oo Oo Oo Oo 0o Oo 100 ^o• o o o o Z) o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (ft) Symbol Group Name % % % % % % By By Std. PIT-3, S-2' 3.0 SM Silty Sand with Gravel 26 47 27 5.9 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project TEST PIT TP-1 F Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters XV �a ti �ro o 0 0 0 00 00 0° oa o' o� o oo� o00 00° ooM oory Q M O' O' O' O' O' 100 0 90 ......... .......... .... ........... ......... .. .......... .... ....... ........ ... ........ .. ......... .......... .. 10 85 .... ..... .... .... ..... ... .... , ...... ._ 15 80 ...... ... ... ...... ................ ....... ....................... ...... ......... ......... ........ . , .......... ..20 75 ... . . .... ... .... ... -_ . ... -25 70, ........ .... ......... ............ ........... .. ,. ......... ....... .. '. .... ,,,,,,,,,,,,,,,,,,,,, ... ........... -" 30 65 ,...... .. .... .... .. .. ........ "" 35 to.. co 60 .._ ... -.._ ... -.. fD -40 2 CD 55 . ... ... .... ... .... .... ... - ..48 IL N G 45 �� . .. .. ... ... ... ... " "" 55 N40 .. ... ...... .. .. ...., .. .. .. ........................ ...... .. ........--- ......... .... 60 � d y 35 . .. _ ...._. . .. _._65 (n 25 _.. 75 20 ......... ..... ..... ............ . .. ._ ,. .. ..... ........ .......... .......... ... ...... , <......., . ... ... 80 15 .. .. _ . ........ -85 10 ..... ... ..... ... """""""" ." 90 5 _.. 95 0100 ry o 0 0 0 o ro <o h a M N �° �` M ry p v co a O Q, O O O O O^ o M ry ro o a ry 0 0 ^0• o o o o Z) o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. DTP-1F,S-1' 7.0 SM Silty Sand 13 55 31 7.5 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 .111 SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Preliminary Hydrogeologic Report New Madrona K-8 Project TEST PIT TP-2F Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters ^ M� \11,MO 0 W ro D M � O O O O O O O O ^� 0� ^O ry0 p0 00 O� O� O� 100 0 90 .... .... ,. ......... ........... ......... .. .......... .... ....... ........ ... ........ .. ......... .......... .. 10 85 ..... ..... .... .... ..... ... .... , ...... ._ 15 80 ...... ..... .... ... ..... ........... ........... ............................... ....... ....................... ...... ......... ........ ........ . , ..,,,,,,,, 75 ...... ..._ ......... _,25 65 .. ... .. ... ,. ... .. , .... " "" 35 to 0 60 .. .._. -. fD 40 2 CD CD 55 .... ... .. .... .... ... -.. 45 c80 .. ........ ... ..... .... ............ ......... .......... .... ............. ..... ...... ..... ........ ... ......... ........ ..,....... .... _. .,, 50 N IL N 45 .. ... ... ... ... ... " ""55 N40, ......... ... ...... ........... ............ ..... .... ...... .......... .. ........--- .. ......... .... 60 � ....... ......... . .. ........ ........ ......... ......... .._ .......... .. .,... ......... .. ......... .... 20 .... ..... ..... ..... .......... ..........., .. .. ......... ......... .......... .... ............ ....... .. .......... ... ......, <.......,. ... . .. 80 15 ..... ...._ ...... ......._ ....................... ----. _ .... :_ .... ...._ ...... ....... _ . ..... ........ -85 10 .. _ -. .... ........ .. _ 90 0 _ N O O O O O N <o h b ^b o b M ry ^ a R. 10 0 o 0 b M N 0 0 0 0 o 0 0 0 o Oo Oo Oo Oo 0o Oo 100 ^o• o o o o Z) o• o' Grain Size (mm) Sample Depth USCS Group USCS Gravel Sand Fines < 20pm < 2pm WC Tested Review ASTM Identification (11) Symbol Group Name % % % % % % By By Std. TP-2F, S-1' 6.0 SM Silty Sand with Gravel 29 58 13 7.3 AKV JFL C136 N Test specimen did not meet minimum mass recommendations. 0 ca >J_ Z a N O O N N N Z <1 U) M O O N O O N N N SHANNON & WILSON, INC. - 400 NORTH 34TH STREET - SUITE 100 - SEATTLE, WASHINGTON - 98103 - MAIN (206) 632-8020 - FAX (206) 695-6777 ANALYTICAL LABORATORY TEST RESULTS 21-1-22082-004 EN wk,51-hs 26276 Twelve Trees Lane, Suite C - Poulsbo,WA98370 ® (360)779-5141 - Fax (360)779-5150 I � M M. . = � "r Inv —r;—. , Pit Seattle, WA 98125 1 1 74 11�11 jlll Sample Date: 7/29/16 pH 1:2 soil to wt Phosphonis &W PPFn Potassium NH40Ac ppm Calcium NH4OAc nieqt100 g KAagneSiUM NH4OAc nW100 g Sodium NH4QAc nW1 00 g SMP Buffer Index* Organic KAafter 1-01 Nitrate -Nitrogen Ka pprn Sol Saft 1:2 soil iAoter dS/m Soil Fertility Levels ................ 4 PH Phosphorus (P) Potassium (K) Calcium Magnesium Neutral High Low Low Medium Low Salinity Negligible a www.spectra-lab.com W1 PAPLACUMdRed 2014 b=- ram= illag go P SPECTRA Laboratories-- Kitsap ...Where experience matters 26276 Twelve Trees Lane, Suite C - Poulsbo,WA98370 - (360)779-5141 - Fax (360)779-5150 - wwwspectra-lab.com i ► Sample F. 7129/16 PH 1.2 soil to M Phosphorus Bray pprn Potassium NH4GAc ppTr, Calcium NH4QAc nvW100 g Magnesium NH4OAc mecVl 00 g Sodium NF14QAc rraW100 g SMP Buffer Index* Organic Matter Lol % by w� Nitrate -Nitrogen Ka pprr Sul, saii 1:2 scirwater 6ij . ar 11 NA- Not analyzed 11-111 44,11, J I "I'll, --- . "I'll I'll, i . 0r .► 291T, 9X- e LDW Medium High Sofl Ferfifity Levels 9 Uff I Y -* 42 1 Xd L40d& k-M PH Moderately Acid 5.2-6.0 Phosphorus (P) Medium 2040 ppm Potassium (K) Low <150 ppm Calcium Low <5 meq/1 OOg Magnesium Low <0.5 meq/100g Nitrate -Nitrogen Low <10 ppm EC (Sol Salts) Salinity Negligible <0.4 dS/m W 'aot E SPECTRA Laboratories - Kits ...Where experience inarters 26276Twelve beesLane,Suite C a Poulsbo,WA98370 @ (360)779-5141 * Fax(360)779-5150 - www.specLra-lab.com. Project: Madrona K-8 Lab Work Order #: 161057 Sample Date: 7/29/16 Sample Received: 8/1/16 Recommendation: SF 1: The pH of this area is best suited for turf, vegetable gardens and bedding plants (>6.0). The use of sulfatearti-f-iTti futili7f,-r-, I r, * - il - * �W 1�i� # sir I ��� - 4-11 wo 074-4,6JI-01lik to our native plants, orlde pA can tie adjusted downward by broadcasting 2 lbs of finely ground elemental sulfur or 6 lbs of iron sulfate per 1000 sq ft, soil for every 1/2to I pH unit decrease desired. Repeat this application every 3 months until the desired amount of sulfur has been added. (Iron sulfate works faster.) A pH requirement sheet has been included to help you decide if the pH needs to be adjusted to meet yourneeds. The calcium and magnesium levels are low, but in an acceptable ratio to one another. Increase both by incorporating 50 lbs of gypsum and 20 lbs of Epsom salts per 1000 sq ft of soil. The macromitrient levels of nitrogen, phosphorus and potassium are all low. Incorporate a complete fertilizer such as 10 lbs of 10-20-20 plus 12 lbs of 0-0-60 per 1000 sq ft. The goal should be approximately 1 lbs of actual nitrogen, 2 lbs Of P205 and 9 lbs of K20 per 1000 sq ft. SF 2: The pH of this soil is closer to that needed for native plants, but still acceptable for turf. The pH can be lowered further as stated above for natives. The buffer pH indicates that timing is not needed, but the calcium and magnesium levels are low. Increase as stated above. The macronutrient levels are low. Incorporate a complete fertilizer such as 10 lbs of 10-20-20 plus 7 lbs of 0-0-60 per 1000 sq ft. The goal should be approximately I lbs of actual nitrogen, 2 lbs Of P205 and 6 lbs of K,20 per 1000 sq Both areas: The soluble salts. and sodium content are low indicating that excess salts have not built up to a level that will harm plants. The organic matter is low in SF- I and borderline in SF-2. Adding 2-4 inches of compost or other top -dressing will be of benefit. More nitrogen may need to be added periodically during the growing season (April, July and late October -November) at the rate of one lb actual nitrogen per 1000 sq ft of soil (for example, 5 lbs of 21 -0-0) if a rapid growth is desired. The reuse of grass iCund, s-Lixoduced fmm a mubkfu Ift take the place of one of the nitrogen applications for turf during the growing season or a good grade of compost or manure can be substituted for one of the fertilizer applications. Spread 1/4 inch deep over the soil, compost will supply nutrients and increase the organic matter content of any soil, which in turn will boost nutrient and water -holding capacity. For turf maintenance, Washington State University studies have shown that grass uses N:P:K in the ratio of 3:1:2 and it is helpful to use a fertilizer with that ratio of N:P:K in future applications. For ongoing maintenance of woody ornamentals, once a year in the spring they can be fertilized lightly (5 lbs per 1000 sq ft) with a complete fertilizer such as 10-20-20. Thank you for the opportunity to help you prepare healthy landscape. Nancy Parrott Laboratory Supervisor WDOE Accreditation #C594 This report is issued solely for the person or company to whom it is addressed. This laboratory accepts responsibility only for the due performance of analysis according to industry accepted practice. Spectra Laboratones - KitsaD or its enmlovees 9.re -rot reanif 4x 4 -Fir Isik -f -rm- 0 SPECTRA Laboratories — Kitsap, LL 26276 Twelve Trees Lane, Suite C Poulsbo, WA 9337 (360) 77 -5141 FAX (60) 7 9- 150 www,Wsslabs.com Wa a� a -to � i o o cif. ¢ #ix a I 3F to g g_ss� y RrOje�i anagerlRepori T` < ) € M U) ! fCif �Ct m C3 C7 ante 4 Telephone - d� Earl ECL a* �' CO l� Z a Lab ID a eAJ f I F� g=, tea, �- rt rl S 6 s 10 11 12 0 Routine Disposal 0 Hazardous sample disposal Special Instructions ❑ Return to Client (Coat or disposal VWII be billed to client) TOtal of �rltairrers ,,�° gh ' r.a CtC Bela eeaeat? irtta�t? Relinquished by: Cent an t 1 a !7 p Y Dale . r * Time _. Tertt at re i ? l� (PH ►d (Signal gam les irtta�t? Received by: LAVJ Received Via Company r Date Time (prin) (Signature) T. ui tandard (10 Business days) Relinquished by: Company Date Time 13 Rush (specify date needed) (print) (Signature) Ft, ther (specify) Received by: Company Date Time �t of c v *,Yg,, ruay apply (Prino (Signature) — Samples ceived after 12 noon will be considered as reddtudd the following Wetness day SATernplateASample Manager enfiSPECTRA Cf1C 092515 Rev. 1.1 11104114 Page of • 1 1 IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL/ENVIRONMENTAL REPORT 21-1-22082-004 SHANNON & WILSON, INC. Attachment to and part of Report 21-1-22082-004 Geotechnical and Environmental Consultants Date: October 31, 2016 To: Ms. Taine Wilton Edmonds School District #15 IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL/ENVIRONMENTAL REPORT CONSULTING SERVICES ARE PERFORMED FOR SPECIFIC PURPOSES AND FOR SPECIFIC CLIENTS. Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant. THE CONSULTANT'S REPORT IS BASED ON PROJECT -SPECIFIC FACTORS. A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set of project -specific factors. Depending on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope -of -service limitations imposed by the client. To help avoid costly problems, ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used: (1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors which were considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts; for example, groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events, and should be consulted to determine if additional tests are necessary. f ll [��' l i 7 �rZ�7 i�� 1 ��� I � ►17_� � [il �"�_I7 �;1:%7. � �'? E;'� [�1 i [LR�11LIr] �r� I � � � �� Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your consultant can work together to help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be particularly beneficial in this respect. Page 1 of 2 1/2016 A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your consultant's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another party is retained to observe construction. THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work with other project design professionals to explain relevant geotechnical, geological, hydrogeological, and environmental findings, and to review the adequacy of their plans and specifications relative to these issues. BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT. Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final boring logs and data are customarily included in geotechnical/environmental reports. These final logs should not, under any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you, you should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared, and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale. ZAPt;�l3I>AkVLqW-[1M� *X6-TA:WA Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in their contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant's liabilities to other parties; rather, they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms Practicing in the Geosciences, Silver Spring, Maryland Page 2 of 2 1/2016 HVdnJgeOlOgiCRepO[t By: Shannon & Wilson, Inc. Date: November 29, 2016 MadmnaSchoo —EdmondsScboo District Excellence. Innovation. Service. Value.. Hydrogeologic Report New Madrona K-8 Project 9300 236t' Street SW Edmonds, Washington November 29, 2016 Submitted To: Ms. Taine Wilton Edmonds School District #15 20420 681h Avenue West Lynnwood, Washington 98036 By: Shannon & Wilson, Inc. 400 N 34th Street, Suite 100 Seattle, Washington 98103 21-1-22082-003 n TABLE OF CONTENTS Page 1.0 INTRODUCTION.................................................................................................................. I 2.0 SITE DESCRIPTION............................................................................................................2 2.1 Site Topography.........................................................................................................2 2.2 Site Drainage and Wetlands.......................................................................................2 3.0 GEOLOGIC CONDITIONS..................................................................................................2 3.1 Regional Geology and Hydrology..............................................................................2 3.2 Local Geology and Hydrogeology.............................................................................4 4.0 SUBSURFACE EXPLORATION AND TESTING..............................................................6 4.1 Drilling and Testing Program.....................................................................................6 4.2 Findings......................................................................................................................7 4.2.1 Observed Geologic Conditions....................................................................7 4.2.2 Groundwater Levels and Monitoring...........................................................8 4.2.3 Aquifer Hydraulic Properties.......................................................................9 4.2.4 Groundwater Quality.................................................................................10 4.2.5 Pilot -scale Injection Well Testing..............................................................10 4.2.6 Full-scale Injection Well Testing...............................................................10 5.0 GROUNDWATER MODELING OF PLANNED INJECTION WELLFIELD..................11 5.1 Overview..................................................................................................................11 5.2 Conceptual Site Model(CSM).................................................................................11 5.3 Model Development and Calibration.......................................................................12 5.4 Model Simulation (Base Case).................................................................................12 5.5 Sensitivity Analysis..................................................................................................13 6.0 STORMWATER QUALITY DISCUSSION.......................................................................13 7.0 CONCLUSIONS AND RECOMMENDATIONS...............................................................14 7.1 Injection Well Recommendations............................................................................14 7.1.1 General.......................................................................................................14 7.1.2 Well Design Recommendations.................................................................15 7.1.3 Injection Well Materials............................................................................17 7.2 Additional Recommendations..................................................................................19 8.0 LIMITATIONS....................................................................................................................20 9.0 REFERENCES.....................................................................................................................22 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 i n TABLE OF CONTENTS (cont.) 1 2 3 4 5 6 7 8 9 10 FIGURES Vicinity Map Site and Exploration Plan Surficial Geologic Map Deer Creek Water Supply Protection Area Map Generalized Subsurface Profile A -A' Generalized Subsurface Profile B-B' Inflow Test Results at Pilot UIC Well IW-1 Inflow Test Results at UIC Well IW-2 Conceptual UIC Well Design Proposed UIC Well Array Map APPENDICES Subsurface Explorations Geotechnical Laboratory Testing Hydrogeologic Data and Analyses Groundwater Modeling Important Information About Your Geotechnical/Environmental Report 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 11 SHANNON &WILSON, INQ HYDROGEOLOGIC REPORT NEW MADRONA K-8 PROJECT 9300 236`" STREET SW EDMONDS, WASHINGTON 1.0 INTRODUCTION The Edmonds School District No. 15 (the District) contracted Shannon & Wilson, Inc. (Shannon & Wilson) to conduct a preliminary hydrogeologic analysis for the new Madrona K-8 Project (the project), located in Edmonds, Washington (Figure 1). The project is located within the NE 1/4 of the SE 1/4 of Section 36, Township 27 N, Range 4 E, Willamette Meridian, at 9300-236t" Street SW (Snohomish County tax parcel 27033600404600). The District plans to construct the new Madrona K-8 School on the east portion of the approximately 40-acre property. New stormwater management facilities will be required for approximately 13 acres of the site. The purpose of this study was to evaluate the feasibility of using dry wells (or underground injection control [UIC] wells) for project stormwater flow control. Our scope of services, presented in our proposals to the District dated March 16, 2016, August 15, 2016, and September 27, 2016, included: ■ Observation well drilling, installation, and development at two location (designated OW-1 and OW-2); ■ Observation well sampling and field hydraulic conductivity (slug) testing (well OW-1); ■ Observation well groundwater level monitoring (wells OW-1 and OW-2); ■ Pilot and full-scale UIC well drilling, installation, and inflow testing (designated as UIC wells IW-1 and IW-2, respectively); ■ Laboratory testing of selected soil samples for grain size analysis and moisture content; ■ Groundwater modeling to evaluate the proposed UIC well spacing and layout, groundwater mounding, and seepage potential for the nearby ravine slope; ■ Meetings with the District; and ■ Preparation of this report, which includes the results of our subsurface explorations, field and laboratory testing, and hydrogeologic analyses. Our scope of services was authorized by the District's Purchase Order No. 2001500281, dated March 25, 2016; Purchase Order No. 2001500440, dated August 23, 2016; and Purchase Order No. 2001600097, dated October 12, 2016. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 SHANNON &WILSON, INQ 2.0 SITE DESCRIPTION 2.1 Site Topography The approximately 40-acre property includes two steeply sloped wooded areas aligned north to south; one is a ravine located along the eastern property boundary, and the other is a forested incline located near the middle of the property (Figure 2). The existing Madrona Elementary School is located in the northeast corner of the property, and the former Woodway Elementary School is located in the opposite southwest corner of the property. We understand that the planned new construction will occupy the east half of the property, where the existing grade elevation is currently approximately 445 to 455 feet. The project's elevation datum is referenced to the North American Vertical Datum of 1988 (NAVD88). In addition to school buildings and parking lots, the property currently includes a running track, a baseball field, and soccer fields. The areas surrounding the property consist primarily of residential developments. 2.2 Site Drainage and Wetlands A series of catch basin grates exist along the inside of the track. The project survey performed by Penhallegon Associates Consulting Engineers, Inc. (PACE) shows that these storm drains, along with storm drainage from the existing Madrona Elementary School, discharge to the top of the steep wooded slope in the middle of the property. The survey also identified storm drain discharges to the top of the wooded ravine located on the eastern property boundary. As indicated in Figure 2, three wetland areas were identified in our recent Wetland and Stream Delineation Report (Shannon & Wilson, 2016a). Wetlands A and C are on the wooded slope in the middle of the property and are downgradient from the track storm drain discharges. Seepage emerges within these wetlands, which were delineated between about elevations 410 and 398 feet on this slope. We concluded in our wetland report that these wetlands are supported predominantly by groundwater seeps. Wetland B, which is within the wooded ravine located on the eastern property boundary, is located downgradient of the storm drain outlets associated with the existing Madrona Elementary School and the play fields. We concluded that Wetland B is likely supported by surface flow from the surrounding ravine, the storm drain inputs from the school, and a seasonally high groundwater table. 3.0 GEOLOGIC CONDITIONS 3.1 Regional Geology and Hydrology The project site is located in the Puget Lowland, an elongated topographic and structural depression filled with a sequence of glacial and nonglacial sediments that unconformably overlie 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 2 SHANNON &WILSON, INQ bedrock. The area has been glaciated seven or more times in the past 2.4 million years. During the last glacial advance, known as the Vashon stade, the ice was greater than 3,000 feet thick in the project area. The Vashon ice sheet receded from the area about 16,500 years ago, leaving topography characterized by low -rolling relief about 500 feet above sea level, with some deeply cut ravines and broad valleys. Since then, present-day geologic processes, such as erosion and deposition by streams, landslides, and human activities, have modified the ground surface. The primary geologic units of significance for the project in the area are summarized as follows: Vashon Ablation Till (Qvat). Ablation till soils were deposited by one of several depositional processes that take place along the margins of glacial ice and have variable characteristics. Qvat is commonly composed of stratified or irregular bodies, including a heterogeneous mixture of loose to dense gravel, sand, silt, and clay. Qvat may contain scattered cobbles and boulders. Qvat is commonly reworked or modified through sediment slumping or stream action after initial deposition. Seasonally perched groundwater is common near the base of this unit. Vashon Lodgement Till (Qvt). Vashon lodgement till soils were deposited at the base of an advancing glacial ice sheet and were subsequently overridden by the ice. Qvt is typically a nonsorted diamict consisting of very dense, silty sand with gravel and silty gravel with sand; fines are typically nonplastic to low -plasticity. Qvt has a consistency and strength similar to very soft rock. Qvt may contain interbeds, dikes, and lenses of cohesionless silt, sand, and gravel, as well as cohesive clay and silt. This unit can also contain fractures, and cobbles and boulders are common. Perched groundwater may be encountered within this unit. Vashon Till -Like Deposits (Qvd). Vashon till -like deposits are nonsorted to poorly sorted diamicts and are intermediate between glacial till and glacial outwash. These sediments may have been reworked by subglacial streams flowing in channels beneath the ice. Qvd soils have a similar grain size distribution to Qvt (although generally lower fines content), but are generally more variable in composition. Perched groundwater may occur within this unit. Vashon Advance Outwash Deposits (Qva). Vashon advanced outwash consists of glaciofluvial sediment deposited as the glacial ice advanced through the Puget Lowland. Deposits of Qva consist of dense to very dense, poorly graded sand to well -graded sand to silty sand, with varying amounts of gravel and scattered cobbles. Saturated Qva deposits form a productive regional aquifer, and the formation is known to heave when encountered during drilling. Layers of relatively coarse sand within the unsaturated Qva tend to cave during drilling. Where layers of low - permeability soil exist, localized perched groundwater may occur in the Qva above the regional aquifer. Transitional Bed Deposits (Qtb). Transitional bed deposits are transitional between Vashon glacial and pre-Vashon nonglacial deposits. They are typically fine-grained, 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 SHANNON &WILSON, INQ consisting mostly of thick or thin beds and laminae of clay, silt, and fine sand (Minard, 1983). The major surface water features in project area are Echo Lake and Lake Ballinger (approximately 4,700 southeast and 6,000 feet east of the project, respectively), and Deer Creek, about 5,500 feet northwest of the project. 3.2 Local Geology and Hydrogeology The following summarizes the local surficial and subsurface geology based on published reports, databases, and previous studies: ■ According to a published geologic map (Minard, 1983; Figure 3) and our previous 22 project test pits and 11 shallow soil borings (Shannon & Wilson, 2016b), the project site is underlain at a shallow depth by glacial till. The top of the till was identified by our previous test pits and shallow borings as starting at between ground surface and 10 feet deep. ■ The transition from glacial lodgement till (Qvt) to glacial advance outwash (Qva) occurs at approximately elevation 380 to 400 feet on the steep wooded slope in the middle of the property (Minard, 1983). ■ Boring logs for the nearby Brightwater Project (CDM, 2006) and other nearby wells indicate that the Qva is laterally extensive in the area. ■ Based on Brightwater Project borings MW-4 and E-106 (drilled about 1,500 feet south of the project site along 244t" Street SW), transitional bed (Qtb) deposits underlie the Qva soils locally at about elevation 201 feet (CDM, 2006). The following summarizes the local groundwater conditions based on published reports, online databases, and previous studies: The online Washington State Department of Ecology (Ecology) water resources and well log databases (Ecology, 2016a and 2016b) identify multiple irrigation and domestic wells in southwest Edmonds vicinity that are completed in the Qva aquifer. With one possible exception, none of these wells appears to be within 1/4-mile of the portion of the site undergoing redevelopment. No municipal water supply wells are reported to be within 1/4-mile of the site. We identified one domestic use groundwater right that has been registered for a well in the vicinity of Firdale Village (Ecology, 2016a). The well's location was not specified on the water right documentation, but the owner's address (9619 - 242nd Place SW, Edmonds) is within 1/4-mile of the site, cross -groundwater gradient to the project (Figure 4). 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 4 SHANNON &WILSON, INQ ■ The top of the Qva aquifer occurs between elevations 288 and 278 feet in the vicinity of Brightwater Project exploratory boring MW-4, in the Firdale Village area (CDM, 2006). ■ The groundwater level in the Qva aquifer is at approximately elevation 259 to 261 feet in City of Edmonds observation well A-2, located approximately 4,500 feet west of the project site (Shannon & Wilson, 2013). ■ Prior to our current site work, we estimated the hydraulic gradient in the Qva aquifer in the southwest Edmonds area to be to the west at about 0.008 foot per foot (foot/foot). The expected annual groundwater level fluctuation in the Qva aquifer is between about 2 and 5 feet (Shannon & Wilson, 2013; CDM, 2006). ■ The project site straddles the mapped ten-year time -of -travel zone for a Class A municipal water supply protection area (Figure 4; PACE, 2002). This water source consists of a spring that produces water from the basal Qva aquifer in the Deer Creek ravine. Olympic View Water and Sewer District (Olympic View) owns the Deer Creek water supply and treatment facility. Figure 4 indicates that the hydraulic gradient for the Qva aquifer is approximately west/northwest in the project vicinity. Thomas and others (1997) rated the Qva aquifer in the Project site and most of the vicinity of southwest Edmonds as having a low sensitivity to contamination, based on aquifer characteristics. However, the Deer Creek water supply protection plan states that the Washington State Department of Health assigned the Deer Creek source a high susceptibility rating and established a testing program. The Deer Creek source susceptibility analysis included a review of both geologic and land use factors (PACE 2002). We understand from Robinson Noble, Inc. (Robinson Noble), Olympic View's hydrogeologic consultant, that the Deer Creek source testing is currently performed after the supply has been treated. Robinson Noble also stated that Deer Creek has multiple monitoring wells located upgradient of the spring source, which are currently not being sampled. From our conversations with Olympic View and Robinson Noble, we understand that Olympic View recently drilled a test well at 8605-228th Street SW and that they are in the process of developing a new water supply well in this vicinity (Figure 4). The test well was reportedly drilled to about 700 feet deep, and it is located about 3,300 feet northeast of the project site. As of the date of this report, its log was not yet available on the online Ecology well log viewer. Mr. Max Wills of Robinson Noble stated that the intake zone was revised (made more shallow) after the test well's initial construction and testing. He said that the well is now screened within the Qva aquifer. Olympic View personnel said it may soon be supplemented by a second new well. Olympic View personnel stated that they are not currently using this or other wells in the project vicinity. We suggested to Olympic View, via Robinson Noble, the advantage of working together with them to obtain concurrent Qva aquifer water level measurements at the test well and the Madrona K-8 Qva wells. These measurements could assist in better defining the local Qva gradient. As of the date of this report, we have not received a response from Olympic View. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 5 SHANNON &WILSON, INQ 4.0 SUBSURFACE EXPLORATION AND TESTING 4.1 Drilling and Testing Program Our drilling and testing program consisted of the following: Subcontracted Holt Services, Inc. to drill three borings, including installation of two observation wells and one pilot dry well. These were drilled using the sonic core drilling method: — Observation well OW-1, drilled to 185.5 feet below ground surface (bgs); screened 175.4 to 185 feet bgs. Pilot dry well IW-1, drilled to 91.2 feet bgs; screened 63.3 to 90.4 feet bgs. IW-1 is located approximately 25 feet east of OW-1. Observation well OW-2, drilled to 190 feet bgs; screened 179.2 to 183.9 feet bgs; vibrating wire piezometers (VWPs) at 66.3 feet (VWP1) and 146.3 feet (VWP2). Subcontracted Malcolm Drilling Company, Inc. to complete one full-scale dry well, using the auger drill method: Full-scale dry well, IW-2, drilled to 120.4 feet bgs; screen exposed to formation from about 62 to 119.7 feet bgs. IW-2 is located approximately 14 feet northwest of OW-2. ■ Observed construction of observation wells OW-1 and OW-2 and pilot dry well IW-1. Construction details for the wells and VWPs are presented in the boring logs and in Tables A- I and A-2 in Appendix A. ■ Observed construction of full-scale dry well IW-2. Well construction details are presented in the boring log and in Table A-1 in Appendix A. ■ Logged and photographed the sonic core soil samples and logged the auger cuttings. Collected sub -samples for laboratory geotechnical analysis. ■ Estimated the approximate well locations and reference elevations based on field measurements. ■ Developed observation wells OW-1 and OW-2 using an inertial -style pump (Waterra) equipped with a combination surge block and check valve. Measured groundwater quality field parameters during well development at OW-1, and observed purge water sediment content during well development at OW-2. ■ Collected groundwater samples from observation well OW-1 to establish baseline groundwater quality in the Qva aquifer. Analyzed the sample for petroleum hydrocarbon -related constituents and primary and secondary drinking water parameters. Measured groundwater quality field parameters immediately before sample collection. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 6 SHANNON &WILSON, INQ Performed a "slug" test in OW-1 to estimate the hydraulic conductivity of the Qva aquifer. ■ Commenced long-term groundwater level monitoring in OW-1 in April 2016 by installing a Levelogger and a data logging barometer (Barologger). Commenced long-term groundwater level monitoring in the well at OW-2 in August 2016, installing a Levelogger. Performed periodic data downloads, coupled with manual readings of the OW-2 VWPs and dry wells IW-1 and IW-2. Performed an inflow test in pilot dry well IW-I by adding water at known rates for a selected time periods and monitoring water levels at IW-1 and OW-1 before, during, and after the inflow test. Step testing — performed four inflow steps at approximately 14, 38, 72, and 103 gallons per minute (gpm), maintaining each rate for approximately 1 hour; and Short-term constant rate injection test, lasting about 4.3 hours, at an average rate of about 110 gpm. ■ Performed an inflow test in full-scale dry well IW-2 by adding water at known rates for a selected time periods and monitoring water levels at IW-2, OW-2, and OW-1 before, during, and after the inflow test. Step testing — performed four inflow steps at approximately 87, 114, and 128 gpm, maintaining each rate for approximately 39 to 99 minutes; and Short-term constant rate injection test, lasting about 15.9 hours, at an average rate of about 141 gpm. 4.2 Findings 4.2.1 Observed Geologic Conditions Appendix A presents the exploration logs and includes a Soil Description and Log Key that explains the terms used in the soil classifications and descriptions. Figures 5 and 6 present in profile generalized illustrations of the subsurface conditions we observed at the four borings. The results of these borings and hydrogeologic information interpreted from other studies in the vicinity are summarized as follows: ■ Near -surface soils consisting primarily of Qvat and weathered Qvt extend to a depth of about 10 and 14 feet. Some surficial fill is also present. ■ Interbedded Vashon lodgement till (Qvt) and till -like deposits (Qvd) occur beneath the near -surface soils to about 38 to 50 feet bgs. Interbedded Qva and Qvd layers are present below approximately 38 to 50 feet, to about 60 to 72 feet bgs. Perched groundwater was observed to about 61 feet bgs in these deposits. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 7 SHANNON &WILSON, INQ Below about 60 to 61 feet bgs, encountered soils consisted predominantly of Qva, which are present to the maximum explored depth of 190 feet (approximately elevation 255 feet). Scattered layers of silty sand are present within the unsaturated Qva, particularly at and below about 134 to 147 feet (OW -I and OW-2, respectively); some of these layers appear to be intermediate between Qva and Qvd. ■ Transitional bed deposits (Qtb) were not encountered by the project borings, but they may be present below the maximum exploration depth of 190 feet. Based on other deep explorations in the vicinity, Qtb deposits might be expected to occur below about 244 feet bgs (about elevation 201 feet). Soil treatment capacities of the Qva between the target UIC depth of about 120 feet and the top of the Qva regional aquifer are low to medium, as defined by the Guidance for UIC Wells that Manage Stormwater (Ecology, 2006). These treatment capacity rankings are based on the grain size analyses presented in Appendix B and summarized in Appendix C, Table C-4: ■ OW-1 vicinity: We observed approximately 10 cumulative feet of medium treatment capacity soils between 120 feet bgs and the top of the Qva regional aquifer; the remaining soils (about 37 feet cumulative thickness) have a low treatment capacity. ■ OW-2 vicinity: We observed approximately 14 cumulative feet of medium treatment capacity soils between 120 feet bgs and the top of the Qva regional aquifer; the remaining soils (about 33 feet cumulative thickness) have a low treatment capacity. 4.2.2 Groundwater Levels and Monitoring As indicated in the boring logs in Appendix A, we observed shallow wet seams and layers in the Qvat/weathered Qvt deposits at IW-1, OW-1, and OW-2. These were as shallow as 5.5 to 8.5 feet bgs in OW-1, about 9 to 14 feet bgs in IW-1, and about 12 feet bgs at OW-2. Similarly, we observed additional wet seams and layers within the Qvt/Qvd soils in the 0W-2/IW-2 vicinity at about 23, 35, and 45 feet bgs. Perched groundwater may be feeding the wetlands identified on the site slopes (Shannon & Wilson, 2016a). We encountered a possible perched groundwater zone within the interbedded Qvd/Qva soils, between about 48 and 57 feet bgs at IW-1 and at about 50 to 53 feet bgs at OW-1. Perched water was present at IW-2 within the interbedded Qvd/upper Qva soils from about 49 to 61 feet bgs. Soil within this zone caved during drilling at IW-2, necessitating the installation of temporary surface casing. A possible zone of perched water was encountered at approximately 132.5 to 136.5 feet bgs at OW-1, associated with a silty sand Qva layer. However, this saturated zone may also have been associated with residual water introduced during the drilling process. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 8 SHANNON &WILSON, INQ Hydrographs of the Qva aquifer groundwater levels measured to date at OW-1 and OW-2 are presented in Appendix C. The highest observed levels to date in the regional Qva aquifer at the site are approximately 167.1 to 167.3 feet bgs (elevation 278.0 to 277.4 feet) at OW-1 and OW-2, respectively. The range of fluctuation in the Qva aquifer water level observed to date is about 1.8 feet (April to November 2016 at OW-1). Apart from during and immediately after their respective injection well testing periods, we] Is IW-1 and IW-2 have been dry to date. The VWP installed at 66.3 feet bgs at OW-2 has also been dry, including during the IW-2 test. The VWP installed at 146.3 feet bgs at OW-2 measured water temporarily mounding at that depth during and immediately after the IW-2 test, as shown in Appendix C. The top of the unsaturated portion of the Qva unit is about 60 to 61 feet bgs (elevation 385 or 384 feet) in the OW-1/OW-2 vicinity. The unsaturated thickness of the targeted Qva infiltration receptor soils is about 72 feet (if perched water is present in the Qva at 132.5 feet bgs at OW-1) or about 106 feet (based on the highest groundwater level measured to date at OW-1). We estimated the Qva aquifer gradient by comparing groundwater elevations measured at the project wells to the approximate groundwater elevation we measured during a previous study at City of Edmonds observation well A-2 (Shannon & Wilson, 2013). Well A-2 is located about 4,500 feet west of the site. Based on these data, the Qva aquifer gradient beneath the project site is about 0.002 foot/foot to the west/northwest (Figure 4). 4.2.3 Aquifer Hydraulic Properties We performed single -well "slug" tests in observation well OW-1 to determine the local horizontal hydraulic conductivity (Kh) of the Qva aquifer (Appendix C). The OW-1 test results indicate a Kh of 55 feet/day (3.8 x 10-2 feet/minute). We estimated the Kh for soil samples collected from project borings IW-2, OW-1, and OW-2 using empirical methods (Table C-4, Appendix C). The results indicated the following: • The estimated Kh value for the till -like deposits (Qvd) sample from OW-1 was less than 0.01 foot/day. The Kh estimates for the 21 Qva unit samples range from 0.05 to 626 feet/day (3 x 10-5 to 0.43 feet/minute). Excluding the highest value as an outlier, the arithmetic and geometric mean Kh values of the remaining 20 samples are 38 and 11 feet/day (2.3 x 10-2 and 7.4 x 10-3 feet/minute), respectively. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 9 SHANNON &WILSON, INC 4.2.4 Groundwater Quality In general, the OW-1 sample indicates that the groundwater quality of the Qva aquifer groundwater quality is good beneath the project site. An exception is the relatively high concentration of manganese, 344 parts per billion (ppb), which is almost seven times the secondary (aesthetic) drinking water standard of 50 ppb. Manganese occurs naturally in soil and groundwater. The extent to which manganese dissolves into groundwater depends on the amount of oxygen in the water and, to a lesser extent, upon the pH of the water. If the oxygen content of groundwater is low, manganese tends to dissolve more readily. The zone from which the OW -I groundwater sample was collected contains scattered organics, the decomposition of which depletes the oxygen content of the groundwater. This may contribute to the relatively high groundwater manganese concentration. Table C-1 in Appendix C summarizes the laboratory test results for the OW-1 groundwater sample and comparable drinking water standards. Appendix C also contains the associated laboratory data report. 4.2.5 Pilot -scale Injection Well Testing Figure 7 presents the results of the pilot -scale injection well test at IW-1. During the first four injection steps (approximately 1 hour each, at about 14, 38, 72, and 103 gpm), the water column height in IW-1 ranged from approximately 2 to 18 feet (89 to 72 feet bgs). However, these four steps did not run long enough for the water level to stabilize. The fifth step lasted approximately 4.3 hours. The inflow rate varied between about 107 and 126 gpm during this step, with an average inflow rate of 110 gpm. At this inflow rate, the IW-1 water column height stabilized at approximately 24 feet, which is 67 feet below grade and 4 feet below the top of the well screen. Based on these data, and as summarized in Table C-3 (Appendix C): The observed injection specific capacity of IW-1 is approximately 4.6 gpm/foot of water level rise and the approximate K for the tested zone is 24 feet/day (1.7 x 10-2 feet/minute). The test did not cause the groundwater level in nearby observation well OW-1 to increase by a measurable amount. 4.2.6 Full-scale Injection Well Testing Figure 8 presents the results of the full-scale injection well test at IW-2. During the first three injection steps (which lasted between 39 and 99 minutes each at rates of 87, 114, and 128 gpm), the peak water column heights in IW-2 ranged from approximately 12 to 17 feet (or 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 10 SHANNON &WILSON, INQ 108 to 103 feet bgs). However, the water level did not stabilize during these steps. The fourth step lasted for 15.9 hours, at an average inflow rate of about 141 gpm. At this inflow rate, the IW-2 water level was relatively stable at about 99 feet below grade, representing a head rise above the borehole bottom of about 21 feet. Based on these data, and as summarized in Table C- 3 (Appendix C): The observed injection specific capacity of IW-2 is approximately 6.7 gpm/foot of water level rise and the approximate K for the tested zone is 30 feet/day (2.0 x 10-2 feet/minute. The test caused the groundwater level in OW-2 VWP2 to rise by 5 feet at the end of the injection phase of the test. This rise fully dissipated during the subsequent 3.5 days. A small increase in the groundwater level (less than 0.3 foot) occurred in observation well OW-2 in response to the test. 5.0 GROUNDWATER MODELING OF PLANNED INJECTION WELLFIELD 5.1 Overview We performed groundwater modeling to determine the feasibility of the planned UIC wellfield. In particular, the modeling was conducted to evaluate potential groundwater mounding, well operational constraints, and the potential for seepage to occur at the slopes to the west of the UIC wellfield. The modeling consisted of the following: 1. Establishing a detailed conceptual site model; 2. Developing and calibrating the numerical model; 3. Simulating the planned 16-well UIC wellfield for a specified storm event; and 4. Testing the sensitivity of the model results to parameter uncertainty. Appendix D presents the full details of the modeling approach, results, and limitations. 5.2 Conceptual Site Model (CSM) Based on the four deep borings and our understanding of the local hydrogeology, we have developed the following CSM for the project site: ■ Relatively low permeability Qvt and Qvd soils are situated above a thick layer of relatively permeable Qva sand. ■ The upper Qva deposits are interbedded with Qvd soils down to a depth of 60 to 72 feet (elevation 385 to 373 feet). The base of the perched zone observed within the interbedded Qva/Qvd zone is 61 feet bgs (elevation 384 feet). The Qva is predominantly unsaturated from 61 to 167 feet bgs (elevations 384 to 278 feet). 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 SHANNON &WILSON, INQ ■ The regional Qva aquifer extends from 167 feet bgs (elevation 278 feet) to at least 244 feet bgs (elevation 201 feet) ■ Potentially perching layers of silty sand are scattered within the generally unsaturated Qva. These layers occur primarily below 147 feet bgs (elevation 298 feet) at OW-1 and OW-2, and possibly as shallow as 134 feet bgs (elevation 311 feet) at OW-1. ■ At each deep UIC well, a surface casing and seal will be installed to isolate the overlying Qvt, Qvd, and saturated upper Qva layers from the unsaturated underlying Qva soils (Figure 9). Stormwater discharge to the UICs will be directed into the unsaturated Qva soils to a maximum depth of about 120 feet (about elevation 325 feet). 5.3 Model Development and Calibration The model uses the U.S. Geological Survey's numerical groundwater flow code MODFLOW- 2005 (Flarbaugh, 2005) to simulate the unsaturated zone and groundwater flow system in the project area. The model occupies an area 2,400 feet by 2,000 feet, and it extends from land surface to elevation 225 feet. The model uses the following three layers to simulate the subsurface soils described in the CSM: ■ Layer 1 — unsaturated Qva outwash (land surface to elevation 298 feet) ■ Layer 2 — a 5-foot thick, low permeability perching layer (from elevation 298 to 293 feet) ■ Layer 3 — saturated Qva outwash (elevation 293 to 225 feet) We calibrated the model transiently to the full-scale injection test performed using UIC well IW-2. This involved adjusting the material properties of the three layers to enable the model to best reproduce the observed changes in groundwater levels. Table D-1 in Appendix D present the final modeled material properties. 5.4 Model Simulation (Base Case) We used the calibrated model to simulate the planned UIC wellfield for a specified storm event. This Base Case involved the following: ■ 16 UIC wells, grouped in four areas (Areas 1 through 4), each with three to five wells spaced at 30 to 50 feet (Figure 10); ■ The UIC wells inject water into model layer 1; and ■ The simulated injection was for a 100-year, 24-hour storm event. The peak hourly injection rate for each well ranged from 102 to 130 gpm. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 12 SHANNON &WILSON, INQ The results indicate that the simulated storm event would temporarily raise water levels by up to 11 feet (to a peak elevation 310 feet) at the center of UIC Area 2 (135 feet bgs), and by up 7 feet (to elevation 306 feet) at the center of the three other UIC areas (139 feet bgs). Although some mounding interference would occur between adjacent UIC wells in each area, the operational groundwater level would not be higher than the top of the designed well screens (at elevation 375 to 380 feet). The model also predicts that the groundwater would not increase to less than 70 feet below land surface at the slope to the west of the wellfield areas. 5.5 Sensitivity Analysis To evaluate the effect on the Base Case results of key model parameter uncertainty, we performed three sensitivity cases. These involved the re -simulating the 24-hour storm with (a) the Qva aquifer Kh and Kv values reduced by a factor of 10, (b) the elevation of the 5-foot thick perching layer increased by 15 feet, and (c) a combination of (a) and (b). The most conservative case (c) results indicate that the induced perched water table would rise to a peak of elevation 328 feet at the center of UIC Area 2, which is 117 feet bgs. The water would remain more than 50 feet below the toe of the slope to the west of UIC Area 2. 6.0 STORMWATER QUALITY DISCUSSION We understand that the District plans to employ source controls and to treat site stormwater based on the expected pollutant loads, in accordance with the local stormwater code requirements (City of Edmonds, 2010; Ecology, 2005 and 2006). We understand that the District plans to incorporate bioretention for treatment and infiltration of some site stormwater, with drainage from the bioretention being routed to some of the UIC wells. This best management practice (BMP) will target shallow, unsaturated soils with moderate permeability, e.g., Qvat, fill, and weathered Qvt. In areas where these soils have sufficient permeability, some flow control benefit will be realized by this BMP. Additional flow control will be provided by the proposed UIC wells. The introduction of nutrients into UIC wells may contribute to biofouling of the wells, thereby reducing their effective life span (National Research Council [NRC], 1994). To manage phosphorus and nitrogen at the bioretention facilities, we recommend incorporating the following elements into the bioretention facility BMP design, in accordance with the applicable stormwater code (City of Edmonds, 2010) and as described in the Low Impact Development Technical Guidance Manual for Puget Sound (Puget Sound Action Team, 2005; Puget Sound Partnership, 2012): 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 13 SHANNON &WILSON, INQ Use only mature, stable compost, without biosolids or manure constituents. Employ elevated under -drains to create a fluctuating anoxic/aerobic zone below the drain pipes. We contacted Ecology (Ms. Mary Shaleen-Hansen, Water Quality Section; Mr. Douglas Howie, Senior Stormwater Engineer) to discuss UIC management and common reasons for UIC well failure. Ms. Shaleen-Hansen recommended that the site UIC well management plan address coliform, pesticides, and herbicides (i.e., through source control) to prevent introduction of these contaminants into the UIC wells. Although Mr. Howie was not familiar with UIC well fouling due to the introduction of nutrients, he stated that UIC well failures are typically due to the introduction of total suspended solids (TSS). In our experience, TSS-fouled UIC wells are challenging to redevelop, even more so than biofouled wells. Therefore, sediment fouling should be avoided whenever possible. Part of an effective TSS management policy is to prevent construction site runoff from entering UIC wells, as it can have elevated TSS levels. UIC wells should be also protected from receiving runoff from recently landscaped areas until those areas have stabilized, in accordance with the locally applicable stormwater manual. 7.0 CONCLUSIONS AND RECOMMENDATIONS Based on our observations at the current borings and our previous site test pits and shallow borings, the infiltration potential of the site's shallow native soils is generally low. Infiltration of some stormwater at dispersed facilities is feasible on portions of the site (Shannon & Wilson, 2016b). In general, shallow site soils are not feasible for the concentrated infiltration of large volumes of stormwater, but infiltration into the underlying unsaturated, relatively low -fines - content Qva soils is feasible. 7.1 Injection Well Recommendations 7.1.1 General We recommend that the UIC well construction activities of the District's drilling contractor be observed by the District's own hydrogeologic/geotechnical representative, under separate contract to the District. We recommend that the selected drilling contractor submit a drill plan and qualifications to the District's hydrogeologic/geotechnical representative for approval prior to beginning work. During UIC well installation, we recommend that we provide field observation of UIC well installation and field testing, as the District's representative, so that timely adjustments to array layout can be made, if needed. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 14 SHANNON &WILSON, INQ Based on the IW-1 and IW-2 inflow tests, the use of UIC wells at the project site is feasible for stormwater management. The top of the target infiltration zone (unsaturated, sandy Qva soils with predominantly low fines content) is about 60 to 61 feet bgs at the locations explored by OW-1, OW-2, IW-1, and IW-2. The depth to this contact may vary across the site. Based on the OW-1 log, perched groundwater may be present in the Qva at about 132.5 feet bgs in that area. The top of the regional Qva aquifer is at about 167 feet bgs. Ecology does not allow stormwater to be discharged directly into an aquifer via UIC wells. We recommend that the UIC well depths be limited to about 115 to 120 feet (approximately 330 to 325 feet), which will allow for up to about 47 feet of separation between the UIC wells and the top of the Qva aquifer. We understand that the District proposes to install UIC wells in four array clusters, with UIC wells spaced approximately 30 to 50 feet apart (Figure 10). We recommend the wells be spaced no closer than 30 feet on center in order to reduce interference between the wells. Greater spacing creates less interference and results in more efficient UIC well operation. We recommend that the newly installed UIC wells be flow tested shortly after installation in order to confirm the expected UIC performance assumptions. 7.1.2 Well Design Recommendations There are two general types of deep UIC well designs in common use locally. These include: (a) large -diameter boreholes filled with sand and/or gravel infiltration media (with or without a vertical transmission casing and screen), and (b) traditional screened wells, which have a smaller filter -packed zone around the well screen or no artificial filter pack at all. Based on our communication with the project team, we understand that the former, option a, is planned for the project, and we have based our design recommendations on this understanding. Auger rigs are commonly used to perform this type of drilling. Auger drilling and installation techniques typically involve drilling a cased hole through the zone through which a seal will be placed and an open or temporarily cased hole in the infiltration receptor zone. Drilling is typically accomplished with a solid stem or bucket auger. Unit cost estimates for drilling and installing this type of UIC well are roughly $30,000 to $40,000, excluding surface vault and distribution system completion, spoils handling, well development, and field testing. Unit well drilling costs are greater if few wells are installed. Based on our explorations and testing and assuming similar conditions as encountered at by the four deep site borings, the recommended full-scale UIC well short-term specific capacity estimate is 6.7 gpm/foot of screen. Assuming good control over TSS and nutrients and relatively 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 15 SHANNON &WILSON, INQ uniform site conditions, we recommend applying a divisive correction factor (CF) of 2 to this UIC well capacity. Applying this CF results in a UIC well design specific capacity of about 3.3 gpm/foot of screen in the unsaturated Qva. This assumes the UICs will have similar construction to IW-2, with a minimum diameter of 24 inches and total depth of about H 5 to 120 feet. Our UIC well design recommendations are presented below and are illustrated in Figure 9. Figure 9 conceptually illustrates construction aspects of a hybrid UIC well that combines infiltration media backfill with a vertical transmission casing and screen. The actual well depths and construction methods and details may differ, based on encountered hydrogeologic conditions and project goals. Construction steps include the following: ■ Drill a large -diameter hole (e.g., 36- to 40-inch) to facilitate construction of a surface seal. This borehole should be drilled to about 1 to 5 feet below the base of the Qvt/Qvd/saturated upper Qva soils (contact estimated to be about 60 to 65 feet bgs, or about elevation 385 to 380 feet). Maintain an open borehole through this upper zone using a temporary casing. The borehole diameter should be at least 4 inches larger than the nominal diameter of the planned permanent surface casing. Drill a smaller diameter hole (e.g., 24-inch) from the depth of the bottom of the planned permanent surface casing to about 50 to 60 feet into the unsaturated Qva soils (total depth of about 115 to 120 feet, or to about elevation 330 to 325 feet). Alternatively, temporary casing may be used to drill to the bottom of the hole. No drilling additives should be used, with the possible exception of water. Install a permanent 30- to 36-inch inside diameter (I.D.) steel casing. This casing should be installed to about 1 to 5 feet below the base of the larger diameter hole. Construct a surface seal between the permanent casing and the borehole annulus. The intent of the surface seal is to (a) protect the Qva infiltration receptor soils from direct inflows of surface water and (b) prevent the draining of the overlying perched zones. Depending on drilling approach, the permanent surface casing and seal may be placed before or after the boring is drilled to its final depth and the vertical transmission casing/screen assembly is installed. We recommend the lower portion of the surface seal consist of bentonite chips (minimum 10 feet thick). Then place additional sealing material (bentonite, neat cement, or neat cement grout, in accordance with Washington Administrative Code (WAC) 173-160 sealing requirements) from the top of the bentonite chip seal to the ground surface. The lower bentonite chip seal should be installed in such a way so as to prevent the upper annular sealants from intruding into the target infiltration soils or the interior of the permanent surface casing. Install the vertical transmission casing. We recommend using 8-inch LD casing and screen. Concurrently install to the same depth a polyvinyl chloride (PVC) observation pipe casing and screen. (The purpose of the PVC pipe is to facilitate measurement of the water level in the UIC well during periods of stormwater inflow.) 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 16 SHANNON &WILSON, INQ Use steel centralizers on the 8-inch I.D. casing and screen, on about 20-foot centers, and secure the PVC pipe to the centralizers. Backfill the 24-inch borehole around the 8-inch I.D. screen with washed, rounded, UIC 4x8 filter sand. If temporary casing was not used to drill the lower borehole, it may be necessary to tremie the filter into place in order to reduce borehole wall caving. Extend the UIC 4x8 filter sand to about 5 feet above the depth of the permanent surface casing. Once the UIC 4x8 filter sand has been placed, we recommend using water to settle it around the screened zone, topping off the UIC 4x8 sand as necessary to bring it back to about 5 feet inside the permanent casing. We recommend placing UIC gravel around the pipes within the permanent surface casing, to approximately 4 feet below the planned invert of the inlet pipe into the permanent storm drain manhole (SDMH). Perform flow testing after the UIC gravel has been emplaced, topping off the gravel as necessary. During installation of the permanent SDMH, we recommend placing two layers above the UIC gravel, consisting of a 6-inch minimum layer of UIC 4x8 filter sand and a 6-inch minimum layer of UIC filter sand. The intent of the UIC filter sand is to provide supplementary filtering of low -quantity UIC inflows. The UIC filter sand should be replaced as it becomes clogged. To protect the upper UIC filter sand from erosion, we recommend placing a pad of quarry spalls (approximately 6 inches thick) within the SDMH, with the top of the pad about 6 inches below the inlet pipe elbow. The permanent steel surface casing should be cut off approximately 3 feet below the invert of the inlet pipe to the SDMH. To maintain UIC well function, it is critically important to protect the UIC wells from TSS loading while the site is under construction, as well as during normal site use. No construction -related stormwater should be discharged to the UICs, and the site should be fully stabilized prior to bringing the UICs online. Accordingly, we recommend that, while the site is under construction and not fully stabilized, and prior to installation of the permanent SDMH over a UIC, the UIC's steel surface casing be left temporarily slightly above grade. We recommend that the top of the surface casing be temporarily protected with a welded top plate or a locking monument until the permanent SDMH is installed. During UIC operation, we recommend a combination of source control measures and pre-treatment to the site stormwater to remove or reduce the expected types and quantities of pollutants prior to its being discharged to the UIC arrays, in accordance with the local stormwater code (City of Edmonds, 2010) and the UIC Guidance (Ecology, 2006). 7.1.3 Injection Well Materials We recommend the following materials be used for UIC well construction: ■ UIC Vertical Transmission Casing, Screen, and Bottom Cap. Due to its high durability and high open area relative to PVC machine -slotted screen, we recommend using stainless steel screen in the UIC wells. The recommended UIC vertical 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 17 SHANNON &WILSON, INQ transmission casing, screen, and bottom cap material is 8-inch T.D., 304 stainless steel, with threaded or welded joints. The recommended screen is continuous -slot (0,020-inch slots), approximately 50 feet long. Steel centralizers on approximately 20-foot centers are recommended to facilitate placement of the casing in the center of the borehole. We recommend that the screened interval be installed in a borehole with a diameter of approximately 24 to 36 inches. UIC Observation Pipe Casing, Screen, and Bottom Cap. The recommended U1 vertical observation pipe casing, screen, and bottom cap material is 2-inch I.D., Schedule 40 or Schedule 80 PVC with tbreadedjoints. The recommended screen i factory macbine-slotted (0.020-inch slots), approximately 10 feet long. We recommend that the top of the pipe be equipped with a removable watertight plug. We recommend that the PVC pipe be secured to the transmission casing centralize] UIC Surface Casing and Seal. The recommended UTC surface casing is steel, 30- to 36-inch T.D., meeting ASTM International A53 A or B, with 0.375-incb wall thickness and with welded or threaded joints. We recommend the surface casing be installed in a borehole that is at least 4 inches larger in diameter than the nominal surface casing diameter. We recommend seal materials meeting the WAC 173-160 Sealing Material Standard be placed in the annulus between the perrnanent steel surface casing and the borehole wall. We recommend that •the bottom of the annular seal material consist of bentonite chips (minimum 10 feet thick). Above the bentonite chips, we recommend that the annular seal consist of neat cement, neat cement grout, or bentonite, in accordance with WAC 173-160. medium specification, with a recommended gradation of: U.S. Standard Sieve Size Percent Passing % (9.5 millimeter [mm]) 100 4 (4.75 min) 95 to 100 8 (2.36 min) 70 to 100 16 (1.18 mm) 40 to 90 30 (0.60 mm) 25 to 75 50 (0.30 min) 2 to 25 100 (0.15 min) <4 200 (0.075 min) <2 M 21-1-22082-003-R] f/wp/lkn 21-1-22082-003 18 SHANNON &WILSON, INQ Percent Passing % (9.5 mm) 4 (4.75 mm) 8 (2.36 mm) 30 (0.60 mm) 200 (0.075 mm) ■ IC Gravel. We recommend the UIC gravel consist of free -draining, rounded, granular material, with a gradation of: '/2 (12.5 mm) % (9.5 rnm) 4 (4.75 mm) 8 (2.36 mm) 100 (0.15 mm) r. = 100 80 to 100 5to15 0 to 10 0 to 0.6 Filter materials used in UIC construction should be should be: ■ Free from organics, debris, or other deleterious material. ■ Stockpiled in such manner that they are protected from contamination by other site materials (e.g., fine sediment) and from segregation by rainfall, as appropriate. 7.2 Additional Recommendations We recommend that the performance of the UIC clusters be monitored so that UIC array performance over time can be tracked and appropriate maintenance or UIC well rehabilitation scheduled. We recommend the installation and monitoring of data logging transducers in some or all of the wells, coupled with periodic manual water level measurements. We recommend that a regular and perpetual maintenance program be performed for all of the site infiltration facilities to reduce siltation and bio-fouling, in accordance with the local stormwater code requirements. Groundwater observation wells should be protected through the facility construction process and be used to facilitate measurement of facility performance. If the wells are damaged during construction, they should be repaired or properly abandoned, in accordance with WAC 173-160. If the District desires to monitor the downstream effects of the planned UIC array, then we would recommend the installation of downgradient observation wells prior to the UIC arrays being brought online. Such wells could function as monitoring points for measuring variations in Qva aquifer water levels (and, if desired, for tracking aquifer water quality over time). Appropriate locations for such wells are to the west/northwest of the planned UIC arrays. These might be 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 19 SHANNON &WILSON, INQ drilled at or beyond the toe of the slope but still on the District property. If these wells are installed, then an additional observation well installed upgradient (east) of the UIC array would also be useful in measuring Qva aquifer water levels and possibly background water quality. As indicated by Figure 4, the project site is within the mapped ten-year time -of -travel zone of the water supply protection area for the Deer Creek municipal water supply surface water source. We recommend coordinating stormwater infiltration efforts in the project area with the Olympic View to facilitate their compliance with Washington State Department of Health source water protection requirements established under the Watershed Control Program. Olympic View's water supply protection plan (plan) for Deer Creek (PACE, 2002) notes that Olympic View does not maintain any authority over land use regulations and requirements. However, Olympic View's plan recommends the following regulatory and protective measures be considered by land use agencies (i.e., City of Edmonds), as applicable to the ten-year capture zone illustrated in Figure 4: ■ Encourage public education as being critical to the overall effectiveness of protecting the Deer Creek water supply. ■ Discourage use of chemical fertilizers. ■ Require that oil- and detergent -based waste materials be treated by the sanitary sewer system, as appropriate. ■ Encourage protection of surface water bodies and groundwater wells through public awareness. ■ Cooperate with land use and emergency response agencies (i.e., implement a spill response plan, with accompanying notification of the proper authorities and Olympic View of potential threats to the water supply system). 8.0 LIMITATIONS The analyses, conclusions, and recommendations contained in this report are based on site conditions as they presently exist. We assume that the current field explorations are representative of the subsurface conditions at the proposed infiltration facilities; i.e., the subsurface conditions everywhere in the vicinity of the proposed infiltration facilities are not significantly different from those disclosed by the field explorations. Within the limitations of the scope, schedule, and budget, the analyses, conclusions, and recommendations presented in this report were prepared in accordance with generally accepted professional geotechnical and hydrogeologic principles and practice in this area at the time this report was prepared. We make no other warranty, either express or implied. These conclusions and recommendations were based on our understanding of the project as described in this report and the site conditions as 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 20 C-11 SHANNON MILSON, INC interpreted from the field explorations. Regulatory agencies may reach different conclusions than Shannon & Wilson. Unanticipated soil conditions are commonly encountered and cannot be fully determined by merely taking soil samples or completing test explorations. Such unexpected conditions frequently require that additional expenditures be made to attain a properly constructed project. Therefore, a contingency fund is recommended to accommodate such potential extra costs. This report was prepared for the exclusive use of the District. It should be made available to prospective contractors for information on factual data only, and not as a warranty of subsurface conditions such as those interpreted from the exploration logs and presented in the discussions of subsurface conditions included in this report. Shannon & Wilson has prepared Appendix E, "Important Information About Your Geotechnical/Environmental Report," to help you understand the use and limitations of our report. Apart from the baseline Qva aquifer groundwater sampling at well OW-1, the scope of our services did not include an environmental assessment or evaluation regarding the presence or absence of hazardous or toxic materials in the soil, surface water, groundwater, or air, on or below or around the site. Shannon & Wilson has qualified personnel to assist you with these services should they be necessary. I Paul L. Van Home, LHG Martin Page, PE, LEG Senior Hydrogeologist Vice President TM Geotechnical Engineer, LEER, AP, DBIA PVH:SDT:MWP/pvh Report elements related to hydrogeology, geology, and geologic unit designations and descriptions were prepared by or under the direct supervision of Paul L. Van Horne, LHG. General report quality assurance and report elements related to soil descriptions were provided by Martin W. Page, PE, LEG, 21-1-22082-003-Rlf/wp/lkn 21-1-22082-003 21 SHANNON &WILSON, INQ 9.0 REFERENCES CDM, 2006, Geotechnical data report, Brightwater conveyance system, west contract, Report prepared for King County Department of Natural Resources and Parks, Wastewater Treatment Division, by CDM, Bellevue, Wash., July. City of Edmonds, 2010, Stormwater code supplement to Edmonds Community Development Code Chapter 18.30: Edmonds, Wash., April 20. Harbaugh, A.W., 2005, MODFLOW-2005: the U.S. Geological Survey modular ground -water model -- the ground -water flow process: U.S. Geological Survey Techniques of Water - Resources Investigations Book 6, Chapter Al6, 1 v., available: https//t�ubs.usgs.gov/tm/2005/tm6AI6/. Minard, J.P., 1983, Geologic map of the Edmonds east and part of the Edmonds west quadrangles, Washington: U.S. Geological Society MF-1541, 1:24,000 scale. National Research Council (NRC), 1994, Ground water recharge using waters of impaired quality: Committee on ground water recharge, Water science and technology board, Commission on geosciences, environment, and resources: National Academy Press, Washington, D.C., 304 p. Penhallegon Associates Consulting Engineers, Inc. (PACE), 2002, Deer Creek water supply protection plan: Report prepared by PACE, Kirkland, Wash., for Olympic View Water & Sewer District, Edmonds, Wash. Puget Sound Action Team, 2005, Low impact development technical guidance manual for Puget Sound: Olympia, Wash., publication no. PSAT 05-03, May. Puget Sound Partnership, 2012, Low impact development technical guidance manual for Puget Sound: Tacoma, Wash., December. Shannon & Wilson, Inc. (Shannon & Wilson), 2013, Final infiltration study report, SW Edmonds basin study projects #1 and #3, Edmonds, Wash.: Report prepared by Shannon & Wilson, Inc., Seattle, Wash., project no. 21-1-21768-001, for City of Edmonds, Edmonds, Wash., April 5. Shannon & Wilson, Inc. (Shannon & Wilson), 2016a, Revised wetland and stream delineation report, New Madrona K-8 Project, City of Edmonds, Wash.: Report prepared by Shannon & Wilson, Inc., Seattle, Wash., project no. 21-1-22082-002, for Edmonds School District #15, Lynnwood, Wash., August 4. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 22 SHANNON &WILSON, INQ Shannon & Wilson, Inc. (Shannon & Wilson), 2016b, Geotechnical engineering report, New Madrona K-8 Project, 9300 236th Street SW, Edmonds, Wash.: Report prepared by Shannon & Wilson, Inc., Seattle, Wash., project no. 21-1-22082-004, for Edmonds School District # 15, Lynnwood, Wash., October 31. Thomas, B. E.; Wilkinson, J. M.; and Embrey, S. S., 1997, The ground -water system and ground- water quality in western Snohomish County, Washington: U.S. Geological Survey Water - Resources Investigations Report 96-4312, 218 p., 9 plates. Washington State Department of Ecology (Ecology), 2005, Stormwater management in Western Washington: Olympia, Wash., publication no. 05-10-31, 5 v., February. Washington State Department of Ecology (Ecology), 2006, Guidance for UIC wells that manage stormwater: Olympia, Wash., publication no. 05-10-067, December. Washington State Department of Ecology (Ecology), 2016a, Washington State water resources explorer: Available: hops:/lfortressowa. govlecylwaterresources/may/WCLSWebMa1�/WaterResourcesExtalorernas px , accessed November 17, 2016. Washington State Department of Ecology (Ecology), 2016b, Washington State well log viewer: Available: htt s://fortress.wa4 ov/ec y/waterresources/ma / CLSWebMa /default.as x , accessed November 17, 2016. 21-1-22082-003-Rl rrWPnkn 21-1-22082-003 23 (D LEGEND 0 200 400 . - Data Point and Designation Wetland Boundary Scale in Feet Wetland Buffer ow 1 ® Observation Well Designation and Approximate Location N jw-j O Dry Well Designation and Approximate Location At Generalized SITE A Subsurface Profile Map adapted from aerial imagery provided by Google Earth Pro, reproduced by permission granted by Google Earth TM Mapping Service. 0 2000 4000 Approximate Scale in Feet LEGEND M1 - Modified Land QJg - Landslide Deposits QVr - Vashon RecessionalOutwash QVt - Vashon Till QVa - Vashon Advance Outwash Qtb - Transitional Beds QW - Whidbey Formation PROJECT SITE NOTE Map adapted from 1:24,000 USGS geologic map of the Edmonds East and Part of the Edmonds West, WA quadrangle, dated 1983. Filename: J:\211\22082-003\21-1-22082-003 Fig 4.dwg Date: 11-18-2016 Login: SAC NOTES 1. Base map taken from Deer Creek Water Supply Protection Plan, (PACE, 2002). 2. Aquifer gradient direction based on project wells and City of Edmonds Well A-2. Approximate gradient equals 0.002 feet/foot. 0 2000 4000 Approximate Scale in Feet ONon -Project Well Designation and Approximate Location 77 Approximate Aquifer Gradient Direction A West 500 450 400 a) 0 u_ c 0 'm 350 W N is E X 0 Q Q Q Me 250 we] 150 Project Area A' East 500 450 M m m u- c 0 350 > W N m E X 0 L Q Q M 250 M 150 OW-1 Observation Well Designation JW_J Dry Well Designation (Proj. 9' S) — Projection Distance and niractinn Ground Surface Possible Perched Zone Approximate Geologic Contact Vibrating Wire Piezometer Filter Pack Well Screen Bottom of Well o Seep T Regional Groundwater Level 17 Perched Groundwater Level GEOLOGIC UNIT Hf Fill Qvat Vashon Ablation Till Qvt Vashon Lodgement Till Qvd Vashon Till -like Deposits Qva Vashon Advance Outwash Qtb Transitional Beds (Fine Grained) 0 50 100 Vertical Scale in Feet 0 200 400 Horizontal Scale in Feet Vertical Exaggeration = 4X B South 500 460 420 t:e a> m u_ c 0 W 340 m E X 0 L Q i11 260 ME 180 140 B' North 500 460 420 t:e i11 M WE :M .M LEGEND OW-1 Observation Well Designation JW_J Dry Well Designation (Proj. 9' S) — Projection Distance and niractinn Ground Surface Possible Perched Zone Approximate Geologic Contact Vibrating Wire Piezometer Filter Pack Well Screen Bottom of Well Seep Regional Groundwater Level Perched Groundwater Level GEOLOGIC UNIT Hf Fill Qvat Vashon Ablation Till Qvt Vashon Lodgement Till Qvd Vashon Till -like Deposits Qva Vashon Advance Outwash Qtb Transitional Beds (Fine Grained) 0 40 80 Vertical Scale in Feet 0 100 200 Horizontal Scale in Feet Vertical Exaggeration = 2.5X 61 JIM 130 -'' 120 t . — — --__ — — ' - — __-----'___- — i•�Itti t tJ Jttt { ttj}$ {t�/. SijE t tit 3 i.p t ft { Y} t � 4 7� tf t .{{ Itf { t tlttl}'J f SI 2 ttt� .: l} - _- .-... - _1EI��4%ttY t,G�st{ttitff Yt�:f}tf ti fstil£'{ t3S}ftt `,t}4�2"#i{�f t�}tc{t t Jf}. 66 �Y}I fair {tit$t�it:it :tits J,,;f,A,4 t ttEttl�'1iktso-tl,3lrhtti�tttItt�{i{,tt�#�tEi{tYriE{ktl tt J--1-- 110 _ ': — _ Top of Screen Depth 100 71 _ - __ _ __ _ _ __ -- - — -- Bottom of Screen Depth - 90 E - - _ .-... _------- ....... ., _ ....................... ..... - - �, - - - -- - - - - IW-1 Transducer Data - - 80 -..._ - - 76Approximate Inflow Rate 70 o__...._. 1 - 1 1 - — — m m .... .. .... - 60 CU E a, ... 81 50 o �' -_ 40 86 _ _ _ 30 20 - .;r_ .._.-.. - - - 91 10 0 100 200 300 400 500 600 700 800 900 1000 Elapsed Time (Minutes) NOTES Hydrogeologic Report New Madrona K-8 Project 1. The dry well injection test at test well IW-1 was performed from 10:03 to 18:34 on 4/25/2016. Edmonds, Washington IW-1 is screened at approximately 63.3 to 90.4 feet below grade, with filter pack from 59.2 to 91.2 feet deep. Borehole diameter was approximately 10.5 inches, drilled to 91.2 feet. INFLOW TEST RESULTS AT 2. Tap water (44,107 gallons) was introduced at the top of the 6-inch-diameter PVC casing, using a fire hydrant. 3. gpm = gallons per minute PILOT UIC WELL IW-') "n 4. Fire hydrant flow became inconsistent late in test, possibly due to increased local water demand. Gi 5. Black and white reproduction of this color original may lead to incorrect interpretation. November 2016 21-1-22082-003 V SHANNON & WILSON, INC' FIG. ? Geotechnical and Environmental Consultants IW-1-IW-1 Plot LL-11/22/2016-pvh 50 70 80 m 0 90 0 m m 100 0 L 110 fi IJ .t 140 SKI E Q 100 a' a� of 80 0 a� iU E 60 0 CL Q. Q Elf, 20 130 0 0 200 400 600 800 1000 1200 Elapsed Time (Minutes) NOTES 1. The injection test at dry well IW-2 was performed from 10/11/2016 9:09 to to 4:09 on 10/12/2016. IW-2 screen is approximately 28.3 to 119.7 feet below grade, with filter pack from about 3 to 120.4 feet deep. Filter -packed hole diameter is 30 inches from 0 to about 44 feet and approximately 24 inches from 44 to 120.4 feet. Steel 30-inch-diameter surface casing was sealed in place to 60.5 feet deep. The surface seal extends down to about 62 feet deep. 2. Tap water (153,933 gallons) was introduced at the top of the filter -packed borehole, using a fire hydrant. 8-inch stainless steel screen (20-slot) is exposed to the formation from about 62 to 119.7 feet. 3. gpm = gallons per minute 4. Black and white reproduction of this color original may lead to incorrect interpretation. 1400 1600 :Me IW-2-IW-2 Plot LL-11/22/2016-pvh 0 0 m 0 J 0 N N N 0 UIC Filter Sand for Supplementary Filtering (Min. 6" Thick, To Replace as Needed) UIC 4x8 Filter Sand, Washed, Rounded (Min. 6" Thick) Temporary UIC Well Vault with Welded or Locking Cover (To Be Replaced Later By Storm Quarry Spalls Pad Drain Manhole) (-6" Thick) Base of Qvt/Qvd or 2" 0 Threaded, Sch. 40 or Sch. Base of Perched 80 PVC Blank Casing, Top Min. Qvd/Qva Aquifer, 6" Above Top of 8" 0 Casing Whichever is Deeper--,__ ___ Unsaturated Qva 1-5' Below Contact Deposits 8" 0, 304 Stainless Steel Blank Casing, Threaded or Welded Joints Geologic Contact (Est. Depth 60-70', As Identified by Engineer's Representative) —10' of 2" 0, Threaded, Machine Slotted, Sch. 40 or Sch. 80 PVC Screen (0.020" Slots) 2" 0 Threaded PVC End Cap Bentonite, Neat Cement, or Neat Cement Grout Seal Stormwater from Distribution Manifold, Pretreated As Appropriate 36-40" 0 Borehole, Min. 4" Larger Than Surface Casing \---- Bentonite Chip Seal (Min. 10' Thick) Steel Surface Casing (30-36" 0, 0.375" Wall Thickness) 8" 0 Threaded or Welded 304 Stainless Steel End Cap Minimum 5' --115-120- ---- Seasonal High Qva Aquifer Water Level --yam Qva Aquifer Not to Scale NOTES 1. Surface casing and seal to conform to WAC 173-160. 2. Employ best management practices, as appropriate and following approved stormwater manual, to provide any required pre-treatment to water discharged to UIC wells. 3. Provide steel centralizers for 8" 0 casing and screen, installed on approximately 20' spacing. UIC Gravel, Washed, Rounded 24"-36" 0 Borehole UIC 4x8 Filter Sand, Washed, Rounded —50' of 8" 0, Continuous -Slot, 304 Stainless Steel Screen (0.020" slots), Threaded or Welded Joints. * (Required separation may be greater depending on pre-treatment, groundwater mounding potential, vadose zone treatment capacity, and pollutant loading.) Fly 99040117►:I_\ SUBSURFACE EXPLORATIONS 21-1-22082-003 SHANNONMLSORING APPENDIX A SUBSURFACE EXPLORATIONS TABLE OF CONTENTS Page A.1 GENERAL...................................................................................................................... A-1 A.2 SOIL BORINGS............................................................................................................. A -I A.2.1 Sonic Core Borings........................................................................................... A-1 A.2.2 Auger Boring.................................................................................................... A-2 A.3 SOIL SAMPLING AND LOGGING............................................................................. A-3 A.4 WELL AND VIBRATING WIRE PIEZOMETER (VWP) INSTALLATION ............. A-3 A-1 Summary of Well Installation Details A-2 Summary of Vibrating Wire Piezometer Installation Details FIGURES A-1 Soil Description and Log Key (3 sheets) A-2 Log of Sonic Core IW-1 A-3 Log of Boring IW-2 A-4 Log of Sonic Core OW-1 A-5 Log of Sonic Core OW-2 21-1-22082-003-R1 f AA/wp/ik 21-1-22082-003 A-i APPENDIX A SUBSURFACE EXPLORATIONS A.1 GENERAL The subsurface exploration program for the project was conducted by Shannon & Wilson, Inc. (Shannon & Wilson). The purpose of the exploration program was to evaluate the feasibility of deep underground injection control (UIC) wells for use in project site stormwater management. The subsurface exploration program consisted of three sonic core soil borings and one auger boring. The sonic core borings included a pilot UIC well (IW-1) and two observation wells (OW-1 and OW-2). Holt Services, Inc. (Holt) of Edgewood, Washington, completed the sonic core borings between April 4 and 21, 2016 (OW-1, IW-1), and between August 17 and 19, 2016 (OW-2), under subcontract to Shannon & Wilson. A full-scale UIC well (IW-2) was installed in the auger boring. Malcolm Drilling Company, Inc. (Malcolm) of Kent, Washington, completed IW-2 between October 5 and 6, 2016, under subcontract to Shannon & Wilson. We measured the approximate well locations in relation to previously mapped site features. PACE Engineers, Inc. provided surveyed well monument lid elevations for OW-2 and IW-2, and we measured the approximate monument and grade elevations at IW-1 and OW-1 based on the data provided for OW-2. Figure 2 shows the approximate exploration locations. Figure A-1 presents a Soil Description and Log Key that explains the terms used in the soil classifications and descriptions. The logs of the soil borings are presented as Figures A-2 through A-5. Approximate grade elevations are presented on the logs. A.2 SOIL BORINGS A.2.1 Sonic Core Borings Holt drilled the sonic core soil borings using a track -mounted, Terra Sonic International 150CC Compact Crawler sonic drill rig. Observation well boring OW-1 was completed on April 7, 2016, to a depth of 185.5 feet below ground surface (bgs). The pilot UIC well boring (IW-1) was completed on April 21, 2016, to 91.2 feet bgs. Observation well boring OW-2 was completed on August 19, 2016, to 190 feet bgs. Holt used the rotosonic (sonic) drilling method to drill the borings. Sonic drilling uses high -frequency vibratory motion applied to the top of the drill column, along with down pressure 21-1-22082-003-R1 f AA/wp/]k 21-1-22082-003 A-1 and rotation, to obtain nearly continuous core samples of soil. Soil samples were obtained using a 4-inch inside diameter (I.D.) core barrel for the observation well installation and a 7-inch I.D. core barrel for the pilot UIC well installation. As the drill column was advanced into the ground, soil entered the core barrel. After advancing the core barrel (termed a core "run"), the core barrel was removed from the borehole, and the soil core was extracted from the core barrel into labelled plastic bags. Each core run was typically about 10 feet long, although shorter runs were used in harder drilling situations. After retrieval of the soil core for a specific interval, a temporary casing was vibrated to the bottom of the sampled interval. The casing was then cleared of slough, and the drill column and core barrel were advanced, starting at the bottom of the temporary casing. Drilling and sampling progress was generally easier at the larger diameter sonic core boring, IW-1, where the 7-inch core barrel was used, than at OW-1 and OW-2, where the 4-inch core barrel was used. The fines content in some samples appeared to be lower in the larger diameter IW-1 sonic core samples that in the smaller diameter sonic core samples collected from OW-1 at the same depths. Holt's opinion was that the larger diameter tooling used at IW-1 allowed coarse gravels and cobbles to more easily enter the core barrel during sampling. When penetrating unsaturated soils, sonic core drilling and sampling were also easier if water was added during the sampling runs. Generally, the sonic core runs were drilled without adding water, so that the locations of perched groundwater zones, if any, could better be estimated. Holt drummed the sonic core drill cuttings and spoils, removing them for disposal after the completion of each sonic core boring. A.2.2 Auger Boring Malcolm completed the full-scale UIC well IW-2 on October 6, 2016, to 120.4 feet bgs. Malcolm used a Bauer BG-24 track -mounted auger drill rig to drill IW-2. Malcolm initially drilled open -hole to about 56 feet bgs. Some caving occurred at 51 to 56 feet, so Malcolm proceeded to install temporary (one -meter diameter) casing to maintain an open borehole to 61 feet. Malcolm drilled the remainder of the boring open -hole with 24-inch auger. Malcolm used a crane to install the permanent steel surface casing to 60.5 feet deep prior to completing the drilling of the boring. Malcolm placed the 30-inch I.D. steel surface casing to 60.5 feet deep and sealed it in place. Before placing the permanent surface casing, a bentonite chip seal was installed at 59.5 to 62 feet. The 30-inch I.D. casing was then temporarily backfilled with cuttings to 30 feet deep and cemented in place. The temporary one -meter diameter casing was then removed, and the cement was allowed to cure overnight. The top of cement was 10 feet bgs the 21-1-22082-003-R1 f AA/wp/]k 21-1-22082-003 A-2 next morning, and bentonite chip seals were placed from 7 to 10 feet bgs and at 0 to 1 foot. The temporary backfill placed at 1 to 7 feet consisted of filter sand. The upper 10 feet of temporary annular backfill will be replaced when the project moves to construction. Cement was found to have intruded the temporary spoils inside the 30-inch casing up to about 44 feet below grade; this material was drilled out using a 24-inch solid stem auger and was separately stockpiled from the other borehole cuttings. Some caving was experienced during drilling at about 51 feet and again at about 99 feet; these zones are identified on the boring log. Malcolm switched from a solid stem auger to a bucket auger at 101.5 feet deep to reduce caving. Auger boring IW-2 was drilled without adding water. We noted that the fines content of the auger cuttings appeared to be lower than that observed in the samples collected from similar depths at adjacent the OW-2 sonic core boring (Appendix B). Most of the auger spoils from the IW-2 boring were disposed of by Clearcreek Contractors, Inc., of Marysville, Washington. Auger spoils that were intruded by cement during the installation of the permanent IW-2 surface casing seal were disposed of by Bravo Environmental NW, Inc., of Seattle, Washington, under subcontract to Malcolm. A.3 SOIL SAMPLING AND LOGGING Shannon & Wilson representatives observed and logged the drilling operations at each of the sonic core borings (IW-1, OW-1, and OW-2) and the auger boring (IW-2). We photographed and collected sub -samples of the IW-1 and OW-2 soil cores in field, and also logged cuttings and collected grab samples from the auger boring, IW-2. Shannon & Wilson geologists logged and photographed the OW-1 soil cores in Shannon & Wilson's warehouse. Shannon & Wilson geologists also reviewed the IW-1, IW-2, and OW-2 photographs and samples. We transferred representative soil samples collected from the soil cores and auger cuttings to our Seattle, Washington, laboratory for analysis (see Appendix B). The boring logs in this report represent our interpretation of the field logs. A.4 WELL AND VIBRATING WIRE PIEZOMETER (VWP) INSTALLATION For the sonic core borings IW-1, OW-1, and OW-2, the wells were installed through the temporary casing, which was withdrawn as the annular backfill was placed. The wells were constructed of threaded Schedule 40 polyvinyl chloride (PVC) casing and machine -slotted (0.020-inch) PVC screen. The PVC casing was 6-inch I.D. for IW-1 and 2-inch I.D. for OW-1 and OW-2. The screened intervals were filter -packed with No. 10-20 Colorado silica sand. A bentonite chip surface seal was placed above each well's filter -packed zone. 21-1-22082-003-R1 f AA/wp/]k 21-1-22082-003 A-3 In addition to the observation well, two VWPs were installed in OW-2. VWP 1 was placed in a zone suspected of potentially containing perched water (at 66.3 feet bgs). VWP2 was placed in a zone where water might be expected to perch during an inflow test (at 146.3 feet bgs). The vertical transmission casing for UIC well IW-2 was constructed of threaded, 304 stainless steel, 8-inch I.D. blank casing and continuous -slot (0.020-inch) screen, with steel centralizers. Malcolm used a crane to install the 8-inch I.D. casing and screen after the borehole was completed to 120.4 feet bgs. The inside of the permanent 30-inch I.D. surface casing and the borehole annulus below the surface casing were filled with CalPortland Product 8700 (4x8) filter sand. A vertical observation pipe consisting of threaded, 2-inch I.D., PVC blank casing and machine -slotted screen (0.020-inch slots) was placed in the same borehole as the 8-inch I.D. casing and secured to the steel centralizers. Well construction details are presented on the boring logs in (Figures A-2 through A-5) and in Table A-1. Details of the VWP installations are presented in Table A-2. See Appendix C for further groundwater -related discussions. 21-1-22082-003-R1 f AA/wp/]k 21-1-22082-003 A-4 SHANNON & WILSON, INC. TABLE A -I SUMMARY OF WELL INSTALLATION DETAILS :.. ..... .. ;.Dr :. . .: .. . t. �. ;., i. ., .': .. A ; . IMP M r » nt: :. . , D .. .. , : �. .: . :: In ' " . :..: �' b ' ' I?I '.. ` . ... �. ,A �. r x.. :...... '::. .�'�... .-: A ri.. PP :: a tb .i-.... `' A stir .. . . +nrnn ' �' .. :... �' �r�n _ t , .�St� c P .. .M t . .. 'ain`t ':::�t%s3in .. D� _ S cad ,... p )f.. t _►rein 3lter.F " Screen r: .. l►v Il W . . and .. c1n ._Wejl 3 .urfe An " :'� Bn ec r` :� : has n " - , . eI n�� .' . :Riin. '�. '"r' . etc �Iter . - ..� . I,eatlon. .:`: Skit.: i i? n �Elatn:'. . � Se I► W TiS amen 1].:. . -. t!gin. - a e : EIva1ft>cn . ..... ' D nnee>r' . .. . Mat Till ::.. .* .. M{IKL1IItt nt' ....`; Eleat3 n ' ,;... filter Dei"E' in I . iIl, ; Itan 1e L >l1 , Range. Len lit'- {11it .EIE 4I n t!. Lent' 1'{' ... I..I�I;�::.:ft��t . eet. . . IW-1 BJZ 272 4/21/2016 444.9 2.65 447.6 10.5 6; PVC 0.56 447.0 No. 10-20 59.2 91.2 385.7 - 353.7 0.020 63.3 90.4 381.6 - 354.5 27.1 93.0 354.1 0.45 8; Stainless IW-2 None 10/6/2016 444.4 0.30 444.7 24 Steel3 0.93 443.8 No. 4-8 2.0 120.4 442.4 - 324.0 0.020 28.3 119.7 416.1 - 324.7 91.4 120.3 323.5 0.58 OW-1 BJZ 265 4/7/2016 445.1 3.04 448.2 6.0 2; PVC 0.38 447.8 No. 10-20 170.0 185.5 275.1 - 259.6 0.020 175.4 185.0 269.8 - 260.1 9.7 188.0 259.7 0.34 OW-2 BJX 262 1 8/19/2016 444.7 0.00 444.7 6.0 2; PVC 1 0.83 443.8 1 No. 10-20 174.8 1 184.0 1 269.9 - 260.7 0.020 179.2 1 183.9 1 265.4 - 260.8 1 4.6 1 184.1 1 259.8 0.20 Notes: Elevations based on client electronic survey file dated October 13, 2016, and on differential levels shot with reference to well OW-2 at north end of running track. The reference vertical datum is North American Vertical Datum of 1988 (NAVD 88). 2 Value shown was based on hand measurements during well construction. Unless otherwise noted, depths are referenced to ground surface. 3 At IW-2, a permanent surface casing (30-inch-diameter steel) was installed to 60.5 feet deep and cemented in place. The top of the 8-inch screen was extended up inside the 30-inch surface casing, and the interior of the 30-inch casing was filled with filter material. A 2-inch polyvinyl chloride (PVC) observation pipe was also installed at IW-2 within the 30-inch surface casing to 120.4 feet deep, screened from 60.3 - 120.2 feet deep with a 0.2-foot sump. Well OW-1 was developed on April 12, 2016, using a check valve -type inertial pump equipped with a surge block (Waterra); approximately 68 gallons of water were removed. Well OW-2 was developed on August 24, 2016, using a check valve -type inertial pump equipped with a surge block (Waterra); approximately 37 gallons of water were removed. Approx. = Approximate Ecology = Washington State Department of Ecology No. = Number 21-1-22082-003-RI f-TA-1 /wp/Ik 21-1-22082-003 SHANNON & WILSON, INC. TABLE A-2 SUMMARY OF VIBRATING WIRE PIEZOMETER INSTALLATION DETAILS iq . " Iiuit`Irii`' u: �ipprc► 'i G` V i` i� pprox;, :. urfc ,, TIC `ih : p Tu : try P. Ied crii , Anil ` `elttvu'iru =i ill ` Itler.. Linear' `Itlirat :. '.3I, ". d,. ' `1 , n ;, ., �► a Goa ., , 'ud : :Ec al MIIa� liddit 064ttc� ;:; Surface , Eiiaa .. ct I7► pt p I1 :: a Ser l � ;`lla s ar . Its R a tini .. 100 ...,` , , . t t tI)Iet}`:.~ tip ', 'i'tIsJ ;` fiis. (++Iius. . OW-2, VWP1 B,JX 262 8/19/2016 444.7 66.3 378.4 64.2 68.5 380.5 - 376.2 1624163 50 -0.01636 -0.01331 8930.3 20.7 OW-2, VWP2 BJX 262 8/19/2016 444.7 146.3 298.4 140.8 146.3 303.9 - 298.4 1624739 100 -0.02383 -0.002972 8879.9 20.9 Notes: 1 VWP = vibrating wire piezometer 2 Based on electronic client file provided on October 20, 2016. The reference vertical datum is the North American Vertical Datum of 1988. 3 Value shown was based on hand measurements during VWP construction. 4 Instrument is Geokon Model 4500S. 'Celsius degrees Celcius /=per Approx. = approximate Ecology = Washington State Department of Ecology No. = Number psi = pounds per square inch 21a-22082-003-RI f-TA-2i piuk 21-1-22082-003 Shannon & Wilson, Inc. (S& W), uses a soil identification system modified from the Unified Soil Classification System (USCS). Elements of the USCS and other definitions are provided on this and the following pages. Soil descriptions are based on visual -manual procedures (ASTM D2488) and laboratory testing procedures (ASTM D2487), if performed. S&W INORGANIC SOIL CONSTITUENT DEFINITIONS CONSTITUENT z ------------------ Major FINE-GRAINED SOILS (50%or more fines)' Silt, Lean Clay, Elastic Silt, or Fat Clay COARSE -GRAINED SOILS Mess than 50%fines)' Sand or Grave/4 Modifying (Secondary) 30% or more More than 12% Precedes major coarse -grained: fine-grained: constituent Sandy or Gravelly4 Silty or Clayey 15% to 30% 5% to 12% coarse -grained: fine-grained: Minor with Sand or with Silt or Follows major With Grave14 with Clad constituent /° 30 or more total coarse -grained and 15% or more of a lesser coarse- second coarse - grained constituent grained constituent: is 15% or more: with Sand or with Sand or with Gravels With Gravels 'All percentages are by weight of total specimen passing a 3-inch sieve. 'The order of terms is: Modifying Major with Minor. 3Determined based on behavior. 4Determined based on which constituent comprises a larger percentage. 'Whichever is the lesser constituent. MOISTURE CONTENT TERMS Dry Absence of moisture, dusty, dry to the touch Moist Damp but no visible water Wet Visible free water, from below water table STANDARD PENETRATION TEST (SPT) SPECIFICATIONS Hammer: 140 pounds with a 30-inch free fall. Rope on 6- to 10-inch-diam. cathead 2-1/4 rope turns, > 100 rpm NOTE: If automatic hammers are used, blow counts shown on boring logs should be adjusted to account for efficiency of hammer. Sampler: 10 to 30 inches long Shoe I.D. = 1.375 inches Barrel I.D. = 1.5 inches Barrel O.D. = 2 inches N-Value: Sum blow counts for second and third 6-inch increments. Refusal: 50 blows for 6 inches or less; 10 blows for 0 inches. NOTE: Penetration resistances (N-values) shown on boring logs are as recorded in the field and have not been corrected for hammer efficiency, overburden, or other factors. DESCRIPTION SIEVE NUMBER AND/OR APPROXIMATE SIZE FINES < #200 (0.075 mm = 0.003 in.) ----------- SAND — - -- — ---- — -------- Fine #200 to #40 (0.075 to 0.4 mm; 0.003 to 0.02 in.) Medium #40 to #10 (0.4 to 2 mm; 0.02 to 0.08 in.) Coarse #10 to #4 (2 to 4.75 mm; 0.08 to 0.187 in.) - ----- ------ GRAVEL --- --- --- - Fine #4 to 3/4 in. (4.75 to 19 mm; 0.187 to 0.75 in.) Coarse 3/4 to 3 in. (19 to 76 mm) COBBLES 3 to 12 in. (76 to 305 mm) BOULDERS > 12 in. (305 mm) RELATIVE DENSITY / CONSISTENCY COHESIONLESS SOILS COHESIVE SOILS N, SPT, RELATIVE N, SPT, RELATIVE BLOWS/FT. DENSITY BLOWS/FT. CONSISTENCY < 2 Very soft < 4 Very loose 4-10 Loose 2-4 Soft 10-30 Medium dense 4-8 Medium stiff 30-50 Dense 8 - 15 Stiff > 50 Very dense 15 - 30 Very stiff > 30 Hard WELL AND BACKFILL SYMBOLS Bentonite <> Surface Cement Cement Grout Seal Bentonite Grout Asphalt or Cap Bentonite Chips Slough Silica Sand 11 r Inclinometer or l I Non -perforated Casing Perforated or Screened Casing m Vibrating Wire Piezometer PERCENTAGES TERMS'' z Trace < 5% Few Little 5 to 10% 15 to 25% Some 30 to 45% Mostly 50 to 100% 'Gravel, sand, and fines estimated by mass. Other constituents, such as organics, cobbles, and boulders, estimated by volume. 2Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org. MAJOR DIVISIONS GROUP/GRAPHIC SYMBOL TYPICAL IDENTIFICATIONS GW • 66 Well -Graded Gravel; Well -Graded Gravel with Sand Gravel GP o a° Poorly Graded Gravel; Poorly Graded Gravels (less than 5% fines) (more than 50% o p Gravel with Sand of coarse fraction retained on No. 4 sieve) Silty or ClayeySiltyyGravel; Silt Gravel with Sand Gravel A Gravel; Clayey Gravel with COARSE-(morefines) than 12/Clayey GRAINED Sand SOILS SW Well -Graded Sand; Well -Graded Sand (more than 50% retained on No. 200 sieve) Sand with Gravel (less than 5% fines) SP Poorly Graded Sand; Poorly Graded Sands Sand with Gravel (50% or more of coarse fraction passes the No. 4 Silty or SM Silty Sand; Silty Sand with Gravel sieve Clayey Sand (more than 12% fines) Sc Clayey Sand; Clayey Sand with Gravel ML Silt; Silt with Sand or Gravel; Sandy or Gravelly Silt Inorganic Silts and Clays CL Lean Clay; Lean Clay with Sand or (liquid limit less Gravel; Sandy or Gravelly Lean Clay than 50) Organic OIL =— Organic Silt or Clay; Organic Silt or Clay with Sand or Gravel; Sandy or FINE-GRAINED SOILS _ _ — — — Gravelly Organic Silt or Clay (50% or more passes the No. 200 sieve) MH Elastic Silt; Elastic Silt with Sand or Gravel; Sandy or Gravelly Elastic Silt Inorganic CH Fat Clay; Fat Clay with Sand or Gravel; Silts and Clays li uid limit 50 or (q Sandy or Gravelly Fat Clay more) Organic Silt or Clay; Organic Silt or Organic OH / Clay with Sand or Gravel; Sandy or Gravelly Organic Silt or Clay HIGHLY - ORGANIC Primarily organic matter, dark in PT Peat or other highly organic soils (see SOILS color, and organic odor ASTM D4427) NOTE: No. 4 size = 4.75 mm = 0.187 in.; No. 200 size = 0.075 mm = 0.003 in. NOTES 1. Dual symbols (symbols separated by a hyphen, i.e., SP-SM, Sand with Silt) are used for soils with between 5% and 12% fines or when the liquid limit and plasticity index values plot in the CL-ML area of the plasticity chart. Graphics shown on the logs for these soil types are a combination of the two graphic symbols (e.g., SP and SML 2. Borderline symbols (symbols separated by a slash, i.e., CUML, Lean Clay to Silt, SP-SM/SM, Sand with Silt to Silty Sand) indicate that the soil properties are close to the defining boundary between two groups. Poorly Graded Narrow range of grain sizes present or, within the range of grain sizes present, one or more sizes are missing (Gap Graded). Meets criteria in ASTM D2487, if tested. Well -Graded Full range and even distribution of grain sizes present. Meets criteria in ASTM D2487, if tested. CEMENTATION TERMS' Weak Crumbles or breaks with handling or slight finger pressure. Moderate Crumbles or breaks with considerable finger pressure. Strong Will not crumble or break with finger pressure. DESCRIPTION APPROX. PLASITICITY VISUAL -MANUAL CRITERIA INDEX RANGE Nonplastic A 1/8-in. thread cannot be rolled < 4 at any water content. Low A thread can barely be rolled and 4 to 10 a lump cannot be formed when drier than the plastic limit. Medium A thread is easy to roll and not 10 to 20 much time is required to reach the plastic limit. The thread cannot be rerolled after reaching the plastic limit. A lump crumbles when drier than the plastic limit. High It takes considerable time rolling > 20 and kneading to reach the plastic limit. A thread can be rerolled several times after reaching the plastic limit. A lump can be formed without crumbling when drier than the plastic limit. Mottled Irregular patches of different colors. Bioturbated Soil disturbance or mixing by plants or animals. Diamict Nonsorted sediment; sand and gravel in silt and/or clay matrix. Cuttings Material brought to surface by drilling. Slough Material that caved from sides of borehole. Sheared Disturbed texture, mix of strengths. Angular Sharp edges and unpolished planar surfaces. Subangular Similar to angular, but with rounded edges. Subrounded Nearly planar sides with well-rounded edges. Rounded Smoothly curved sides with no edges. Flat Width/thickness ratio > 3. Elongated Length/width ratio > 3. ATD At Time of Drilling Diam. Diameter Elev. Elevation ft. Feet FeO Iron Oxide gal. Gallons Horiz. Horizontal HSA Hollow Stem Auger I.D. Inside Diameter in. Inches lbs. Pounds MgO Magnesium Oxide mm Millimeter MnO Manganese Oxide NA Not Applicable or Not Available NP Nonplastic O.D. Outside Diameter OW Observation Well pcf Pounds per Cubic Foot PID Photo -Ionization Detector PMT Pressuremeter Test ppm Parts per Million psi Pounds per Square Inch PVC Polyvinyl Chloride rpm Rotations per Minute SPT Standard Penetration Test USCS Unified Soil Classification System qu Unconfined Compressive Strength VWP Vibrating Wire Piezometer Vert. Vertical WON Weight of Hammer WOR Weight of Rods Wt. Weight Interbedded Alternating layers of varying material or color with layers at least 1/4-inch thick; singular: bed. Laminated Alternating layers of varying material or color with layers less than 1/4-inch thick; singular: lamination. Fissured Breaks along definite planes or fractures with little resistance. Slickensided Fracture planes appear polished or glossy; sometimes striated. Blocky Cohesive soil that can be broken down into small angular lumps that resist further breakdown. Lensed Inclusion of small pockets of different soils, such as small lenses of sand scattered through a mass of clay. Homogeneous Same color and appearance throughout. 'Reprinted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org. 2Adapted, with permission, from ASTM D2488 - 09a Standard Practice for Description and Identification of Soils (Visual -Manual Procedure), copyright ASTM International, 100 Barr Harbor Drive, West Conshohocken, PA 19428. A copy of the complete standard may be obtained from ASTM International, www.astm.org. Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington SOIL DESCRIPTION AND LOG KEY November 2016 21-1-22082-003 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants Total Depth: 91.2 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 10.5 in. TnprlevaUon:_- 444.92 ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: NIA ___ I U Hon�oamm: Offset: Other Comments: Refer to the report text for a proper understanding of the -50 E to 0 %Water Content subsurface materials and drilling methods. The stratification E 2 CL lines indicated below represent the approximate boundaries a) U) co U) between material types, and the transition may be gradual. 0 20 40 60 Gray -brown, Silty Sand with Gravel (SM); fine to coarse sand; nonplastic fines; diamict. Fill/Ablation TilliWeathered Till (Hf/Qvat/Qvt) - Hand -excavated to 1 foot. Standing water ............... about 1 foot below IW-1 grade in adjacent 9.0 Gray -brown, Silty Sand with Gravel (SM); wet; coarse sand; diamict pockets. X. Perched groundwater at about 11 feet during Y., ............... 12 Gray -brown to gray, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; 16 Till (Qvt) Iron oxide staining from 14 to 18 feet. LEGEND Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) 7771 Bentonite-cement Grout Bentonite Chips/Pellets Bentonite Grout * Ground Water Level ATD Hydrogeologic Report * Ground Water Level in Well New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. LISCS designation is based on visual -manual classification and selected lab testing. LOG OF SONIC CORE IW-1 Gentechnical and Environmental Consultants Sheet 1 of 5 REV - Approved for Submittal Total Depth: 91.2 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 10.5 in. Top Elevation: - 444.92 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION Refer to the report text for a proper understanding of the E E Q to subsurface materials and drilling methods. The stratification CL E o lines indicated below represent the approximate boundaries a) co (� between material types, and the transition may be gradual. - Gray from 20 to 25 feet Gray to gray -brown, Silty Sand with Gravel and 28.0 Cobbles (SM) to Silty Gravel with Sand (GM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; few subrounded cobbles; nonplastic fines; diamict pockets. Till -Like Deposits/Till (Qvd/Qvt) - Iron oxide staining from 31 to 32 feet. r Gray -brown, Silty Sand with Gravel and 38.0 Cobbles (SM) to Silty Gravel with Sand and Cobbles (GM); moist; fine, subrounded to CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content CL N a 22 ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... 24 ...:...:...:...:........ ............... ...... :...:............. ..:...:...:...:... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 26 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 28 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... 30 ........ ..................................................................................................................... ......... ......... 34 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... ................... .... .... .... .... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 36 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... .................................................................................................................. ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ... ......... ......... ......... ......... ......... ......... ......... ......... 38 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE IW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-2 Geotechnical and Environmental Consultants Sheet 2 of 5 REV 3 - Approved for Submittal Total Depth: 91.2 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 10.5 in. Top Elevation: - 444.92 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. subangular gravel; fine to coarse sand; trace to few subrounded cobbles; nonelastic fines; diamict pockets. Till -Like Deposits/Advance Outwash (Qvd/Qva) - Added water at 40 feet. � o m � Q E E 0 U) U) Gray -brown, y Sand Silt ); moist to wet; 45.0 ( SM fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict pockets. Till -Like Deposits/Advance Outwash (Qvd/Qva) Gray brown, Poorly Graded Sand with Silt and 48.0 Gravel (SP-SM) to Silty Sand with Gravel (SM); wet; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few silty sand pockets. Advance Outwash/Till-Like Deposits (Qva/Qvd) Gray, Silty Sand with Gravel (SM); moist; fine, 57.5 r subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict. a Till -Like Deposits (Qvd) CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U w 42 . ........ ..................................................................................................................... ......... ......... 44 ...:...:...:...:.............................................. .... .... .... ....... . ........ .................................................................................................................. ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... .... ......... ......... ......... ......... ......... ......... ......... 46 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... . 48 50 . .... .... .... .... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... 52 ............... .... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... 54 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... 56 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... 58 ............... ....... .... .... .... .... .... .... .... .... ....... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE IW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-2 Geotechnical and Environmental Consultants Sheet 3 of 5 REV 3 - Approved for Submittal Total Depth: 91.2 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 10.5 in. Top Elevation: - 444.92 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION � o O %Fines (<0.075mm) Refer to the report text for a proper understanding of the -Q Q %Water Content subsurface materials and drilling methods. The stratification CL T E o to CL lines indicated below represent the approximate boundaries a) co (� ) between material types, and the transition may be gradual. 0 20 40 60 61.0 Gray -brown, Poorly Graded Sand with Gravel Y � Y (SP), Poorly Graded Sand (SP), and Poorly 62 Graded Sand with Silt (SP-SM); moist; fine, subrounded to suban ular gravel; fine to 9 coarse sand; nonplastic fines. Advance Outwash (Qva) 64 ................................................................. ...:...:...:...:...:...:...:...:...:......:...:...:...:....... . :... :... :... :...... ........................... :.•. ::.. 66 ...... ................... ... ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:.... 68 :...:...:...:...:...:...:...:...:... ................... .... - Pockets of silt sand at 69 to 69.5 feet. Y ................... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... .... .... .... .... .... .... .... .... .... 70 ............... .... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... 72 :...:...:...:...:...:...:...:...:...... :...:...:...:...:...:...:...:...:... ... . 74 .......................... :...:...:...:...:...:...:...:...:...... :...:...:...:...:...:...:...:...:... :...:. ...... .................................................................................:...:...:...:...:...:...:...:...:... ........ J :.•. 76 ....................... ...................:...:...:... :...:......:...:... . ...................................... . ...:...:...:...:::...:::::::::::::::::::::::::::::: :.• ......................... ................. ....................... ... 78 r Layer of silty sand at 78 to 78.5 feet. .•=� •:� r ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:... 7 9. 0 •' 0 = Gray -brown, Poorly Graded Sand (SP) to ° Poorly Graded Sand with Silt SP-SM • moist CONTINUED NEXT SHEET 0 20 40 60 LEGEND * Sample Not Recovered Well Screen and Sand Filter N[21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ` ® Bentonite Chips/Pellets ® Bentonite Grout ca SZ Ground Water Level ATD Hydrogeologic Report = s Ground Water Level in Well New Madrona K-8 Project co NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. N 0 2. Groundwater level, if indicated above, is for the date specified and may vary. N 3. USCS designation is based on visual -manual classification and selected lab testing. N LOG OF SONIC CORE IW-1 LU o November 2016 21-1-22082-003 Of w UJ SHANNON & WILSON, INC. FIG. A-2 Geotechnical and Environmental Consultants Sheet 4 of 5 � REV 3 - Approved for Submittal Total Depth: 91.2 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 10.5 in. Top Elevation: - 444.92 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: SOIL DESCRIPTION � -5O %Fines (<0.075mm) Refer to the report text for a proper understanding of the -Q Q to %Water Content subsurface materials and drilling methods. The stratification CL T E o CL lines indicated below represent the approximate boundaries a) � (� ) between material types, and the transition may be gradual. 0 20 40 60 fine to medium sand; trace subrounded gravel; .................................................................................................................. nonp lastic fines. Advance Outwash Qva c ) - Last sample on 4/19/2016 was to 80 feet; 82 ' hole was cased to 70 feet. Dry to bottom of open hole feet at start of day on 80 P � ) Y :.:.. ..................................................................................................................... 4/20/2016. 84 ............ .......... ...:...:...:...:...:...... :...:...:...:...:...:...:...:...:... Fr :. 86 :...:...:...:...:...:...:...:...:...... ... . - Trace cobbles below 87.5 feet. 88 :.•................... ::.. 90 91.2' BOTTOM OF BORING COMPLETED 04/20/2016 92 .........................................................................................:...:...:...:...:...:...:... ......... ..................................................................................................................... ......... ......... NOTE: Well installed on 4/21/2016. Bottom ......... ......... ......... of sump cap was perforated with 5 small holes for drainage; approximately 1 inch of sediment 94 ...:...:...:...:...:...:...:...:..........:...:...:...:...:...:...:...:..........:...:...:...:...:...:...:...:...:... ..................................................................................................................... accumulated in the sump during 4/25/2016 injection test, plugging the drain holes. ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... J 96 a z ll ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:... 98 iT 0 J 0 20 40 60 LEGEND * Sample Not Recovered ( Well Screen and Sand Filter N[21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ` ® Bentonite Chips/Pellets ® Bentonite Grout ca SZ Ground Water Level ATD Hydrogeologic Report = s Ground Water Level in Well New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. N 0 2. Groundwater level, if indicated above, is for the date specified and may vary. N 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF SONIC CORE IW-1 N LU o November 2016 21-1-22082-003 Ui w SHANNON & WILSON, INC. FIG. A-2 Geotechnical and Environmental Consultants Sheet 5 of 5 REV 3 - Approved for Submittal Total Depth: 120.4 ft. wonxing: Drilling Method: Bucket ALkqer Holeoiam.: �}4 in. TnprlevaUon:_- 444.41ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. Gentechnical and Environmental Consultants Sheet 1 of 7 Total Depth: 120.4 ft. Northing: Drilling Method: Bucket Auger Hole Diam.: 24 in. Top Elevation: - 444.41 ft. Easting: Drilling Company: Malcolm Drilling Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Bauer BG-24 Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. SOIL DESCRIPTION o O % Fines (<0.075mm) Refer to the report text for a proper understanding of the Q m Q %Water Content subsurface materials and drilling methods. The stratification CL T E o to CL lines indicated below represent the approximate boundaries a) co (� a)between material types, and the transition may be gradual. n gn An Fn 22 :...:...:...:...:...:...:...:...:...... Seepage from about 23 to 26 feet with trace :> m C boulders to 15-inch-diameter. := m 24 G .. 26 ...:...:...:...:...:...:...:...:...:... ................... :....... ...... :.................. ........ 28 ...............:...:...... :...:...:...:...:...:...:...:...:...... :...:...:...:...:...:...:...:...:... . ,. 30 32 :...:...:...:...:...:...:...:...:...... 34 J 36 ::::: Tl] 37.0 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:... Gray, Silty Sand with Gravel and Cobbles (SM); moist; fine to coarse, subrounded to 38 r subangular gravel; fine to coarse sand; ...:...:...:...:...:...:...:...:..........:...:...:...:...:...:...:...:..........:...:...:...:...:...:...:...:...:... L nonplastic fines diamicfi more dense and a less sand than above). 411 CONTINUED NEXT SHEET 0 20 40 60 LEGEND * Sample Not Recovered Well Screen and Sand Filter N® Grab Sample ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ❑ ® Bentonite Grout SZ Ground Water Level ATD Hydrogeologic Report = s Ground Water Level in Well New Madrona K-8 Project NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. ni 0 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF BORING IW-2 W o November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-3 Geotechnical and Environmental Consultants Sheet 2 of 7 REV 3 - Approved for Submittal Total Depth: 120.4 ft. Northing: Drilling Method: Bucket Auger Hole Diam.: 24 in. Top Elevation: - 444.41 ft. Easting: Drilling Company: Malcolm Drilling Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Bauer BG-24 Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the E E Q to subsurface materials and drilling methods. The stratification CL E o lines indicated below represent the approximate boundaries a) co (� between material types, and the transition may be gradual. Till (Qvt) ,0 Gray -brown, Silt Sand with Gravel SM ; wet; 47.0 y y ( ) : zG 9 nG fine to coarse subrounded to suban ular gravel; fine to coarse sand; low plasticity fines; diamict pockets. 49.0 Till -Like Deposits (Qvd) Gray -brown, Poorly Graded Sand with Silt (SP-SM); wet; trace to few, fine to coarse, 3G rounded to subrounded gravel; fine to coarse sand; seepage and caving during open -hole 9 9 p drilling. Advance Outwash (Qva) - With cobbles from about 52 to 54 feet. - Drilled open hole from 0 to 54 feet; caved to 52 feet after auger pass from 51 to 54 feet; set 1 m. casingto 61 feet to control caving. g 55.0 Brown -gray, Silty Gravel with Sand (GM); wet; fine to coarse, subangular to subrounded aG gravel; fine to coarse sand; nonelastic to low plasticity fines; diamict pockets. Till -Like Deposits/Advance Outwash (Qvd/Qva) �& 5 G CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter ® Grab Sample ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content CL N a 42 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... . ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 44 ......... .................................................................................................................. ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 46 ...:...:...:...:...:...:...:...:...:......:...:... .... .... .... .... .... .... ....... ................... :...............:...:...:...:... . ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... 48 ................... . 50 52 54 56 58 ...:...:........... ............... ...... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF BORING IW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-3 Geotechnical and Environmental Consultants Sheet 3 of 7 REV 3 - Approved for Submittal Total Depth: 120.4 ft. wonxing: Drilling Method: Bucket ALkqer Holeoiam.: �}4 in. TnprlevaUon:_- 444.41ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. Gentechnical and Environmental Consultants Sheet 4 of 7 Total Depth: 120.4 ft. wonxing: Drilling Method: Bucket ALkqer Holeoiam.: �}4 in. TnprlevaUon:_- 444.41ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. Gentechnical and Environmental Consultants Sheet 5 of 7 Total Depth: 120.4 ft. wonxing: Drilling Method: Bucket ALkqer Holeoiam.: �}4 in. TnprlevaUon:_- 444.41ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. Gentechnical and Environmental Consultants Sheet 6 of 7 Total Depth: 120.4 ft. Northing: Drilling Method: Bucket Auger Hole Diam.: 24 in. Top Elevation: - 444.41 ft. Easting: Drilling Company: Malcolm Drilling Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Bauer BG-24 Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 39-in. (1-m.) hole from 0 to 61 ft. SOIL DESCRIPTION o O % Fines (<0.075mm) Refer to the report text for a proper understanding of the Q m Q %Water Content subsurface materials and drilling methods. The stratification CL T E o to CL lines indicated below represent the approximate boundaries a) � (� a)between material types, and the transition may be gradual. n gn An r'o 120.4 BOTTOM OF BORING COMPLETED 10/6/2016 NOTE: Well casing and screen: 8-inch 122 threaded 304 stainless steel, with 4 centralizers on about 30-foot centers. Surface casing: 30-inch steel to 60.5 feet deep. Well screen (0.020-inch 124 continuous -slot) from approximately 28.3 feet deep (top is inside 30-inch surface casing) to 119.7 feet deep, with 0.6-foot sump. 24-inch borehole 126 and interior of 30-inch casing filter -packed with 48 sand. Observation pipe (2-inch Schedule 40 PVC) installed in filter pack adjacent 128 to 8-inch casing and screen, with 0.020-inch machine -slotted screen from approximately 60.3 to 120.2 feet 130 deep, and a 0.2-foot sump. Approximately 1.2 feet of sediment accumulated in the 8" sump and screen during the 10/11-10/12/2016 132 injection test. LEGEND * Sample Not Recovered = Well Screen and Sand Filter ® Grab Sample ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. 134 136 138 ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ..... ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... .... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF BORING IW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-3 Geotechnical and Environmental Consultants Sheet 7 of 7 REV 3 - Approved for Submittal Total Depth: 185.5 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 6 in. TnprlevaUon:_- 445. 11ft._ Easng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. Gentechnical and Environmental Consultants Sheet 1 of 10 Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. (GM); moist; trace to few subrounded cobbles; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict. Till (Qvt) - Bottom of temporary 7-inch casing set at 20 feet. - Gray -brown to gray below 25 feet. Gray -brown, Silty Sand with Gravel (SM) to Silty Gravel with Sand (GM): moist: fine to 39.0 o m � Q E T co U) U) CONTINUED NEXT SHEET LEGEND * Sample Not Recovered = Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U 22 ........ ..................................................................................................................... ......... ......... 24 ....................... ....................... .... .... .... ....... ........ .................................................................................................................. ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... .... ......... ......... ......... ......... ......... ......... ......... ......... ......... 26 ......... ......... .... .... .... .... ....... ......... ................... .... .... .... .... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 28 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ...... ..................................................................................................................... ......... ......... ......... .. .... ......... ......... ......... ......... : ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 30 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..... ..................................................................................................................... ......... ......... ......... .... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... .................................................................................................................. ......... ..................................................................................................................... ......... ......... ......... ......... ... ......... ......... ......... ......... ......... ......... 32 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 34 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 36 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 38 ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 2 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict. Till -Like Deposits/Till (Qvd/Qvt) - Drilled tight and sticky from 40 to 50 feet. - Stopped on 4/4/2016 after sampling to 50 feet. Added water during cleanout run from 40 to 50 feet, prior to sample run 7. Gray -brown, Silty Sand with Gravel (SM) to Silty Gravel with Sand (GM); moist to wet; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict pockets. Advance Outwash/Till-Like Deposits (Qva/Qvd) - Moist below 53 feet. 50.0 Gray, Silty Sand with Gravel (SM); moist; fine 55.5 to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict pockets; easier drilling than above. y Till -Like Deposit/Advance Outwash (Qvd/Qva) Y o m � Q E T co U) U) F CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U 42 . ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... .................................................................................................................... ........ ......... ......... ......... ......... .......... ......... ......... ......... ......... ..... .... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... 44 .................................................................................................................. ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ .... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... 46 ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ........ ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ...... ..................................................................................................................... 48 : ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ..................................................................................................................... ......... ......... ......... .. .... ......... ......... ......... ......... ........ ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 50 ...:...:...:...:...:...:...:...:...:......:...:... ......... .... .... .... .... .... .... ....... ......... ........ ......... ......... 52 54 ::::::::::::::::::::::::::::::::: 56 ........ ......... ......... 58 ..................................................................................................................... ........ ......... ......... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 3 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. Gray -brown, Poorly Graded Sand with Silt (SP-SM); moist; few fine to coarse, subrounded to subangular gravel; fine to medium sand; nonplastic fines. Advance Outwash (Qva) - Layer of poorly graded gravel with sand from 62.1 to 62.5 feet. - Layer of silty sand with gravel from 62.5 to 63 feet. Gray -brown, Poorly Graded Sand with Gravel and Cobbles (SP); moist; trace subrounded cobbles; fine to coarse, subrounded to subangular gravel; fine to coarse sand; trace nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand (SP) to Silty Sand (SM); moist; few fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few diamict pockets. ,Advance Outwash (Qva) Gray -brown, Poorly Graded Gravel with Silt, Sand, and Cobbles (GP -GM); moist; trace subangular cobbles; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines. AAdvance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; fines content may be elevated due to drilling method. Advance Outwash (Qva) - Hard drilling 77 to 80 feet. - Added water during cleanout run at 70 to 80 feet. prior to sample run 10. � o m � Q E E 0 U) U) 65.0 68.5 70.0 72.5 CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U w Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 4 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. E CL a) o -Q E f jco m Q E Gray -brown, Poorly Graded Sand with Silt and 80.0< Gravel (SP-SM) to Silty Sand with Gravel < (SM); moist; fine to coarse, subrounded to < subangular gravel; fine to coarse sand; < nonplastic fines. < Advance Outwash (Qva) < o< < 86.7 < < Gray -brown, Poorly Graded Sand with Gravel (SP) to Poorly Graded Gravel with Sand (GP); < moist; fine to coarse, subrounded to < subangular gravel; fine to coarse sand; < nonplastic fines. < Advance Outwash (Qva) < - Added water during cleanout run from 80 to r<< 90 feet, prior to sample run 11. < Gray -brown, Poorly Graded Sand with Silt, 93.5 Gravel, and Cobbles (SP-SM) to Silty Sand with Gravel and Cobbles (SM); moist; trace subangular cobbles; fine to coarse, subrounded to subangular gravel; fine to 96.0 coarse sand; nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Gravel (SP); moist; fine subrounded to subangular gravel; fine to coarse sand; trace nonplastic 98.5 fines. Advance Outwash(Qva) L CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout a Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U [w Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 5 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. Gray -brown, Silty Sand with Gravel and Cobbles (SM); moist; trace subrounded cobbles; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines. lAdvance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Poorly Graded Sand (SP); moist; fine subrounded to subangular gravel; fine to coarse sand; nonplastic fines. Advance Outwash (Qva) Layer of silty sand from 101 to 101.3 feet. Gray -brown, Poorly Graded Sand with Gravel (SP) to Poorly Graded Sand with Silt and Gravel (SP-SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines. (Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Silty Sand (SM); moist; trace to few, fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; fines content may be elevated due to drilling method. Advance Outwash (Qva) - Added water during cleanout run from 100 to 110 feet and during extraction of sample run 13. Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few silty sand pockets. Advance Outwash (Qva) � o m � Q E E 0 U) U) 105.0 '•. 107.5 112.5 CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U w 102 ........ ..................................................................................................................... ......... ......... 104 106 ... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... 108 ........................................................................... 110 .... .... .... .... .... .... .... ....... .... .... .... .... .... .... .... .... ....... . 112 . 114 ........ ..................................................................................................................... ......... ......... ......... ......... ......... 116 ..................................................................................................................... ......... ..................................................................................................................... ......... ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... ......... ......... ......... ......... 118 . ........ ......... ......... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 6 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. - Tried adding second 10-foot core barrel so could sample and clean out at same time. Coring hard and slow. Added water during extraction of sample run 14. Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM); moist; fine to coarse, subrounded to subangular gravel; fine to medium sand; nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Poorly Graded Sand (SP); moist; trace to few fine, subrounded to subangular gravel; fine to medium sand; nonplastic fines; few silty sand pockets from 123 to 125 feet. Advance Outwash (Qva) - Added water during cleanout run from 120 to 130 feet and during extraction of sample run 15. Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Silty Sand (SM); moist; trace subangular, fine gravel; fine to medium sand; nonplastic fines; few silty sand clasts. Advance Outwash (Qva) - Last sample on 4/5/2016 was to 140 feet; hole was cased to 130 feet. Possible perched water measured at 132.5 feet at start of day on 4/6/2016 (hole had caved to 133.5 feet). Gray -brown, Silty Sand (SM); wet; trace fine, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; slight diamict texture. Advance Outwash (Qva) 0 % Fines (<0.075mm) Q • % Water Content to O a)� 0 U) co to >� > N 0 0 122.0 130.0 Gray -brown, Silty Sand (SM) to Poorly Graded Sand with Silt SP-SM ; moist trace fine CONTINUED NEXT SHEET LEGEND * Sample Not Recovered = Well Screen and Sand Filter [2] Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. 122 ..................................................................................................................... ......... ........ ......... ......... ......... ......... 124 126 ...:...:...:...:...:...:...:...:...:... ................... .... .... .... .... ....... ... .... .... .... .... .... .... 128 ... 130 ........ ......... ......... 132 134 ...:...:...:...:.:...:...:...:...:..... 136 ...................... ................... .... .... .... .... ....... ..................................................................................................................... ......... ........ ......... ......... ......... ......... 138 ...:...:...:...:...:...:...:...:...:......:...:...:...:...:...:...:...:...:...... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 7 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 445.11 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few silty sand clasts. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Poorly Graded Sand (SP); trace fine, subrounded to subangular gravel; fine to medium sand; nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt (SP-SM); moist; fine to medium sand; nonplastic fines. `Advance Outwash (Qva) Gray -brown, Silty Sand (SM); moist; fine sand; nonplastic fines. Advance Outwash (Qva) � o m � Q E E 0 U) U) Gray -brown to gray, Silty Sand with Gravel 151.8 ; (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; fines content may be elevated due to drilling method. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Poorly Graded Sand with Gravel (SP); moist; fine subrounded to subangular gravel; fine to medium sand; 157.0rl (nonplastic fines. Advance Outwash (Qva) Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Poorly Graded Sand (SP); moist; trace to few fine, subrounded to subangular CONTINUED NEXT SHEET LEGEND * Sample Not Recovered = Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U w Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-1 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-4 Geotechnical and Environmental Consultants Sheet 8 of 10 REV 3 - Approved for Submittal Total Depth: 185.5 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 6 in. TnprlevaUon:_- 445. 11ft._ Easng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. Gentechnical and Environmental Consultants Sheet 9 of 10 Total Depth: 185.5 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 6 in. TnprlevaUon:_- 445. 11ft._ Easng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: Terrasonic Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 20 ft. NOTES / Refer mKEY for explanation msymbols, codes, abbreviations and definitions. e.Groundwater level, nindicated above, /xfor the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. Hydmgaoogic Report New K4odmnaK-8Project | Edmonds, Washington I LOG OF SONIC CORE OW-1 November 2010 21'1-22082'003 Gentechnical and Environmental Consultants Sheet 10 of 10 REV - Approved for Submittal Total Depth: 190 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 6 in. TnprlevaUon:_- 444.67 ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. Gentechnical and Environmental Consultants Sheet 1 of 7 Total Depth: 190 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 444.67 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. SOIL DESCRIPTION zl� Refer to the report text for a proper understanding of the E E Q to subsurface materials and drilling methods. The stratification E o CL lines indicated below represent the approximate boundaries a) � (� between material types, and the transition may be gradual. - Brown to gray -brown from 30 to 31 feet. - Wet from approximately 35 to 35.5 feet. 35 Gray -brown, Silty Sand with Gravel (SM); wet; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; diamict pockets. Till -Like Deposits (Qvd/Qva) - Advanced below 50 feet with 6-inch casing. Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Poorly Graded Gravel with Silt and Sand (GP -GM); wet; fine to coarse, subrounded to angular gravel; fine to coarse sand; nonplastic fines. Advance Outwash/Till-Like Deposits (Qva/Qvd) CONTINUED NEXT SHEET LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well -L Ground Water Level in VWP NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. 55 0 % Fines (<0.075mm) • % Water Content .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... .................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... .......................:...:...:...... :...:...:...:...:...:...:...:...:... 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-5 Geotechnical and Environmental Consultants Sheet 2 of 7 REV 3 - Approved for Submittal Total Depth: 190 ft. wonxing: Drilling Method: Sonic Core Holeoiam.: 6 in. TnprlevaUon:_- 444.67 ft._ Eas ng: Drilling Company: Rodmam.: 1&IA___ U Vert. Datum: &AVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: NIA U Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. Gentechnical and Environmental Consultants Sheet 3 of 7 Total Depth: 190 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 444.67 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. SOIL DESCRIPTION Refer to the report text for a proper understanding of the subsurface materials and drilling methods. The stratification lines indicated below represent the approximate boundaries between material types, and the transition may be gradual. Gray -brown, Poorly Graded Sand with Silt and Gravel (SP-SM) to Silty Sand with Gravel (SM); trace to little, fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; fines content may be elevated due to drilling method. Advance Outwash (Qva) Gray -brown, Well Graded Sand with Silt and Gravel (SW-SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few silty sand seams; fines content may be elevated due to drilling method. Advance Outwash (Qva) - With layers of poorly graded sand with silt below 109 feet. Gray -brown, Well Graded Sand with Silt, Gravel, and Cobbles (SW-SM); moist; trace subrounded cobbles; fine to coarse, subrounded to subangular gravel; fine to coarse sand; nonplastic fines; fines content may be elevated due to drilling method. Advance Outwash (Qva) � o m � Q E E 0 U) U) i1mi I M Xo - Layer of poorly graded sand with silt and gravel from approximately 118.3 to 119 feet. < CONTINUED NEXT SHEET LEGEND * Sample Not Recovered = Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well -L Ground Water Level in VWP NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. O % Fines (<0.075mm) • % Water Content U w ...................................................... 95 100 ..................................................................................................................... ......... ......... ......... ......... ......... ......... 105 ......... ......... ......... ......... ......... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... 110 ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 115 0 20 40 60 Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-5 Geotechnical and Environmental Consultants Sheet 4 of 7 REV 3 - Approved for Submittal Total Depth: 190 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 444.67 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. SOIL DESCRIPTION � o � O %Fines (<0.075mm) Refer to the report text for a proper understanding of the -Q Q � to %Water Content subsurface materials and drilling methods. The stratification CL T E o CL lines indicated below represent the approximate boundaries a) co (� ) between material types, and the transition may be gradual. 0 20 40 60 v - Sampled to 126 feet and cased to 110 feet on 8/17/2016. No recovery from 121 to 126 ..................................................................................................................... feet (sample fell out of core barrel). Hole was open and dry to 118 feet on morning of ° ° ...... ......... ........ 8/18/2016. 125 - Added water prior to sample run 15 to assist 126.0' with sample retrieval. ' ' ............................................................................ Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Silty Sand (SM); moist; few fine, : subrounded to subangular gravel; fine to coarse sand; nonplastic fines; few poorly 130.0 , 130 , • : graded sand with silt seams; fines content may be elevated due to drilling method. ..................................................................................................................... ... .:::::::: Advance Out(Qva) ° ...................................................................................................... Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Silty Sand (SM); moist; trace to few, fine to coarse, subrounded to subangular 135 gravel; fine to medium sand; nonplastic fines. Advance Outwash (Qva) ..................................................................................................................... - Layer of silty sand at 136.5 to 137 feet. Y. *� 140 142.0 ; , . ......... ......... .... ....... . Gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to medium sand; nonplastic fines; fines content may be elevated 145 .................................................................................................................. to drilling method. 145.5 •' , ; . Adue Advance Outwash (Qva) ..................................................................................................................... ... ......... ......... Gray, Silty Sand (SM); moist; few fine to coarse, subrounded to subangular gravel; fine ......... ......... ......... to coarse sand; nonplastic fines; few baked, .. . o ` . . . . . . . . . . . . . . . . . . CONTINUED NEXT"" 0 20 40 60 LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout * Ground Water Level ATD Hydrogeologic Report s Ground Water Level in Well New Madrona K-8 Project Ground Water Level in VWP NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF SONIC CORE OW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. FIG. A-5 Geotechnical and Environmental Consultants Sheet 5 of 7 REV 3 - Approved for Submittal Total Depth: 190 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 444.67 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. SOIL DESCRIPTION � o � O %Fines (<0.075mm) Refer to the report text for a proper understanding of the -Q Q � to %Water Content subsurface materials and drilling methods. The stratification CL T E o CL lines indicated below represent the approximate boundaries a) co (� ) between material types, and the transition may be gradual. 0 20 40 60 elevated due to drilling method. Advance Outwash (Qva) ........................................... ............................................. - Increased silt below 147 feet. - Added water prior to sample run 19. o 0 ......... ......... ......... Gray -brown, Silty Sand with Gravel (SM); moist; fine to coarse, subrounded to subangular gravel; fine to coarse sand; o 155 ......... ......... ......... o ......... ......... ......... nonplastic fines; diamict; fines content may be 156.5 ......... ......... ......... elevated due to drilling method. Till -Like Deposits/Advance Outwash (Qvd/Qva) .... . .................................. Gray -brown, Poorly Graded Gravel with Silt and Sand (GP -GM) to Poorly Graded Gravel 160.0 , ; . • 160 with Sand (GP); moist; fine to coarse, ......... ......... ......... ......... ......... ......... subrounded to subangular gravel; fine to "' coarse sand; nonplastic fines. dvance Outwash (Qva) o ................................................................................... .................................. Gray, Silty Sand with Gravel (SM); wet; fine, subrounded to subangular gravel; fine to .:• 165 coarse sand; nonplastic fines (possibly baked during drilling); few diamict clasts; trace silt seams; fines content may be elevated due to .. drilling method. ". Advance Outwash/Till-Like Deposits N (Qva/Qvd) 170 ......... ..................................................................................................... ......... ......... Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Silty Sand (SM); moist; few fine to : ..... ......... coarse, subrounded to subangular gravel; fine 172.5 , , • to medium sand; nonplastic fines; few sandy silt seams; trace mica Advance Outwash (Qva) :. 175 ......... ......... ......... - Saturated below about 169 feet, and drilled hard/tight from 170 to 172 feet. ......... ......... ......... Gray -brown, Poorly Graded Sand with Silt (SP-SM) to Poorly Graded Sand (SP); wet; • trace to few fine gravel; nonplastic fines; fine CONTINUED NEXT SHEET 0 20 40 60 LEGEND * Sample Not Recovered Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout * Ground Water Level ATD Hydrogeologic Report s Ground Water Level in Well New Madrona K-8 Project Ground Water Level in VWP NOTES Edmonds, Washington 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. LOG OF SONIC CORE OW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. FIG. A-5 Geotechnical and Environmental Consultants Sheet 6 of 7 REV 3 - Approved for Submittal Total Depth: 190 ft. Northing: Drilling Method: Sonic Core Hole Diam.: 6 in. Top Elevation: - 444.67 ft. Easting: Drilling Company: Holt Services Inc. Rod Diam.: N/A Vert. Datum: NAVD 88 Station: Drill Rig Equipment: TerraSonic Hammer Type: N/A Horiz. Datum: Offset: Other Comments: 7-in. hole from 0 to 50 ft. SOIL DESCRIPTION o O % Fines (<0.075mm) Refer to the report text for a proper understanding of the -Q E Q to 0 % Water Content subsurface materials and drilling methods. The stratification E o CL lines indicated below represent the approximate boundaries a) U)CU (� between material types, and the transition may be gradual. 0 20 40 60 to coarse sand; trace mica. 180.0 Advance Outwash (Qva) ......... . - Layer of silty, fine to medium sand (SM) ::' " ..................................................................................................................... from 175.5 to 176 feet. 00: - Cased to 180 feet before sample run 22. ::::: N Gray -brown, Poorly Graded Sand (SP); wet; nonplastic fines; fine to coarse sand (trace to 185 few coarse sand); no to trace fine to coarse, ......... ..................................................................................................................... ......... ......... ......... ......... ......... subrounded gravel; trace mica. Advance Outwash (Qva) :.: ......................................................................................................... - Heaved to 172 feet after sample run 22. ......... ......... ......... Cased to 185 feet and washed out heave prior to well installation. 190.0 190 ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... BOTTOM OF BORING COMPLETED 8/19/2016 ......... ..................................................................................................................... ......... ......... ......... ......... ......... NOTE: Well installed on 8/19/2016. ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 195 ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ........ ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 200 ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ........ ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 205 ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ........ ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ..................................................................................................................... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... ......... 0 20 40 60 LEGEND * Sample Not Recovered = Well Screen and Sand Filter [21 Soil Core (as in Sonic Core Borings) ® Bentonite-Cement Grout ® Bentonite Chips/Pellets ® Bentonite Grout SZ Ground Water Level ATD 1 Ground Water Level in Well -L Ground Water Level in VWP NOTES 1. Refer to KEY for explanation of symbols, codes, abbreviations and definitions. 2. Groundwater level, if indicated above, is for the date specified and may vary. 3. USCS designation is based on visual -manual classification and selected lab testing. Hydrogeologic Report New Madrona K-8 Project Edmonds, Washington LOG OF SONIC CORE OW-2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. I FIG. A-5 Geotechnical and Environmental Consultants Sheet 7 of 7 REV 3 - Approved for Submittal EWa,SLY1 M.I. 11111 11 I ' SHANNON SON, ING - 21-1-22082-003 SHANNON 6\MLS- ON, ING R I- j 014111 ocei a, 101 [W3. 0 W.11 00 IX-14 0) 1A0xiIl►rlI I le TABLE OF CONTENTS Page B.1 VISUAL CLASSIFICATION ......................................................................................... B-1 B.2 WATER CONTENT DETERMINATION ...................................................................... B-1 B.3 GRAIN SIZE DISTRIBUTION ANALYSIS .................................................................. B-1 B.4 CONSIDERATIONS ....................................................................................................... B-2 B.5 REFERENCES ................................................................................................................ B-2 Laboratory Terms Sample Types Laboratory Test Summary TABLES NUM11 Grain Size Distribution Plot, Boring IW-2 Grain Size Distribution Plot, Boring OW-1 Grain Size Distribution Plot, Boring OW-2 21-1-22082-003-R] f-AB/wp/lk 21-1-22082-003 B-i SHANNON S- , ING R I - We performed geotechnical laboratory testing on selected soil samples retrieved from the three borings completed for the New Madrona K-8 Project's Geotechnical Report. The laboratory testing program included tests to classify the soil and provide data for hydrogeologic studies related to underground injection control well feasibility and design. We performed visual classification on retrieved samples. Our laboratory testing program included water content determinations and grain size distribution analyses. The following sections describe the laboratory test procedures. B.1 VISUAL CLASSIFICATION We visually classified soil samples retrieved from the borings using a system based on ASTM International (ASTM) D2487-11, Standard Test Method for Classification of Soil for Engineering Purposes (ASTM, 2011), and ASTM D2488-09a, Standard Recommended Practice for Description of Soils (Visual -manual Procedure) (ASTM, 2009). Appendix A summarizes our classification system. We assigned a Unified Soil Classification System (USCS) group name and symbol, based on our visual classification of particles finer than 76.2 millimeters (3 inches). We revised visual classifications using results of the index tests discussed below. I 0 of 01301111401 a 11 a 0 oI.1u 11►`/_r 0 [130 We tested the water content of selected samples in accordance with ASTM D2216-10, Standard Method for Laboratory Determination of Water (Moisture) Content of Soil, Rock, and Soil - aggregate Mixtures (ASTM, 2010). Comparison of the water content of a soil with its index properties can be useful in characterizing soil unit weight, consistency, compressibility, and strength. The tables in Appendix B and boring logs in Appendix A include the water content test results. Grain size distribution analyses separate soil particles through mechanical or sedimentation processes. Grain size distributions are used to classify the granular component of soils and can correlate with soil properties, including frost susceptibility, permeability, shear strength, liquefaction potential, capillary action, and sensitivity to moisture. Appendix B includes grain size distribution analysis results in graphical format. Grain size distribution plots provide tabular 21-1-22082-003-Rl f AB/wp(Ik 21-1-22082-003 B-1 SHANNON S- , ING information about each specimen, including: USCS group symbol and group name, water content, constituent (i.e., cobble, gravel, sand, and fines) percentages, coefficients of uniformity and curvature, if applicable, personnel initials, ASTM standard designation, and testing remarks. Constituent percentages are presented in the Laboratory Test Summary in this appendix and fines contents are plotted as data points in borings logs in Appendix A. Sieve Analysis: We performed mechanical sieve analyses on selected soil specimens to determine the grain size distribution of coarse -grained soil particles, in accordance with ASTM C136/C136M-14, Standard Test Method for Sieve Analysis of Fine and Coarse Aggregates (ASTM, 2014). BA CONSIDERATIONS Drilling and sampling methodologies may affect the outcome of prescribed geotechnical laboratory tests. Refer to the field exploration discussion in this report for a discussion of these potential effects. Instances of limited recovery may have resulted in test samples not meeting specified minimum mass requirements, per ASTM standards. Test plots show which samples do not meet ASTM specified minimum mass requirements. B.5 REFERENCES ASTM International (ASTM), 2009, Standard practice for description and identification of soils (visual/manual procedure), D2488-09a: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 11 p., available: www,astm.or . ASTM International (ASTM), 2010, Standard test methods for laboratory determination of water (moisture) content of soil and rock by mass, D2216-10: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 7 p., available: www.astm.org. ASTM International (ASTM), 2011, Standard practice for classification of soils for engineering purposes (unified soil classification system), D2487-11: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.08, soil and rock (I): D420 - D5876, 12 p., available: www.astm.org. ASTM International (ASTM), 2014, Standard test method for sieve analysis of fine and coarse aggregates, C136-14: West Conshohocken, Pa., ASTM International, Annual book of standards, v. 04.02, concrete and aggregates, 5 p., available: www.astip.org. 21-1-22082-003-Rl f AB/wp(Ik 21-1-22082-003 B-2 g:r_lL,ILr owat+wi16Y•1LMILI � % Percent * Sample specimen weight did not meet required minimum mass for the test method ASTM Std. ASTM International Standard Ce Coefficient of curvature Clay -size Soil particles finer than 0.002 millimeter cm Centimeter cm Square centimeter Coarse -grained Soil particles coarser than 0.075 min (cobble-, gravel- and sand -sized particles) Cobbles Soil particles finer than 305 mm and coarser than 76.2 min Cn Coefficient of uniformity CU Consolidated Undrained E Axial strain Fine-grained Soil particles finer than 0.075 nun (silt- and clay -sized articles) ft Feet m Wet unit weight Gravel Soil particles finer than 76.2 min and coarser than 4.75 min GS Specific gravity of soil solids Hn Initial height AH Change in height AHI.ad End of load increment deformation in Inch in Cubic inch LL Liquid Limit min Minute nun Millimeter µm Micrometer MPa Mega -Pascal NP Non -plastic OC Organic content p Total stress p' Effective stress Pa Pascal pef Pounds per cubic foot PI Plasticity Index PL Plastic Limit psf Pounds per square foot q Deviatorie stress Sand Soil particles finer than 4.75 min and coarser than 0.075 min sec Second Silt Soil particles finer than 0.075 min and coarser than 0.002 min t Time to n% primary consolidation tload Duration of load increment tsf Short tons per square foot USCS Unified Soil Classification System UU Unconsolidated-Undrained WC Water content 21-1-22082-003-R1-AA-Lab Tables -Terms and Test SummarylwpAk 21-1-22082-003 SHANNON & WILSON, INC. SAMPLE TYPES 2SS 2ST 3HSA 3SS 4SS 6SS CA MC CA SPT CORE DM DMR GRAB GUS OSTER PITCHER PMT PO PT ROCK SCORE SHI SH2 SH3 SPT SS ST STW TEST TR TW UNDIST VANE WATER 2.5" O.D. Split Spoon Sample 2" O.D. Thin -Walled Tube 3" CME HSA Sampler 3" O.D. Split Spoon Sample Soil particles finer than 0.002 millimeter 6" I.D. Split Spoon Sample Modified California Sampler Standard Penetration Test (SPT) Rock Core + 3.25" O.D. Split Spoon Sample 3.25" Sampler With Internal Rinas Grab Sample 3.0" O.D. GUS Samph 3.0" O.D. Osterber>? Sam 3" O.D. Pitcher Sample Pressuremeter Test (f failed) Porter Penetration Test Sampl 2.5" O.D. Thin -Walled Tube Rock Core Sample Soil Core (as in Sonic Core Borij 1" Plastic Sheath 2" Plastic Sheath with Soil Reco, 2" Plastic Sheath with no Soil Rec 2.0" O.D. Split Spoon Samp1E 3" O.D. Thin -Walled Tube 3" O.D. Thin -Walled Tube Sample Test Interval TR Test Thin Wall Sample Undisturbed Sample Vane Shear Water sample for Probe Loe 21-1-22082-003-RI-AA-I.ab Tables -Terms and Test Summary/wp/lk 21-1-22082-003 SHANNON & WILSON, INC. LABORATORY TEST SUMMARY s,. ; zs ,. . , ,, .. =i Britt ., C7trhUtt. > ,E; IW-2 91 S-12 GRAB SP 7.3 17* 78* 4.3* 4.0 0.8 Poorly Graded Sand with Gravel IW-2 98 S-14 GRAB SP 3.3 37* 62* 0.8* 8.5 0.5 Poorly Graded Sand with Gravel IW-2 111 S-16 GRAB SW-SM 5.1 21 * 71 * 8.6* 7.9 1.3 Well -graded Sand with Silt and Gravel IW-2 119 S-18 GRAB SW-SM 5.0 11 81 8.7 6.3 1.4 Well -graded Sand with Silt OW-1 Soil particles finer than 0.002 millimeter R-7 SCORE SM 5.2 22 56 22 Silty Sand with Gravel OW-1 63.5 R-8 SCORE SP-SM 4.8 7* 84* 9.5* 4.8 2.2 Poorly Graded Sand with Silt OW-1 87.5 R-10 SCORE SP 9.1 34* 61* 4.5* 17.9 0.4 Poorly Graded Sand with Gravel OW-1 108 R-11 SCORE SM 4.7 7* 74* 19* Silty Sand OW-1 125 R-14 SCORE SP-SM 6.5 2 90 8.1 3.8 1.6 Poorly Graded Sand with Silt OW-1 135 R-15 SCORE SM 9.2 4* 70* 26* Silty Sand OW-1 153 R-17 SCORE SP-SM 5.0 4* 88* 8* 4.1 1.5 Poorly Graded Sand with Silt OW-1 182 R-21 SCORE SP-SM 18.6 7 88 5.1 2.3 1.2 Poorly Graded Sand with Silt OW-2 12 R-2 SCORE 10.8 OW-2 56 R-7 SCORE SP-SM 10.4 19* 74* 7.3* 5.6 0.8 Poorly Graded Sand with Silt and Gravel OW-2 72 R-9 SCORE SP-SM 15.2 2* 89* 9* 4.2 1.7 Poorly Graded Sand with Silt OW-2 82 R-10 SCORE SM 6.3 5* 78* 16* Silty Sand OW-2 91.5 R-11 SCORE SM 8.8 12* 68* 20* Silty Sand OW-2 107 R-12 SCORE SW-SM 3.8 26* 62* 12* Well -graded Sand with Silt and Gravel OW-2 128 R-15 SCORE SM 4.7 14* 70* 16* Silty Sand OW-2 137.5 R-17 SCORE SP-SM 4.3 5* 88* 7.4* 3.1 2.6 Poorly Graded Sand with Silt OW-2 151.5 R-19 SCORE SM 6.2 10* 56* 34* Silty Sand OW-2 154 R-19 SCORE SP-SM 1.8 36* 58* 5.2* 15.3 0.5 Poorly Graded Sand with Silt and Gravel OW-2 182.5 R-22 SCORE SP 15.1 10* 87* 2.8* T77377 1.0 Poorly Graded Sand 21-1-22082-003-RI-AB-Lab Tables -Terms and Test Summary/wpRk 21-1-22082-003 S win will SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Hydrogeologic Report New Madrona K-8 Project BORING IW-2 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters 11\11 1ry W , P M , � M 14 1 i b n0 ry0 bO �00 ,�00 `y0� O� O� O' Ory O� OO OO O' O' W O' 100 0 95 ..... .... ..... _ . 5 90 .. ..... .............. ....... , .. ,,,,,,,,,,, ... _. .. ,,,,, ,,,,,,,,,, .. .... .,,,,,,,,,, . .. .......................10 85 ......... ..... ,........ ;:. ..... .... , ........ ._ 15 80 ., ....... ....... .... .. ... .... .... .. ....... ...... ... ... ..,,,, ,,. :. ....... .. ,,... ....... . ..20 75 .... ... ..... .._ . ....._ 70 ,,,,, ....... .. .... ..... ............................ .. ,, ............ .. ,,,,,,,, ,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,, ... .........,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,, . . . ...... ... .................. . 30 65 ._ _ ._ .... _ _- ... _ - 35 (n N 60 .. .... ...... ... .. N 40 D 55 ._ . ... .... ... ... " " 45 n 50 ..... .. .. .......... . ..... .... ......... ..,,, ... .... ......... ......... .... .... i.. .,.. .,.. ., ..... .... . O „50 LL 45 .. .. .... .. ... .., ... " "" 55 6 N K cD40,..... ...................... .. .. ............. .. .. ........... ... ,..;. ..... .....,.,, ........... .................. ...60� d N 35 ...... ..._ . . ......._ .......... ......... ..... ....._. _ 65 N 20 ....... _. ... <..... ... ....... ......... .. ... ........... ....... ....... .. ......... ...... ... ... ..,.. ................. ... ........ .. ... .. ... 80 15 ,..._ ..... .. ......... ......... .. ... .... ....._. ........ ........ _.85 10 _... . ......... .. .. ........ .._ 90 5 .. 95 ry o 0 0 0 ^O 0 co ^o P ^ ti O' O" ^y O� Ob 0�7 Ory O� 00 Ob 0�7 Ory 100 Op O" O" O' O' Q, O O O O O Grain Size (mm) Sample Depth USCS Grou USCS Gravel Sand Fines <20pm <2Nm WC Tested Review ASTM Identification (tt) Symbol Group Name °% % % % % % By By Std. m IW-2, S-12* 91.0 SP Poorly Graded Sand with Gravel 17 78 4.3 7.3 AKV C136 N 0 ■ IW-2, S-14* 98.0 SP Poorly Graded Sand with Gravel 37 62 0.8 3.3 AKV C136 A IW-2, S-16* 111.0 SW-SM Well -Graded Sand with Silt and Gravel 21 71 8.6 5.1 SAB C136 N 0 �? IW-2, S-18 119.0 SW-SM Well -Graded Sand with Silt 11 81 8.7 5.0 AKV C136 >J_ Test specimen did not meet minimum mass recommendations. m a N O O N N N Z Q Q V) C7 Q� a 0 0 N O N N N SHANNON & WILSON, INC. • 400 NORTH 34TH STREET • SUITE 100 • SEATTLE, WASHINGTON • 98103 • MAIN (206) 632-8020 • FAX (206) 695-6777 S win will SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Hydrogeologic Report New Madrona K-8 Project BORING OW-1 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters W , o° b M , o o° o° o° o0 � 0° O' O' O' O' O' O' o' O' 100 0 95 ... .� .. .. ..5 90 ..... ........ ... .. .. , ......... .. ............ . ,,,,,,,,,,,,,,,, \\ ... .. ,,,,, ,,,,,,,,,, .... .,,,,,,,,,, . .. .....................,.10 85 15 80 .. ... .... .. .. ..... .. .. .. ............ .............. ..............,,,,, ,,. .. ....... .. ,,... ....... 20 75 70. ,,,,,,, ,,,,,,, , ... ... _. ... , .. ..... .. ,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,, ................... .. 30 65 .. .... ..... :... ......... " 35 (n N 60 .. .... ..... ..... .... N 40 N D > 55 - ... .... ... ... "45 n C50 ........... ... .. ,..... .... ....... ...... ... ....... .. ......... ... .. .... ,.. .,.. .,.. ., ... .... .,, O 50 N ... . N U N40 .. ... ...................... ...,,,,,,,,, .............. ..., ... ... ...... .. ,..... ..... . ,................................. 60 N d � 35 30 _ , .. .. ,. 70 25 75 20 ..... .. <. ... ........ ... ......... ,.. .. .... _. ......... ..... ..... ................. .... ... ..... ,... ................. . ... ......... .. ... .. ...80 15 ......._ . .. ..... ......... ......... ..... ..._ . ....._............. ........ ........ _.85 10 5 .. 95 ti 0 �o P ^, O' O ti , O' ^y 00 Ob O? Ory o 00 OHO Oa O" O� Op O" O" O' O' O" O O O O O � Grain Size (mm) Sample Depth USCS Grou USCS Gravel Sand Fines <20pm <2Nm WC Tested Review ASTM Identification (tt) Symbol Group Name °% % % % % % By By Std. m OW-1, R-7 55.7 SM Silty Sand with Gravel 22 56 22 5.2 JCS JFL D422 N 0 ■ OW-1, R-8* 63.5 SP-SM Poorly Graded Sand with Silt 7 84 9.5 4.8 AKV JFL C136 A OW-1, R-10* 87.5 SP Poorly Graded Sand with Gravel 34 61 4.5 9.1 JCS JFL C136 N 0 OW-1, R-11* 108.0 SM Silty Sand 7 74 19 4.7 JCS JFL C136 >J_> Z O OW-1, R-14 125.0 SP-SM Poorly Graded Sand with Silt 2 90 8.1 6.5 JCS JFL C136 m a 0 OW-1, R-15* 135.0 SM Silty Sand 4 70 26 9.2 JCS JFL C136 0 A OW-1, R-17* 153.0 SP-SM Poorly Graded Sand with Silt 4 88 8.0 5.0 JCS JFL C136 N N OW-1, R-21 182.0 SP-SM Poorly Graded Sand with Silt 7 88 5.1 18.6 JCS JFL C136 N Z Test specimen did not meet minimum mass recommendations. ¢ c� c a O N O N N N SHANNON & WILSON, INC. • 400 NORTH 34TH STREET • SUITE 100 • SEATTLE, WASHINGTON • 98103 • MAIN (206) 632-8020 • FAX (206) 695-6777 S win will SHANNON FaWILSON, INC. GRAIN SIZE DISTRIBUTION PLOT Hydrogeologic Report New Madrona K-8 Project BORING OW-2 Edmonds, Washington Gravel Sand Fines Coarse Fine Coarse Medium Fine Silt Clay -Size Mesh Opening in Inches Mesh Openings per Inch, U.S. Standard Grain Size in Millimeters O W , b M , ry � 0 0 � y M b n0 ti0 b0 00 ^00 ry00 O� O� p OOOO O O W O 100 0 95 90 . .... ......... .. .. ............ ....,,,... ,,,, ..... ,,,,,,,,,,,,,,, ...._. .. ,,,,, ,,,,,,,,,, .. ....,,,,,,,,,, ,,, .................. _...10 85 ,..._ ...... ...... ,........ ;:. ..... .... , ........ ._ 15 80 ..... ... ...... ............ .... .. ................. .. \ ......... ... ,,. :. ....... .. , , .. ....... ... 20 75 ... ... ..... .._ . ....._ 70 ,,, ,,,,,,, ,,,,,, ,, .. , .... ., .. ... ,,. .......... .. .....,,,, .. ,,,,,,,,,,,,,,,,,, , ,,,,,,,,,,,,,,,,,,,,,,, . , .........,,,,,,,,,,,,, ,,,,,,,,,,,,,,,,,,,,,,,,, ,,,,,,,,, . . . ...... ... .................. . 30 65 _. _- ... _ -35 N 60 40 D 55 ... .. ..45 50 .. .... .. .. ..... ....... .. .. ... ......... ,,, ....... ,,, ... ,...... .... ..... ..... . O „50 IL N C 45 �. .. .. 55 6 N K N40, ............................ ...... .... .. ... .. ....... ............. ,... ..... . ....,, . „ ............................... 60 d N 35 ... ... i ... -_ _ . .. 30 .. . ..... _. .,. .. 70 25 _. 75 20 ....... ... ...., ... <........ ........... .. ... ... .. ............... .... ... ...... ... ..,.. ... ..,.. ................. . ... ........ .. ... ... ... 80 15 ........ ......... ......._ . ..... .... ....._. ......_ ........ _.85 10 5 .. 95 ti ^ 0 co P ^i ti O' O' O' �7 N 0 Ob 0�7 100 OyO� OG O OO� OO OON O Grain Size (mm) Sample Depth USCS Grou USCS Gravel Sand Fines <20pm <2Nm WC Tested Review ASTM Identification (tt) Symbol Group Name °% % % % % % By By Std. m 0 OW-2, R-7* 56.0 SP-SM Poorly Graded Sand with Silt and Gravel 19 74 7.3 10.4 AKV JFL C136 N 0 ■ OW-2, R-9* 72.0 SP-SM Poorly Graded Sand with Silt 2 89 9.0 15.2 AKV JFL C136 A OW-2, R-10* 82.0 SM Silty Sand 5 78 16 6.3 AKV JFL C136 N 0 OW-2, R-11* 91.5 SM Silty Sand 12 68 20 8.8 AKV JFL C136 >J_> Z O OW-2, R-12* 107.0 SW-SM Well -Graded Sand with Silt and Gravel 26 62 12 3.8 AKV JFL C136 m El OW-2, R-15* 128.0 SM Silty Sand 14 70 16 4.7 AKV JFL C136 a 0 OW-2, R-17* 137.5 SP-SM Poorly Graded Sand with Silt 5 88 7.4 4.3 AKV JFL C136 V N OW-2, R-19* 151.5 SM Silty Sand 10 56 34 6.2 AKV JFL C136 Z ¢ A OW-2, R-19* 154.0 SP-SM Poorly Graded Sand with Silt and Gravel 36 58 5.2 1.8 AKV JFL C136 i U* OW-2, R-22* 182.5 SP Poorly Graded Sand 10 87 2.8 15.1 AKV JFL C136 c a O N O N N N Test specimen did not meet minimum mass recommendations. SHANNON & WILSON, INC. • 400 NORTH 34TH STREET • SUITE 100 • SEATTLE, WASHINGTON • 98103 • MAIN (206) 632-8020 • FAX (206) 695-6777 SHANNON q . APPENDIX C HYDROGEOLOGIC DATA AND ANALYSES 21-1-22282-003 APPENDIX C HYDROGOLOGIC DATA AND ANALYSES TABLE OF CONTENTS Page C.1 OBSERVATION WELL DEVELOPMENT...................................................................C-1 OBSERVATION C.3 OBSERVATION WELL SLUG TESTING....................................................................C-2 CA GROUNDWATER LEVEL MONITORING..................................................................C-3 C.4.1 Monitoring Wells and Instrumentation.............................................................C-3 C.4.2 Results...............................................................................................................C-3 C.4.3 Local Groundwater Flow and Gradient.............................................................C-4 C.5 PILOT DRY WELL IW-1 FIELD TESTING.................................................................C-4 C.5.1 Test Procedure...................................................................................................C-4 C.5.2 Results...............................................................................................................C-5 C.6 FULL-SCALE DRY WELL IW-2 FIELD TESTING.....................................................C-5 C.6.1 Test Procedure...................................................................................................C-5 C.6.2 Results...............................................................................................................C-6 1'0 • C.8 REFERENCES................................................................................................................C-7 C-1 Baseline OW -I Groundwater Quality Data C-2 Summary of OW -I Slug Test Analyses C-3 Summary of IW-1 and IW-2 Inflow Test Results C-4 Summary of Soil Analyses 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-i TABLE OF CONTENTS (cont.) FIGURES C-1 Slug Tests — Observation Well OW-1 C-2 Falling Head Slug Test 1 — Observation Well OW-1 C-3 Rising Head Slug Test 1 — Observation Well OW-1 C-4 Falling Head Slug Test 2 — Observation Well OW-1 C-5 Rising Head Slug Test 2 — Observation Well OW-1 C-6 Falling Head Slug Test 3 — Observation Well OW-1 C-7 Rising Head Slug Test 3 — Observation Well OW-1 C-8 Observation Well OW-1 Groundwater Depth with Precipitation Data C-9 Observation Well OW-1 Groundwater Depth with Barometric Pressure Data C-10 Observation Well OW-2 Groundwater Depth with Precipitation Data C-11 Observation Well OW-2 Groundwater Depth with Barometric Pressure Data C-12 Barometric Efficiency Estimate for Observation Well OW-1 C-13 Barometric Efficiency Estimate for Observation Well OW-2 C-14 Observation Well OW-1 Response to IW-1 Test C-15 OW-2 Observation Well and VWP2 Response to IW-2 Test LABORATORY REPORT Fremont Analytical, Inc. Report, Lab ID: 1604140, dated April 21, 2016 (29 pages) 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-ii APPENDIX C I:W01 Z1#10IQEll"[a17_�(KVRe117_1►1\"I Ix.� C.l OBSERVATION WELL DEVELOPMENT We developed observation wells OW-1 and OW-2 on April 12 and August 24, 2016, respectively. We developed each well to remove sediment from the screened zone and filter pack and to improve hydraulic connection to the Vashon advance outwash (Qva) aquifer soils. We developed both wells using an inertial -style pump (Waterra) equipped with a clean, acetal combination surge block and check valve that was attached to high -density polyethylene tubing. We measured field parameters (pH, specific conductance, temperature, and turbidity) during development of OW-1 using a YSI model 556 multi -parameter meter and an HF Scientific, Inc. turbidity meter. We measured sediment content of the discharged water during development of OW-2. We surge -blocked the screened intervals, purging approximately 68 (OW-1) and 37 gallons (OW-2) during development. A smaller volume was purged from OW-2 due to its shorter screen length (4.6 versus 9.7 feet at OW-1). Measured field parameters stabilized during development, and the screens were cleared of sediment. C.2 OBSERVATION WELL SAMPLING On April 14, 2016, we collected a groundwater sample from observation well OW-1 to measure baseline groundwater quality in the regional Qva aquifer before performing infiltration testing. We sampled well OW-1 using the same equipment that we used during development, with the exception that a clean, stainless steel check valve was used instead of the Acetal combination surge block/check valve. We purged OW-1 before sampling and collected the groundwater sample after field parameters had stabilized. We purged approximately 12.5 gallons of water (about 4.5 well casing volumes) from well OW-1 prior to sample collection. We delivered the groundwater sample under chain -of -custody procedures to a subcontracted laboratory, Fremont Analytical in Seattle. The sample was tested for petroleum hydrocarbon - related constituents and primary and secondary drinking water parameters. Table C-1 presents the field parameters measured immediately before sample collection and a summary of the laboratory test results. Table C-I also provides a comparison to Washington State groundwater quality standards. The laboratory data report is also presented in this appendix. In general, the OW-1 sample results indicate that the Qva aquifer groundwater quality onsite is good. An exception was the relatively high concentration of manganese, 344 parts per billion 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-1 (ppb), which is almost seven times higher than the secondary (aesthetic) drinking water standard of 50 ppb. Manganese occurs naturally in soil and groundwater in the Puget Sound region. The extent to which manganese dissolves into groundwater depends on the amount of oxygen in the water and, to a lesser extent, upon the pH of the water. If the oxygen content of groundwater is low, manganese tends to dissolve more readily. The zone from which the OW-1 groundwater sample was collected contains scattered organics, the decomposition of which depletes the oxygen content of the groundwater. This may contribute to the relatively high groundwater manganese concentration. C.3 OBSERVATION WELL SLUG TESTING On April 14, 2016, we performed single -well field "slug" tests in observation well OW-1 to estimate the horizontal hydraulic conductivity (Kh) of the Qva aquifer. A slug test estimates the Kh of the saturated sediments immediately surrounding the screened zone of a well. The testing involved inducing a rapid change in water level in the well by introducing or removing a sealed, internally weighted, polyvinyl chloride (PVC) slug. Raising the water level was achieved by lowering the slug below the static water level to displace water within the well casing. This procedure is termed a "falling head test" because the water level falls with time back to the static level. Lowering the water level was achieved by quickly removing the slug from the well. This is termed a "rising head test" because the water level rises back to the static level after the slug is removed. We measured the water level recovery rate back to static using a data logging pressure transducer (Levelogger), supplemented by manual readings. Figure C-1 presents the slug test data for the three falling head and three rising head tests for well OW-1. We analyzed the slug test data using the method developed by Bouwer and Rice (1976), as modified by Bouwer (1989). We used the computer modeling software program AQTESOLV for Windows (HydroSOLVE, Inc., 2010) to plot and interpret the six test data sets. Figures C-2 through C-7 present the slug test interpretation plots and Table C-2 summarizes the slug test results. The Kh results range between 52 and 77 feet per day (feet/day), or 3.2 x 10-2 to 5.4 x 10-2 feet/minute; the average Kh is 55 feet/day (3.8 x 10-2 feet/minute). This range is towards the low end of the Kh estimated from grain size data for two Qva aquifer soil samples collected at 182 and 182.5 feet deep at OW-1 and OW-2, respectively (64 and 92 feet/day, Table C-4). 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-2 CA GROUNDWATER LEVEL MONITORING C.4.1 Monitoring Wells and Instrumentation We have performed groundwater level monitoring in observation wells OW-1 and OW-2 since shortly after their installation. We deployed data logging transducers (Leveloggers) in wells OW-1 and OW-2 to collect frequent groundwater level data, and we installed a barometer (Barologger) in well OW-1 to collected barometric pressure data. The Leveloggers measure absolute pressure (atmospheric plus water pressure); we used the Barologger data to remove the atmospheric pressure contribution to the Levelogger readings. The data logging transducers continue to measure groundwater levels in wells OW-1 and OW-2. C.4.2 Results Figures C-8 through C-11 are groundwater level, barometric pressure, and local precipitation hydrographs for the period up to November 5, 2016. Figures C-9 and GLl show that the groundwater levels in wells OW-1 and OW-2 responded to barometric pressure changes. We evaluated the barometric efficiencies of wells OW-1 and OW-2 by comparing well water level variations to changes in atmospheric pressure. We calculated the barometric efficiencies of wells OW-1 and OW-2 to be approximately 90 and 86 percent, respectively (Figures C-12 and C-13). This means that when the atmospheric pressure increases, the well water level decreases by a similar amount. Conversely, when the atmospheric pressure decreases, the well water level increases. During the April 12 to November 5, 2016, monitoring period, the measured groundwater level in well OW-1 ranged from 167.1 to 168.9 feet below grade, or Elevation 277.0 to 276.2 feet, representing a fluctuation range of about 1.8 feet (Figures C-8 and C-9). During the August 24 to November 5, 2016, monitoring period, the measured groundwater level in well OW-2 ranged from 167.3 to 1689 feet below grade or Elevation 277.4 to 275.8 feet, representing a fluctuation range of about 1.6 feet (Figures C-10 and C-11). Two vibrating wire piezometers (VWPs) were installed in boring OW-2 at depths of approximately 663 (VWP1) and 146.3 feet (VWP2). The shallow VWP1 was dry throughout the monitoring period (August 24 to November 5, 2016). The deeper VWP2 was also dry during part of the monitoring period. However, VWP2 occasionally measured water about 1/z-inch above the sensor tip. In our experience, this is consistent of a VWP installed above the water table, and the occasional "wet" reading does not necessarily indicate the presence of perched 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-3 groundwater. Alternatively, it may indicate a passing wetting front or the effects of varying barometric pressure on the VWP readings. We also collected occasional manual readings at dry wells IW-1 and IW-2. Both wells have been dry to date, except during and immediately following their respective inflow tests (see sections C.5 and C.6). Air blows audibly from the IW-1 and IW-2 well casings at times, in response to changing atmospheric pressure. These wells sometimes also develop slight suction, also in response to changing atmospheric pressure. C.4.3 Local Groundwater Flow and Gradient We estimated the local Qva aquifer gradient by comparing August 26, 2016, groundwater elevations measured at the project wells to the approximate groundwater elevation we measured during a previous study at City of Edmonds observation well A-2 (Shannon & Wilson, Inc., 2013). Observation well A-2 is located about 4,500 feet west of the site (Figure 4). The on -site groundwater elevations on August 26, 2016, were approximately 277.30 and 276.46 feet (OW-1 and OW-2, respectively). On October 2, 2012, the A-2 well groundwater elevation was approximately 259.46 feet, based on an approximate A-2 grade elevation of 315 feet. Based on these data, the Qva aquifer gradient beneath the project site is about 0.002 foot/foot to the west/northwest (Figure 4). C.5 PILOT DRY WELL IW-1 FIELD TESTING C.5.1 Test Procedure We performed an inflow test in pilot underground injection control (UIC) well IW-1 on April25, 2016. This test consisted of directing water from a hydrant through a 2.5-inch-diameter fire hose and 2-inch-diameter PVC pipe into the dry well. We conducted the inflow testing for a period of 8.5 hours. We measured the inflow to the well using an inline flow meter. We measured the water Ievel in IW-1 manually through a stilling pipe and by using Level oggers installed at the well bottom. We also measured the groundwater level in OW-1 before, during, and after the IW-1 inflow test, both manually and using a Levelogger. We conducted the IW-1 inflow test as a series of steps, with each step representing a higher average flow rate into the well. We performed the first four inflow steps at approximately 14, 38, 72, and 103 gallons per minute (gpm); we maintained these inflow rates for approximately I hour each (Figure 7). However, these four steps did not run long enough for the water level to stabilize. The fifth step lasted for 4.3 hours. The fifth step's inflow rate was more variable, initially reaching a maximum of approximately 126 gpm, which was sufficient to 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-4 completely submerge the screened interval of the well. However, the flow rate from the hydrant began to fluctuate and drop off, possibly due to late afternoon increased domestic use of water at the adjacent apartment complex. The fifth step stabilized between 116 and 107 gpm, averaging 110 gpm over the last hour of the test. At this inflow rate, the IW-1 water level was approximately 67 feet below grade, or 4 feet below the top of the well screen, representing a head rise above the borehole bottom of 24 feet. C.5.2 Results We used the calculated OW-1 barometric efficiency to filter the OW-1 groundwater level data so that the OW-1 well response to the IW-1 inflow test could be analyzed (Figure C-14). Based on these data, the observed specific capacity of IW-1 is approximately 4.6 gpm/foot, and the Kh for the tested zone is 24 feet/day (1.7 x 10_2 feet/minute) (Table C-3). The groundwater level measured in well OW-1 did not immediately respond to the inflow test performed in IW-1. After adjusting the raw OW-1 groundwater level data for barometric efficiency, it was apparent that there was a slight antecedent rising trend in the OW-1 groundwater level during the test. This rising trend continued for a day after the IW-1 test and served to mask any effect of the IW-I test on the groundwater level measured in OW-1. The OW-1 groundwater level rose again slightly (0.1 foot), starting about four days after the test and peaking six days after the test; in our opinion, this change is too small to definitely attribute to the inflow test. Based on these observations, the interbedded silty sand layers within the Qva unit (e.g., between about 134 and 160 feet deep) likely delayed the vertical infiltration of water into the Qva regional aquifer in the IW-1 test area. C.6 FULL-SCALE DRY WELL IW-2 FIELD TESTING C.6.1 Test Procedure We performed an inflow test in full-scale UIC well IW-2 on October 11 to 12, 2016 (Figure 8). This test consisted of directing water from a hydrant through a 2.5-inch-diameter fire hose and 2-inch-diameter PVC pipe into the dry well for 19 hours. We measured the inflow to the well using an inline flow meter. We measured the water level in IW-2 manually through the 2-inch-diameter observation pipe installed in the filter pack and electronically using Leveloggers installed at the bottom of the 2- and 8-inch-diameter casings. We also manually and electronically measured the groundwater level in wells OW-2 and OW-1 before, during, and after the IW-2 inflow test. We recorded VWP readings at OW-2 using data loggers during and after the inflow test period. 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-5 C.6.2 Results We used OW-1 water levels measured during and after the IW-2 inflow test to filter out the effects of barometric pressure changes and other trends from the water levels measured at observation well OW-2 (Figure C-15). This enabled us to analyze the OW-2 well response to the IW-2 test. OW-2 is located approximately 14 feet from IW-2. Little change in groundwater level occurred in observation well OW-2 (an increase in water level of about 0.3-foot during the three days following the IW-2 test). The shallow VWPl installed 66.3 feet below grade at OW-2 has remained dry to date. During and immediately after the IW-2 inflow test, water temporarily mounded at the interval measured by the deep VWP2 (installed at 146.3 feet deep at OW-2). This mound dissipated and VWP2 was dry again three and a half days after the end of the IW-2 test (Figure C-15). Based on these observations, the interbedded silty sand layers within the Qva (e.g., between about 147 and 160 feet deep) likely delay the vertical infiltration of water into the Qva regional aquifer in the IW-2 test area. C.7 GRAIN SIZE -BASED HYDRAULIC CONDUCTIVITY (K) ESTIMATES We performed grain size analyses (Appendix B) on selected soil samples from IW-2, OW-1, and OW-2. Table C-4 presents grain size -based estimated K values for selected soil samples, based on the Hazen (1893) approach. The estimated K value for the tested till -like deposits (Qvd) sample from OW-1 (at 55.7 feet deep) was less than 0.01 foot/day. The grain size -based K estimates for the 21 Qva unit samples range from 0.05 to 626 feet/day (3 x 10-5 to 0.43 feet/minute), which is a variation of over four orders of magnitude. If the highest value is considered an outlier and is excluded, the arithmetic and geometric mean K values of the remaining 20 Qva samples are 38 and 11 feet/day (2.3 x 10-2 and 7.4 x 10-3 feet/minute), respectively. We suspect that the process of driving the sonic core barrel through unsaturated granular Qva soils resulted in some degree of sample pulverization, thereby increasing the fines content of some of the samples above their natural state. We have identified on the logs presented in Appendix A those sample cores where portions of the sample appeared dusty, indicating potential sample degradation due to the sampling process. We observed less apparent sample degradation in the larger diameter core samples collected at IW-1, as well as where samples were 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-6 collected within saturated zones and where water was added during the drilling process. A comparison of sample grain size distributions for samples collected from auger boring IW-2 and those from similar depths collected from adjacent sonic core OW-2 indicates that the fines content of the auger samples was typically lower than that of the sonic core samples (Appendix B and Table C-4). NEM101011011ry� Bouwer, Herman, 1989, The Bouwer and Rice slug test — an update: Ground Water, v. 27, no. 3, p. 304-309. Bouwer, Herman, and Rice, R.C., 1976. A slug test method for determining hydraulic conductivity of unconfined aquifers with completely or partially penetrating wells: Water Resources Research, v. 12, no. 3, p. 423-428. Hazen, A., 1893, Some physical properties of sands and gravels, with special reference to their use in filtration: Massachusetts State Board of Health 24' Annual Report, pub. doc. no. 34, p. 539-556. HydroSOLVE, Inc., 2010, AQTESOLV/Pro!, v. 4.50.002: Reston, Va., HydroSOLVE, Inc. Shannon & Wilson, Inc., 2013, Final infiltration study report, SW Edmonds basin study projects #1 and #3, Edmonds, Wash.: Report prepared by Shannon & Wilson, Inc., Seattle, Wash., 21-1-21768-001, for City of Edmonds, Edmonds, Wash., April 5. 21-1-22082-003-Rl f AC/wp(Ik 21-1-22082-003 C-7 SHANNON & WILSON, INC. TABLE C-1 BASELINE OW-1 GROUNDWATER QUALITY DATA e+m�t�tu4>�� . , `` n1�th�d' zau 46- 9i � .; rtetb3 = A • � i... 4�4�ail�f Field Parameters PH Field 6.5-8.5 7.1 Temperature IT) Field 10.9 Specific Conductance (uS/cm) Field 700 330 Dissolved Oxygen (mg/L) Field 4.1 Turbidity (NTU) Field 1.5 Total Metals (ug/L) Antimony EPA Method 200.8 6 ND<0.2 Arsenic EPA Method 200.8 0.05 5 ND<I Barium EPA Method 200.8 1,000 28.6 Beryllium EPA Method 200.8 4 ND<0.2 Cadmium EPA Method 200.8 5 5 ND<0.2 Chromium EPA Method 200.8 50 50 1.67 Copper EPA Method 200.8 1,000 ND<0.5 Iron EPA Method 200.8 300 ND<100 Lead EPA Method 200.8 AL-15 15 ND<I Manganese EPA Method 200.8 50 344 Mercury EPA Mehod 245.1 2 2 ND<0.1 Nickel EPA Method 200.8 100 2.94 Selenium EPA Method 200.8 10 ND<I Silver EPA Method 200.8 50 ND<0.2 Sodium EPA Method 200.8 RL=20,000 12,900 Thallium EPA Method 200.8 2 ND<0.2 Zinc EPA Method 200.8 5,000 27.3 Anions (mg/L) Chloride EPA Method 300.0 250 6.38 Cyanide, Total SM 4500-CN C, E 0.2 ND<0.05 Fluoride EPA Method 300.0 2 or 4 ND<0.1 Nitrite-N EPA Method 300.0 1 0.159 Nitrate-N EPA Method 300.0 10 1.01 Total Nitrate and Nitrite EPA Method 300.0 10 1.17 Ortho-phosphate EPA Method 300.0 ND<0.2 Sulfate EPA Method 300.0 250 22.6 Phosphorous, Total (as P) EPA Method 365.3 ND<0.2 Other Color (Color Units) SM 2120B 15 ND Total Dissolved Solids (mg/l.) SM 2540C 500 182 Petroleum Hydrocarbons (ug/1:.,) Diesel (Fuel Oil) NWTPH-Dx/Dx Ext. 500 ND<50 Ileavy Oil NWTPH-Dx/Dx Ext. 500 ND<100 Gasoline NWTPH-Gx 1,000 ND<50 Volatile Organic Compounds (ug/1:.,) Benzene EPA Method 8260C 1 5 ND<I Toluene EPA Method 8260C 1,000 ND4 Ethylbenzene EPA Method 8260C 700 ND<I m,p-Xylene EPA Method 8260C 1,000 (Total Xylenes) ND<l o-X lease EPA Method 8260C ND<I Notes: bold- constituent exceeded regulatory standard < less than AL, = action level established by the U.S. Environmental Protection Agency (EPA) for water distribution system C Celsius em- centimeters 1, liter MCI., = maximum contaminant level ing = milligrams MTCA- Model Toxics Control Act NTU = Nephelometric turbidity mots NWTPH-Dx/Dx Ext. = Northwest Total Petroleum Hydrocarbons-Diesel/Diese-extended NWTPH-Gx = Northwest Total Petroleum Hydrocarbons -Gasoline ND = not detected RL EPA -recommended level for those on a sodium-restrictdiet SM- Standard Method ug = micrograms uS = micro Siemens WAC = Washington Administrative Code 21-1-22082-003-Rlf TC-1/wp/lk 21-1-22082-003 SHANNON & WILSON, INC. TABLE C-2 SUMMARY OF OW-1 SLUG TEST ANALYSES ........ ......... P ` 1 , . (?la er l n . , : f tl V'' i r. tt i± C r ctlr it , ter Avis tr:, � '11 llak+r: ,: Ti t Lil th . Ct Tit=1:1 51 eetc, G'VO01± S>+:. 11N�rer i et li 11tda :. ; .e 11 el/n : ` B 11. ` : 1[Tnitt Te> d Falling Head Test 1 45 1.6E-02 3.2E-02 Rising Head Test 1 50 1.8E-02 3.5E-02 Falling Head Test 2 54 1.9E-02 3.7E-02 OW-1 4/14/2016 Rising Head Test 2 168.3 52 1.8E-02 3.6E-02 SP-SM/SP Qva Falling Head Test 3 55 2.0E-02 3.8E-02 Rising Head Test 3 77 2.7E-02 5.4E-02 Geomean 55 1.9E-02 3.8E-02 Notes: bgs = below ground surface cm/sec = centimeters per second Kh = horizontal hydraulic conductivity K" = vertical hydraulic conductivity min = minute 21-1-22082-003-R1 f TC-2/wp/1k 21-1-22082-003 SHANNON & WILSON, INC. TABLE C-3 SUMMARY OF I V-1 AND IW-2 INFLOW TEST RESULTS Iprnrrnate., . . "'. rarxlmnfe' ":: " Io 'ttf 1es# . '+rilv'rr ;A' rtrxlmate `fit tSecItiq.' ":" ker: ; clPaullr . ;13tydrntilie :,: .,"Ti+Iraiall '; ?rprtrtfe. Iis�hnr i T}Iselaar e, I .eliirti Tst`SCIuu" :Tesltian. ":' ottam "Ts.SreElan" ::uizt, inure 1lle Co tlnctitrty, . .:. eirrdurtrv>ty,. CarnainItvi, IniPI} elil it 1 «e th' 1? ,th .'. € it ' I+r Eleuatinn_': n "E1eval ct , .," I en " L..' s* ;IIeIc` .11Iatlitxs lumber.'.' 'ffJtl' ' CnfC "', fet/ua ",; TJnzttcsted " IW-1 444.9 4/25/2016 110 21174 4.6 67A 91.2 377.5 353.7 23.8 23.8 OA4 24 8.4E-03 1.7E-02 Qva IW-2 1 444.4 1 10/11-10/12/20161 141 1 27141 1 6.7 1 99.3 1 120.4 1 345.1 1 324.0 1 21.1 1 21.1 1 1.00 1 30 1.0E-02 I 2.0E-02 va Notes: i Discharge to well (q) is the average measured over the last approximately one hour of the test period. 2 Equation for K estimation is from U.S. Department of the Interior, 1990. Procedure for constant head hydraulic conductivity tests in single drill holes, U.S. Bureau of Reclamation 7310-89, in Earth Manual, Part 2, 3rd ed. p. 1255, Equation 2 (for L > = 1 Or). L= Water Column Height (H), which is the approximately stabilized water height in the well above the total drilled depth. cm/sec = centimeters per second cu R = cubic feet gpm = gallons per minute min = minute NAVD 88 North American Vertical Datum of 1988 I- = In '' , where L=' lOt- (2) 01 _= 2 sink-1 ? , Where 1Or T.� r (3) where: = hydraulic conductivity, ft/yr or cin/s y = constant taste of flow into the test interval, ft3/yr or CM-1/s Z = length of the test interval, ft or co F-1 = differential head of water at test interval, ft or cant r radius of the borehole, ft or cr i In = natural logarithm, log, sinh-1 _— inverse hyperbolic sine sinlr'i a In (,v -F xr + l 21-1-22082-003-RisrC-34p/lk 21-1-22082-003 SHANNON & WILSON, INC. TABLE C-4 SUMMARY OF SOIL ANALYSES .. ........... . pprnx mite ctr�111a .;,.. :., TYuekttCSSOI ,tryLtayers: `:' . i0ve key s }Yflcetlf,Sn r tpYo ililaf iTyc nGc on7neiricy,'i CttEe?prefyd. `J�CapacitySetwreliUf 4 "irreRe9zilts 'A`fivjPreeM pa8si .. ; :ur`m :,.`zen 3$;'f. ' . `' ifsEEnept. ,'. . . tt'eeh a Agillfl`a` ,y ;fi36°lu:iac, W.ailnscnne.' f[E1.'Ate :,, Y} $53'' ;.:. ., �G+tll�S 6 '. tr`1iS11h i1CCr6up t ifi� YC IW-2 9] Auger 17 79 4.3 0.46 0.17 82 2.9E-02 5.7E-02 SP Low Qva LW-2 98 Auger 37 62 0.8 210 OA7 626 2.2E-01 4 3E-01 SP Low Qva IW-2 111 Auger 21 71 8.6 0.56 0.099 28 9.8h; 03 1.9E-02 SW SM Medium Qva IW-2 119 Auger 11 81 8.7 0.44 0.094 25 8.8E-03 1.7E-02 SW-SM Low Qva I 0W-1 55.7 ; Sonic Care 22': 56 22 0.95 0,0015 Yes 0,006 2,3E-06 4.4E-06 SM _ Medium Qvd OW-1 63.5 Sonic Core 7 84 9.5 0.33 0.080 18 6.4E 03 1 3E-02 SP-SM Medium Qva OW-1 87.5 SonicCore 34 62 4.5 1.4 0.17 82 2.9h; 02 5.7F-02 SP Low Qva OW-1 108 Sonic Core 7 74 19 0.33 0.021 Yes 1.3 4 4E-04 8 7E-04 SM Medium Qva 10 OW-1 125 Sonic Core 2 90 8.1 0.30 0.088 22 7.7E-03 1.5E-02 SP-SM how Qva OW-1 135 Sonic Core 4 70 26 0.28 0.0080 Yes 018 6.4E-05 13E-04 SM Medium Qva OW 1 153 Sonic Core 5 88 8.0 0.33 0.092 24 8.5h; 03 1.7F-02 SP-SM Low Qva OW-1 182 Sonic Core 7 88 5.1 0.32 0.15 Yes 64 2.3E-02 4.4E-02 SP-SM Below water table Qva OW-2 56 Sonic Core 19 74 7.3 0.58 0.15 64 2.3E-02 4.4E-02 SP-SM Low Qva OW-2 72 Sonic Core 2 89 9.0 0.30 0.083 20 6.9E-03 1 4E-02 SP-SM Low Qva OW-2 82 SonicCore 5 78 17 0.30 0.029 Yes 2.4 8.4E 04 1.7F-03 SM Medium Qva OW-2 91.5 Sonic Core 12 68 20 0.31 0.014 Yes 0.6 2.0E-04 39E-04 SM Medium Qva OW-2 107 Sonic Core 26 62 12 _ 1.2 0047 Yes 6.3 22E 03 4.3E 03 SW SM Medium Qva 14 OW-2 128 Sonic Core 14 70 16 0.42 0.024 Yes 1.6 5.8E-04 1.1E-03 SM Medium Qva OW-2 137.5 SonicCore 5 88 7.4 0.36 0.13 48 1.7h; 02 3.3F-02 SP-SM Low Qva OW-2 151.5 Sonic Core 10 56 34 0.27 0.0040 Yes 0,045 1.6E-05 3AE-05 SM Medium QvalQvd OW-2 154 Sonic Core 37 58 5.2 2.2 0.25 177 6.3E-02 1.2E-01 SP-SM Low Qva OW-2 182.5 Sonic Core 10 87 2.8 0.41 0.18 92 3.2E-02 6 4E-02 SP Below water table Qva Ceomean of Qva Samples 13 4.6E-03 9.0E-03 tiores: Trcahnent capacity classification from Table 5.2: Vadose7,one Treatment Capacity, in Guidance fir UIC Wells that Manage Stanmvater (W ashingtm State Deparnnent of Fcology, 2006). Hazen, A., 1893, Some physical properties of sand and gravels Massachusetts State Board ofHealth, 24thAnnual Report. % percent ASTM = ASTM lnternational em/sce = centimeters per second min minute ton = millimeters UIC = u rdergrou r d injection control USCS = Unified Soil Classification System 21-1-22082-003-R1f TC-41wp11k 21-1-22082-003 LEGEND ~�A Falling Head Test #1 —Rising Head Test #1 —Falling Head Test #2 Rising Head Test #2 Falling Head Test #3 Rising Head Test #3 O 2 4 O O 10 12 14 16 18 Time (Seconds) I OW-1 Slug xnalysis-ow-1Slug Test pmw1momo1e-pv OW-1 Slug Analysis-OW-1 FH1-11/23/2016-pvh OW-1 Slug Analysis-OW-1 RM -1 1/23/2016-pvh OW-1 Slug Analysis-OW-1 FH2-11/23/2016-pvh OW-1 Slug Analysis-OW-1 RH2-11/23/2016-pvh OW-1 Slug Analysis-OW-1 FH3-11/23/2016-pvh OW-1 Slug Analysis-OW-1 RH3-11/23/2016-pvh OW-1 Water Levels -Figure C-8 - OW-1 Precip-11/23/2016-pvh 166.5 - - - - - - ._ 34 -- - !- -- -- - -- - -- - - - - - - ! - - 33.8 167.0 33.6 ai..... ...... _ ...- ... _ _ ........ _ ....-.. 1-... ....!.. P-... _... L ... ... 334 ...-........... 0 167.5 - - --- _ _ __ ____ _VJ - 33.2 v o - - -- '- - - - - ! 33 m CL 0168.0 - - - - - - a �...._ 32.8 E _ _. �.... . co OW-1 Transducer Data 32.6 168.5 ® OW-1 Manual Data - - r- - so�IW-1 Testing -- - - - IW-2 Testing - - - - - - _ 32.4 Barometric Pressure 169.0 32.2 4/11/16 5/2/16 5/23/16 6/13/16 7/4/16 7/25/16 8/15/16 9/5/16 9/26/16 10/17/16 11/7/16 Date (Local Time) Hydrogeologic Report New Madrona K-8 Project NOTES Edmonds, Washington 1. The screen in observation well OW-1 is approximately 175.4 to 185.0 feet below ground surface, OBSERVATION WELL OW-1 (approximately elevation 269.8 to 260.1 feet NAVD88). GROUNDWATER DEPTH WITH -t1 2. Black and white reproduction of this color original may lead to incorrect interpretation. BAROMETRIC PRESSURE DATA Gi November 2016 21-1-22082-003 n �p SHANNON & WILSON, INC. FIG. C-9 Geotechnical and Environmental consultants OW-1 Water Levels -Figure C-9 - OW-1 BP-11/23/2016-pvh OW-2 Water Levels -Figure C-10 - OW-2 Precip-11/23/2016-pvh 167.0 ___r_ m___ m_____ _r____ _ ------ -_-- m_- -- --- ; ---,-- 34.0 167.2 _... _ - - _ __ __ 33.8 " 167.4 .... 33.6 m 167.6 33.4 tv - 70 167.8 33.2 o - ,LL -5 168.0 33.0 m Q.... p 168.2 _ .. m' i 32.8 v L .... .. .... ,._ ,. , ,. ..-... E 168.4 _ 32.6 m 0 C� _ _ a;...... _ 168.E . , a , ::_ _ _ , :: 32.4 168.8 OW-2 Well Transducer Data ® OW-2 Manual Data 32.2 - � . �K���IW-2 Testing Period Barometric Pressure - -- - -i- - - - 169.0 - — - _ 32.0 8/22/16 8/29/16 9/5/16 9/12/16 9/19/16 9/26/16 10/3/16 10/10/16 10/17/16 10/24/16 10/31/16 11/7/16 Date (Local Time) Hydrogeologic Report NOTES New Madrona K-8 Project Edmonds, Washington 1. The screen in observation well OW-2 is approximately 179.2 to 183.9 feet below ground surface, (approximately elevation 265.4 to 260.8 feet (NAVD88)). OBSERVATION WELL OW-2 2. Groundwater level data for the OW-2 well were filtered using OW-1 data to remove the effects of regional GROUNDWATER DEPTH WITH -n aquifer trends during and after the IW-2 test period. BAROMETRIC PRESSURE Gi 3. Black and white reproduction of this color original may lead to incorrect interpretation. n November 2016 21-1-22082-003 0 SHANNON & WILSON, INC. FIG. C-11 Geotechnical and Environmental Consultants OW-2 Water Levels -Figure C-11 - OW-2 BP-11/23/2016-pvh 0.3 0.2 -0.2 -0.3 -0.3 -0.2 -0.1 0.0 0.1 0.2 0.3 Change in Barometric Pressure (Feet of water) NOTES 1. The screen in observation well OW-1 is approximately 175.4 to 185.0 feet below ground surface, (approximately elevation 269.8 to 260.1 feet (NAVD88)). 2. Barometric efficiency estimate of approximately 90% based on data collected between 5/6/16 and 5/10/16. OW-1 Water Levels -Figure C-12 - OW-1 BE Plot-11/23/2016-pvh 0.2 0.2 0.1 C: -0.1 U DIVA -0.2 -0.3 -0.4 -0.3 -0.2 -0.1 0.0 0.1 Change in Barometric Pressure (Feet of water) NOTES The screen in observation well OW-2 is approximately 179.2 to 183.9 feet below ground surface, (approximately elevation 265.4 to 260.8 feet (NAVD88)). Barometric efficiency estimate of approximately 86% based on data collected between 9/6/16 and 9/18/16. OW-2 Water Levels -Figure C-13 - OW-2 BE-11/23/2016-pvh 168.0 - _ _ _ -- _ _ ____ _r_ _m_ ____ _r_ _ _ __ _ _ - _ 33.9 ......._ _ ..._... _ _ ,..................... ......, ....... ....... ....................._ .. . _ ..__. _ , ....... ...... � �. 168.1 - - - - - - - - - - - -- - 33.8 168.2 33.7 a� m 168.3 _ 33.6 .. .._ �.. - CO a _ 0 168.4 _ ... ... o 33.5 a� ._ 168.5 33.4 zo ex m - - - -- - - - -- - CO - CL 0 168.6 ._ -_ _' . - - -- _ _. '- _ __ - -� --- - - -- - 33.3 v .- ...._.... .....__ - - L .... _ .x,... _ ... :. ...., ..... .... _ r... .. ......., ...... ..... . ..... __ ., ........ . ....... _........ ....... .. _..... E ° -0168.7 33.2 ..... ......_ ......... ...... ... ....� CO o_...... .... ...... -- - - -_ _ 0 - OW-1 Transducer Data 168.8 33.1 - __- -- OW-1 Manual Data - - - - - - - - - - - - IW-1 Testing 168.9 a OW-1 Transducer Data Adjusted for Barometric Efficiency 33 _.... _ _ ... _............. ..................... . ........._ _ ........._ . ._.... _ , ....... ,. - Barometric Pressure 169.0 _ _. ... - �-- - J---- -+ 32.9 4/22/16 4/24/16 4/26/16 4/28/16 4/30/16 5/2/16 5/4/16 5/6/16 Date (Local Time) NOTES 1. The screen in observation well OW-1 is approximately 175.4 to 185.0 feet below ground surface, (approximately elevation 269.8 to 260.1 feet NAVD88). 2. Pilot dry well IW-1 was completed on 4/21/16 to 91.2 feet deep (approximately elevation 353.7 feet NAVD88). IW-1 infiltration test was performed on 4/25/16 from 10:03-18:34. 3. Black and white reproduction of this color original may lead to incorrect interpretation. OW-1 Water Levels -Figure C-14 - OW-1 IW-1 Test-11/23/2016-pvh 140.0 145.0 m m LL - - o 0IW-2 Testing Period _...................... ;..... _............. ;...... ..... ...... .......... ..... .... ;-... zo 155.0 OW-2 VWP2 Data mCL - - -- - s ..... OW-2 VWP2 Sensor Depth O - 165.0 -- 170.0 _ __ __ ___ ------- ___;_ _____- _ _--------- ______- __ _______ -_ w______ _----- 10/11 /16 10/12/16 10/13/16 10/14/16 10/15/16 10/16/16 10/17/16 10/18/16 Date (Local Time) NOTES 1. The screen in observation well OW-2 is approximately 179.2 to 183.9 feet below ground surface, (approximately elevation 265.4 to 260.8 feet (NAVD88)). 2. Dry well IW-2 was completed at 120.4 feet deep (approximately elevation 324.0 feet). The IW-2 Infiltration test was performed from 10/11/16 9:09 to 10/12/16 4:09. 3. Groundwater level data for the OW-2 well were filtered using OW-1 data to remove the effects of regional aquifer trends during and after the IW-2 test period. 4. The OW-2 VWP2 sensor is approximately 146.3 feet deep (approximately elevation 298.4 feet). 5. The OW-2 VWP1 sensor is approximately 66.3 feet deep (approximately elevation 378.4 feet). It has remained dry during the monitoring period to date (8/24-11/5/16). 6. Black and white reproduction of this color original may lead to incorrect interpretation. OW-2 Water Levels -Figure C-15 - OW-2 Test-11/23/2016-pvh 3600 Fremont Ave. N. Seattle, WA 98103 T: (206) 352-3790 F: (206) 352-7178 infoCoUremontanalldical.com Shannon & Wilson Paul Van Horne 400 N. 34th Street, Suite 100 Seattle, WA 98103 RE: Madrona K-8 School Lab ID: 1604140 April 21, 2016 Attention Paul Van Horne: Fremont Analytical, Inc. received 2 sample(s) on 4/14/2016 for the analyses presented in the following report. Color by SM2120 Cyanide by SM 4500-CN C, E Diesel and Heavy Oil by NWTPH-DX/DX Ext. Gasoline by NWTPH-Gx Ion Chromatography by EPA Method 300.0 Mercury by EPA Method 245.1 Total Metals by EPA Method 200.8 Total Dissolved Solids (TDS) by SM 2540C Total Phosphorous by EPA Method 365.3 Volatile Organic Compounds by EPA Method 8260C This report consists of the following: - Case Narrative - Analytical Results - Applicable Quality Control Summary Reports - Chain of Custody All analyses were performed consistent with the Quality Assurance program of Fremont Analytical, Inc. Please contact the laboratory if you should have any questions about the results. Thank you for using Fremont Analytical. Sincerely, DOD/FLAP Certification #L23711 IS0/1CC 17025:2005 ORELAP Certification: WA 100009-007 (NELAP Recognized) Revision v1 www.fremontanalytical.com A Mike Ridgeway President DoDIELAP Certification #L2371, 1SO11CC 17025:2005 ORELAP Certification: WA 100009-007 (NELAP Recognized) Revision vl www.fremontanalylical.com fi�� CLIENT: Project: Lab Order: Lab Sample ID 1604140-001 1604140-002 Shannon & Wilson Madrona K-8 School 1604140 Client Sample ID OW-1-041416 Trip Blank Date: 0510512016 Work Order Sample Summary Date/Time Collected 04/14/2016 11:18 AM 04/13/2016 12:48 PM Date/Time Received 04/14/2016 4:07 PM 04/14/2016 4:07 PM Revision v1 Note: If no "Time Collected" is supplied, a default of 12:OOAM is assigned Case Narrative W O#: 1604140 Date: 4/21/2016 CLIENT: Shannon & Wilson Project: Madrona K-8 School I. SAMPLE RECEIPT: Samples receipt information is recorded on the attached Sample Receipt Checklist. 11. GENERAL REPORTING COMMENTS: Results are reported on a wet weight basis unless dry -weight correction is denoted in the units field on the analytical report ("mg/kg-dry" or "ug/kg-dry"). Matrix Spike (MS) and MS Duplicate (MSD) samples are tested from an analytical batch of "like" matrix to check for possible matrix effect. The MS and MSD will provide site specific matrix data only for those samples which are spiked by the laboratory. The sample chosen for spike purposes may or may not have been a sample submitted in this sample delivery group. The validity of the analytical procedures for which data is reported in this analytical report is determined by the Laboratory Control Sample (LCS) and the Method Blank (MB). The LCS and the MB are processed with the samples and the MS/MSD to ensure method criteria are achieved throughout the entire analytical process. 111. ANALYSES AND EXCEPTIONS: Exceptions associated with this report will be footnoted in the analytical results page(s) or the quality control summary page(s) and/or noted below. 1604140-001 E C-COLOR has been Sub Contracted. Revision v1 Qualifiers & Acronyms W O#: 1604140 Date Reported: 4/21/2016 Qualifiers: * - Flagged value is not within established control limits B - Analyte detected in the associated Method Blank D - Dilution was required E - Value above quantitation range H - Holding times for preparation or analysis exceeded I - Analyte with an internal standard that does not meet established acceptance criteria J - Analyte detected below Reporting Limit N - Tentatively Identified Compound (TIC) Q - Analyte with an initial or continuing calibration that does not meet established acceptance criteria (<20%RSD, <20% Drift or minimum RRF) S - Spike recovery outside accepted recovery limits ND - Not detected at the Reporting Limit R - High relative percent difference observed Acronyms: %Rec - Percent Recovery CCB - Continued Calibration Blank CCV - Continued Calibration Verification DF - Dilution Factor HEM - Hexane Extractable Material ICV - Initial Calibration Verification LCS/LCSD - Laboratory Control Sample / Laboratory Control Sample Duplicate MB or MBLANK - Method Blank MDL - Method Detection Limit MS/MSD - Matrix Spike / Matrix Spike Duplicate PDS - Post Digestion Spike Ref Val - Reference Value RL - Reporting Limit RPD - Relative Percent Difference SD - Serial Dilution SGT - Silica Gel Treatment SPK - Spike Surr - Surrogate Revision v1 - ,- Fremont, Analytical Report W O#: 1604140 Date Reported: 4/21/2016 Client: Shannon & Wilson Collection Date:4/14/2016 11:18:00 AM Project: Madrona K-8 School Lab ID: 1604140-001 Matrix: Groundwater Client Sample ID: OW-1-041416 Analyses Result RL Qual Units DF Date Analyzed Diesel and Heavy Oil by NWTPH-Dx/Dx Ext. Batch ID: 13481 Analyst: CM Diesel (Fuel Oil) ND 50.0 pg/L 1 4/19/2016 11:45:00 PM Heavy Oil ND 100 pg/L 1 4/19/2016 11:45:00 PM Surr: 2-Fluorobiphenyl 73.5 50-150 %Rec 1 4/19/2016 11:45:00 PM Surr: o-Terphenyl 77.5 50-150 %Rec 1 4/19/2016 11:45:00 PM Gasoline by NWTPH-Gx Batch ID: R28812 Analyst: NG Gasoline ND 50.0 pg/L 1 4/15/2016 4:35:49 AM Surr: 4-Bromofluorobenzene 99.4 65-135 %Rec 1 4/15/2016 4:35:49 AM Surr: Toluene-d8 98.8 65-135 %Rec 1 4/15/2016 4:35:49 AM Volatile Organic Compounds by EPA Method 8260C Batch ID: R28811 Analyst: NG Benzene ND 1.00 pg/L 1 4/15/2016 4:35:49 AM Toluene ND 1.00 pg/L 1 4/15/2016 4:35:49 AM Ethylbenzene ND 1.00 pg/L 1 4/15/2016 4:35:49 AM m,p-Xylene ND 1.00 pg/L 1 4/15/2016 4:35:49 AM o-Xylene ND 1.00 pg/L 1 4/15/2016 4:35:49 AM Surr: Dibromofluoromethane 102 45A-152 %Rec 1 4/15/2016 4:35:49 AM Surr: Toluene-d8 94.3 40.1-139 %Rec 1 4/15/2016 4:35:49 AM Surr: 1-Bromo-4-fluorobenzene 97.2 64.2-128 %Rec 1 4/15/2016 4:35:49 AM Ion Chromatography by EPA Method 300.0 Batch ID: R28832 Analyst: MW Fluoride ND 0.100 mg/L 1 4/15/2016 12:09:00 PM Chloride 6.38 0.100 mg/L 1 4/15/2016 12:09:00 PM Nitrite 0.159 0.100 mg/L 1 4/15/2016 12:09:00 PM Nitrate 1.01 0.100 mg/L 1 4/15/2016 12:09:00 PM Nitrate+Nitrite 1.17 0.100 mg/L 1 4/15/2016 12:09:00 PM Ortho-Phosphate ND 0.200 mg/L 1 4/15/2016 12:09:00 PM Sulfate 22.6 0.300 mg/L 1 4/15/2016 12:09:00 PM Mercury by EPA Method 245.1 Batch ID: 13469 Analyst: MW Mercury ND 0.100 pg/L 1 4/18/2016 3:00:59 PM Total Metals by EPA Method 200.8 Batch ID: 13468 Analyst: TN Antimony ND 0.200 pg/L 1 4/15/2016 2:29:17 PM Revision v1 Fremont, Analytical Report W O#: 1604140 Date Reported: 4/21/2016 Client: Shannon & Wilson Collection Date:4/14/2016 11:18:00 AM Project: Madrona K-8 School Lab ID: 1604140-001 Matrix: Groundwater Client Sample ID: OW-1-041416 Analyses Result RL Qual Units DF Date Analyzed Total Metals by EPA Method 200.8 Batch ID: 13468 Analyst: TN Arsenic ND 1.00 pg/L 1 4/15/2016 2:29:17 PM Barium 28.6 0.500 pg/L 1 4/15/2016 2:29:17 PM Beryllium ND 0.200 pg/L 1 4/15/2016 2:29:17 PM Cadmium ND 0.200 pg/L 1 4/15/2016 2:29:17 PM Chromium 1.67 0.500 pg/L 1 4/15/2016 2:29:17 PM Copper ND 0.500 pg/L 1 4/15/2016 2:29:17 PM Iron ND 100 pg/L 1 4/15/2016 2:29:17 PM Lead ND 1.00 pg/L 1 4/15/2016 2:29:17 PM Manganese 344 2.00 pg/L 1 4/15/2016 2:29:17 PM Nickel 2.94 0.500 pg/L 1 4/15/2016 2:29:17 PM Selenium ND 1.00 pg/L 1 4/15/2016 2:29:17 PM Silver ND 0.200 pg/L 1 4/15/2016 2:29:17 PM Sodium 12,900 100 pg/L 1 4/15/2016 2:29:17 PM Thallium ND 0.200 pg/L 1 4/15/2016 2:29:17 PM Zinc 27.3 1.50 pg/L 1 4/15/2016 2:29:17 PM Cyanide by SM 4500-CN C, E Batch ID: 13500 Analyst: NG Cyanide, Total ND 0.0500 mg/L 1 4/21/2016 10:03:00 AM Total Phosphorous by EPA Method 365.3 Batch ID: 13510 Analyst: KT Phosphorus, Total (As P) ND 0.200 mg/L 1 4/21/2016 2:25:00 PM Total Dissolved Solids (TDS) by SM 2540C Batch ID: R28863 Analyst: KT Total Dissolved Solids 182 5.00 mg/L 1 4/19/2016 4:04:00 PM Revision v1 �,,__SPECTRA Laboratories ...Where experwncr matterS ........................ 2221RossWay 0 TaconrdWA98421 '* (253)272-4850 * Fax(253)572-9838 0 www,spectra-lab.com 05/05/2016 Fremont Analytical Seattle, WA 98103 Attn: Mike Ridgeway SPECTRA LABORATORIES Steve Hibbs, Laboratory Manager a6/mkw Client ID: 1604140-001 E Sample Matrix: Groundwater Date Sampled: 04/14/2016 Date Received: 04/18/2016 Spectra Project: 2016040430 Spectra Number: I Result its Method ND Color Units SM 2120B a • I c7meg� c.t!cm 233�P�cr: I o�: 1 ARDRESS Ejam"FU111-am I — FremontAnalyncal, Inc. 360OFremontRve. N. Seattle, WA 98103 TEL: 206-352--3790 F.9X. 206352-7178 Website: www.fremontanalytical.com SUBODNTRATOIL COMPANY: Spectra SPECTRA Laboratories SPECIALTFONsCOMMENTs: ADD SS: Please readts to Michael Ridgeway n Chelsea Ward - mridgewa em ytical.coni; 2221 Ross ay � ytical.com CcrY.STATE, ZIP: Tacoma, WA 9421 PII - (253) 272-450 FAX (253) 572-98 EIS - Ac a: t1 I SAMPLE ID CLIENT SAMPLE M 1 1604140-001 _- -1-041416 r_rnl e%n 1c7-an-a; ._----.-.--.-_.._-.- BOTTLE TYPE - MATRIX DATE COLLECTED NUMBER OF COMMENTS: McL'hgn®I d yy .. CONTAINERS HOT Sampk Nofati AWt ormj Sample Dwmip mm. ® HDPE NON Ground r 4/14/2016 11:1 :00 AM -------------- RAN 11" Dtr REPORT TRANSMITTAL DESIRED: ❑ HARDCOPY(ex4a cm) ❑ FAX UWMAIL ❑ ONLINE FOR LAB USE ONLY Tempofsampim 'DC An=pt to Cool? Commptk: Date: 412112016 QC SUMMARY REPORT Cyanide by SM 4500-CN C, E Sample ID: MB-13500 SampType: MBLK Units: mg/L Prep Date: 4/20/2016 RunNo: 28891 Client ID: MBLKW Batch ID: 13500 Analysis Date: 4/21/2016 SegNo: 543216 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Cyanide, Total NO 0.0500 Sample ID: LCS-13500 SampType: LCS Units: mg/L Prep Date: 4/20/2016 RunNo: 28891 Client ID: LCSW Batch ID: 13500 Analysis Date: 4/21/2016 SegNo: 543205 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Cyanide, Total 0.250 0.0500 0.2500 0 99.8 80 120 Sample ID: 1604152-001ADUP SampType: DUP Units: mg/L Prep Date: 4/20/2016 RunNo: 28891 Client ID: BATCH Batch ID: 13500 Analysis Date: 4/21/2016 SegNo: 543209 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Cyanide, Total NO 0.0500 0 20 Sample ID: 1604152-001AMS SampType: MS Units: mg/L Prep Date: 4/20/2016 RunNo: 28891 Client ID: BATCH Batch ID: 13500 Analysis Date: 4/21/2016 SegNo: 543210 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Cyanide, Total 0.274 0.0500 0.2500 0.02350 100 80 120 Sample ID: 1604152-001AMSD SampType: MSD Units: mg/L Prep Date: 4/20/2016 RunNo: 28891 Client ID: BATCH Batch ID: 13500 Analysis Date: 4/21/2016 SegNo: 543211 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Cyanide, Total 0.205 0.0500 0.2500 0.02350 72.6 80 120 0.2741 28.8 30 S NOTES: S - Outlying spike recovery(ies) observed. A duplicate analysis was performed and recovered within range. Revision v1 Page 11 of 29 Date: 412112016 QC SUMMARY REPORT Ion Chromatography by EPA Method 300.0 Sample ID: MB-R28832 SampType: MBLK Units: mg/L Prep Date: 4/15/2016 RunNo: 28832 Client ID: MBLKW Batch ID: R28832 Analysis Date: 4/15/2016 SegNo: 541986 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Fluoride ND 0.100 Chloride ND 0.100 Nitrite ND 0.100 Nitrate ND 0.100 Nitrate+Nitrite ND 0.100 Sulfate ND 0.300 Sample ID: LCS-R28832 SampType: LCS Units: mg/L Prep Date: 4/15/2016 RunNo: 28832 Client ID: LCSW Batch ID: R28832 Analysis Date: 4/15/2016 SegNo: 541987 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Fluoride 2.09 0.100 2.000 0 105 90 110 Chloride 2.88 0.100 3.000 0 96.0 90 110 Nitrite 2.97 0.100 3.000 0 98.9 90 110 Nitrate 3.03 0.100 3.000 0 101 90 110 Nitrate+Nitrite 6.00 0.100 6.000 0 100 90 110 Sulfate 15.6 0.300 15.00 0 104 90 110 Sample ID: 1604140-001DDUP SampType: DUP Units: mg/L Prep Date: 4/15/2016 RunNo: 28832 Client ID: OW-1-041416 Batch ID: R28832 Analysis Date: 4/15/2016 SegNo: 541989 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Fluoride ND 0.100 0 20 Chloride 6.37 0.100 6.376 0.133 20 Nitrite 0.161 0.100 0.1594 0.874 20 Nitrate 1.02 0.100 1.011 0.709 20 Nitrate+Nitrite 1.18 0.100 1.171 0.732 20 Sulfate 22.6 0.300 22.62 0.142 20 Revision v1 Page 12 of 29 Date: 412112016 QC SUMMARY REPORT Ion Chromatography by EPA Method 300.0 Sample ID: 1604140-001DMS SampType: MS Units: mg/L Prep Date: 4/15/2016 RunNo: 28832 Client ID: OW-1-041416 Batch ID: R28832 Analysis Date: 4/15/2016 SegNo: 541990 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Fluoride 2.08 0.100 2.000 0.06680 101 80 120 Chloride 8.98 0.100 3.000 6.376 86.7 80 120 Nitrite 3.05 0.100 3.000 0.1594 96.5 80 120 Nitrate 3.95 0.100 3.000 1.011 98.1 80 120 Nitrate+Nitrite 7.01 0.100 6.000 1.171 97.3 80 120 Sulfate 37.2 0.300 15.00 22.62 97.3 80 120 Sample ID: 1604140-001DMSD SampType: MSD Units: mg/L Prep Date: 4/15/2016 RunNo: 28832 Client ID: OW-1-041416 Batch ID: R28832 Analysis Date: 4/15/2016 SegNo: 541991 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Fluoride 2.09 0.100 2.000 0.06680 101 80 120 2.084 0.161 20 Chloride 8.97 0.100 3.000 6.376 86.3 80 120 8.978 0.136 20 Nitrite 3.04 0.100 3.000 0.1594 96.2 80 120 3.053 0.286 20 Nitrate 3.92 0.100 3.000 1.011 97.0 80 120 3.953 0.792 20 Nitrate+Nitrite 6.97 0.100 6.000 1.171 96.6 80 120 7.006 0.571 20 Sulfate 37.0 0.300 15.00 22.62 95.8 80 120 37.22 0.623 20 Revision v1 Page 13 of 29 Date: 412112016 QC SUMMARY REPORT Total Phosphorous by EPA Method 365.3 Sample ID: MB-13510 SampType: MBLK Units: mg/L Prep Date: 4/21/2016 RunNo: 28899 Client ID: MBLKW Batch ID: 13510 Analysis Date: 4/21/2016 SegNo: 543434 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Phosphorus, Total (As P) ND 0.200 Sample ID: LCS-13510 SampType: LCS Units: mg/L Prep Date: 4/21/2016 RunNo: 28899 Client ID: LCSW Batch ID: 13510 Analysis Date: 4/21/2016 SegNo: 543435 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Phosphorus, Total (As P) 2.17 0.200 2.000 0 109 65 135 Sample ID: 1604140-001HDUP SampType: DUP Units: mg/L Prep Date: 4/21/2016 RunNo: 28899 Client ID: OW-1-041416 Batch ID: 13510 Analysis Date: 4/21/2016 SegNo: 543437 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Phosphorus, Total (As P) ND 0.200 0 30 Sample ID: 1604140-001HMS SampType: MS Units: mg/L Prep Date: 4/21/2016 RunNo: 28899 Client ID: OW-1-041416 Batch ID: 13510 Analysis Date: 4/21/2016 SegNo: 543438 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Phosphorus, Total (As P) 1.90 0.200 2.000 0.01800 94.2 65 135 Sample ID: 1604140-001HMSD SampType: MSD Units: mg/L Prep Date: 4/21/2016 RunNo: 28899 Client ID: OW-1-041416 Batch ID: 13510 Analysis Date: 4/21/2016 SegNo: 543439 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Phosphorus, Total (As P) 2.18 0.200 2.000 0.01800 108 65 135 1.902 13.5 30 Revision v1 Page 14 of 29 Date: 412112016 QC SUMMARY REPORT Total Dissolved Solids (TDS) by SM 2540C Sample ID: MB-R28863 SampType: MBLK Units: mg/L Prep Date: 4/19/2016 RunNo: 28863 Client ID: MBLKW Batch ID: R28863 Analysis Date: 4/19/2016 SegNo: 542617 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Total Dissolved Solids ND 5.00 Sample ID: LCS-R28863 SampType: LCS Units: mg/L Prep Date: 4/19/2016 RunNo: 28863 Client ID: LCSW Batch ID: R28863 Analysis Date: 4/19/2016 SegNo: 542618 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Total Dissolved Solids 304 10.0 300.0 0 101 65 135 Sample ID: 1604140-001DDUP SampType: DUP Units: mg/L Prep Date: 4/19/2016 RunNo: 28863 Client ID: OW-1-041416 Batch ID: R28863 Analysis Date: 4/19/2016 SegNo: 542620 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Total Dissolved Solids 203 5.00 182.0 10.9 30 Revision v1 Page 15 of 29 Date: 412112016 QC SUMMARY REPORT Total Metals by EPA Method 200.8 Sample ID: MB-13468 SampType: MBLK Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 Client ID: MBLKW Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541791 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Antimony ND 0.200 Arsenic ND 1.00 Barium ND 0.500 Beryllium ND 0.200 Cadmium ND 0.200 Chromium ND 0.500 Copper ND 0.500 Iron ND 100 Lead ND 1.00 Manganese ND 2.00 Nickel ND 0.500 Selenium ND 1.00 Silver ND 0.200 Sodium ND 100 Thallium ND 0.200 Zinc ND 1.50 Sample ID: LCS-13468 SampType: LCS Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 Client ID: LCSW Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541792 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Antimony 4.52 0.200 5.000 0 90.4 85 115 Arsenic 101 1.00 100.0 0 101 85 115 Barium 99.3 0.500 100.0 0 99.3 85 115 Beryllium 5.16 0.200 5.000 0 103 85 115 Cadmium 5.70 0.200 5.000 0 114 85 115 Chromium 92.5 0.500 100.0 0 92.5 85 115 Copper 96.2 0.500 100.0 0 96.2 85 115 Iron 1,090 100 1,000 0 109 50 150 Lead 45.3 1.00 50.00 0 90.7 85 115 Revision v1 Page 16 of 29 Date: 412112016 QC SUMMARY REPORT Total Metals by EPA Method 200.8 Sample ID: LCS-13468 SampType: LCS Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 Client ID: LCSW Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541792 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Manganese 100 2.00 100.0 0 100 85 115 Nickel 95.5 0.500 100.0 0 95.5 85 115 Selenium 9.94 1.00 10.00 0 99.4 85 115 Silver 4.66 0.200 5.000 0 93.2 85 115 Sodium 991 100 1,000 0 99.1 50 150 Thallium 2.27 0.200 2.500 0 90.7 85 115 Zinc 100 1.50 100.0 0 100 85 115 Sample ID: 1604116-001CDUP SampType: DUP Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 Client ID: BATCH Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541794 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Antimony 0.202 0.200 Arsenic ND 1.00 Barium 38.1 0.500 Beryllium ND 0.200 Cadmium ND 0.200 Chromium 0.722 0.500 Copper ND 0.500 Iron ND 100 Lead ND 1.00 Manganese 5.17 2.00 Nickel 0.939 0.500 Selenium ND 1.00 Silver ND 0.200 Sodium 54,300 100 Thallium ND 0.200 Zinc 2.95 1.50 NOTES: R - High RPD observed. The method is in control as indicated by the LCS. 0.4710 80.1 30 R 0 30 37.74 0.955 30 0 30 0 30 0.5610 25.1 30 0.5540 10.9 30 0 30 0 30 5.155 0.320 30 0.7520 22.1 30 0 30 0 30 57,370 5.44 30 0 30 2.528 15.5 30 Revision v1 Page 17 of 29 Date: 412112016 QC SUMMARY REPORT Total Metals by EPA Method 200.8 Sample ID: 1604116-001CMS SampType: MS Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 ;lient ID: BATCH Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541795 analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Antimony 22.8 0.200 25.00 0.4710 89.3 70 130 Arsenic 532 1.00 500.0 0.8205 106 70 130 Barium 530 0.500 500.0 37.74 98.5 70 130 Beryllium 24.9 0.200 25.00 0 99.7 70 130 Cadmium 28.0 0.200 25.00 0.01600 112 70 130 Chromium 517 0.500 500.0 0.5610 103 70 130 Copper 489 0.500 500.0 0.5540 97.8 70 130 Iron 5,250 100 5,000 45.56 104 50 150 Lead 220 1.00 250.0 0.07550 87.9 70 130 Manganese 508 2.00 500.0 5.155 100 70 130 Nickel 492 0.500 500.0 0.7520 98.3 70 130 Selenium 51.5 1.00 50.00 0 103 70 130 Silver 17.0 0.200 25.00 0 67.8 70 130 S Sodium 60,500 100 5,000 57,370 62.9 50 150 Thallium 11.2 0.200 12.50 0.006500 89.4 70 130 Zinc 508 1.50 500.0 2.528 101 70 130 NOTES: S - Outlying spike recovery(ies) observed. A duplicate analysis was performed and recovered within range. Sample ID: 1604116-001CMSD SampType: MSD Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 ;lient ID: BATCH Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541796 analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Antimony 22.7 0.200 25.00 0.4710 89.1 70 130 22.79 0.171 30 Arsenic 525 1.00 500.0 0.8205 105 70 130 531.7 1.30 30 Barium 522 0.500 500.0 37.74 96.9 70 130 530.4 1.55 30 Beryllium 24.0 0.200 25.00 0 96.0 70 130 24.92 3.79 30 Cadmium 27.9 0.200 25.00 0.01600 111 70 130 28.03 0.560 30 Chromium 497 0.500 500.0 0.5610 99.4 70 130 516.6 3.79 30 Copper 482 0.500 500.0 0.5540 96.3 70 130 489.4 1.55 30 Iron 5,310 100 5,000 45.56 105 50 150 5,246 1.13 30 Revision v1 Page 18 of 29 Date: 412112016 QC SUMMARY REPORT Total Metals by EPA Method 200.8 Sample ID: 1604116-001CMSD SampType: MSD Units: pg/L Prep Date: 4/15/2016 RunNo: 28822 Client ID: BATCH Batch ID: 13468 Analysis Date: 4/15/2016 SegNo: 541796 Analyte Result RL SPK value SPK Ref Val %REC LowLimit Hight_imit RPD Ref Val %RPD RPDLimit Qual Lead 216 1.00 250.0 0.07550 86.4 70 130 219.8 1.76 30 Manganese 507 2.00 500.0 5.155 100 70 130 507.5 0.177 30 Nickel 493 0.500 500.0 0.7520 98.4 70 130 492.2 0.156 30 Selenium 49.2 1.00 50.00 0 98.3 70 130 51.48 4.62 30 Silver 18.7 0.200 25.00 0 75.0 70 130 16.96 10.0 30 Sodium 60,100 100 5,000 57,370 54.7 50 150 60,510 0.679 30 Thallium 11.1 0.200 12.50 0.006500 88.5 70 130 11.18 1.03 30 Zinc 507 1.50 500.0 2.528 101 70 130 508.0 0.150 30 Revision v1 Page 19 of 29 Date: 412112016 QC SUMMARY REPORT Mercury by EPA Method 245.1 Sample ID: MB-13469 SampType: MBLK Units: pg/L Prep Date: 4/18/2016 RunNo: 28842 Client ID: MBLKW Batch ID: 13469 Analysis Date: 4/18/2016 SegNo: 542145 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Mercury ND 0.100 Sample ID: LCS-13469 SampType: LCS Units: pg/L Prep Date: 4/18/2016 RunNo: 28842 Client ID: LCSW Batch ID: 13469 Analysis Date: 4/18/2016 SegNo: 542146 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Mercury 2.27 0.100 2.500 0 90.8 85 115 Sample ID: 1604092-001ADUP SampType: DUP Units: pg/L Prep Date: 4/18/2016 RunNo: 28842 Client ID: BATCH Batch ID: 13469 Analysis Date: 4/18/2016 SegNo: 542148 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Mercury ND 0.100 0 20 Sample ID: 1604092-001AMS SampType: MS Units: pg/L Prep Date: 4/18/2016 RunNo: 28842 Client ID: BATCH Batch ID: 13469 Analysis Date: 4/18/2016 SegNo: 542149 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Mercury 2.41 0.100 2.500 0 96.4 80 120 Sample ID: 1604092-001AMSD SampType: MSD Units: pg/L Prep Date: 4/18/2016 RunNo: 28842 Client ID: BATCH Batch ID: 13469 Analysis Date: 4/18/2016 SegNo: 542150 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Mercury 2.40 0.100 2.500 0 96.0 80 120 2.410 0.416 20 Revision v1 Page 20 of 29 Date: 412112016 QC SUMMARY REPORT Diesel and Heavy Oil by NWTPH-Dx/Dx Ext. Sample ID: MB-13481 SampType: MBLK Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: MBLKW Batch ID: 13481 Analysis Date: 4/19/2016 SegNo: 542740 Analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) ND 50.0 Heavy Oil ND 100 Sum 2-Fluorobiphenyl 50.6 80.00 63.3 50 150 Sum o-Terphenyl 53.8 80.00 67.3 50 150 Sample ID: LCS-13481 SampType: LCS Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: LCSW Batch ID: 13481 Analysis Date: 4/19/2016 SegNo: 542739 Analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) 676 50.0 1,000 0 67.6 65 135 Sum 2-Fluorobiphenyl 58.8 80.00 73.5 50 150 Surr: o-Terphenyl 60.5 80.00 75.6 50 150 Sample ID: 1604132-002BDUP SampType: DUP Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: BATCH Batch ID: 13481 Analysis Date: 4/19/2016 SegNo: 542716 Analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) ND 51.8 Diesel Range Organics (C12-C24) 559 51.8 Heavy Oil 2,270 104 Sum 2-Fluorobiphenyl 65.9 82.88 79.6 Sum o-Terphenyl 59.4 82.88 71.6 NOTES: R - High RPD observed. The method is in control as indicated by the LCS. DRO - Indicates the presence of unresolved compounds eluting from dodecane through tetracosane (C12-C24). 0 30 459.7 19.5 30 878.6 88.5 30 R 50 150 0 50 150 0 Revision v1 Page 21 of 29 Date: 412112016 QC SUMMARY REPORT Diesel and Heavy Oil by NWTPH-Dx/Dx Ext. Sample ID: 1604140-001BMS SampType: MS Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: OW-1-041416 Batch ID: 13481 Analysis Date: 4/20/2016 SegNo: 542718 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) 668 49.9 998.9 37.33 63.2 65 135 S Sum 2-Fluorobiphenyl 59.0 79.91 73.8 50 150 Sum o-Terphenyl 58.9 79.91 73.7 50 150 NOTES: S - Outlying spike recovery(ies) observed. A duplicate analysis was performed and recovered within range. Sample ID: 1604140-001BMSD SampType: MSD Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: OW-1-041416 Batch ID: 13481 Analysis Date: 4/20/2016 SegNo: 542719 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) 714 49.8 996.3 37.33 67.9 65 135 668.4 6.56 30 Sum 2-Fluorobiphenyl 59.8 79.71 75.1 50 150 0 0 Surr: o-Terphenyl 61.5 79.71 77.2 50 150 0 0 Sample ID: 1604155-005EDUP SampType: DUP Units: pg/L Prep Date: 4/18/2016 RunNo: 28866 Client ID: BATCH Batch ID: 13481 Analysis Date: 4/20/2016 SegNo: 542729 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Diesel (Fuel Oil) ND 50.0 0 30 Heavy Oil ND 100 0 30 Surr:2-Fluorobiphenyl 55.2 79.97 69.0 50 150 0 Sum o-Terphenyl 56.7 79.97 70.9 50 150 0 Revision v1 Page 22 of 29 Date: 412112016 QC SUMMARY REPORT Gasoline by NWTPH-Gx Sample ID: LCS-R28812 SampType: LCS Units: pg/L Prep Date: 4/14/2016 RunNo: 28812 Client ID: LCSW Batch ID: R28812 Analysis Date: 4/14/2016 SegNo: 541564 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Gasoline 502 50.0 500.0 0 100 65 135 Surr: Toluene-d8 24A 25.00 97.8 65 135 Sum 4-Bromofluorobenzene 25.0 25.00 99.9 65 135 Sample ID: MB-R28812 SampType: MBLK Units: pg/L Prep Date: 4/14/2016 RunNo: 28812 Client ID: MBLKW Batch ID: R28812 Analysis Date: 4/14/2016 SegNo: 541565 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Gasoline ND 50.0 Surr: Toluene-d8 24.9 25.00 99.8 65 135 Sum 4-Bromofluorobenzene 24.9 25.00 99.7 65 135 Sample ID: 1602099-051AMS SampType: MS Units: pg/L Prep Date: 4/15/2016 RunNo: 28812 Client ID: BATCH Batch ID: R28812 Analysis Date: 4/15/2016 SegNo: 541555 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Gasoline 540 50.0 500.0 0 108 65 135 H Surr: Toluene-d8 25.2 25.00 101 65 135 H Surr: 4-Bromofluorobenzene 25.4 25.00 101 65 135 H Sample ID: 1602099-051AMSD SampType: MSD Units: pg/L Prep Date: 4/15/2016 RunNo: 28812 Client ID: BATCH Batch ID: R28812 Analysis Date: 4/15/2016 SegNo: 541556 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Gasoline 557 50.0 500.0 0 111 65 135 540.1 3.07 30 H Surr: Toluene-d8 24.6 25.00 98.2 65 135 0 0 H Sum 4-Bromofluorobenzene 24.6 25.00 98.6 65 135 0 0 H Revision v1 Page 23 of 29 Date: 412112016 QC SUMMARY REPORT Gasoline by NWTPH-Gx Sample ID: 1604115-005ADUP SampType: DUP Units: pg/L Prep Date: 4/15/2016 RunNo: 28812 Client ID: BATCH Batch ID: R28812 Analysis Date: 4/15/2016 SegNo: 541558 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Gasoline ND 50.0 0 30 Sum Toluene-d8 25.0 25.00 99.8 65 135 0 0 Sum 4-Bromofluorobenzene 25A 25.00 101 65 135 0 0 Revision v1 Page 24 of 29 Date: 412112016 QC SUMMARY REPORT Volatile Organic Compounds by EPA Method 8260C Sample ID: LCS-R28811 SampType: LCS Units: pg/L Prep Date: 4/14/2016 RunNo: 28811 Client ID: LCSW Batch ID: R28811 Analysis Date: 4/14/2016 SegNo: 541551 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Benzene 17.2 1.00 20.00 0 86.1 69.3 132 Toluene 19.3 1.00 20.00 0 96.4 61.3 145 Ethylbenzene 18.2 1.00 20.00 0 91.1 72 130 m,p-Xylene 37.0 1.00 40.00 0 92.6 70.3 134 o-Xylene 18.6 1.00 20.00 0 93.0 72.1 131 Surr: Dibromofluoromethane 23.1 25.00 92.2 45.4 152 Surr: Toluene-d8 27A 25.00 110 40.1 139 Sum I-Bromo-4-fluorobenzene 25.6 25.00 102 64.2 128 Sample ID: MB-R28811 SampType: MBLK Units: pg/L Prep Date: 4/14/2016 RunNo: 28811 Client ID: MBLKW Batch ID: R28811 Analysis Date: 4/14/2016 SegNo: 541552 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Benzene ND 1.00 Toluene ND 1.00 Ethylbenzene ND 1.00 m,p-Xylene ND 1.00 o-Xylene ND 1.00 Surr: Dibromofluoromethane 26.0 25.00 104 45.4 152 Surr: Toluene-d8 23.7 25.00 94.9 40.1 139 Surr:1-Bromo-4-fluorobenzene 24.6 25.00 98.3 64.2 128 Sample ID: 1602099-051AMS SampType: MS Units: pg/L Prep Date: 4/14/2016 RunNo: 28811 Client ID: BATCH Batch ID: R28811 Analysis Date: 4/14/2016 SegNo: 541536 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Benzene Toluene Ethylbenzene m,p-Xylene 20.1 1.00 20.00 0 101 65.4 138 18A 1.00 20.00 0 91.8 64 139 19.5 1.00 20.00 0 97.4 64.5 136 39.9 1.00 40.00 0 99.8 63.3 135 Revision v1 Page 25 of 29 Date: 412112016 QC SUMMARY REPORT Volatile Organic Compounds by EPA Method 8260C Sample ID: 1602099-051AMS SampType: MS Units: pg/L Prep Date: 4/14/2016 RunNo: 28811 Client ID: BATCH Batch ID: R28811 Analysis Date: 4/14/2016 SegNo: 541536 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual o-Xylene 20.0 1.00 20.00 0 100 65.4 134 H Surr: Dibromofluoromethane 26.3 25.00 105 45.4 152 H Surr: Toluene-d8 24.1 25.00 96.4 40.1 139 H Sum I-Bromo-4-fluorobenzene 24.9 25.00 99.8 64.2 128 H Sample ID: 1602099-051AMSD SampType: MSD Units: pg/L Prep Date: 4/14/2016 RunNo: 28811 Client ID: BATCH Batch ID: R28811 Analysis Date: 4/14/2016 SegNo: 541537 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Benzene 20.3 1.00 20.00 0 101 65.4 138 20.12 0.693 30 H Toluene 18A 1.00 20.00 0 92.0 64 139 18.36 0.218 30 H Ethylbenzene 20.8 1.00 20.00 0 104 64.5 136 19.48 6.41 30 H m,p-Xylene 41.5 1.00 40.00 0 104 63.3 135 39.90 3.88 30 H o-Xylene 20.8 1.00 20.00 0 104 65.4 134 20.02 3.92 30 H Surr: Dibromofluoromethane 25.9 25.00 104 45.4 152 0 0 H Surr: Toluene-d8 23.8 25.00 95.1 40.1 139 0 0 H Surr:1-Bromo-4-fluorobenzene 25.5 25.00 102 64.2 128 0 0 H Sample ID: 1604115-005ADUP SampType: DUP Units: pg/L Prep Date: 4/15/2016 RunNo: 28811 Client ID: BATCH Batch ID: R28811 Analysis Date: 4/15/2016 SegNo: 541544 Analyte Result RL SPK value SPK Ref Val %REC LowLimit HighLimit RPD Ref Val %RPD RPDLimit Qual Benzene ND 1.00 0 30 Toluene ND 1.00 0 30 Ethylbenzene ND 1.00 0 30 m,p-Xylene ND 1.00 0 30 o-Xylene ND 1.00 0 30 Surr: Dibromofluoromethane 25.5 25.00 102 45.4 152 0 Surr: Toluene-d8 23.1 25.00 92.4 40.1 139 0 Sum 1-Bromo-4-fluorobenzene 24.9 25.00 99.4 64.2 128 0 Revision v1 Page 26 of 29 Date: 412112016 QC SUMMARY REPORT Volatile Organic Compounds by EPA Method 8260C Sample ID: 1604115-005ADUP SampType: DUP Units: pg/L Prep Date: 4/15/2016 RunNo: 28811 ;lient ID: BATCH Batch ID: R28811 Analysis Date: 4/15/2016 SegNo: 541544 analyte Result RL SPK value SPK Ref Val %REC Lowl-imit HighLimit RPD Ref Val %RPD RPDLimit Qual Revision v1 Page 27 of 29 Sample Log~UnCheck List Client Name: SW Work Order w"muac 1604140 Logged by: Erica Silva Date Received: 4/14/2016*07:00PM Chain of Custod 1. |sChain ofCustody complete? Yes IV] No Not Present Z How was the sample delivered? Client Loa 3. Coolers are present? Yes IvIl No 1:1 NA 1:1 4. Shipping container/cooler ingood condition? Yes lu4 No 1:1 5. Custody Seals present onshipping montainencvo|o,? Yes No Not Required (Refer mcomments for Custody Seals not intact) 8. Was anattempt made mcool the samples? Yes V No 1:1 wx E] 7. Were all items received vuatemperature of >8~Cm10.0^C Yes �� No 1-1 wx [1 8.Smmp|a(u)inproper oontaina,(o)? Yes W No El 0�Sufficient sample volume for indicated mm(u)r voo No 10.Are samples properly preserved? Yes No 11.Was preservative added mbottles? Yon V No [] wx [1 H2SO4mO01H 12.|uthere homuspaoainthe VOA vials? Yes No wx 1g.Did all samples containers arrive ingood condition (unbmmen)r vno V No El 14. Does paperwork match bottle labels? Yes IV No E 15.Are matrices correctly identified onChain cxCustody? Yes -1 No [� 16.|snclear what analyses were requested? Yes No 17.Were all holding times able mbomet? vno �� No 1] Si3ecial Handlina (if applicable) 18.Was client notified oxall discrepancies with this order? vnn No wx Person Notified: Date: r By Whom: Regarding: Client Instructions: °Note: ooD/EmPand Tm|require items muereceived m4'C"/- TC Revision v1 APPENDIX D GROUNDWATER MODELING 21-1-22082-003 " 1 1 ,19 Z�111►1111AZI Ill Of iU [0] 1104 0 I [!i TABLE OF CONTENTS Page D.1 INTRODUCTION.......................................................................................................... D-1 D.2 MODELING APPROACH............................................................................................. D-1 D.3 MODEL STRUCTURE AND LAYERING................................................................... D-2 DA HYDRAULIC PARAMETERS..................................................................................... D-2 D.5 BOUNDARY CONDITIONS AND INITIAL GROUNDWATER LEVELS ............... D-2 D.6 UNDERGROUND INJECTION CONTROL WELL RECHARGE SIMULATIONS.. D-3 D.7 SUMMARY.................................................................................................................... D-4 D.8 REFERENCES............................................................................................................... D-4 TABLE D-1 Modeled Hydrostratigraphic Layers and Hydraulic Properties .......................... D-2 FIGURES D-1 Model Domain and Boundaries D-2 Planned UIC Wells D-3 Model Mesh in Northern UIC Wellfield Area D-4 Model Sections North -South and West -East Through Well IW-2 D-5 Model Input Hydrograph & Predicted Groundwater Levels at UIC Areas — Base Case D-6 Predicted Groundwater Levels Along Transect Through UIC Area 2 — Base Case D-7 Model Input Hydrograph & Predicted Groundwater Levels at UIC Area 2 — Sensitivity Cases D-8 Predicted Groundwater Levels Along Transect Through UIC Area 2 — Sensitivity Case 3 21-1-22082-003-Rl f AD/wp/]k 21-1-22082-003 D-i SHANNON LINC. " 1 1 D.1 INTRODUCTION We developed a three-dimensional groundwater model (model) based on the site explorations and our conceptual hydrogeologic model. The objective of the model was to predict the likely groundwater response to the planned underground injection control (UIC) wellfield operation. In particular, the model was used to evaluate water mounding above potential perching layers and the potential for seepage to occur at the slopes to the west and east of the school property. This appendix provides a description of the model setup and a summary of the modeling results. The proposed UIC wellfield consisting of 16 wells in 4 clusters of either 3 or 5 wells each. The UIC well spacing within the clusters ranged from 30 to 50 feet, based on the proposed layout provided by KPFF Consulting Engineers. We simulated the recharge occurring into the unsaturated zone of the Vashon advance outwash (Qva) unit that overlies a 5-foot-thick perching layer and a deeper, saturated Qva aquifer. D.2 MODELING APPROACH The model was constructed using numerical modeling techniques to simulate unsaturated zone and groundwater flow conditions for the project area. The model approach included: ■ Selecting an appropriate numerical model and the supporting software. ■ Constructing a three-dimensional representation of the model area that includes the hydrogeologic framework, hydraulic properties, and boundary conditions. ■ Performing simulations for one base and three sensitivity case scenarios. ■ Evaluating model results. We used the U.S. Geological Survey's numerical groundwater flow code MODFLOW-2005 (Harbaugh, 2005) to simulate the groundwater flow system in the project area. We used the graphical interface program Groundwater Vistas version 6 (Environmental Simulations Incorporated, 2016) as a pre- and post -processor to create and manage model input and output files for MODFLOW-2005. 21-1-22082-003-Rl f AD/wp/]k 21-1-22082-003 D-1 SHANNON LINC. D.3 MODEL STRUCTURE AND LAYERING Figure D-1 shows the model domain which has dimensions 2,400 feet by 2,000 feet. The model grid consists of computational cells with dimensions ranging from 30 feet by 30 feet to 2.5 feet by 2.5 feet in plan view, with the smallest cells assigned at and near the planned UIC wells (Figure D-2). The model's upper surface (top of layer 1) was established by interpolating a digital elevation map dataset for the area to the model grid (Figure D-3). Vertically, the model thickness ranges from about 230 feet thick beneath the school property to 125 feet in the valley area west of the school (Figure D-4). The model base is at Elevation 225 feet. The vertical thickness of the model is divided into three layers based on the conceptual hydrogeologic profiles. DA HYDRAULIC PARAMETERS The main hydraulic parameters in the model are hydraulic conductivity (horizontal and vertical) and storage coefficients (unconfined and confined). We assigned the model hydraulic conductivity values based on empirical correlations with grain size test results from samples collected during Shannon & Wilson, Ine.'s subsurface explorations at the site, slug test results, and the two pilot -scale recharge tests. As no formal testing was performed to estimate the storage coefficients, we used professional judgment to assign parameter values. Table D-1 presents the modeled parameters for each layer. TABLE D-1 MODELED HYDROSTRATIGRAPHIC LAYERS AND HYDRAULIC PROPERTIES H ttl t11 , . y lir 'd raylic' onduiti�ity. +txnclutla�E1 ild, R iuc3T Layer 1 30 3 Greater than 350 to 52 to 162 Unsaturated Qva 298. outwash. 0.1, 1 x 10-5 Low permeability 2 0.1 0.01 298 to 293 5 perching layer within Qva. 3 30 3 293 to 225 68 Qva outwash aquifer. The model uses MODFLOW Constant Head boundary conditions along the northern and southern limits of the domain to simulate groundwater inflow and outflow, and to establish initial 21-1-22082-003-Rl f AD/wp/]k 21-1-22082-003 D-2 SHANNON LINC. (existing) groundwater conditions. For the purpose of this evaluation, these heads were Elevations 299 and 300 feet, respectively. Therefore, the existing groundwater levels are slightly above the base of layer 1. D.6 UNDERGROUND INJECTION CONTROL WELL RECHARGE SIMULATIONS For the Base Case model run, we simulated a total stormwater recharge hydrograph that we were provided by the design engineers KPFF Consulting Engineers. This hydrograph represents a 100-year, 24-hour storm event. We distributed this flux between the 16 wells that are part of the four clusters of UIC wells (Areas 1, 2, 3, and 4; Figure D-2). The recharge flux was assigned to model layer 1. We used 24 hourly model stress periods to simulate the storm event. The peak hourly recharge rate per well ranged from 102 to 130 gallons per minute. Figure D-5 shows the model -predicted water level response to the 24-hour storm event at the centers of the four UIC Areas and the total input hourly hydrograph. These modeled responses represent the anticipated temporary perching of infiltrating water above the lower permeability silty sand layer that is situated above the regional aquifer. The results indicate that the storm event would temporarily raise water levels to a peak of Elevation 310 feet at the center of UIC Area 2 (which has five UIC wells), and to below Elevation 306 feet at the center of the three other UIC areas. Figure D-6 shows the predicted hydrograph for four points along a 400-foot-long east -west transect extending from the center of UIC Area 2 (OW-2) to the bottom of the ravine located west of the UIC arrays (which is at about Elevation 370 feet). The results indicate that the mounding effect of the storm would diminish to the west of OW-2, and the temporarily perched water table would come within 70 feet of the slope surface. To evaluate the effect that uncertainty of key model parameters on the Base Case results, we performed three sensitivity cases. These involved the re -simulating the 24-hour storm with the following changes to the Base Case model: ■ Sensitivity Case 1 — lower the Qva aquifer Kh and Kv to 3 and 0.3 feet per day, respectively; Sensitivity Case 2 — increase the elevation of the 5-foot-thick perching layer by 15 feet; and ■ Sensitivity Case 3 — combination of Cases 1 and 2. Figure D-7 shows the predicted results for the three sensitivity cases and the Base Case at the center of UIC Area 2 (OW-2), and Figure D-8 shows the predicted hydrographs for four points along the east -west transect from OW-2. The results indicate that the induced perched water table would rise to a peak of Elevation 328 feet at the center of UIC Area 2 (for the most conservative Sensitivity Case 3), which is 117 feet below ground surface. As with the Base 21-1-22082-003-Rl f AD/wp/]k 21-1-22082-003 D-3 SHANNON MLSON. INC. Case, the water would remain more than 50 feet below the toe of the slope to the west of UIC Area 2 for Sensitivity Case 3. For the Base Case scenario, the model predicts that the water table will rise by between 7 and 11 feet at the center of the four UIC areas during a 100-year, 24-hour storm event. The resulting mound would be 70 feet or more below the surface of the nearby ravine slope. We ran a limited sensitivity analysis of the Base Case involving reducing the hydraulic conductivity of the Qva unit by a factor of 10 and increasing the elevation of the perching unit by 15 feet. The most conservative sensitivity case resulted in the peak rise in the water table at the UIC area of up to 14 feet, to a maximum elevation of 328 feet (which is 117 feet below ground surface). The resulting mound would be 50 feet or more below the surface of the nearby ravine slope for the most conservative sensitivity case. Our model provides a framework for estimating how much groundwater mounding may result during the given storm assuming the UIC wells are 100 percent efficient. The Base Case modeling predicted an operating water level of up to about 18 feet inside the UIC wells during the design storm event. However, depending on the well drilling method, development, and maintenance practices, the actual initial UIC well efficiencies will be less (e.g., 50 to 75 percent). Additionally, UIC well efficiency typically decreases with time of operation, depending on the degree of inflow water quality control and well maintenance frequency. Therefore, we would expect the operating water level in the UIC wells to increase in the future. For example, at 50 percent well efficiency, the operating water level inside the UIC wells might be closer to about 36 feet for the modeled storm. D.8 REFERENCES Environmental Simulations Incorporated (ESI), 2012, Groundwater Vistas, v. 6: Reinholds, Pa., Environmental Simulations Incorporated. Harbaugh, A. W., 2005, MODFLOW-2005: the U.S. Geological Survey modular ground -water model --the ground -water flow process3: U.S. Geological Survey Techniques of Water - Resources Investigations Book 6, Chapter Al6, 1 v., available: ht Ts:/lpubs.u&s s. gov/tm/2005/tm6A 16/. 21-1-22082-003-Rl f AD/wp/]k 21-1-22082-003 D-4 Southern Constant Northern Constant Head boundary Head boundary (elev. 300ft) (elev. 299ft) South Well OW-2 North 455' 0 > Unsaturated Qva unit 0J ED 293 --- Low K layer 225' 1 Zva aquifer West Well OW-2 East 400'--- Unsaturated Qva unit 31 ------- ------ Low K layer .......... . . . 225'1 1 1 1 1 1 1 1 1 lilt Qva aquifer Hydrogeologic Report New Madrona K-8 Project 0 250 500 Edmonds, Washington MODEL SECTIONS NORTH -SOUTH & Scale in Feet WEST -EAST THROUGH WELL IW-2 Vertical exaggeration = x2 November 2016 21-1-22082-003 SHANNON & WILSON, INC. FIG. D-4 Geotechnical and Environmental Consultants 315 2000 °° Input Hydrograph OBS-1 (UIC Areal) OW-2 (UIC Area 2) 3 OBS-3 (UIC Area 3) OBS-4 (UIC Area 4) 310 1500 Q- � ao o M 3{{ Uj 305 ___________________________________________________________________________________________.. 1000 Q- � 3 o = U. � a �rz x 300 500 295 0 rHNMd Lnt.0r`00M0r1NMcrLnl9r`porno,-iNM'zrLn(.or`1brnorHNM'zTLnQ0r`oorno,-iNM'zTLnt.0r`00 `-1 rH rH rH rH T-1 rH rH rH `H N N N N N N N N N N M M M M M M M M M M cl' c1' cr n* Cr Cr cl' cr 'IT Time (hours) Hydrogeologic Report Notes: New Madrona K-8 School 1. Observation point locations shown on Fiqure 10 Edmonds, Washington MODEL INPUT HYDROGRAPH & 2. Input hydrograph provided by KPFF PREDICTED GROUNDWATER LEVELS AT -n UIC AREAS - BASE CASE November 2016 21-1-22082-003 v SHANNON & WILSON, INC- FIG. D-5otechnical FGe and Environmental Consultants 315 2000 Input Hydrograph OW-2 (UIC Area 2) OBS-5 (70 ft west of OW-2) OBS-6 (100 ft west of OW-2) 310 013S-7 (400 ft west of OW-2) 1500 a. O aA o 4F M > 4� M cc a� 4a W 305 ••_ 3 1000 Q- 4� j# err c 40, OOil i C� O 300 _ 500 295---- 7----- 7 ----- 1 aaa7aaaa7 araaaa7----- ;----- r----- Taaaaaraaaa7aaaaar aa1------ raaaa7 ---- 7aaaa7 r----- r----- r ----- _ 0 ci N M dt Ln lD r- 00 01 O -i N M d' Ln l0 r, 00 Ql O 1H N M It to lD n 00 Ql rl c-I -1 rl ci -1 -1 rl ci rl N N N N N N N N N N O -1 N M It to l0 r" 00 Ol O -1 N M d' Ln l0 r, 00 M M M M M M M M M M d' It d' dt It It d' d' d' Time (hours) Hydrogeologic Report Notes: New Madrona K-8 School Edmonds, Washington 1. Observation point locations shown on Fiqure 10 PREDICTED GROUNDWATER LEVELS 2. Input hydroqraph provided by KPFF ALONG TRANSECT -n 3. OW-2 elev = 445 feet; OBS-5 = elev. 444 ft; OBS-6 = elev. 450 ft; OBS-7 = elev. 370 ft THROUGH UIC AREA 2 - BASE CASE November 2016 21-1-22082-003 v SHANNON & WILSON, INC. FIeotechnical FG and Environmental Consultants Madrona Model Ann D tables and fi2ures - sdt 11-16- 340 2000 =Input Hydrograph --4— Base Case (OW-2) --*—Sensitivity Case 1 Sensitivity Case 2 Sensitivity Case 3 330 1600 P-11 E 320 ""g .... .. ... CL 1200 .2 > Uj CL 0 310 .................................... LL 800 P 0 300 400 290 0 r-1 (N rn It Lf) �0 r, 00 M 0 r-1 (N rn lzr Ln �D r, 00 a) 0 1-1 r14 rn :t Ln �D r� 00 a) 0 r-4 (14 ro t Ln Lo r, 00 Cn C) 1H CN On �t Lr) Lo r- 00 r-i r-1 r-i r-1 r-i r-1 rH r-1 r-i r-1 C-4 (N r14 r14 r14 r14 r14 r14 r14 r14 ro rn ro rn ro rr) ro M M M q:T 'ZI, q:T �zf q:T �7r 1:T Zzr 1-:T Time (hours) Hydrogeologic Report Notes: New Madrona K-8 School Edmonds, Washington 1. Observation point locations shown on Fiqure 10 MODEL INPUT HYDROGRAPH & 2. Input hydroqraph provided bv KPFF PREDICTED GROUNDWATER LEVELS AT -n UIC AREA 2 - SENSITIVITY CASES November 2016 21-1-22082-003 FSHANNON & WILSON, INC. FI G eotechnical and Environmental Consultants 340 2000 Input Hydrograph OW-2 (UIC Area 2) 335 AAAn OBS-5 (70 ft west of OW-2) 0BS-6 (100 ft west of OW-2) OBS-7 (400 ft west of OW-2) 1500 330 .. E CL � ao o > 41 cc IV 4a L 325 _________ ... 1000 Q- a� � 0 3 _ U. o � 320 __._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._ C ilia i3 11' } ' tut . �. t -� 500 s 315............................ w.v.v.v.v.v.v.vw..................................... ............................. 3101 0 i--I N M d' Ln to r� oo a) O rH N M d' Ln to r, oo m O rH N M d' Ln w r� w m O rH rH -1 `-I rH rH `H `-I rH rH N N N N N N N N N N M M N M d' u) Ca r� w M O r-I N M dt Ln la r, oo M CO rn M CO M M M d- d d d d- d' d d d Time (hours) Hydrogeologic Report Notes: New Madrona K-8 School Edmonds, Washington 1. Observation point locations shown on Fiqure 10 2. Input hydrograph provided by KPFF PREDICTED GROUNDWATER LEVELS ALONG TRANSECT -n 3. OW-2 elev = 445 feet; OBS-5 = elev. 444 ft; OBS-6 = elev. 450 ft; OBS-7 = elev. 370 ft THROUGH UIC AREA 2 - SENSITIVITY CASE 3 November 2016 21-1-22082-003 v 00 SHANNON & WILSON, INC. FIG. D-8 FGeotechnical and Environmental Consultants APPENDIX E IMPORTANT INFORMATION ABOUT YOUR GEOTECHNICAL/ENVIRONMENTAL REPORT 21-1-22082-003 SHANNON & WILSON, INC. Attachment to and part of Report 21-1-22082-003 Geotechnical and Environmental Consultants Date: November 29, 2016 To: Ms. Taine Wilton Edmonds School District #15 IMPORTANT INFORMATION ABOUTTOUR GEOTECHNICAL/ENVIRONMENTAL REPORT .�Z�P.��71�1►[rl+���/C�3�. a�� :I i�1.=1�13�1:Z•�=C�313C�1�1isZ�I�.�<<I7.��7���=C�l3C��1�1�1►��� Consultants prepare reports to meet the specific needs of specific individuals. A report prepared for a civil engineer may not be adequate for a construction contractor or even another civil engineer. Unless indicated otherwise, your consultant prepared your report expressly for you and expressly for the purposes you indicated. No one other than you should apply this report for its intended purpose without first conferring with the consultant. No party should apply this report for any purpose other than that originally contemplated without first conferring with the consultant. THE CONSULTANT'S REPORT IS BASED ON PROJECT -SPECIFIC FACTORS. A geotechnical/environmental report is based on a subsurface exploration plan designed to consider a unique set of project -specific factors. Depending on the project, these may include: the general nature of the structure and property involved; its size and configuration; its historical use and practice; the location of the structure on the site and its orientation; other improvements such as access roads, parking lots, and underground utilities; and the additional risk created by scope -of -service limitations imposed by the client. To help avoid costly problems, ask the consultant to evaluate how any factors that change subsequent to the date of the report may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used: (1) when the nature of the proposed project is changed (for example, if an office building will be erected instead of a parking garage, or if a refrigerated warehouse will be built instead of an unrefrigerated one, or chemicals are discovered on or near the site); (2) when the size, elevation, or configuration of the proposed project is altered; (3) when the location or orientation of the proposed project is modified; (4) when there is a change of ownership; or (5) for application to an adjacent site. Consultants cannot accept responsibility for problems that may occur if they are not consulted after factors which were considered in the development of the report have changed. SUBSURFACE CONDITIONS CAN CHANGE. Subsurface conditions may be affected as a result of natural processes or human activity. Because a geotechnical/environmental report is based on conditions that existed at the time of subsurface exploration, construction decisions should not be based on a report whose adequacy may have been affected by time. Ask the consultant to advise if additional tests are desirable before construction starts; for example, groundwater conditions commonly vary seasonally. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or groundwater fluctuations may also affect subsurface conditions and, thus, the continuing adequacy of a geotechnical/environmental report. The consultant should be kept apprised of any such events, and should be consulted to determine if additional tests are necessary. [u[���.�:ZX%I���l ��i Ili• I T� �[�Iil+'?/_1:T�:Z�I7��Y[�li<I�1_�111ZtI���l � �� �� Site exploration and testing identifies actual surface and subsurface conditions only at those points where samples are taken. The data were extrapolated by your consultant, who then applied judgment to render an opinion about overall subsurface conditions. The actual interface between materials may be far more gradual or abrupt than your report indicates. Actual conditions in areas not sampled may differ from those predicted in your report. While nothing can be done to prevent such situations, you and your consultant can work together to help reduce their impacts. Retaining your consultant to observe subsurface construction operations can be particularly beneficial in this respect. Page 1 of 1/2016 A REPORT'S CONCLUSIONS ARE PRELIMINARY. The conclusions contained in your consultant's report are preliminary because they must be based on the assumption that conditions revealed through selective exploratory sampling are indicative of actual conditions throughout a site. Actual subsurface conditions can be discerned only during earthwork; therefore, you should retain your consultant to observe actual conditions and to provide conclusions. Only the consultant who prepared the report is fully familiar with the background information needed to determine whether or not the report's recommendations based on those conclusions are valid and whether or not the contractor is abiding by applicable recommendations. The consultant who developed your report cannot assume responsibility or liability for the adequacy of the report's recommendations if another parry is retained to observe construction. THE CONSULTANT'S REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when other design professionals develop their plans based on misinterpretation of a geotechnical/environmental report. To help avoid these problems, the consultant should be retained to work with other project design professionals to explain relevant geotechnieal, geological, hydrogeologieal, and environmental findings, and to review the adequacy of their plans and specifications relative to these issues. BORING LOGS AND/OR MONITORING WELL DATA SHOULD NOT BE SEPARATED FROM THE REPORT. Final boring logs developed by the consultant are based upon interpretation of field logs (assembled by site personnel), field test results, and laboratory and/or office evaluation of field samples and data. Only final boring logs and data are customarily included in geotechnical/environmental reports. These final logs should not, under any circumstances, be redrawn for inclusion in architectural or other design drawings, because drafters may commit errors or omissions in the transfer process. To reduce the likelihood of boring log or monitoring well misinterpretation, contractors should be given ready access to the complete geotechnical engineering/environmental report prepared or authorized for their use. If access is provided only to the report prepared for you, you should advise contractors of the report's limitations, assuming that a contractor was not one of the specific persons for whom the report was prepared, and that developing construction cost estimates was not one of the specific purposes for which it was prepared. While a contractor may gain important knowledge from a report prepared for another party, the contractor should discuss the report with your consultant and perform the additional or alternative work believed necessary to obtain the data specifically appropriate for construction cost estimating purposes. Some clients hold the mistaken impression that simply disclaiming responsibility for the accuracy of subsurface information always insulates them from attendant liability. Providing the best available information to contractors helps prevent costly construction problems and the adversarial attitudes that aggravate them to a disproportionate scale. Because geotechnical/environmental engineering is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in their contracts, reports, and other documents. These responsibility clauses are not exculpatory clauses designed to transfer the consultant's liabilities to other parties; rather, they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. The preceding paragraphs are based on information provided by the ASFE/Association of Engineering Firms Practicing in the Geosciences, Silver Spring, Maryland Page 2 of 2 1/2016 Wetland and Stream Delineation Report By: Shannon & Wilson, Inc. Date: May 18, 2016 Madrona School — Edmonds School District Appendix E Wetland and Stream Delineation Report New Madrona K-8 Project City of Edmonds, Washington Excellence. Innovation. Service. Value. RMHOMM May 18, 2016 Submitted To: Ms. Taine Wilton Edmonds School District #15 20420 681h Avenue West Lynnwood, Washington 98036 By: Shannon & Wilson, Inc. 400 N 34th Street, Suite 100 Seattle, Washington 98103 21-1-22082-002 SHANNON MI -SON, INC Page 1.0 INTRODUCTION..................................................................................................................1 2.0 SITE DESCRIPTION............................................................................................................1 3.0 METHODS.............................................................................................................................2 4.0 DOCUMENT REVIEW.........................................................................................................3 5.0 WETLAND DELINEATION................................................................................................3 5.1 Wetland A..................................................................................................................3 5.2 Wetland B...................................................................................................................4 5.3 Wetland C...................................................................................................................5 5.4 Uplands.......................................................................................................................6 6.0 REGULATIONS ....................................................................................................................6 6.1 Federal. Regulations....................................................................................................6 6.2 State Regulations........................................................................................................7 6.3 City of Edmonds (City)..............................................................................................8 6.3.1 Wetlands Regulations ..................................................................................8 6.3.2 Other Critical Areas...................................................................................1.0 7.0 CLOSURE............................................................................................................................11 8.0 REFERENCES.....................................................................................................................1.2 TABLES 1 Wetland Impact Compensatory Mitigation Ratios..................................................7 2 Required Measures to Minimize Impacts (ECDC 23.50.040(F)(2).........................8 1 Vicinity Map 2 Wetland Delineation Map 21-1-22082-002-R1f/wp/]kn FIGURES 1 21-1-22082-002 SHANNON MI -SON, INC TABLE OF CONTENTS (cont.) APPENDICES A Wetland Delineation. Methodology B Wetland Determination Data Forms — Western Mountains, Valleys, and Coast Region C Wetland Rating Forms — Western Washington D Important Information About Your Wetland Delineation/Mitigation and/or Stream Classification Report 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 11 SHANNON WILSON, INC. WETLAND AND STREAM DELINEATION REPORT NEW MADRONA K-8 PROJECT CITY OF EDMONDS, WASHINGTON 1.0 INTRODUCTION Shannon & Wilson, Inc. (Shannon & Wilson) was contracted by the City of Edmonds School District (District) No. 15 to conduct a wetland and stream delineation for the New Madrona K-8 Project, located in Edmonds, Washington (Figure 1). The District plans to construct a new Madrona K-8 school on the south side of the approximately 40-acre property, located at 9300 236th Street SW (Snohomish County tax parcel 27033600404600). The project is located within Section 36 of Township 27 N, Range 4 E, Willamette Meridian. The wetland and stream delineation is intended to assist the District and design team in the site selection and conceptual design process. The scope of services for our wetland and stream delineation was limited to the following tasks: ■ Conduct a background review of information relating to the site. ■ Complete a wetland delineation on project site. ■ Estimate approximate wetland boundaries within 200 feet of the property boundary. ■ Delineate the ordinary high water mark (OHWM) of onsite streams. ■ Categorize wetlands using the 2014 Washington State Wetland Rating System for Western Washington.' ■ Complete a wetland delineation report describing our findings including categories and standard buffer widths. 2.0 SITE DESCRIPTION The approximately 40-acre property is dissected by two steeply sloped wooded areas running in north -south alignments; one is a ravine located along the eastern property boundary and the other is a forested incline located near the middle of the property. The existing Madrona Elementary School is located in the northeast corner of the property and the former Woodway Elementary School is located in the opposite southwest corner of the property. Recreational areas including a track and baseball field, and soccer fields are located in the southeast and northwest corners of the property. The areas surrounding the property consist primarily of residential development. ' The original scope also included wetland categorization under the 2004 Washington State Wetland Rating System for Western Washington, but a subsequent City critical areas regulations update rendered those forms obsolete and they are not included in this final report. n-l-zzosz-ooz-Rlfrwp/]kn 21-1-22082-002 SHANNON WILSON, The property is well used by local residents for recreation. During our site visits, we observed many people walking dogs in trail systems located throughout the sloped wooded areas as well, as many joggers on the track. A series of catch basin grates were observed along the inside of the track. The survey performed for the property shows that these storm drains, along with storm drain from the existing Madrona Elementary School, discharge to the top of the steep wooded slope in the middle of the property. The survey also identifies storm drain discharges to the top of the wooded ravine located on the eastern property boundary. 3.0 METHODS Shannon & Wilson conducted the wetland delineation fieldwork on July 6 and 7, 2015. Potential wetlands were identified using methods described in the Corps Wetlands Delineation Manual (U.S. Army Corps of Engineers [Corps] Waterways Experiment Station, 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Corps Engineer Research and Development Center, 2010). Potential wetland areas were determined using the triple -parameter approach, which considers vegetation types, soil conditions, and hydrologic conditions. For an area to be considered wetland, it must display each of the following: (a) dominant plant species that are considered hydrophytic by the accepted classification indicators, (b) soils that are considered hydric under federal definition, and (c) indications of wetland hydrology, in accordance with the federal definition. Appendix A provides a detailed description of methodology used. Typically, the OHWM of streams are delineated following the guidance within Ecology's technical report Determining the Ordinary High Water Mark on Streams in Washington State (Ecology, 2010). However, no onsite streams were observed; therefore, no OHWM delineations occurred. Identified wetlands were delineated by using pink "wetland boundary" flagging and pink pin flags. Data point locations were marked with orange flagging and orange pin flags. 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 2 SHANNON WILSON, INC. 4.0 DOCUMENT REVIEW Prior to conducting fieldwork, we reviewed the following background information: ■ U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (MRCS) Web Soil Survey interactive mapping system ■ U.S. Fish and Wildlife Service (USFWS) National Wetland Inventory (NWI) Wetlands Mapper interactive mapping system ■ Washington Department of Fish and Wildlife (WDFW) SalmonScape mapping system ■ WDFW PHS on the Web interactive mapping system The MRCS web soil survey identifies the site soils as Alderwood gravelly, sandy loam; 15 to 30 percent slopes; Alderwood-Urban land complex; 2 to 8 percent slopes; and 8 to 1.5 percent slopes (USDA, 2015). These soil series are identified as non-hydric, however they may contain areas of hydric inclusions. Neither the NWI map, the WDFW SalmonScape application, nor the WDFW PHS on the Web application identify streams, wetlands, or other fish and wildlife habitat conservation areas on the property (USFWS, 2015.and WDFW, 2015.and 2016). 5.0 WETLAND DELINEATION Three wetlands (identified as Wetland A, B, and C) were delineated in the project area (Figure 2). Descriptions of the wetland and adjoining uplands follow. Vegetation is described below by common name, with the scientific name and indicator status in parentheses for the first use. Soils are described with the associated Munsell® Color Charts color. Wetlands were characterized according to the updated 2014 version of the "Washington State Wetland Rating System for Western Washington" (Ecology, 2014) as required by the City, Corps, and Ecology (see Appendix B for Wetland Determination Data Forms and Appendix C for Wetland Rating Forms). 5.1 Wetland A Wetland A (approximately 0.02 acre) was delineated on the wooded slope located in the middle of the property, downgradient from storm drain outfalls identified on the survey. A trail system on the slope allows human and pet access to the wetland. Wetland A is classified as a palustrine scrub -shrub wetland according to the Cowardin classification and is a slope wetland according to hydrogeomorphic classification. 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 SHANNON WILSON, Dominant vegetation in. Wetland A includes a shrub strata of salmonberry (Rubus spectabilis, FAC), English laurel (Prunus laurocerasus, NI), mountain ash (Sorbus sitchensis, FAC), as well as an emergent strata of lady fern (Athyrium cyclosorum, FAC) (see Appendix B, Data Sheet DP-7). Soil in Wetland A is generally characterized by a surface horizon of black (I OYR 2/1) loam extending to 5 inches below ground surface (bgs), underlain by a grayish brown (I OYR 5/2) sand with dark yellowish brown (I OYR 4/6) redoximorphic concentrations in the matrix. Soil observed in Wetland A meets the depleted below dark surface (A11) and depleted matrix (173) hydric soil indicators. During the site visit, seeps were observed throughout Wetland A. Hydrology in Wetland A is likely supported by a combination of storm drain discharges from the upgradient storm drain outfalls and groundwater. Water in the data pit was observed at 1.1.5 inches bgs and the soil was saturated to the surface. Wetland A was rated according to Ecology's 2014.wetland rating manual (Ecology, 2014). Wetland A is rated as a Category IV wetland (Appendix Q. 5.2 Wetland B Wetland B (approximately 0.4 acre) was delineated within the wooded ravine located on the eastern property boundary. A network of walking paths run adjacent to and through parts of the wetland. Wetland B is classified as a palustrine forested wetland according to the Cowardin classification and as a depressional wetland according to the hydrogeomorphic classification. Dominant vegetation in Wetland B includes a forested strata of western red cedar (Thuja plicata, FAC) and red alder (Alnus rubra, FAC), as well as an emergent strata of slough sedge (Carex obnupta, OBL), yellow -flag iris (Iris pseudocorus, OBL), and reed canarygrass (Phalaris arundinacea, FACW) (see Appendix B, Data Sheet DP-3). Soil in Wetland B is generally characterized by a black (I OYR 2/1) silt loam extending to 4 inches bgs underlain by a very dark gray (I OYR 3/1) silt loam with gray (I OYR 6/1) depletions and dark yellowish brown (I OYR 4/6) and grayish brown (I OYR 5/2) redoximorphic concentrations extending to 17 inches bgs, underlain by a very dark gray (I OYR 3/1) silt loam extending to 18 inches bgs, underlain by a very dark gray (I OYR 3/1) silt loam with gray (I OYR 6/1) depletions and dark yellowish brown (I OYR 4/6) and grayish brown (I OYR 5/2) redoximorphic concentrations extending to at least 20 inches bgs. The redoximorphic and depletions observed in the soil below 4 inches bgs appeared blocky and mixed up within the n-l-zzowz-ooz-Rlfwp/]kn 21-1-22082-002 4 SHANNON WILSON, matrix suggesting that the soil may have been disturbed in the past. Soils observed in Wetland B meet the redox dark surface (176) hydric soil indicator. Wetland B is located downgradient of the storm drain outlets associated with the existing Madrona Elementary School and the play fields. Drainage patterns were observed upgradient of Wetland B in the ravine. While these areas showed indication of past surface water flow, they were not dominated by hydric vegetation and did not meet wetland hydric soil indicators. Hydrology in Wetland B is likely predominantly supported by surface flow from the surrounding ravine, the storm drain inputs from the school, and a seasonally high groundwater table. Wetland B was rated according to Ecology's 2014 wetland rating manual (Ecology, 201.4). Wetland B is rated as a Category III wetland (Appendix Q. 5.3 Wetland C Wetland C (approximately 0.1 acre) was delineated south of Wetland A along the wooded slope located in the middle of the property, downgradient from the storm drain discharges identified on the survey. A trail system on the slope allows human and pet access to the wetland. Wetland C is classified as a palustrine emergent wetland according to the Cowardin classification and as a slope wetland according to hydrogeomorphic classification. Dominant vegetation in Wetland C includes a shrub strata of western red cedar, an emergent strata of lady fern, and creeping nightshade (Solanum dulcamara, FAC) (see Appendix B, Data Sheet DP-6). Soil in Wetland C is generally characterized by a black (IOYR 2/1) loam, underlain by a grayish brown (IOYR 5/2), gravelly, loamy sand with dark yellowish brown (IOYR 4/4) redoximorphic concentrations in the matrix extending to at least 14 inches bgs. Soils observed in Wetland C meet the depleted below dark surface (A11) and the depleted matrix (F3) hydric soil indicators. During the site visit, seeps were observed throughout Wetland C. Hydrology in Wetland C is likely predominantly supported by a combination of the upgradient storm drain discharges and groundwater. Soil in the data pit was saturated to the surface. Wetland C was rated according to Ecology's 2014 wetland rating manual (Ecology, 2014). Wetland C is rated as a Category IV wetland (Appendix Q. 21-1-22082-002-Rlfwp/]kn 21-1-22082-002 5 SHANNON WILSON, 5.4 Uplands Uplands observed on the project site consist predominantly of developed school structures and recreational facilities as well as portions of the wooded slope and. The play fields are dominated by a variety of grasses, dandelion (Taraxacum officinale, facultative upland [FACU]), hairy cat's ear (Hypochaeris radicata, FACU), and clover (Trifolium repens, facultative [FAC]). The wooded areas are dominated by western red cedar, Douglas -fir (Pseudotsuga menziesii, FACU), hemlock (Tsuga heterophylla, FACU), red elderberry (Sambucus racemosa, FACU), holly (Ilex aquifolium, FACU), English laurel, sword fern (Polystichum munitum, FACU), and English ivy (Hedera helix, FACU) (see Appendix B, Data Sheets DP-1, DP-2, DP-4, and DP-5). Upland soils on the property generally consisted of a surface horizon comprised of dark yellowish brown (IOYR 3/4) to black (5YR 2.5/1) loam in the upper 2 to 5 inches bgs, underlain by dark yellowish brown (IOYR 3/4 and 4/4) to light olive brown (2.5Y 5/3) loamy sand to silt loam extending to at least 16 inches bgs. In areas closer to the wetland boundaries, redoximorphic concentrations were observed below 5 inches. However, the soil profiles in these areas do not meet wetland hydric soil indicators. No saturation was observed in the upland soils although surface drainage patterns were observed in the ravine and below storm drain outfalls on the western slope. 6.0 REGULATIONS Several local, state, and federal regulations apply to development proposals in and/or near wetlands and streams. A summary of applicable regulatory implications is given below. 6.1 Federal Regulations The Corps' review process under Section 404 of the Clean Water Act (CWA) is required for projects involving discharges of dredges or fill materials into waters of the United States, including non -isolated wetlands and streams. We did not observe a hydrologic surface connection between the onsite wetlands and a Water of the U.S. Therefore, the Corps may consider the onsite wetlands to be isolated and not subject to the CWA. However, this determination would need to be made by the Corps through a "Jurisdictional Determination." If the Corps takes jurisdiction over the site wetlands, impacts to the wetlands would require compensatory wetland mitigation. The Corps, in cooperation with Ecology, has developed guidance for conducting wetland mitigation in western Washington (Ecology and others, 2006). For unavoidable impacts to Category III and Category IV wetlands, the Corps and Ecology 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 6 SHANNON WILSON, recommend the on -site and in -kind permittee-responsible mitigation ratios shown in Table 1. based on area (area of mitigation: area of wetland impact.) TABLE 1 WETLAND IMPACT COMPENSATORY MITIGATION RATIOS ,Rethshxt artitoxL2/) 01&,ta . And, ; of ,04,644:{ . ' 41A cl w+ ibtbtishmen it i ab rli tii n and nha nc rne "Ea haan+ enW t tie v ,� o r ttoy: R a `ittatia�. � �: � �� � � , C1nl III 2:1 4:1 1:1 R/CC and 2:1 1:1 R/C and 4:1 E 8:1 RH IV 1.5:1 3:1 1:1 R/CC a1nd 1:1 1:1 R/C and 2:1 E 6:1 6.2 State Regulations Ecology has been authorized to implement Section 401 of the CWA for Water Quality Certification in Washington for most projects that require Corps permits under CWA Section 404. Typically, projects requiring a CWA Section 404 permit also require a CWA Section 401 Water Quality Certification. If the onsite wetlands are determined to be isolated, the project would not require a Section 401 Water Quality Certification. The purpose of the 401 certification process is to ensure that federally permitted or federally funded activities comply with the federal CWA, state water quality laws, and any other applicable state laws. Some general requirements for Section 401, if it is required, include pollution spill prevention and response measures, disposal of excavated or dredged material in upland areas, use of fill material that does not compromise water quality, clear identification of construction boundaries, and provision for site access to the permitting agency for inspection. If the Corps does not take jurisdiction over the onsite wetlands under the CWA, Ecology still has regulatory authority to protect isolated wetlands under the State Water Pollution Control Act (Chapter 90.48 Revised Code of Washington). Ecology would perform an administrative review of the project and would issue an Administrative Order for unavoidable impacts to isolated wetlands. 21-1-22082-002-Rlfwp/]kn 21-1-22082-002 7 SHANNON WILSON, 6.3 City of Edmonds (City) 6.3.1 Wetlands Regulations The City regulates wetlands and wetland buffers under Chapter 23.50 of the Edmonds Community Development Code (ECDC) (City, 201.6).2 Based on our field observations and using the 2014 Wetland Rating System for Western Washington, Wetlands A and C are Category IV wetlands and Wetland B is a Category III wetland (Appendix Q. The City requires a 60-foot standard buffer around Category III wetlands and a 40-foot standard buffer around Category IV wetlands, with implementation of the following minimization measures when applicable (Table 2 and Figure 2) (ECDC 23.50.040(F)(1-2)). TABLE 2 REQUIRED MEASURES TO MINMINIZE IMPACTS (ECDC 23.50.040(F)(2)) Dlstra . ...R al; Maares tctMlin%I acts Lights Direct lights away from wetland. Noise • Locate activity that generates noise away from wetland. • If warranted, enhance existing buffer with native vegetation plantings adjacent to noise source immediately adjacent to the outer wetland buffer. Toxic runoff . Route all new, untreated runoff away from wetland while ensuring wetland is not dewatered. • Establish covenants limiting use of pesticides within 150 feet of wetlands. • Apply integrated pest management. Stormwater runoff • Retrofit stormwater detention and treatment for roads and existing adjacent development. • Prevent channelized flow from lawns that directly enters the buffer. • Use Low Impact Development (LID) techniques (per Puget Sound Action Team publication on LID techniques). Change in water Infiltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces regime and new lawns. Pets and human . Use privacy fencing OR plant dense vegetation to delineate buffer edge and to disturbance discourage disturbance using vegetation appropriate for the ecoregion. • Place wetland and its buffer in a separate tract or protect with a conservation easement. Dust Use best management practices to control dust. Disruption of corridors . Maintain connections to offsite areas that are undisturbed. or connections . Restore corridors or connections to offsite habitats by replanting. 2 The Edmonds City Council adopted revisions to these regulations in May 2016, so all code references below are taken from the track changes version of the code provided in the Council's agenda packet. Accordingly, there remain some typographical errors in that version with respect to section numbering. 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 8 SHANNON WILSON, In accordance with. ECDC 23.50.040(F)(2), the City may require increased buffer widths on a case -by -case basis when a larger buffer is necessary to protect wetland functions and values. The City bases this determination on the following criteria: ■ A larger buffer is needed to protect other critical areas; ■ The buffer or adjacent uplands has a slope greater than 15 percent or is susceptible to erosion and standard erosion control measures will not prevent adverse impacts to the wetland; ■ The buffer area has minimal vegetative cover. In lieu of increasing the buffer width where existing buffer vegetation is inadequate to protect the wetland functions and values, development and implementation of a wetland buffer enhancement plan may substitute. ■ The wetland and/or buffer is occupied by a federally listed threatened or endangered species, a bald eagle nest, a great blue heron rookery, or a species of local importance; and it is determined by the director that an increased buffer width is necessary to protect the species. ECDC 23.50.040(G) allows for buffer reduction only when existing buffer vegetation is inadequate; the buffers of the existing wetlands are primarily densely vegetated with a mix of native tree and shrub species so this provision may not be applicable. Based on our understanding of the current development proposal, there may be some small areas of existing buffer that are lawn and ballfields that would be impacted. Under ECDC 23.50(G)(3), the City allows for buffer averaging with buffer enhancement if the following requirements are met: ■ The buffer averaging and enhancement plan provides evidence that wetland functions and values will be: — Increased or retained through plan implementation for those wetlands where existing buffer vegetation is generally intact; or — Increased through plan implantation for those wetlands where existing buffer vegetation is inadequate to protect the functions and values of the wetland. The wetland contains variations in sensitivity due to existing physical characteristics or the character of the buffer varies in slope, soils, or vegetation, and the wetland would benefit from a wider buffer in places and would not be adversely impacted by a narrower buffer in other places; ■ The total area contained in the buffer area, or the total buffer area existing on a subject parcel for wetlands extending off -site, after averaging is no less than that which would be contained within a standard buffer; and 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 9 SHANNON WILSON, ■ The buffer width at any single location is not reduced by more than twenty-five percent (25%) of the standard o buffer width. However, wetland buffer averaging that also modifies the erosion hazard area and/or its buffer would not be allowed by the ECDC without a geotechnical analysis and demonstration that the wetland buffer averaging and erosion or landslide hazard area buffer modification would not adversely impact the wetlands. Wetland buffer reduction through buffer enhancement may also be allowed if buffer averaging is not feasible on site (ECDC 23.50.040(G)(4)). ECDC 23.50.040(G)(8) describes potential permitted uses within wetland buffers, including conservation and restoration activities, passive recreation (such as trails), and stormwater management facilities. The proposed development of a new school and fire access road are not allowed uses within wetland buffers. Tf buffer averaging or reduction with enhancement is not sufficient to address the need for placement of structures, then a variance and additional buffer mitigation would be required. 6.3.2 Other Critical Areas The City regulates critical areas including wetlands (addressed in Section 6.3.1), fish and wildlife habitat conservation areas, geologically hazardous areas, critical aquifer recharge areas, frequently flooded areas, and shorelines under ECDC Title 23 Natural Resources. Fish and wildlife habitat conservation areas include streams, state priority habitats and areas associated with state priority species, and federally designated threatened or endangered species, among others. The site investigation and document reviews did not identify any streams or other fish and wildlife habitat conservation areas on site or within 225 feet. This scope of services did not include professional assessment of other regulated critical areas. However, some observations about potential geologically hazardous areas is warranted given the affect this critical area can have on site development, particularly when it overlaps with wetlands and wetland buffers. Based on soils mapping, available topographic information, and the City's definitions of geologically hazardous areas (ECDC 23.80.020), the presence of erosion and/or landslide hazard areas on the eastern and western sides of the property at or near Wetlands A, B, and C and their buffers seems likely. A geotechnical report would be required to establish the appropriate building setback and buffer from the top and toe of any erosion or landslide hazards. An additional analysis would be required to alter the hazard area, the minimum building setback and any required buffer (ECDC 23.80.070(A)(1-2)). A hazards analysis must demonstrate the following: 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 10 SHf3NNON 6WiLSJii. INC. The alteration will not increase surface water discharge or sedimentation to adjacent properties beyond predevelopment conditions, In The alteration *11 not decrease slope stability on adjacent properties, and wi Such alterations will not adversely impact other critical areas (ECDC 23.80.070(A)(3)). �--,hannon & Wilson will be providing the necessary geotechnical analyses under-q- separate scope of work. The findings and conclusions documented in this report have been prepared for specific application to this project, and have been developed in a manner consistent with that level of care and skill normally exercised by members of the environmental science profession currently practicing under similar conditions in the area, and in accordance with the terms and conditions set forth in our agreement. The conclusions and recommendations presented in this report are professional opinions based on interpretation of information currently available to us, and are made within the operational scope, budget, and schedule constraints of this project. No warranty, express or implied, is made. Shannon & Wilson has prepared Appendix D, "Important Information About Your Wetland Del ineation/Mitigation and/or Stream Classification Report," to assist you and others in Sarah Corbin, PWS Biologist 21-1-22082-002-Rlf/wp/lkn 21-1-22082-002 SHANNON WILSON, 8.0 REFERENCES City of Edmonds (Edmonds), 2016, City of Edmonds City Code Chapter 23.50 Wetlands: Edmonds, Wash., May 2016. U.S. Department of Agriculture (USDA), Natural Resources Conservation Service, 2015, Web soil survey. Available: http://websoilsurvey.sc.egov.usda.gov/App/HomePage.htm. Accessed: August 2015. U.S. Army Corps of Engineers (Corps) Waterways Experiment Station, 1987, Corps of Engineers wetlands delineation manual: Vicksburg, Miss., U.S. Army Corps of Engineers Waterways Experiment Station, Wetlands Research Program Technical Report Y-87-1, 1.43 p., available: http://www.wli.nres.usda.gov/delineation/. U.S. Army Corps of Engineers (Corps) Engineer Research and Development Center, 2010,. Regional supplement to the Corps of Engineers wetland delineation manual: western mountains, valleys, and coast region (version 2.0): Vicksburg, Miss., U.S. Army Corps of Engineers Engineer Research and Development Center, Final report ERDC/EL TR-10-3, 152 p. U.S. Fish and Wildlife Service (USFWS), 2015, Web map service: FWS_Wetlands_WMS: U.S. Fish and Wildlife Service. Open geographical information systems consortium version: 1.3. Available: http://www.fws.gov/wetlands/Data/WebMapServices. Accessed: August 2015.. Washington State Department of (Ecology), U.S. Army Corps of Engineers Seattle District, and U.S. Environmental :Protection Agency Region 10, 2006, Wetland Mitigation in Washington. State — Part 1: Agency Policies and Guidance (Version 1): Olympia, Wash, Washington State Department of Ecology, Publication no. 06-06-1.1a. Washington State Department of Ecology (Ecology), 2010, Determining the ordinary high water mark on streams in Washington State, second review draft: Lacey, Wash., Washington State Department of Ecology, Publication no. 08-06-001. Washington State Department of Ecology (Ecology), 2014, Washington State wetland rating system for western Washington: Olympia, Wash., Washington State Department of Ecology, Publication no. 1.4-06-029, 126 p. Washington State Department of Fish and Wildlife (WDFW), 2015, SalmonScape mapping application, accessed July 2015, available: http://a Ts.wdfw.wa.gov/salmonscape/map.html Washington State Department of Fish and Wildlife (WDFW), 2016,.PHS on the Web mapping application, accessed March 2016, available: httpa://apps.wdfw.wa.Zov/phsontheweb/ 21-1-22082-002-Rlfrwp/]kn 21-1-22082-002 12 0 200 400 Scale in Feet Rae-TWOFi', • Data Point and Designation Wetland Boundary Wetland Buffer Map adapted from aerial imagery provided by Google Earth Pro, reproduced by permission granted by Google Earth TM Mapping Service. SHANNON ILA APPENDIX A WETLAND DELINEATION METHODOLOGY 21-1-22082-002 TABLE OF CONTENTS Page A.1 WETLAND VEGETATION.......................................................................................... A-1 A.2 HYDRIC SOILS............................................................................................................. A-3 A.3 WETLAND HYDROLOGY.......................................................................................... A-3 A.4 DISCLAIMER................................................................................................................ A-4 A.5 REFERENCES............................................................................................................... A-4 A-1 Definitions of Plant Indicator Status................................................................... A-2 AppendixA_Methodology (Western Mtns) Dec 20 12/ A-1 21-1-22082-002 12 01010 1 1 101 guy I By N 29 Lei0110M The triple -parameter approach, as required in the Washington State Department of Ecology's (Ecology's) 1997 Washington State Wetlands Identification and Delineation Manual, the United States Army Corps of Engineers' (the Corps') 1987 Corps of Engineers Wetland Delineation Manual, and the Corps' 2010 Regional Supplement to the Corps of'Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0) was used to identify and delineate the wetlands on the site described in this report. The triple -parameter approach requires that vegetation, soils, and hydrology are each evaluated to determine the presence or absence of wetlands. An area is considered to be a wetland if each of the following is met: (a) dominant hydrophytic vegetation is present in the area, (b) the soils in the area are hydric, and (c) the necessary hydrologic conditions within the area are met. A determination of wetland presence was made by conducting a Routine Delineation. Corresponding upland and wetland plots were recorded to characterize surface and subsurface conditions and more accurately determine the boundaries of on -site wetlands. A.1 WETLAND VEGETATION Hydrophytic plants are plant species specially adapted for saturated and/or anaerobic conditions. These species can be found in areas where there is a significant duration and frequency of inundation, which produces permanently or periodically saturated soils. Hydrophytic species, due to morphological, physiological, and reproductive adaptations, have the ability to grow, effectively compete, reproduce, and thrive in anaerobic soil. Indicators of hydrophytic vegetation are based on the wetland indicator status of plant species on the national wetland plant list (Lichvar, 2012). Plants are categorized as Obligate (OBL), Facultative Wetland (FACW), Facultative (FAC), Facultative Upland (FACU), or Upland (UPL). Species in the facultative categories (FACW, FAC, and FACU) are recognized as occurring in both wetlands and non - wetlands to varying degrees. Most wetlands are dominated mainly by species rated as OBL, FACW, or FAC (Table A-1). AppendixA_Methodology (Western Mtns) Dec 2012/ 21-1-22082-002 A- I TABLE A-1 PLANT INDICATOR STATUS GROUPS Plant Indicator Status Categories Obligate Wetland (OBL) — Plants that almost always occur in wetlands. Facultative Wetland (FACW) — Plants that usually occur in wetlands, but may occur in non -wetlands. Facultative (FAC) — Plants that occur in wetlands or non -wetlands. Facultative Upland (FACU) — Plants that usually occur in non -wetlands, but may occur in wetlands. Obligate Upland (UPL) — Plants that almost never occur in wetlands. (Lichvar, 2012) The approximate percentage of absolute cover for each of the different plant species occurring within the tree, sapling/shrub, woody vine, and herbaceous strata was determined. Trees within a 30-foot radius; sapling/shrubs and woody vines within a 15-foot radius; and herbaceous species within a 5-foot radius of each data point were identified and noted. However, where site conditions merited it, the dimensions of the tree, sapling/shrub, woody vine, and herbaceous strata were modified. The dominance test is the primary hydrophytic vegetation indicator and it is used in all wetland delineations. Dominant plant species are considered to be those that, when cumulatively totaled in descending order of absolute percent cover, exceed 50 percent of the total absolute cover for each vegetative stratum. Any additional species individually representing 20 percent or greater of the total absolute cover for each vegetative strata are also considered dominant. Hydrophytic vegetation is considered to be present when greater than 50 percent of the dominant plant species within the area had an indicator status of OBL, FACW, or FAC. If a plant community does not meet the dominance test in areas where hydric soils and wetland hydrology are present, vegetation is reevaluated using the prevalence index, plant morphological adaptations for living in wetlands, and/or abundance of bryophytes (e.g., mosses) adapted to living in wetlands. The prevalence index is a weighted average that takes into account the abundance of all plant species within the sampling area to determine if hydrophytic vegetation is more or less prevalent. Using the prevalence index, all plants within the sampling area are grouped by wetland indicator status and absolute percent cover is summed for each group. Total cover for each indicator status group is weighted by the following multipliers: OBL=1, FACW=2, FAC=3, FACU=4, UPL=5. The prevalence index is calculated by dividing the sum of the weighted totals by the sum of total cover in the sampling area. A prevalence index of 3.0 or less indicates that hydrophytic vegetation is present. AppendixA_Methodology (Western Mtns) Dec 2012/ 21-1-22082-002 A-2 A.2 HYDRIC SOILS Hydric soils are defined as soils that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part (USDA SCS, 1994). Repeated periods of saturation and inundation for more than a few days, in combination with soil microbial activity, causes depletion in oxygen (anaerobic conditions) and results in delayed decomposition of organic matter and reduction of iron, manganese, and sulfur elements. As a result of these processes, most hydric soils develop distinctive characteristics observable in the field during both wet and dry periods. (USDA MRCS, 201.0). These characteristics may be exhibited as an accumulation of organic matter; bluish -gray, green -gray, or low chroma and high value soil colors; mottling or other concentrations of iron and manganese; and/or hydrogen sulfide odor similar to a rotten egg smell. The USDA Natural. Resources Conservation. Service (MRCS) has developed official hydric soil indicators as summarized in Field Indicators of Hydric Soils in the United States (USDA MRCS, 2010). These indicators were developed to assist in delineation of hydric soils and are based predominantly on hydric soils near the margins of wetlands. Some hydric soils, including soils within the wettest parts of wetlands, may lack any of the approved hydric soil indicators. If a hydric soil indicator is present, the soil is determined to be hydric. If no hydric soil indicator is present, additional site information is used to assess whether the soil meets the definition of hydric soil. Identification of hydric soils was aided through observation of surface hydrologic characteristics and indicators of wetland hydrology (e.g., drainage patterns). Soil characteristics were observation at several data points, placed both inside and outside the wetland. Holes were dug with a shovel to the depth needed to document an indicator or to confirm the absence of hydric soil indicators. Soil organic content was estimated visually and texturally. Soil colors were examined in the field immediately after sampling. Dry soils were moistened. Soil colors were determined through analysis of the hue, value, and chroma best represented in the Munsell® Soil Color Chart. A.3 WETLAND HYDROLOGY Wetland hydrology is determined by observable evidence that inundation or soil saturation have occurred during a significant portion of the growing season repeatedly over a period of years so that wet condition have been sufficient to produce wetland vegetation and hydric soils. Wetland hydrology indicators give evidence of a continuing wetland hydrologic regime. Wetland hydrology criteria were considered to be satisfied if it appeared that wetland hydrology was AppendixA_Methodology (Western Mtns) Dec 2012/ 21-1-22082-002 A-3 present for at least 5 to 12.5 percent (12 to 31 days) of the growing season. The growing season in western Washington is typically considered to be from March 1 to October 31 (244 days). However, the growing season is considered to have begun when: (a) evidence of plant growth has begun on two non -evergreen vascular plants, and (b) the soil reaches a temperature of 41 degrees Fahrenheit at 1.2 inches. The Seattle District Corps of Engineers requires 1.4 consecutive days of inundation or saturation for a wetland hydrology to be considered present. Wetland hydrology was evaluated by direct visual observation of surface inundation or soil saturation in data plots. The area near each data point was examined for indicators of wetland hydrology. Wetland hydrology indicators are categorized as primary or secondary based on their estimated reliability. Wetland hydrology was considered present if there was evidence of one primary indicator or at least two secondary indicators. Some primary indicators include surface water, a shallow water table or saturated soils observed within 12 inches of the surface, dried watermarks, drift lines, sediment deposits, water -stained leaves, and algal mat/crust. Some secondary indicators include a water table within 1.2 to 24 inches of the surface during the dry season; drainage patterns; a landscape position in a depression, drainage, or fringe of a water body; and a shallow restrictive layer capable of perching water within 1.2 inches of the surface. IX! 1Tf.Y • This methodology was prepared for reference use only and is not intended to replace Ecology's 1997 Washington State Wetlands Identification and Delineation Manual, the 1987 Corps of Engineers Wetland Delineation Manual, or the Corps' 2010 Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0). A.5 REFERENCES Munsell Color, 1992,.Munsell soil color charts: Newburgh., N.Y., Macbeth. Division of Kollmorgen Instruments Corporation, 1 v. Lichvar, R. W., 2012, The national wetland plant list: U. S. Army Corps of Engineers Engineer Research and Development Center, Report ERDCC/CRREL TR-1.2-11, 224 p., available: http://rsgisias.crrel.usace.army.mil/NWPL/doc/proc 2012/ERDC-CRREL TR-12-11 NWPL 2012.pdf. AppendixA_Methodology (Western Mtns) Dec 2012/ 21-1-22082-002 A-4 U.S. Army Corps of Engineers Engineer Research and Development Center, 2010, Regional supplement to the Corps of Engineers wetlands delineation manual: western mountains, valleys and coast region, Version 2.0: Vicksburg, Miss., U. S. Army Corps of Engineers Engineer Research and Development Center, Report ERDC/EL TR-10-3, 153 p. U.S. Army Corps of Engineers Waterways Experiment Station, 1987, Corps of Engineers wetlands delineation manual: Vicksburg, Miss., U.S. Army Corps of Engineers Waterways Experiment Station, Wetlands Research Program Technical Report Y-87-1, 143 p., available: http://www.wli.nres.usda.gov/delineation/. U.S. Department of Agriculture (USDA) Soil Conservation Service (SCS), 1994,.Changes in hydric soils of the United States: Washington, D.C., Office of the Federal Register, FR 59 (133): 35680-35681, July 13. U.S. Department of Agriculture (USDA) Natural Resources Conservation Services (MRCS), 2010, Field indicators of hydric soils in the United States, Version 7.0, L.M. Vasilas, G.W. Hurt, and C.V. Noble (eds.), USDA, NRCS, in cooperation with the National Technical Committee for Hydric Soils. Washington State Department of Ecology, 1997, Washington state wetlands identification and delineation manual: Olympia, Wash., Washington State Department of Ecology, Report 96-94. AppendixA_Methodology (Western Mtns) Dec 2012/ A-5 21-1-22082-002 SHANNON ILA APPENDIX B WETLAND DETERMINATION DATA FORMS - WESTERN MOUNTAINS, VALLEYS, AND COAST REGION 21-1-22082-002 WETLAND DETERMINATION I T F — Western Mountains, Valleys, and Coast Region Project/Site; "° ` ° ityl ounty,r r It t " (1A a� 0 Ali L5� Sampling late A icant/O ner" � � �" e� :°k s a � State � L Sam p Ing Point 2" lnrtestlgator(s). IVA rtasnw Township, mange: ,> i g".,y ? , Landforrn (hllislepe, terrace, e c1 l '.t � T, l Local relief (concave, convex, none). � � 4...,_ � Slope Subregion (L ): A La I, Ltnp' Daturn; Soil dap Unit Name, f� �r l i' I, T.t r°ic. r, tt ` �004!,!L5 N1dVi classification: A Are climatic t hydrologic conditions on the site typical for this time of year? Yes Z No (If no, explain in i emorks.) Are Vegetation Sail or Hydrology significantly disturbed? Are 'NormalCircumstances" present des ( No Are wegetalittn Steilor Hydrology _ naturally problematic? (if needed, explain any answers in Remarks.) SUMMARY OF FINDINGS -- Attach site map sbowlqpsampling point locations, transects, Important features, etc. Hydrophytic Vegetation Present? yes - No Hydric Soil Present? Yes No L is the Sampled Area V/ Welland Hydrology Present's Yes No 4W within a Watland a Yes No i emarks VEGETATION — Use scientific names of plants. f"t Absolute Dominant Indicator Damloance Test works h ob T' r ,tg, (Plotsize,_ - - Number of Dominant Species t; That Are 08L, FA W, or FA : (A) Taal Number of Dominant Species Across All Strata; " (B) 3: Percent of Dominant Species ( t i = Total t}wtrr That Are 08L, FA W, or FA .: ( S) Sar�linoPShrub Stratum (Pla side. p. Prevalence Index orltsiteetw t" °Total s rsvdr of^ MrtRWy h ' 0I3L species f f x t FA W species Q x 2 - _(2— rAC species x 3 = '4 r ) r FA U species x 4 S fpt (Plot size: } djdj_aa - Taal hover UPL species 1, ta�ttt , r 'o clurrrn'Totats: t (A) 5 ( ) .? a.ti;t p.l a Prevalence indent = f31A 5 Hydrophydc Vegetation Indicators. 4, _ 1 - Rapid Test for Hydrophytic Vegetation 2 a Dominance Testis g% inn ��.[t k� t t .(' � � a a I - Prevalence Indent Is s3,0' 7; , ,, ' rr k i T t,=. 4 W Morphological Adaptations' (Provide supporting &data in Remarks or on a separate sheet) g ; _ Wetland Non -Vascular Plants' io. Pr bleroatic Hydrophytic'Veget lion' (.xploin) 11, 'Indicators of hydric soil and rrrettand hydrology must be present, uniesd disturbed or problematic" Total cover � ore wine (P9eI si�c:l -.a a� Hydrophytic 2 Vegetation Present? Yea o c Total tower % Bare Ground in Herb Stratum t w f�etrtarks. All US Array Corps of Engineers Western Mountains, Valleys, and Coast — Version 10 l Sampling Reini Profile Description, (Describe to the depth needed to document the ndicatiar or confilmn the absence of indicators.) Depth Matrix Redo Features finehesl i t ( n istl ° �� °r� _ Tex Rorrrrif t 2f,)/ .I( l`()�lfe.. ��, fir'{" N • � t r -,f r1 e. CmCancentration, D-Depletion, RivizReducpd Matrix, CS=Covered or Coated Sand trains. 21_ocalk m. PL=Pare Link , M Matrix. Hydric Soil Indicators: (Applicable to all L Rs, unless otherwise meted.) Indicators for Problematic Hydric Snils�; Histo of (A I) Sandy Redox (S) — 2 cor Muck (At0) — Histic Fpipedon (A2) Stripped Matrix (S8) lied Parent material (TF ) Slack Histie (A #) Loamy Murky Mineral (171) (axe pt MLRA1) Very Shallow Dark Surface (TF12) Hydrogen Sulfide (A4p Loamy Cleyed Matrix (F2) — Other (Explain in Remarks) Depleted Below Dark Surface (At 1) — Depleted Matrix (F3) Thick Dark Surface (A`l) i edox Dark Surface (F6) alndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) weliand hydrology must be present; Sandy Geyed'Matrix (84) RedoX Depressions (178) unless disturbed or problematic, Restrictive Layer If present): Type, .� Depth (inches): Hydric Soil present? Yes No Remarks: ell HYDROLOGY Weiland Hydrology Indicators., Primary indicatorL(IgUMin of onei h SerLr indlcatrirsr pry eeuiredt Surface Water(Al) — Water -Stained Leaves () (except Water -Stained Leaves'(89) (MLRA 1, 2, High Water Table (A2) ML A is 2,4A, and 8) 4A, and ) Saturation (A ) Salt Crust (811) Drainage Patterns (810) Water Marks (B1) Aquatic Invertebrates. (1318) — Lary- easori WaterTable (C ) Sediment Deposits (I32) Hydrogen Sulfide Odor (Cl) Saturation Visible on Aerial Imagery (09) Daft Deposits (D3) — Oxidized Rhizospheres along Diving Routs (C8) ,;— Geomorphle Position (D2) Algal Mat or Crust ( 4) Presence of Reduce Iran (C4) Shallow Aquitard (D ) --m lron Deposits. ( ) Recent tron Reduction in Tilted Soils (C) — FAC-Neutral Test (D5) Surface Soil Cracks (D') _-Stunted or Stressed Plants (D1) (L.I R A) Raised Ant Mounds (0) (LRR A) , Inundation Visible on Aerial Imagery (07) � Other (Explain in Remarks) Frost -Heave Hummocks (D7) Sparsely Vegetated Concave Surface (S) Field Dtisarvations. Surfers Water Present? Yes No V Depth (inches); Water Table Present? yes No Depth (inches):. Saturation Present? yes No Ditplh (inches), Watland Hydrology Present? 'des No lrrrtRrdes ilia :trip r� Describe Recorded' Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks° z .r "' US'Army Corps of Fnglneers Western Mountains 'alleys, and Crust Version 2,0 WETLAND DETERMINATION DATA F — Western Mountains, Valleys, and Coast Region yPro) Jaurky Gate:a Appiicandl srner ai I° 1 t§ X late: artnpling Point, Inv stigator(s} _ . ry .i't° : 4 i "i . ki ts, Township, Rangy ; Lsndforrat (h llclape, t rr a r etc �• i�, , Gaa I relief (concave, convex, no a): � � lope Subregion (LRR): a Lot: Lang: Datum tail dap Unit #ame: r2hi't ter). le:. i° , � �f W1 Ck@515t11 tion. Are climatic f hydrologic, renditions on t -site typical for this time of years 'des No (if no, explain In Remarks) Are Vegetation Cori or Hydrology significantly disturbed? Are `Normal Circumstances' present? Yes "t No Are Vegetation Sail or Hydrology naturally problematic? (if wedded, explain any answers In Remarks.) SUMMARY OF FINDINGS Attach site slap showing sampling point locations, transects, important features, etc, Hydrophytic Vegetation Present? Yes No ° Is the Sampled Area Hdriu Soil Present? Yes No Weiland Hydrology Present? 'des No 1, Within a wetland"? Yes No �w4 @.'?` e21l F' ,.i •,�. 3k�#0 �§ �n}f ya�t}kki } v' $3. t 4 kkf#i'kYk�naes "ail► T" 'i i -� Use s i scientific, ofmpi rtts. i I Dominant ominant Indicator Dominance Test worksh t: Tree Crakrtrn (Plot size: save-aPe l s� s--- Number of Dominant Species 1. °' i S y t ,,.ii r°' t) ar iL i � f L That A, OBL, FACW, or FAf •. „qr (A) I, ', t Total Number of Dominant `r .r w I , ° q F °�. l r� Species Across All Straw (�y 4. Total Cover Percent of Dominant Species That Are 0BL, FACW, or FACC � (AIB) Saofina/S rub Strati (Plot size: f l Prevalence Index worksheet: r° Far,.cra rarw 'a Pd]UI#I�dv bv: ` 3. a, s ,l1a1 € ?ld'•r°v �,° t". 4�� ffgL species x Ia 7 FACW species x = t FAC species x 3x d: FAUU species x 4 = r ,�� r drb lr" um Total Cover (Plat size: l UPL species , ( _ x s = r ro 1. tr tr#r"a I° , 'iw'r la t ?t�fttili'`r t wd toiumnTotals, (A) a (B) 2; Vt ""r,`# ', t Prevalence Index $/A 3 " t f R,.Hydrophytic Vegetation Indicators: 4 ' a,+ r,, Irt t ,rr 1 - Rapid felt for Hydraphyiicegetaldeta r wLl2 - Dominance Test Is O% 3 - Prevalence: Index is i5,01 7- 4 - Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) u. a ^ Wetland Non -Vascular Plants 10, Problematic Hydrophytic Vegetatlon' (Explain) 1 t. ° Indicators of hydric soil and wetland hydrology merit t �r-�'_= Taiui over be present, unless disturbed or problematic.Npodv.5 in tratr� (Plat size: t 1 gg rtt k' }' ig Jw,,Ym� orc,t ov z /, ; .w = G h#yt#rapliy41C vegetation Present? Y otal Mta r,. TCorner % Baru Ground In Herb Stratum k�drnsrksa US Army Corps of Engineers Western Mountains, Valleys, and Coast — Version 2.0 IL Sampling Point Profile Description: (Describe to the depth needed to document the Indicator or confirm the absence of Indicators.) Depth fylRW eciox Fep S 5 44 s. I. -" _,r `� j,. �,—'� d�%,�V Me `"xtt:gg i = nl:entratlen, f plptien iVt�F du l #ri tav rgr aP l �nq rarn�. "Location: PL=Fore L giLn M Matrix. Hydric $oil Indicators; (Applicable to all JLRRs, oolo s otherwise noted.) indicatem for Problematic H drla, Bulls'; ltistosol (A)) Sandy Rodox (S) 2 crra Muck (A1p) 1-listed pipedon (A2) Stripped Matrix (Sb) — Red Parent Material (7F2) Black Histic (A) Loamy Ducky Mineral (F1) (except L 1) - Very hallow Dark Surface (TF12) — Hydrogen Sulfide (A4) - Loamy Gloved matrix (F2) — Dther;(explain in remarks) Depleted Below mark Surface (Al 1) „ Depleted Matrix (F ) Thick Dark Surface (A1) Redox Dark Surface (FF) 21ndicators of hydrophytic vegetation and Sandy Mucky Mineral ( 1) Depleted Dark Surface (7) wetland hydrology must be present,: Sandy Gleyed Matrix (S4) — Rebus Depressions (Fit) unless disturbed or problematic. Restrictive Layer (if present) - z Type: . Depth (lnches): Hydric $oil Present"? 'fee No Remarks: HYDROLOGY Wetland Hydrology Indicators. P-mumf iall that aDDIVISu.rsndr� InlirVtcsrts t2 uc mart reel+ir d _ Surface Water (All — 'stater -Stained Leaves (BO) (except Water -Stained leaves: (SO) (MLRA 1, High Water Table (A2) MURA 1, 2, 4A, and 413) 4A, and d ) Saturation (A3) — Salt Crust (B11) Drainage Patterns (Paid) Water Marks (81) ,,Aquatic Invertebrates ( i3) � Dry -Season beater Table ( 2) _ $edirmerat Deposits (B2) — Hydrogen Sulfide Odor (Cl) _ Saturation Visible on Aerial Imagery ( 9) Drift Deposits (83) Oxidized Rhl ospheres along Living Roots (C3) Geornorphic Position (02) Algal Mat or Crust (84) Presence of Reduced Iron (D4) Shallow Aguitard (D) Irian Deposits (65) Recent Iron Reduetion in "tilled Soils (CO) _ FA Neutral Test (D,5) Surface Soil Cracks (8) Stunted or stressed Plants (01) (LRR.A) raised Ant Mounds (DB) (LRR A) Inundation Visible on Aerial Imagery (87) Other (Explain in Remarks) Frost -Heave ummock$ (137) — Sparsely Vegetated Concave Surface (88) Field old ervatlonsa Surface Water Present? Yes No (inches): Water Table Present"? Yes rDdpth No Depth (inches): Saturation Present's Yes No Depth finches): Wetland Hydrology Present"? Yea _ No includes a ills frin e Describe Recorded Data (strewn garage, monitoring well, aerial photos, previous inspections), if available,- Remarks, US Army Corps of Engineers Western Mountains, Valleys, and Coast — Version 2.0 WETLANDT I T DATA FORM — Western Mountains, Valleys, and Coast Region Pro)bcly ite: t # CItyr nonty: re. y�... � ' a 4 tr_ s Sampling Date. State: �.,1 am iingl'rilr$t: ^.' <„�a.. i iecvast�gator(s), ,, ? Section. Township, Range,ry - b � 4+" Landform (hillslope, tern ce, etc.), i, Local relie (concav convex, none); C)t , CA T�# Slope Subregion (LRR), d Lat �r a.�d P' .... ! }�r`'°tl �a r., ✓" Soil Map Unit blame. �,,�-�" li° rt �t�n + �� Long, notum. gyp/ j y� 7 �Y W I cflQmRslticatlori. Are climatic rhydrologic conditions on the site typical forthis time of year? Yes No (If no, explain in Remark&) Are Vaget ticn Soil or Hydrology significantly distorbod? ., ? Are "Normal circumstances" present? Yes .L No Are Vegetation Soil or Hydrology . naturally problematic? A., , (If needed, explain any answers in: Remarks.) SUMMARY OF FINDINGS Attach site map showing sampling point llocations, transects, Important features, etc. Hydrophytid Vegetation Present? Yes � �" No � Hydric Soil Presents Yes t o is the Sampled Area � within a'Wetland Yoe Nor ellend Hydrology resent? Yes t, Flo Remarks; i VEGETATION m Use scientific names f plants., i Absolute o minant Indicator Dominance Test urorkatnept, Tr�ra Lrn (Plot size ) 1 ° _ Number of Dominant Species t7,7 That Are 08L, FA r1V, or FA : (A) C Taal Number of Dominant Species Across All Strata, (R) r - Percent of Dominant Species � a4 Total Cover lin t hr size. That Are 08L, FA , or FAQ. (B) (Plot Prevalence Index orksheet: t, __ Total % QoverQf" . i tultioly b OBL species x 1 = t rACVV species x 2 FAC species x 51 FA U species x 4 = _ Total ever (Plot size ) k UPL species x5g .,. f ('.� t ? r` s ,. y olumn Totals: (A) (B) f„;, l)„ _u �'., , , t ,� r Prevalence Index WA — Nydrophytic Vegetation indicators. 4.,, , I* 9 - Rapid Test for Flydraphytic Vegetation 5, = 2 $ Dominance Test is > 0% 5 - Prevalence Index i 01 4 - Morphological Adaptations' (Provide supporting data in Remarks or on a separate shut) 9 5 - Wetland Non -Vascular Plants' t0. _ Problematic HydrophyticVegetation' (Explain) f) Indicators of hydric soil and wetland hydrology must Total over be present, unless disturbed orprolernatic, radv Vlrtratr!rrl (Pict slze ,. l Rydrophytic 2, Vegetation r *, r r Toni Cover ' rasant Y tip Bare round in Herb Stratum " Remarks: 7 US Army Corps of Engineers Western Mountains, galleys, and Coast — Version 2.0 )L Sampling Point:� .� Profile Descriptioru (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Features ling1-1W Qglor i tl QIQr die T e a T r° Rcrrrrr s .,., t� gg n^ yy 1 s F 'Type; m on r�i allorr,,D& letion Ri aReduced Marr&Q&tCoverad or Coated Sand Grains Locatkini PbtPore Li=Matrix._ Hydric Sol] indicators. (Applicable to all LRFts, unless otherwise noted.) Indicatory for Problematic Hydric Solis'; Histosdl (At) — Sandy Redox (SS) 2 ore Muck (At0) Histic Epipedon (A2) - — StrippedMatrix (Sd) — Red Parent Material (TF2) Slack Histic. (A3) Loamy Ducky Liberal (F]) (except MLRA 1) Very Shallow Dark Surface (TF12) Hydrogen Sulfide ( ) — Loamy Gleyed Matrix (172) J Other (Explain in Remarks) Depleted Below [dark Surface (Al 1) Depleted Matrix (F3) Thick Dark Surface (A 1) Redox Dark Surface (FS) 'Indicators of trydrop ytic vegetation and - Sandy Mucky Mineral (S I) Depleted Mark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (Fa) unless disturbed or problematic. Restrictive Layer (if preaerst): Type: Depth (inches): _ Hydric Soil Present? Yes o Remarks. Ic r . ",.a � f 77 § t r psi, � c, 'I Y li: r . IS a (i f.,� s �"`� �� Q, d"'Fi <. c C Y �f ��} ` t�.ri i "i,,.s=a'al . T„•, i '«a ir5 HYDROLOGY Welland Hydrology Indicators: allthat pogly)Secondary Indicators Q ormore r aWired) Surface Water (A1) _... Water -Stained Leaves (Rg) (except Water -Stained Leaves (Sg) {MLRA 1, 2, High Water Table (A2) MLRA 1, 2, 4Ar, and 4) f 4,A, and 4 ) Saturation (A3) — Salt Crust (811) Drainage Patterns (Ri d) Water Marks (Sf) Aquatic Invertebrates (1313)' Dry -Season Water -Table (C2) - Sediment Deposits (2) - � Hydrogen Sulfide Cdbr (Cl) Saturation Visible on Aerial Imagery (CO) — Drift Deposits (W) Oxidized Rhl ospheres along Living Roods (C) l Geomorphic Position ( 2) Algal Met or Crust (84) � Presence of Reduced Iron (C4) Shallow Apuitard (D3) Iron Deposits ( 5) Decent Iron Reduction in Tilled`Solis (C) FAC-Noutral Test (D ); Surface Soil Cracks {SR} — Stunted or Stressed Plants (Dj) (LR A)' Raised ,Ant Mounds (DS) (1L A) Inundation Vls ble on Aerial Imagery (87) lather (Explain In Remarks) r Sparsely Vegetated Concave Surface (Bft) Frost -Heave Hummocks (07) Field b ervatlem Surface Water Present?' Yes No r Depth Cjnchesj; r Water Table Present? `fee No ,Depth (inches): � _ Saturation Present? Yes _ td No Depth (inches). ►�etiand Hydrology Present? fifes No includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), It avallablp: Rernarks: yg ' s° $ r`X.1 de.w.gia,t' ,at, �;,,r, °r i, .�� 1,,. "°� '�:" +,Si,�1.�'*' r US Army Corps of Engineers Western Mountains, Valleys, and Coast — Version 2.0 WETLAND DETERMINATION DATA FORM —Western unt in , Valleys, and Coast Region Project/Site. �� �. � � �€ � ����tt� ,� t� �,��� _ Clly/County' �k�$�Y,°lei lr�� ."k iwsrT4 i��trlri�� j Sampling [ante k Appilcartti�7�rner. �pl j' ` T w jw�.4 �°. " t i . s� mpling Paint: investigator(s)/�_ l� � a � Sectizsi�,Townshtp r�arsge ..M �. Landfarrn (niilsicpe terra t etc,): ' t , . �� . • Gncai reilef (adnca�re, canvex, none) `r.�xr r ' /� Slope ` ): Subregion (LRZR)., Let: tang: Datum: Soil Map Unit Name: � " '" ty� /ir.�isi l ,fr v. tPoatrlr i �� ; t�Wl classification: �� Are ctirnatic l hydrologic conditions on the site typical for this time of year? Yes No (If no, expiain In Remarks.) ,law' Are Vegetation Sail at Hydrology significantly disturbed`/ ATe "Normal Circumstances" present? Yes ' / No Are Vegetation Sail or Hydrology naturally problematic? (If needed, explain any answers In Remarks.) SUMMARY OF FINDINGS-- Attach site m9p showing sampling point locations, transects, Important features, etc. ttydrarahytic Vegetation Present? Yes " ..� . Hydric Soil Present? Yes 0 is the Sampled Area (/1 Welland Hydrology Present. Yes No within a Wettand? 'yes No Remarks VEGETATION — Use Scientific homes of plants. Absolute Dominant indicator DominanceTest works heet. TIttg (Mat sizes ) ° a Number ei Dominant Species That Are CSL. FACW, or PAC. ( Total Number of Dominant 12 Species; Across All Strata: (13) Percent of Dominant Species Total Cover That Are OBL, FAC"it�', car FAC. (A18) t n / iPlot size ) is m a. t'P � TM py „ Prevalence inde werksheet. ro 1„ Tttiai y Ceuer nr, Multiply by_ 3�y tilt Citt. species x 1 �# ... FA.CW species x z FAC species x S T:: ¢¢,� FACU species x 4 a Total Cover (Plot size. ) xl UPpL species r j 1: W £+.; ;k B Y 1�S1 o l h i t Vbpx" t, Jx ( 4 �a8�i�n Totals:ropy rtaNp . 1Ai (^t' la.d1ti / i t ...p / t i .'i Prevalenceindex 81A � ; .. (, ,'t+ Fiydrophytic Vegetation indicators: �t, tRapid Test for Nydrtphytic Vegetation -`DominanceTesti >50% - Prevalence index is 10 4 - Morphological Adaptations' (Provide supporting data in Remarks or an a separate sheet) 9s 5 Welland Non-Vascuiat Plants* 14, _ Problematic Hydrophytic Vegetation' (Explain) 11, 'Indicators of h dric sail and wetland hydrology must }" be present, unless disturbed or problematic. Tatar Cover � a.( ) Woody Xing Stratum (Plat size, 1,„ Hydriophytia Vegetation sx present? Yes c Total Cover` % Bare Ground In Kerb Stratum e�rkat US Army Corps. of Engineers Western Mountains, Valleys, and Coast — Versiort 2,0 K. $OIL Sampling Pirelli 01 Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of Indicators.) Depth ------- lyisirix-- ("z' �r nj 'Typo; Ca°Ccan centratlori.-p 21-ocatirinL: PL=Pdre 0 M=Mamx' Hydric Solll Indicators: jApplicable to all li unless otherwise noted.) In Icato for Problematic Hytirls, Sells", — Hislosel (Al) Sandy Redox (S5) — 2 rim Muck (A10) — Histic Epipedon (A2) — Stripped Matrix (SO) — Red, Parent Material (TF2) Black Hisfic (A3) — Loamy Mucky Mineral (Fl) (except MLRA 1) — Very Shallow Durk Surface (TF 12) Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) — Other (Explain In Remarks) Depleted Below Dark Surface (A)l) Depleted Matrix (F3) Thick Dark Surface (Al 2) Redox Dark Surface (F6) 'Indicators of hydrophyllevegetation and Sandy Mucky Mineral (Sl) Depleted Dark Surface (F7) welland hydrology must be present, Sandy leyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layor lit present): Type: Depth (inches): Hydric $off Present? Yes_ hid Ramarksi HYDROLOGY Wothund Hydrology Indicators: Primary Indicators (minimum of an — Surface Water (Al) — Water -Stained Leaves (139) (except — Water -Stained Leaves (89) (MLRA 1, 2, — High Water Table (A2) MLRA 1, 2, 4A, and 48) 4X and 48) Saturation (A$) — Salt Crust (B11) — Drainage Patterns (B10) Water Marks li — Aquatic Invertebrates (S13) — Dry -Season Water Table (C2) Sediment Deposits ($2) — Hydrogen Sulfide Odor (CI) — Saturation Visible an Aerial Imagery (C9) Drift Deposits (83) — oxidized Rhizospheres along Living Roots (C3) _ Geomorphic Position (02) — Algal Mat or Crust (S4) — Presence of Reduced Iron (C4) — Shallow Aquilard (D3) — Iron Deposits (B5) — Recent Iron Reduction In Tilled Solis (G6) FAG -Neutral Test (05) Surface S0 Cracks (86) — Stunted or Stressed Plants (DI) (LRR A) Raised Ant Mounds (Del (LRR A) Inundation Visible on Aerial Imagery (87) _ Other (Explain in Remarks) Frost -Heave, Hummocks (DI Fleld Observations-. Surface Water Present? Yes No —( bepth (inches); Water Table Present? Yes — -7No Depth (Inches) 'a V Saturation Present? Yes Ito' Depth (Inches). ch a Is) C, _(- fitiettand[Hy4rologlyProsent? Yes_ No_ thintudAq "niffarvfrinaAl oescribe Recorded Data (stream, gan.go, monitoring wall, aerial PhOlOS, previous Inspections), it arraiiainw Remarks; C Ly US Army Corps of Engineers Western Mountains, Vaileys, and Coast - Version 2,0 WETLAND DETERMINATION DATAF astern Mountains," l y ,.and Coast Region , t t .a t Y` „i, Sampling Project/Site: 6s)r t" a 1(i (A tty, �a r ty. P ,. N r r,,=Y,e „ e` Cle te: Applicant(owr r r t `". a, �.. t # w #atd. R mpling Point Investigator(s) Z9°(10�=.,.r.,.t.Si �ectiran, Tou�nshi Ranje._.� . Y Landform (hdlslops, taf race, etc.). t V slope » .:2/ Subregion (LRR)M Lat: Long. Datum-.. oihMap d�nit Names `, „r` t�„»rr», »�»�«� NL+tii oiassifiratfcrn. Are ciizmatic f hydrologic conditions on the site typical for this time of year's Yes � No _ (If no, explain In Remarks.) $ Are Vegetation , Soil or Hydrology significantly disturbed' Are "Normal Ir urnstanres" present? Yes °'J No Are Vegetation `, Soil � or Hydrology naturally problematic? (If needed, explain any answers In Remarks.) SUMMARY OF FINDINGS — Attach site map howirs,gsampling point locations, transacts, important features, etc. Hydrophytic Vegetation Present? Yes No — + is ampied Area Hydric Soil Present? Yes - , No tbo ,.r Wetland Hydrology Present? Yes No tn�` within a gletland Yes —Ito Remarks, VEGETATION — USe scientific names f plants. � Absolute Dominant Indicator Dominance Testworksheot. 1 e tr`atu (Plot Size:.., "� i art dumber of Dominant species That Are OBL, FA W, or PAC: (A) . Total Number of Dominant t o E species Across All strata: (B) 4, Percent o Dominant species � ' " ? u µ � ¢ ... toils d�hr �b a tra arm (Plot tie; t , � t Total corner That :Are t�EL. EACH, or PAS _ ( R) Prevalence index workshoet: _ pp a n t-J 1 sr Multiply bS�, 013E species 1 r 1=A W species Q° x 2 d C� 4. Ac specles x 3 = ) T species r.;w.. x 4 r„ erbLt atr im (Plat size. i t�t� Total Cover UPL species x 5 = 6 t ( - :.;A(�.( column TotaW d�� r't (A) ��r ( ) 1a st ir' {( t 2. " Prevalence Index = RFA---------------- Hydrep ytic Vegetation Indicators 4. 1 - Rapid Test for Hyroprhytic Vegetation 5. �� - Dominance Test is >50% 6. 3 - Prevalence index is 10' 7• 4 - Morphological Adaptationst (Provide supporting .' data in Remarks or on a separate sheet) 9. 5 - Weiland Non -Vascular Plants' 11 _ Problematic Hydrophyfid Vegetation' (Explain) 11, ' Indicators of hydrlc soil and wetland hydrology bust Total Cover be present, unless disturbedor problematic. t gtrmgb i Q eatum (Plot size: ;> y ° tt dro h is y YtY 2. Vegetation Total cover Present? Yes o % Bare Ground in Herb Stratum Remarks. US Army Corps of Engineers Western Mountains, Valleys, and Coast. -Version 2.0 IL Sampling Point, protlle tt acriptlon: IDescribe to the depth needed to document the indicator or confirm the ate nnce of indicators.) Depth Mehl& t r 1i1 eat :: l r i ¢r` Q2lQ W19 ° tls �., `;py�VdP1.< j) �,S51Y Sn S.kY �f P.ki fay.,,( 1,Ty D® ancentraticn, D e Ietian. RM Reduced Matrix, S ever d gr ated Sand t rains, 21-acatidn: PL=Pare Linni M-Matrix, Hydric Soil Indicators. (Applicable to all L.RR9, unless otherwise noted.) in teeters for Problematic Hydric Snails". Histasdl (At) sandy Redox (S ) 2 cm Muck (A10) ' Histic Epipedon (A2) - Stripped Matrix (S) , Red Parent Material (TF2) Slack Histiic (A3) Loamy Mucky Mineral (F 9) foxcept MLRA 1) Very Shallow Dark Surface (TF1 ) Hydrogen Sulfide (M) - Loamy Gleyed Matrix (1`2) Other (Explain in Remarks) Depleted Below Dark Surface (Al I) _: Depleted Matrix (F3) Thick Dark Surface (Al2) Rddox hark Surface (176) 'indicaiors of hydrophyt{c vegetation and Sandy Mucky Mineral (81) Depleted Clark Surface (F) Welland hydrology must be present, Sandy Dieyed Matrix (S4) ; Rodox Depressions (Fd) unless disturbed of problematic. Restrictive Layer (if present). Types Depth (inches): Hydric Snail Present's "yes No Remarks - HYDROLOGY ; WWe#land Hydrology Indicators: — Surface Water (Al) Water Stained Leaves (PO) (except Water-Stalned Leaves ( g) (l LRA 1, 2, High Water Fable (A2) MLRA 1, 2, 4A, and 4) its , and ) Saturation (A3) Salt Crust (1311) Drainage Patterns (0) Water Marks (01) Aquatic invertebrates (813) _ I y-S ason Water Table (C2) Sediment Deposits {S2} Hydrogen Sulfide Odor ( 1) Saturation Visible an Aerial Imagery (DR) Drift Deposits ( 3) Oxidized Rhixosphores along giving Resits ( 3) �Geomorphic Position (D2) Algal Mat or Crust ( ) Presence of Reducedi Iran (C4) Shallow Aquitard (03) , — Iron Deposits (t 5) Recent Iron Reduction in Tilled Sails (Did) � FAD -Neutral Test (D ) Surface Soil Cracks (i36) Stunted or Stressed Plants (D1) (LRR A) m Raised Ant Mounds (Dd) (LRR A) Inundation Visible on Aerial Imagery (87) _ Other (Explain. in Remarks) Frost -Heave Hummocks (D7) ,, Sparsely Vegetated Concave Surface (135) Field Observations Surface Water Present? Yea NoDepth (riches). Water Table Present? Yes No Depth (lnchos). Saturation Present? Yes bib Depth (Inchas): Woltimid Hydrology Present? 'des No roludea ca illa Erin e Describe Recorded Data (strdam gauge, monitoring well, .serial photos„ previous inspections), If available: l�emarirs� US Army Corps of Engineers Western Mountains, Valleys, and Coast— Version 2.0 ; WETLAND DETERMINATIONT FOB Western unt ins, Valleys, and Coast Region rep}n ii it : iiyt aunty; et t� a i i`°-` ampiing Bate �� i AppiicanVOwner � f tr i r " e a of sState: ( Samp ing Point Invstigator(n)e ' ai sir, ;turf �,rfu .'{.�i.,e� ` (nx Y �'. Section, Township, Range'. r °P , L andfr (hill -slope, terrace, etc.). Local relief (concave, convex, none): slope Subregion (inRR)f Lat: Long: Datum: tit e ,M.en Soil Map Unit Name: r €i�, et � ��' � 4E� �a �"i ctassiatlon. Are climatic !'hydrologic conditions on the site typical for.this time of year 7 Yes t/ - No (if no, explain in remarks.) "l�orrnai 'Yes: Are Vegetation Soil , or Hydrology significantly disturbed? Are ir�urnstai���s" present? No - Are Are Vegetation Sail or Hydrology. naturally problematic? (if needed, explain any answers in Remarks,.) SUMMARY OF FINDINGS — Attach site map showing,,samplingpoint locations, transects, important t IJr , etc. w Hydrophytib Vegetation Present? yes=1eithe Hydric Soil Present?' Yes o t,..lad AreaWelland Hydrology Present?- Yes otland? Yes No Remarks. y pp y{t gp VEG A I N — Use scientific names of plants. Absolute Dominant indicator Dominance Test tvorksheetr Tree $j[0j Frrr (Piers "r % orrer i Number of Dominant nt pani c 1. 'C R �^ t .v' That Are 013L, FACWV, or FA , (A) ti fit... ..t,"", t. Total Number of Doininant o, Species Across All Strata: () 4. Percent of Dominant Species 9 rut =Total Cover That .Are 08L, FACW, or FA : - (A#E) 9 aDlin /Shrub Stratum (Plot size. Prevelanoe lndaatworkshaet ___TAU qy r of; Multiply by, 2`081. species r�� 1 . PAW species x 2 m 4. FAC species t x FA U species x 4 , a Total Laver UPL species i x• t x d derb SIMLIM (Plot slza, I Column Totals. (A) (R) 1 " PrevalenceIndex PIA - ' Hydro}ahytic Vssgstatloo Indicators., f. 1 - Rapid Test for Hy rophytic Vegetation 2 - Dominance Test is >50 3 - Prevalence index is Q.01 Y. 4 - Morphological Adaptations' (Provide supporting' data In Remarks or on, a separate sheet) g, 5 - Welland Non -Vascular Plants' 10. Problematic Hydrophyf0c Vegetation' (Explain) 11 x / 'Indicators of hydrib soil and wefland hydrology must I � Total Cover e present, unless disturbed or problematic. WoodVtn r (lo# size I 1 � t . „ Hydroph tic Vegetation pert Present? yes No Total Cover % Bare Ground in Herb Stratum Remarks: US Army Corps of Engineers "Western' Mountains, Valleys, and Coast -Version 2.0 $OIL Sampling Point Profile Description: f0escribe to the depth needed to documentthe Indicator or confirm the absence of Indicators.) Depth Mratrrx Redox E4s g drnnidi "�'� Piri1ni� � �.T Lo 2111 r Rarxrarks /gam{{ +t}�y 2:, Sk{ A: I'""+� `" f} i"%°'�$ w 85 Po+.,✓ 8^5 y¢ e.u,i M1 R } 9,.# L t .r�«•t,«ex, r''+k k1 .. ... Cr 4ri entr tlon, DwDepletlon„ RIirl-reduced Matrix, = PHd or Coated Sand Grains, LoCatlona PL-Pore Llning; t Matrla . flydric ,Solt Indicators: (,Applicable to all Llaks, unless otherwise noted.) .rrr Indicators for Problematic Flydrlo Soile: -T HIslospl (At) ; Sandy Redox (S5) 2 cm Muck (At4) —n- Histic Dpipedon (Q) Stripped Matrix (S) Red Parent Material (TP2) Black Hislic (A3) Loamy Mucky Mineral (Pt) (except ML 1) fiery Shallow Dark Surface (TPt ) - hydrogen Sulfide (Aot) Loamy Gleyed Matrix (P2) Other (Explain In Remarks) Depleted Below Dark Surface (All) _, Depleted Matrix (3) _ Thick Clark Surface (Al 2) Redox Dark Surface (Pg) 3Indlcators of hydrophylicvegetaion and — Sandy Mucky Mineral ($i) Depleted Dark Surface ( 7) wetland hydrology must be present, Sandy Gleyed Matrix (S) Redox Depressions (p"a) - unless disturbed or problematic. Restrictive Layer (if present): Type, Depth (Inches). Hydric.Sall Present? yes No Remarks; HYDROLOGY Intlond'A droiogyIndicators: Prlmea Indf r i f r ' ¢ ry lnd{cato s t2 er mare reaul edt Surface Water (Al) — Water -Stained Leaves (g) (except Water -Stained Leaves (99) (MLRA i, 2, ® High Water Table (A2) MLRA 1, 2,4A, and ) � 4A� and 48) Saturation (A3) Salt Crust (Bl t) Drainage Patterns (Bed) - Water Marks (Bt) .Aquatic Invertebrates (B1) n Dry -Season Water Table (C2) Sediment Deposits (82) Hydrogen Sulfide Oder (Cl) ® Saturation Visible on Aerial Imagery (Cg) Drift Deposits (83) _ Oxidized Rhixospheres along Ltving Boots (C3) — Geomorphic Position (D2) Algal Mat or Crust (B4) Presence of Deduced Iron ( ) Shallow Aquitard (133) - Iron Deposits (B) — Recent Iron Reduction in Tilled Snits ( ) FAC•Nautral Test (05) — Surface Soil Cracks (136)' Stunted or Stressed Plants (Dl) (i A) raised Ant Mounds (DS) (LRR A)' inundation Visible on Aerial Imagery (B7) , — Other (Explain In Remarks) i Frost -Heave Hummocks (D7) . Sparsely Vegetated Concave Surfs (Bd) Field Observations: Surface Water Present? Yes No Depth (Inches): Water Table; Present? Yes No — j" C pth (inches): Saturation Present? 'yes No Depth (inches): Wetiond Hydrology Present? Yes No Includes Ills lrin e Describe Recorded Data (stream .gauge, monitoring well, aerial photos, previous, inspections), if available, Remarks: { ent i r j � 1," ` r r ),,.. / )k.,. tec' 0, a°,r iIr:cl. '=a' t.,l(t ,M ,m- yf� gq O"g R1 >' : �I A US Array Corps of Engineer, Western Mountains, Valleys, and Coast — Version 2.0 VVE I LAW) IJE I EKMINA l IUIq L)A I A rUKM - Western mounta4m, Valleys, ana ioast Reuion Pro'ecUSite: _`?r ECity/County",'- /CountY'- c �LISampling ate: 1_ ,. 'xr � @ � fl Applicant/Owner: State: LU Sarrtpl'ng Point: ! `/1 f InvestigatorisJ: IYI fn a§ V t ,00 ( Section, iownsnip, Range: fl Landform (hlllslope, terrace, etc.): V 61 3 1 Local rclicf (erjneave, erjnvex, none): CfD V1Ur'_ ' Slope (%): Z N Subregion (LRR): A Car. I•ong: Dar m: �� i Still Map Unit Name (' - �A( 4�°%€' ��(���i°�r �� �Ni._Ix/ 9 �� � ��w � ��� 5 Uk�-a.slfication: Hre ciimatic / hydrologic conditions on the site typical Tor rQis time of ear? T es J— No (If no, explain in Remarks_) Are Vegetation Soil VZ or Hydrology significantly distarb.d-! Ar "Normal Cir am.tan ems" pr.unt a Yu. No Are Vegerarion Soil or Hydrology nawrally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS — Attach site map showing sampling point locations, transects, important features, etc. Hydrophytie Vegetation Pflesent"? Yes Nv Hydric Soil Present? YGs No Is trie Samplea Area Wetland Hydrology Present"? YGs No within a Wutla,.d-? Yes Nu Remarks: A VEGETATION — Use scientific names of plants. Tree Stratom (Plot site: ) 1. 2. 3. Absulnti� Dumninant Indicator Dominance Test worksheet: % Cover Species? Status Number of Dominant Species That Are OBL, FACW, or FAC: (A) 4. i = Total Cover Saplmo/Shrub Stratum (P tt/sce: 1 r !( 1. `1 t� ijk'/'&,d`a ` I\tJ u , 7(r%'r., 4, Zr I 2. i✓(A 0 F VtUs `lam I� J., 4. k(',?J9i(A1A fo�F-0 o. Stratum = Total Coo ur r,erb (Plot size: J FTT 3. LIPd4lr} ZF. 5. 6. 7. S. 9. 10. 11. i =Total Cover Woody Vinu Stratom (Plot si«: iS 2. i° Bar Groand in H.rb Stratorin 61 _ Total Cover Remarks Total Number of Dominant Species Across All Strata: Percent of Dominant Speciescoo That Are Onr, FACW, or r-AC: ` � (B ) iA/6J Pn valen;e Index worksheet: Total /° Co a of: M,.Iti I. b.: OBL species x 1 = FACW .pecies x 2 = FAC specks x 3 = FACU species x 4 = UPL species x 5 = Column Totals: (A) BJ PrevalGnc-- Index = B/A = Hydrophyt; Vegetation Indi�ators: _ 1 - Rapid Test for Hydr ophytic Vegetation 2 - Dominance Test is >50 r° _ 3 - Prevalence Index Is 53.0' 4 - Morphological Adaptations' (Proide s,.pporting data in Remarks or on a separate sheet) _ 5 - Wetland Non -Vascular Plants' Problematic Hydrophytie Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, anlesb distarbed or problematic. Hydruphytic Vugutatiun Present? Yes YNu US Army Corps of Engimuurs Western Mountain, Vallay., and Coast - V�r.ion 2.0 SOIL Sampling Point. w� Profile Description. (Describe to the depth needed to document the Indicator or confirm they absence of indicators.l Depth Matrix �claeatawM yy nx 'lygt� =Concentration LI� Se let n, hr9 Reduced Matrix CSC ouered or Coated Sand Grains. kocatlon: PL=Pore LimnI M= latex. Hydrrc Sol] Indicatorsw (,Applicable to all LRRs, unless otherwise noted.) Indicators for problematic Hydric Soils"- - Histosoi 01) - Sandy Redox (S) , 2 cm Muck (Alfa) Histic Epipedon (A) -- Stripped Matrix (S5) Red Parent Material (TF ) Black hlistic (A) Loamy Mucky Mineral (E1) (except MLRA 1) Very Shallow Dark Surface (Ti ) Hydrogen Sulfide (A4) Loamy Cloyed Matrix (F Other (Explain in Remarks) ' Depleted Below Dark Surface (Ali 1) Depleted Matrix (F3) Thick Clark Surface (A1) Redox Dark Surface (Il "Indicators of hydrophytic vegetation and Sandy Mucky Mineral ( 1) Depleted Dark Surface (Fy) wetiond hydrolorg must be present, Sandy Gloyed Matrix (S'f) Redox Depressions (P) unless disturbed or problematic. Restrictive Layer (it present): Types Depth (Inches), htydrlo Still Present? yea No Remarks; HYDROLOGY Welland Hydrology Indicators: P r Secondary Indicators (2 armors reggired) X Surface Water (Al) Water -Stained Leaves i (except — Water Stained Leaves, (B9) (ML A 1, 2, ,High Water Table (A) Jill 1, 2,4A, and s) 4A, and d ) Saturation (A) Salt crust 4811) Drainage Patterns (R10) t _ Water Marks (B1) Aquatic Invertebrates (81) Dry -Season dater Table (E ) Sediment Deposits (fat) Hydrogen Sulfide Odor (Cl) _ Saturation Visible on Aerial Imagery it — Drift deposits (E) Oxidized Rhizospheres along Living foots ( 3) Geomorphic Position (0 ) Algal that or gust (84) Presence of Reduced Iron ( 4) _ Shallow Aquitard ID ) — iron Deposits (B) Recent Iron Reduction In Tilled Soils ( ) � I"A-Neufra3 lest (05) - Surface Sail Cracks (B6) _ Stunted or Stressed Plants (Dl) (I -RR ) � Raised Ant Mounds (D6) (LRR ,) Inundation Visible on Aerial Imagery (87) dither (Explain in Remarks) Rroi Hummocks (t)7) Sparsely Vegetated Concave Surfs (S ) Field Observations: �th Surface Water Presents Yes No Depth (inches): Water Table Present? Yes a^ Rio' Depth (Niches), N .r( . Saturation Present? Yes " No Depth (inches), ' ,t.°i t,r r,, i', Weiland Hydrology Present?" "Yea Ho in�Iudes Ilia file [describe Recorded Data (stream gauge, monitoring well, aerial photos, previous Inspection$), if available; Remarks g) o- p t R fit p} t. US Array Corps of Engineers.. Western Mountains, Valleys, and Coast — Version 2.0 SHANNON ILA APPENDIX C WETLAND RATING FORMS - WESTERN WASHINGTON 21-1-22082-002 Wetland name or number A RATING SUMMARY - Western Washington Name of wetland (or ID #): Wetland A Rated by S. Corbin (PWS) Date of site visit: 7/6 and 7/7/15 Trained by Ecology?.X Yes No Date of training 10/09 and 5/14 HGM Class used for rating Slope Wetland has multiple HGM classes?_Y X N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map Google Earth OVERALL WETLAND CATEGORY IV (based on functions X or special characteristics_) 1. Category of wetland based on FUNCTIONS Category I —Total score = 23 - 27 Category II — Total score = 20 - 22 Category III — Total score = 16 - 19 X Category IV — Total score = 9 - 15 Site Potential H M L H Landscape Potential H L H Value H L H Score Based on Ratings 5 Circle the appropriate ratings M OL H M L M OL H M L M L H M L 4 1 4 ( 13 2. Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H, H, M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L, L, L 1 Wetland name or number A Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 Hydroperiods D 1.4, H 1.2 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 Boundary of area within 150 ft of the wetland (can be added to anotherfigure) D 2.2, D 5.2 Map of the contributing basin D 4.3, D 5.3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 Riverine Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Ponded depressions R 1.1 Boundary of area within 150 ft of the wetland (can be added to another figure) R 2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R 4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R 3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Fringe Wetlands Map'', of: To answer questions: Figure # Cowardin plant classes L 1.1, L 4.1, H 1.1, H 1.4 Plant cover of trees, shrubs, and herbaceous plants L 1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L 2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L 3.3 Slope Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 1 Hydroperiods H 1.2 1 Plant cover of dense trees, shrubs, and herbaceous plants S 1.3 1 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (can be added to figure above) S 4.1 1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 2 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 3 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S 3.3 4 Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number A HGM Classification of Wetlands in Western Washington 1. Are the water levels in the entire unit usually controlled by tides except during floods? C0-,go to2 YES - the wetland class is Tidal Fringe - go to 1.1 1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? O - Saltwater Tidal Fringe (Estuarine,. YES - Freshwater Tidal Fringe Ifyour wesif as°a reshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. NO - go to 3 YES - The wetland class is Flats can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? _The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; _At least 30% of the open water area is deeper than 6.6 ft (2 m). 0-go to YES - The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? X The wetland is on a slope (slope can be very gradual), X The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, X The water leaves the wetland without being impoundLThe -� NO - go to 5 YES tland class is Slope NOTE: Surface water does not pond in these type of wetlan s small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, The overbank flooding occurs at least once every 2 years. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number A NO - go to 6 YES - The wetland class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at sometime during the year? This means that any outlet, if present, is higher than the interior of the wetland. NO-goto7 YES - The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ME= YES - The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a rverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE Ifyou are still unable to determine which of the above criteria apply to your wetland, or ifyou have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update 4 Rating Form - Effective January 1, 2015 Wetland name or number X S 1.1. Characteristics of the average slope of the wetland: (a 1% slope has a 1 ft vertical drop in elevation for every 100 ft of horizontal distance) Slope is 1% or less points = 3 Slope is > 1%-2% points = 2 0 Slope is > 2%-5% points = 1 Slope is greater than 5% points - 0 S 1.2. The soil 2 in below the surface (or duff layer) is true clay or true organic (use MRCS definitions): Yes = 3 No = 0 0 S 1.3. Characteristics of the plants in the wetland that trap sediments and pollutants: Choose the points appropriate for the description that best fits the plants in the wetland. Dense means you have trouble seeing the soil surface (>75% cover), and uncut means not grazed or mowed and plants are higher than 6 in. Dense, uncut, herbaceous plants > 90% of the wetland area points = 6 Dense, uncut, herbaceous plants > Y, of area - 2 Dense, woody, plants > Yz of area oints = 2 Dense, uncut, herbaceous plants > % of area points = 1 Does not meet any of the criteria above for plants points = 0 Total for S 1 Add the points in the boxes above 2 Rating of Site Potential If score is:_12 = H _6-11= M X0-5 = L Record the rating on the first page S 2.0. Does the landscape have the potential to support the water quality function of the site? S 2.1. Is > 10% of the area within 150 ft on the uphill side of the wetland in land uses that generate ts? YeS = o = 0 1 S 2.2. Are there other sources of pollutants coming into the wetland that are not listed in question S 2.1? Other sources dog walkers/ dog poop Yes = No = 0 1 Total for S 2 Add the points in the boxes above 2 Rating of Landscape Potential If score is: X 1-2 = M _0 = L Record the rating on the first page S 3.0. Is the water quality improvement provided by the site valuable to society? S 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on 303(d) list? Yes = 1 = 0 S 3.2. Is the wetland in a basin or sub -basin where water quality is an issue? At least one aquatic resource in the basin is on the 303(d) list. es - No = 0 1 S 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality? Answer YES if there is a TMDL for the basin in which unit is found. Yes = 20o = 0 Total for S 3 Add the points in the boxes above 1 Rating of Value If score is: 2-4 = H X 1= M _0 = L Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Record the rating on the first page 11 Wetland name or number A S 4.1. Characteristics of plants that reduce the velocity of surface flows during storms: Choose the points appropriate for the description that best fits conditions in the wetland. Stems of plants should be thick enough (usually > 118 in), or dense enough, to remain erect during surface flows. 0 Dense, uncut, rigid plants cover > 90% of the area of the wetland points = 1 All other conditions s_=: :> Rating of Site Potential If score is:_1= M X0 = L Record the rating on the first page S 5.0. Does the landscape have the potential to support the hydrologic functions of the site? S 5.1. Is more than 25% of the area within 150 ft upslope of wetland in land uses or cover that generate excess surface runoff? Yes = 1 0 = 0 Rating of Landscape Potential If score is: _1= M X0 = L Record the rating on the first page S 6.0. Are the hydrologic functions provided by the site valuable to society? S 6.1. Distance to the nearest areas downstream that have flooding problems: The sub -basin immediately down -gradient of site has flooding problems that result in damage to human or natural resources (e.g., houses or salmon redds) points = 2 1 Surface flooding problems are in a sub -basin farther down -gradient I oints - 1: No flooding problems anywhere downstream points = 0 S 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control Ian? Yes=2 =0 0 Total for S 6 Add the points in the boxes above 1 Rating of Value If score is: 2-4 = H X1= M _0 = L Record the rating on the first page NOTES and FIELD OBSERVATIONS: Wetland Rating System for Western WA: 2014 Update 12 Rating Form - Effective January 1, 2015 Wetland name or number A H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of % ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. Aquatic bed 4 structures or more: points = 4 Emergent 3 structures: points = 2 X Scrub -shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 Forested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if.• The Forested class has 3 out of 5 strata (canopy, sub -canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % ac to count (see text for descriptions of hydroperiods). Permanently flooded or inundated 4 or more types present: points = 3 Seasonally flooded or inundated 3 types present: points = 2 Occasionally flooded or inundated 2 types present: points = 1 _Saturated only 1 type present: points = 0 Permanently flowing stream or river in, or adjacent to, the wetland Seasonally flowing stream in, or adjacent to, the wetland Lake Fringe wetland 2 points Freshwater tidal wetland 2 points H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ftz. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species 5 - 19 species < 5 species H 1.4. Interspersion of habitats points = 2 points = 1 points = 0 Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. 0:) (*) (00) 0 None = 0 points Low = 1 point Moderate = 2 points All three diagrams in this row are HIGH = 3points Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 13 U Wetland name or number A H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). Standing snags (dbh > 4 in) within the wetland Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered 1 where wood is exposed) At least % ac of thin -stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg -laying by amphibians) X Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata) Total for H 1 Add the points in the boxes above 2 Rating of Site Potential If score is:_15-18 = H _7-14 = M g0-6 = L Record the rating on the first page H 2.0. iiDoes the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 % If total accessible habitat is: > 1/3 (33.3%) of 1 km Polygon points = 3 0 20-33% of 1 km Polygon points = 2 10-19% of 1 km Polygon points = 1 < 10% of 1 km Polygon points = 0 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 % Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in 1-3 patches points = 2 0 Undisturbed habitat 10-50% and > 3 patches points = 1 Undisturbed habitat < 10% of 1 km Polygon points = 0 H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use points = (- 2) -2 <— 50% of 1 km Polygon is high intensity points = 0 Total for H 2 Add the points in the boxes above -2 Rating of Landscape Potential If score is: 4-6 = H _1-3 = M X< 1= L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 It has 3 or more priority habitats within 100 m (see next page) It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) It is mapped as a location for an individual WDFW priority species It is a Wetland of High Conservation Value as determined by the Department of Natural Resources 1 It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 Site does not meet any of the criteria above points = 0 Rating of Value If score is: _2 = H __X_1= M _0 = L Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 Record the rating on the first page 14 Wetland name or number A WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. f or access the list from here: hnail lwdfw.wa.gov/conservation hs list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. Old-growth/Mature forests: Old -growth west of Cascade crest - Stands of at least 2 tree species, forming a multi - layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests - Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old -growth; 80-200 years old west of the Cascade crest. Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 - see web link above). Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. Westside Prairies: Herbaceous, non -forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 - see web link above). Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report - see web link on previous page). Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. X Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland Rating System for Western WA: 2014 Update 15 Rating Form - Effective January 1, 2015 Wetland name or number A CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Category Check off any eriterio that ppply to the wetland: Circle the category when the appropriate criteria are met. SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? The dominant water regime is tidal, Vegetated, and With a salinity greater than 0.5 ppt Yes -Go to SC 1.1 No= Not an estuarine wetland SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? Yes = Category l No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) Cat. 1 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland has at least two of the following features: tidal channels, depressions with open water, or Cat. II contiguous freshwater wetlands. Yes = Category[ No = Category II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? Yes - Go to SC 2.2 No - Go to SC 2.3 Cat. I SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservationlu Value? CategI� No-=_Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland. htt�:J/wwwl.dnr.wa.Gov/nhp/refdesk/datasearc�wnh�wetiands. df Yes - Contact WNHP/WDNR and go to SC 2.4 No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? Yes = Category l No = Not a WHCV SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. se 1 in' SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, tharo-ttoSC3.2 more of the first 32 in of the soil profile? Yes - Go to SC 3.3 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less tli over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on t or pond? Yes - Go to SC 3.3 o = Is not a bog SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AN least a 30° cover of plant species listed in Table 4? Yes = Is a Category I bog No - Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. Cat. I SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? Yes = Is a Category I bog No = Is not a bog Wetland Rating System for Western WA: 2014 Update 16 Rating Form - Effective January 1, 2015 Wetland name or number A SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife's forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. Old -growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi -layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh ed' L"' Yes = Category I = Not a forested wetland for this section Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to sured near the bot o—M Cat. I Yes - Go to SC 5.1 No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). Cat. 11 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland is larger than 1/10 ac (4350 ft2) Yes = Category I No = Category II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: Long Beach Peninsula: Lands west of SR 103 Grayland-Westport: Lands west of SR 105 Cat I Ocean Shores-Copalis: Lands west of SR 115 and SR 109 Yes - Go to SC 6.1 No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M Cat. 11 for the three aspects of function)? Yes = Category[ No - Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? Yes = Category II No - Go to SC 6.3 Cat. III SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? Yes = Category III No = Category IV Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter "Not Applicable' on Summary Form N/A Wetland Rating System for Western WA: 2014 Update 17 Rating Form - Effective January 1, 2015 Wetland Rating Figure ow rdin Class, H drop ri d and Pollutant Generating Surfaces Wetland A Rating Figure 2, One Kilometer Buffer Land Use Lwyataa°- rlua ttv I�n�o°. ement 7aate- i"LralP ?r =-,ve vent Feala:ama�- FBI a' 9 ar- mmamish; The following table lid overviews information For water quality improvement projects (including total maximum daily loeds, or TIVIDI-s) for this water resource... inventory area (4WRIA). Please use links (where available) for more mfr rmatiort an project.,: - Counties ® <inq . Snohomish Waterbodyr Name Pollutants Status' -fMDL Lead Ballinger Labe, Total Phecphorus ._ Approved by EPA - Tricia Shobinm --_ 42E 649 7288 Pear -Evans Greek Basin Fecal Colrfa..rm ----- Approved by EPA Jean Nolari:--- --- -- 4..2.5 649-4-435 Dissolved'iOxygen+ Approved by EPA, ----- Temperature - Cottage Lake Total Fhcsphorus Approved by EPA Tricia Shablom Has an implementation 4.15-549 7288 plan' Issaquah Creek Basin Fecal Cohl'orm Approved by EPA Joan Nralan 425 649-4,425 Little Bear Creek - Fecal Colifearm — Approved by EPA Reph Svricek -- Tributaries. 425-649 7036 Trout Stream: Great Danei . Creek Cutthroat Greek North Greek Fecal ColiFcrm Approved by EPA Ralph Svncelc Has an implementation 425 649-7036 plan Piaers Creek : Fecal C.olifarm.. ,approved by EPA Joan Nolan. 425-649-4425 Sammarnish River Dissolved Oxygen Field work starts' Ral h Svrrtcek — Temperature summer 2015:.. 425 6,49 7036 S^vramo Creek Fecal ColiForm Approved by EPA Ptalch Svri ek Has an implementation 425 6,49 7036 Nefland A Rating Figure 4. WRIA 8 TMDL Screen Capture Wetland name or number _ _ RATING SUMMARY - Western Washington Name of wetland (or ID #): Rated by S Corbin, (PWS) Wetland B Date of site visit: 7/6 and 7/7/15 Trained by Ecology?_X Yes No Date of training 10/09 and 5/ 14 HGM Class used for rating Depressional Wetland has multiple HGM classes?_Y X N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map Gong1P Earth OVERALL WETLAND CATEGORY III (based on functions X or special characteristics_) 1. Category of wetland based on FUNCTIONS Category I —Total score = 23 - 27 Category II — Total score = 20 - 22 X Category III — Total score = 16 - 19 Category IV — Total score = 9 - 15 Circle the appropriate ratings Site Potential H U L H M) L H M L Landscape Potential 8 M L H M L H M Value H M L H M L H L Score Based on Ratings 7 7 4 UM 2. Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H, H, M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L, L, L Wetland Rating System for Western WA: 2014 Update 1 Rating Form - Effective January 1, 2015 Wetland name or number B Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 1 Hydroperiods D 1.4, H 1.2 1 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 1 Boundary of area within 150 ft of the wetland (can be added to anotherfigure) D 2.2, D 5.2 1 Map of the contributing basin D 4.3, D 5.3 2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 4 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 5 Riverine Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Ponded depressions R 1.1 Boundary of area within 150 ft of the wetland (can be added to another figure) R 2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R 4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R 3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Fringe Wetlands Map'', of: To answer questions: Figure # Cowardin plant classes L 1.1, L 4.1, H 1.1, H 1.4 Plant cover of trees, shrubs, and herbaceous plants L 1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L 2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L 3.3 Slope Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Plant cover of dense trees, shrubs, and herbaceous plants S 1.3 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (can be added to figure above) S 4.1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S 3.3 Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number B HGM Classification of Wetlands in Western Washington 1. Are the water levels in the entire unit usually controlled by tides except during floods? C1C- go to 2 YES - the wetland class is Tidal Fringe - go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO - Saltwater Tidal Fringe (Estuarine) YES - Freshwater Tidal Fringe Ifyour wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. NO - go to 3 YES - The wetland class is Flats can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? _The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; _At least 30% of the open water area is deeper than 6.6 ft (2 m). NO - go to 4 YES - The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? The wetland is on a slope (slope can be very gradual), The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, The water leaves the wetland without being impounded. :NO: - :go: �to" DS YES - The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionally in very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, The overbank flooding occurs at least once every 2 years. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number B 0 - go to 6 YES - The wetland class is Riverine e-RiVerine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at sometime during the year? This means that any outlet, if present, is higher than the interior of the wetland. NO - go to 7 YES -The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area wit no no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. NO - go to 8 YES - The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE Ifyou are still unable to determine which of the above criteria apply to your wetland, or ifyou have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update 4 Rating Form - Effective January 1, 2015 Wetland name or number B :DEPRESSIONAL AND FLATS WETLANDS Water Quality Functions - Indicators that the site functions to improve Water quality D 1.0. Does the site have the potential to improve water quality? D 1.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression (QUESTION 7 on key) with no surface water leaving it (no outlet). points 3 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outlet. 3 points = 2 Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 1 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch. points = 1 D 1.2. The soil 2 in below the surface (or duff laver) is true clay or true organic (use NRCS definitions). Yes = 4 ko - 0 0 D 1.3. Characteristics and distribution of persistent plants (Emergent, Scrub -shrub, and/or Forested Cowardin classes): Wetland has persistent, ungrazed, plants > 95% of area points = 5 Wetland has persistent, ungrazed, plants > Yz of area points = 3 1 Wetland has persistent, ungrazed plants > 1/10 of area points Wetland has persistent, ungrazed plants <1/10 of area points = 0 D 1.4. Characteristics of seasonal ponding or inundation: This is the area that is ponded for at least 2 months. See description in manual. 4 Area seasonally ponded is > % total area of wetland .,poi�--4 Area seasonally ponded is > % total area of wetland points = 2 Area seasonally ponded is < X total area of wetland points = 0 Total for D 1 Add the points in the boxes above g Rating of Site Potential If score is:12-16 = H X 6-11 = M 0-5 = L Record the rating on the first page D 2.0. does the landscape have the potential to support the water quality function of the site? D 2.1. Does the wetland unit receive stormwater discharges? es No = 0 1 D 2.2. Is > 10% of the area within 150 ft of the wetland in land uses that generate pollutants? es - 1 No = 0 1 D 2.3. Are there septic systems within 250 ft of the wetland? Yes = 1 Vo = 0� 0 D 2.4. Are there other sources of pollutants coming into the wetland that are not listed in questions D -D 2.3? Source residential, do poopfrom do walkers es = No = o 1 Total for D 2 Add the points in the boxes above 3 Rating of Landscape Potential If score is: X 3 or 4 = H _1 or 2 = M _0 = L Record the rating on the first page D 3.0. Is the water quality improvement provided by the site valuable to society? D 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on t 303(d) list? Yes = 1 0 = 0 D 3.2. Is the wetland in a basin or sub -basin where an aquatic resource is on the 303(d) list? Yes = P No = 0 1 D 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality (answer YES if there is a TMDL for the basin in which the unit is found)? Yes = 2 0 = y 0 Total for D 3 Add the points in the boxes above 1 Rating of Value If score is: 2-4 = H X 1= M 0 = L Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Record the rating on the first page Wetland name or number B DEPRESSIGNAL AND FLATS WETLANDS Hydrologic Functions - Indicators that the site functions to reduce flooding and stream degradation D 4.0. Does the site have the potential to reduce flooding and erosion? D 4.1. Characteristics of surface water outflows from the wetland: Wetland is a depression or flat depression with no surface water leaving it (no outlet) points = 4 4 Wetland has an intermittently flowing stream or ditch, OR highly constricted permanently flowing outletpoints = 2 Wetland is a flat depression (QUESTION 7 on key), whose outlet is a permanently flowing ditch points = 1 Wetland has an unconstricted, or slightly constricted, surface outlet that is permanently flowing points = 0 D 4.2..Depth of storage during wet periods: Estimate the height of ponding above the bottom of the outlet. For wetlands with no outlet, measure from the surface of permanent water or if dry, the deepest part. Marks of poncling are 3 ft or more above the surface or bottom of outlet points = 7 Marks of poncling between 2 ft to < 3 ft from surface or bottom of outlet points = 5 Marks are at least 0.5 ft to < 2 ft from surface or bottom of outlet <15-o Dints �- 3 The wetland is a "headwater" wetland points = 3 Wetland is flat but has small depressions on the surface that trap water points = 1 Marks of poncling less than 0.5 ft (6 in) points = 0 D 4.3. Contribution of the wetland to storage in the watershed: Estimate the ratio of the area of upstream basin contributing surface water to the wetland to the area of the wetland unit itself. The area of the basin is less than 10 times the area of the unit points = 5 3 The area of the basin is 10 to 100 times the area of the unit Dints1_ The area of the basin is more than 100 times the area of the unit points = 0 Entire wetland is in the Flats class points = 5 Total for D 4 Add the points in the boxes above 10 Rating of Site Potential If score is: 12-16 = H X6-11 = M 0-5 = L Record the rating on the first page D 5.0. Does the landscape have the potential to support hydrologic functions of the site? D 5.1. Does the wetland receive stormwater discharges? Yes D1 No = 0 D 5.2. Is >10% of the area within 150 ft of the wetland in land uses that generate excess runoff? (�is: �_ No = 0 D 5.3. Is more than 25% of the contributing basin of the wetland covered with intensive human land uses (residential at >1 residence/ac, urban, commercial, agriculture, etc.)? es = No=O Total for D 5 Add the points in the boxes above 3 Rating of Landscape Potential If score is: X3 = H 1or2=M 0 = L Record the rating on the first page D 6.0. Are the hydrologic functions provided by the site valuable to society? D 6.1. The unit is in a landscape that has flooding problems. Choose the description that best matches conditions around the wetland unit being rated. Do not add points. Choose the highest score if more than one condition is met. The wetland captures surface water that would otherwise flow down -gradient into areas where flooding has damaged human or natural resources (e.g., houses or salmon redds): Flooding occurs in a sub -basin that is immediately down -gradient of unit. points = 2 Surface flooding problems are in a sub -basin farther down -gradient. (jiDints Flooding from groundwater is an issue in the sub -basin. points = 1 The existing or potential outflow from the wetland is so constrained by human or natural conditions that the water stored by the wetland cannot reach areas that flood. Explain why points = 0 There are no problems with flooding downstream of the wetland. points = 0 D 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? Yes = 2 (NO = 0) Total for D 6 Add the points in the boxes above Rating of Value If score is: 2-4=H X 1=M 0 = L Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Record the rating on the first page M Wetland name or number B H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of % ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. Aquatic bed 4 structures or more: points = 4 Emergent 3 structures: points = 2 Scrub -shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 XForested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if.• The Forested class has 3 out of 5 strata (canopy, sub -canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % ac to count (see text for descriptions of hydroperiods). Permanently flooded or inundated 4 or more types present: points = 3 X Seasonally flooded or inundated 3 types present: points = 2 Occasionally flooded or inundated 2 types present: points = 1 —Saturated only 1 type present: points = 0 Permanently flowing stream or river in, or adjacent to, the wetland Seasonally flowing stream in, or adjacent to, the wetland Lake Fringe wetland 2 points Freshwater tidal wetland 2 points H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ftz. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species 5 - 19 species < 5 species H 1.4. Interspersion of habitats points = 2 points = 1 points = 0 Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. 0 (::D (::0:) (*) (00) None = 0 points Low = 1 point Moderate = 2 points 0 All three diagrams in this row are HIGH = 3points Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 13 Wetland name or number B H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. X Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). *Standing snags (dbh > 4 in) within the wetland Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered 3 where wood is exposed) At least % ac of thin -stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg -laying by amphibians) X Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata) Total for H 1 Add the points in the boxes above 5 Rating of Site Potential If score is:_15-18 = H _7-14 = M X 0-6 = L Record the rating on the first page H 2.0. iiDoes the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 If total accessible habitat is: > 1/3 (33.3%) of 1 km Polygon points = 3 20-33% of 1 km Polygon points = 2 0 10-19% of 1 km Polygon points = 1 < 10% of 1 km Polygon points = 0 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 % Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in 1-3 patches points = 2 0 Undisturbed habitat 10-50% and > 3 patches points = 1 Undisturbed habitat < 10% of 1 km Polygon points = 0 H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use oints = (- 2) 2 <_ 50% of 1 km Polygon is high intensity points = 0 Total for H 2 Add the points in the boxes above -2 Rating of Landscape Potential If score is: 4-6 = H _1-3 = M X < 1= L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 It has 3 or more priority habitats within 100 m (see next page) It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) It is mapped as a location for an individual WDFW priority species It is a Wetland of High Conservation Value as determined by the Department of Natural Resources 1 It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 2 habitats 100 CpRjints = 1 or priority (listed on next page) within m Site does not meet any of the criteria above points = 0 Rating of Value If score is: _2 = H _1= M _0 = L Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 Record the rating on the first page 14 Wetland name or number B WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. f or access the list from here: hnail lwdfw.wa.gov/conservation hs list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. Old-growth/Mature forests: Old -growth west of Cascade crest - Stands of at least 2 tree species, forming a multi - layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests - Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old -growth; 80-200 years old west of the Cascade crest. Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 - see web link above). Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. Westside Prairies: Herbaceous, non -forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 - see web link above). Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report - see web link on previous page). Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. X Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland Rating System for Western WA: 2014 Update 15 Rating Form - Effective January 1, 2015 Wetland name or number B CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Category , Check off any criterio that ppply to the wetland: Circle the category when the appropriate criteria are met. SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? The dominant water regime is tidal, Vegetated, and With a salinity greater than 0.5 ppt Yes -Go to SC 1.1 = Not an estuarine wetla d SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? Yes = Category l No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) Cat. 1 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland has at least two of the following features: tidal channels, depressions with open water, or Cat. II contiguous freshwater wetlands. Yes = Category[ No = Category II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? Yes — Go to SC 2.2 No — Go to SC 2.3 Cat. I SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? Yes = Category I No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? htt�:J/wwwl.dnr.wa.Gov/nhp/refdesk/datasearc�wnh�wetiands. df Yes — Contact WNHP/WDNR and go to SC 2.4 No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? Yes = Category l No = Not a WHCV SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 in or more of the first 32 in of the soil profile? Yes — Go to SC 3.3 No — Go to SC 3.2 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less than 16 in deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating o or pond? Yes — Go to SC 3.3 No risnol a bo SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND at eas a 0% cover of plant species listed in Table 4? Yes = Is a Category I bog No — Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. Cat. I SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? Yes = Is a Category I bog No = Is not a bog Wetland Rating System for Western WA: 2014 Update 16 Rating Form — Effective January 1, 2015 Wetland name or number B SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife's forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. Old -growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi -layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that makeup the canopy have an average diameter (dbh) exceedin 21 in(53 cm) Yes = Category I o = Not a forested wetland for this sectio Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs tbmeasured near the bottom Cat. I Yes — Go to SC 5.1 No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing , and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). Cat. 11 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland is larger than 1/10 ac (4350 ft2) Yes = Category I No = Category II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: Long Beach Peninsula: Lands west of SR 103 Grayland-Westport: Lands west of SR 105 Cat I Ocean Shores-Copalis: Lands west of SR 115 and SR 109 Yes — Go to SC 6.1 (No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat function on n t e orm rakes ,H or H,H,M Cat. 11 for the three aspects of function)? Yes = Category[ No — Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? Yes = Category II No — Go to SC 6.3 Cat. III SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? Yes = Category III No = Category IV Cat. IV Category of wetland based on Special Characteristics N/A If you answered No for all types, enter "Not Applicable' on Summary Form Wetland Rating System for Western WA: 2014 Update 17 Rating Form — Effective January 1, 2015 Wetland B Rating Figure 1 . Cowardin Class, Hydroperiod, and Pollutant Generating Surface !!!!I file � i ���r r I CD 0 CD CD U) Lwyataa°- rlua ttv I�n�o°. ement 7aate- i"LralP ?r =-,ve vent Feala:ama�- FBI a' 9 ar- mmamish; The following table lid overviews information For water quality improvement projects (including total maximum daily loeds, or TIVIDI-s) for this water resource... inventory area (4WRIA). Please use links (where available) for more mfr rmatiort an project.,: - Counties ® <inq . Snohomish Waterbodyr Name Pollutants Status' -fMDL Lead Ballinger Labe, Total Phecphorus ._ Approved by EPA - Tricia Shobinm --_ 42E 649 7288 Pear -Evans Greek Basin Fecal Colrfa..rm ----- Approved by EPA Jean Nolari:--- --- -- 4..2.5 649-4-435 Dissolved'iOxygen+ Approved by EPA, ----- Temperature - Cottage Lake Total Fhcsphorus Approved by EPA Tricia Shablom Has an implementation 4.15-549 7288 plan' Issaquah Creek Basin Fecal Cohl'orm Approved by EPA Joan Nralan 425 649-4,425 Little Bear Creek - Fecal Colifearm — Approved by EPA Reph Svricek -- Tributaries. 425-649 7036 Trout Stream: Great Danei . Creek Cutthroat Greek North Greek Fecal ColiFcrm Approved by EPA Ralph Svncelc Has an implementation 425 649-7036 plan Piaers Creek : Fecal C.olifarm.. ,approved by EPA Joan Nolan. 425-649-4425 Sammarnish River Dissolved Oxygen Field work starts' Ral h Svrrtcek — Temperature summer 2015:.. 425 6,49 7036 S^vramo Creek Fecal ColiForm Approved by EPA Ralph Svri ek Has an implementation 425 6,49 7036 Wetland name or number C RATING SUMMARY - Western Washington Name of wetland (or ID #): Rated by S. Corbin (PWS' Wetland C Date of site visit: 7/6 and 7/7/15 Trained by Ecology? X Yes No Date of trainingl0/09 and 5/14 HGM Class used for rating Slope Wetland has multiple HGM classes?_Y X N NOTE: Form is not complete without the figures requested (figures can be combined). Source of base aerial photo/map Google Earth OVERALL WETLAND CATEGORY IV (based on functions or special characteristics_) 1. Category of wetland based on FUNCTIONS Category I —Total score = 23 - 27 Category II — Total score = 20 - 22 Category III — Total score = 16 - 19 X Category IV — Total score = 9 - 15 Site Potential H M H Landscape Potential H M L H Value H M L H Score Based on 5 Ratings Circle the appropriate ratings M H M L M L H M L 7M L H K ) L 4 1 4 1 13 2. Category based on SPECIAL CHARACTERISTICS of wetland CHARACTERISTIC CATEGORY Estuarine I II Wetland of High Conservation Value I Bog I Mature Forest I Old Growth Forest I Coastal Lagoon I II Interdunal I II III IV None of the above Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Score for each function based on three ratings (order of ratings is not important) 9 = H,H,H 8 = H, H, M 7 = H,H,L 7 = H,M,M 6 = H,M,L 6 = M,M,M 5 = H,L,L 5 = M,M,L 4 = M,L,L 3 = L, L, L 1 Wetland name or number C Maps and figures required to answer questions correctly for Western Washington Depressional Wetlands Map of: To answer questions: Figure # Cowardin plant classes D 1.3, H 1.1, H 1.4 Hydroperiods D 1.4, H 1.2 Location of outlet (can be added to map of hydroperiods) D 1.1, D 4.1 Boundary of area within 150 ft of the wetland (can be added to anotherfigure) D 2.2, D 5.2 Map of the contributing basin D 4.3, D 5.3 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) D 3.1, D 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) D 3.3 Riverine Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 Hydroperiods H 1.2 Ponded depressions R 1.1 Boundary of area within 150 ft of the wetland (can be added to another figure) R 2.4 Plant cover of trees, shrubs, and herbaceous plants R 1.2, R 4.2 Width of unit vs. width of stream (can be added to another figure) R 4.1 Map of the contributing basin R 2.2, R 2.3, R 5.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) R 3.1 Screen capture of list of TMDLs for WRIA in which unit is found (from web) R 3.2, R 3.3 Lake Fringe Wetlands Map'', of: To answer questions: Figure # Cowardin plant classes L 1.1, L 4.1, H 1.1, H 1.4 Plant cover of trees, shrubs, and herbaceous plants L 1.2 Boundary of area within 150 ft of the wetland (can be added to another figure) L 2.2 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 Screen capture of map of 303(d) listed waters in basin (from Ecology website) L 3.1, L 3.2 Screen capture of list of TMDLs for WRIA in which unit is found (from web) L 3.3 Slope Wetlands Map of: To answer questions: Figure Cowardin plant classes H 1.1, H 1.4 1 Hydroperiods H 1.2 1 Plant cover of dense trees, shrubs, and herbaceous plants S 1.3 1 Plant cover of dense, rigid trees, shrubs, and herbaceous plants (can be added to figure above) S 4.1 1 Boundary of 150 ft buffer (can be added to another figure) S 2.1, S 5.1 1 1 km Polygon: Area that extends 1 km from entire wetland edge - including polygons for accessible habitat and undisturbed habitat H 2.1, H 2.2, H 2.3 2 Screen capture of map of 303(d) listed waters in basin (from Ecology website) S 3.1, S 3.2 3 Screen capture of list of TMDLs for WRIA in which unit is found (from web) S 3.3 4 Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number C HGM Classification of Wetlands in Western Washington 1. Are -the -water levels in the entire unit usually controlled by tides except during floods? (NO - go to 2 YES - the wetland class is Tidal Fringe - go to 1.1 1.1 Is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? NO - Saltwater Tidal Fringe (Estuarine) YES - Freshwater Tidal Fringe Ifyour wetland can be classified as a Freshwater Tidal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is an Estuarine wetland and is not scored. This method cannot be used to score functions for estuarine wetlands. 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. NO - go to 3 *1 YES - The wetland class is Flats nd can be classified as a Flats wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet all of the following criteria? _The vegetated part of the wetland is on the shores of a body of permanent open water (without any plants on the surface at any time of the year) at least 20 ac (8 ha) in size; _At least . 30% of the open water area is deeper than 6.6 ft (2 m). _ (: NO - go to 4 YES - The wetland class is Lake Fringe (Lacustrine Fringe) 4. Does t e entire wetland unit meet all of the following criteria? The wetland is on a slope (slope can be very gradual), The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks, The water leaves the wetland without being impounded. NO - go to 5 YES - The wetland class is Slope NOTE: Surface water does not pond in these type of wetlands except occasionaffy n very small and shallow depressions or behind hummocks (depressions are usually <3 ft diameter and less than 1 ft deep). 5. Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river, The overbank flooding occurs at least once every 2 years. Wetland Rating System for Western WA: 2014 Update Rating Form - Effective January 1, 2015 Wetland name or number C NO - go to 6 YES - The wetland class is Riverine NOTE: The Riverine unit can contain depressions that are filled with water when the river is not flooding 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at sometime during the year? This means that any outlet, if present, is higher than the interior of the wetland. NO-goto7 YES - The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding? The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ME= YES - The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM classes. For example, seeps at the base of a slope may grade into a rverine floodplain, or a small stream within a Depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within the wetland unit being scored. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the HGM class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. HGM classes within the wetland unit being rated HGM class to use in rating Slope + Riverine Riverine Slope + Depressional Depressional Slope + Lake Fringe Lake Fringe Depressional + Riverine along stream within boundary of depression Depressional Depressional + Lake Fringe Depressional Riverine + Lake Fringe Riverine Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE Ifyou are still unable to determine which of the above criteria apply to your wetland, or ifyou have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating System for Western WA: 2014 Update 4 Rating Form - Effective January 1, 2015 Wetland name or number C S 1.1. Characteristics of the average slope of the wetland: (a 1% slope has a 1 ft vertical drop in elevation for every 100 ft of horizontal distance) Slope is 1% or less points = 3 0 Slope is > 1%-2% points = 2 Slope is > 2%-5% points = 1 Slope is greater than 5% points = 0 S 1.2. The soil 2 in below the surface (or duff layer) is true clay or true organic (use MRCS definitions): Yes = 3 No = 0 0 S 1.3. Characteristics of the plants in the wetland that trap sediments and pollutants: Choose the points appropriate for the description that best fits the plants in the wetland. Dense means you have trouble seeing the soil surface (>75% cover), and uncut means not grazed or mowed and plants are higher than 6 in. Dense, uncut, herbaceous plants > 90% of the wetland area points = 6 0 Dense, uncut, herbaceous plants > Y, of area points = 3 Dense, woody, plants > Y, of area points = 2 Dense, uncut, herbaceous plants > % of area points = 1 Does not meet any of the criteria above for plants points = 0 Total for S 1 Add the points in the boxes above 0 Rating of Site Potential If score is:_12 = H _6-11= M X0-5 = L Record the rating on the first page S 2.0. Does the landscape have the potential to support the water quality function of the site? S 2.1. Is > 10% of the area within 150 ft on the uphill side of the wetland in land uses that generate pollutants? Yes = 1 No = 0 0 S 2.2. Are there other sources of pollutants coming into the wetland that are not listed in question S 2.1? Other sources — Dog walker"og poopYes = 1 No = 0 1 Total for S 2 Add the points in the boxes above I Rating of Landscape Potential If score is: X1-2 = M _0 = L Record the rating on the first page S 3.0. Is the water quality improvement provided by the site valuable to society? S 3.1. Does the wetland discharge directly (i.e., within 1 mi) to a stream, river, lake, or marine water that is on the 303(d) list? Yes = 1 No = 0 0 S 3.2. Is the wetland in a basin or sub -basin where water quality is an issue? At least one aquatic resource in the basin is on the 303(d) list. Yes = 1 No = 0 I S 3.3. Has the site been identified in a watershed or local plan as important for maintaining water quality? Answer YES if there is a TMDL for the basin in which unit is found. Yes = 2 No = 0 0 — Total for S 3 Add the points in the boxes above 1 Rating of Value If score is:2-4 = H _X1= M _0 = L Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 Record the rating on the first page 11 Wetland name or number C S 4.1. Characteristics of plants that reduce the velocity of surface flows during storms: Choose the points appropriate for the description that best fits conditions in the wetland. Stems of plants should be thick enough (usually > 118 in), or dense enough, to remain erect during surface flows. Dense, uncut, rigid plants cover > 90% of the area of the wetland points = 1 All other conditions points = 0 Rating of Site Potential If score is:_1= M _X_0 = L Record the rating on the first page S 5.0. Does the landscape have the potential to support the hydrologic functions of the site? S 5.1. Is more than 25% of the area within 150 ft upslope of wetland in land uses or cover that generate excess surface runoff? Yes = 1 No = 0 0 Rating of Landscape Potential If score is: _1= M _X0 = L Record the rating on the first page S 6.0. Are the hydrologic functions provided by the site valuable to society? S 6.1. Distance to the nearest areas downstream that have flooding problems: The sub -basin immediately down -gradient of site has flooding problems that result in damage to human or natural resources (e.g., houses or salmon redds) points = 2 1 Surface flooding problems are in a sub -basin farther down -gradient points = 1 No flooding problems anywhere downstream points = 0 S 6.2. Has the site been identified as important for flood storage or flood conveyance in a regional flood control plan? Yes=2 No=O 0 Total for S 6 Add the points in the boxes above 1 Rating of Value If score is: _2-4 = H X 1= M _0 = L Record the rating on the first page NOTES and FIELD OBSERVATIONS: Wetland Rating System for Western WA: 2014 Update 12 Rating Form — Effective January 1, 2015 Wetland name or number C H 1.1. Structure of plant community: Indicators are Cowardin classes and strata within the Forested class. Check the Cowardin plant classes in the wetland. Up to 10 patches may be combined for each class to meet the threshold of % ac or more than 10% of the unit if it is smaller than 2.5 ac. Add the number of structures checked. Aquatic bed 4 structures or more: points = 4 X Emergent 3 structures: points = 2 Scrub -shrub (areas where shrubs have > 30% cover) 2 structures: points = 1 Forested (areas where trees have > 30% cover) 1 structure: points = 0 If the unit has a Forested class, check if.• The Forested class has 3 out of 5 strata (canopy, sub -canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the Forested polygon H 1.2. Hydroperiods Check the types of water regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % ac to count (see text for descriptions of hydroperiods). Permanently flooded or inundated 4 or more types present: points = 3 Seasonally flooded or inundated 3 types present: points = 2 Occasionally flooded or inundated 2 types present: points = 1 XSaturated only 1 type present: points = 0 Permanently flowing stream or river in, or adjacent to, the wetland Seasonally flowing stream in, or adjacent to, the wetland Lake Fringe wetland 2 points Freshwater tidal wetland 2 points H 1.3. Richness of plant species Count the number of plant species in the wetland that cover at least 10 ftz. Different patches of the same species can be combined to meet the size threshold and you do not have to name the species. Do not include Eurasian milfoil, reed canarygrass, purple loosestrife, Canadian thistle If you counted: > 19 species 5 - 19 species < 5 species H 1.4. Interspersion of habitats points = 2 points = 1 points = 0 Decide from the diagrams below whether interspersion among Cowardin plants classes (described in H 1.1), or the classes and unvegetated areas (can include open water or mudflats) is high, moderate, low, or none. If you have four or more plant classes or three classes and open water, the rating is always high. C 0 CD 0 None = 0 points Low = 1 point Moderate = 2 points All three diagrams in this row are HIGH = 3points Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 13 Wetland name or number C H 1.5. Special habitat features: Check the habitat features that are present in the wetland. The number of checks is the number of points. Large, downed, woody debris within the wetland (> 4 in diameter and 6 ft long). Standing snags (dbh > 4 in) within the wetland Undercut banks are present for at least 6.6 ft (2 m) and/or overhanging plants extends at least 3.3 ft (1 m) over a stream (or ditch) in, or contiguous with the wetland, for at least 33 ft (10 m) Stable steep banks of fine material that might be used by beaver or muskrat for denning (> 30 degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet weathered where wood is exposed) 1 At least % ac of thin -stemmed persistent plants or woody branches are present in areas that are permanently or seasonally inundated (structures for egg -laying by amphibians) X Invasive plants cover less than 25% of the wetland area in every stratum of plants (see H 1.1 for list of strata) Total for H 1 Add the points in the boxes above 2 Rating of Site Potential If score is:_15-18 = H _7-14 = M X0-6 = L Record the rating on the first page H 2.0. iiDoes the landscape have the potential to support the habitat functions of the site? H 2.1. Accessible habitat (include only habitat that directly abuts wetland unit). Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 If total accessible habitat is: > 1/3 (33.3%) of 1 km Polygon points = 3 20-33% of 1 km Polygon points = 2 0 10-19% of 1 km Polygon points = 1 < 10% of 1 km Polygon points = 0 H 2.2. Undisturbed habitat in 1 km Polygon around the wetland. Calculate: % undisturbed habitat 0 + [(% moderate and low intensity land uses)/2] 0 = 0 % Undisturbed habitat > 50% of Polygon points = 3 Undisturbed habitat 10-50% and in 1-3 patches points = 2 0 Undisturbed habitat 10-50% and > 3 patches points = 1 Undisturbed habitat < 10% of 1 km Polygon points = 0 H 2.3. Land use intensity in 1 km Polygon: If > 50% of 1 km Polygon is high intensity land use points = (- 2) -2 <— 50% of 1 km Polygon is high intensity points = 0 Total for H 2 Add the points in the boxes above -2 Rating of Landscape Potential If score is: 4-6 = H _1-3 = M X< 1= L Record the rating on the first page H 3.0. Is the habitat provided by the site valuable to society? H 3.1. Does the site provide habitat for species valued in laws, regulations, or policies? Choose only the highest score that applies to the wetland being rated. Site meets ANY of the following criteria: points = 2 It has 3 or more priority habitats within 100 m (see next page) It provides habitat for Threatened or Endangered species (any plant or animal on the state or federal lists) It is mapped as a location for an individual WDFW priority species It is a Wetland of High Conservation Value as determined by the Department of Natural Resources It has been categorized as an important habitat site in a local or regional comprehensive plan, in a Shoreline Master Plan, or in a watershed plan Site has 1 or 2 priority habitats (listed on next page) within 100 m points = 1 Site does not meet any of the criteria above points = 0 Rating of Value If score is:_2 = H X 1= M _0 = L Wetland Rating System for Western WA: 2014 Update Rating Form — Effective January 1, 2015 Record the rating on the first page 14 Wetland name or number C WDFW Priority Habitats Priority habitats listed by WDFW (see complete descriptions of WDFW priority habitats, and the counties in which they can be found, in: Washington Department of Fish and Wildlife. 2008. Priority Habitat and Species List. Olympia, Washington. 177 pp. f or access the list from here: hnail lwdfw.wa.gov/conservation hs list/) Count how many of the following priority habitats are within 330 ft (100 m) of the wetland unit: NOTE: This question is independent of the land use between the wetland unit and the priority habitat. Aspen Stands: Pure or mixed stands of aspen greater than 1 ac (0.4 ha). Biodiversity Areas and Corridors: Areas of habitat that are relatively important to various species of native fish and wildlife (full descriptions in WDFW PHS report). Herbaceous Balds: Variable size patches of grass and forbs on shallow soils over bedrock. Old-growth/Mature forests: Old -growth west of Cascade crest - Stands of at least 2 tree species, forming a multi - layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha ) > 32 in (81 cm) dbh or > 200 years of age. Mature forests - Stands with average diameters exceeding 21 in (53 cm) dbh; crown cover may be less than 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old -growth; 80-200 years old west of the Cascade crest. Oregon White Oak: Woodland stands of pure oak or oak/conifer associations where canopy coverage of the oak component is important (full descriptions in WDFW PHS report p. 158 - see web link above). Riparian: The area adjacent to aquatic systems with flowing water that contains elements of both aquatic and terrestrial ecosystems which mutually influence each other. Westside Prairies: Herbaceous, non -forested plant communities that can either take the form of a dry prairie or a wet prairie (full descriptions in WDFW PHS report p. 161 - see web link above). Instream: The combination of physical, biological, and chemical processes and conditions that interact to provide functional life history requirements for instream fish and wildlife resources. Nearshore: Relatively undisturbed nearshore habitats. These include Coastal Nearshore, Open Coast Nearshore, and Puget Sound Nearshore. (full descriptions of habitats and the definition of relatively undisturbed are in WDFW report - see web link on previous page). Caves: A naturally occurring cavity, recess, void, or system of interconnected passages under the earth in soils, rock, ice, or other geological formations and is large enough to contain a human. Cliffs: Greater than 25 ft (7.6 m) high and occurring below 5000 ft elevation. Talus: Homogenous areas of rock rubble ranging in average size 0.5 - 6.5 ft (0.15 - 2.0 m), composed of basalt, andesite, and/or sedimentary rock, including riprap slides and mine tailings. May be associated with cliffs. X Snags and Logs: Trees are considered snags if they are dead or dying and exhibit sufficient decay characteristics to enable cavity excavation/use by wildlife. Priority snags have a diameter at breast height of > 20 in (51 cm) in western Washington and are > 6.5 ft (2 m) in height. Priority logs are > 12 in (30 cm) in diameter at the largest end, and > 20 ft (6 m) long. Note: All vegetated wetlands are by definition a priority habitat but are not included in this list because they are addressed elsewhere. Wetland Rating System for Western WA: 2014 Update 15 Rating Form - Effective January 1, 2015 Wetland name or number C CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Wetland Type Category Check off any eriterio that ppply to the wetland: Circle the category when the appropriate criteria are met. SC 1.0. Estuarine wetlands Does the wetland meet the following criteria for Estuarine wetlands? The dominant water regime is tidal, Vegetated, and With a salinity greater than 0.5 ppt Yes -Go to SC 1.1 No= Not an estuarine wetland SC 1.1. Is the wetland within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Environmental, or Scientific Reserve designated under WAC 332-30-151? Yes = Category l No - Go to SC 1.2 Cat. I SC 1.2. Is the wetland unit at least 1 ac in size and meets at least two of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing, and has less than 10% cover of non-native plant species. (If non-native species are Spartina, see page 25) Cat. 1 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland has at least two of the following features: tidal channels, depressions with open water, or Cat. II contiguous freshwater wetlands. Yes = Category[ No = Category II SC 2.0. Wetlands of High Conservation Value (WHCV) SC 2.1. Has the WA Department of Natural Resources updated their website to include the list of Wetlands of High Conservation Value? Yes — Go to SC 2.2 No — Go to SC 2.3 Cat. I SC 2.2. Is the wetland listed on the WDNR database as a Wetland of High Conservation Value? Yes = Category I No = Not a WHCV SC 2.3. Is the wetland in a Section/Township/Range that contains a Natural Heritage wetland? htt�:J/wwwl.dnr.wa.Gov/nhp/refdesk/datasearc�wnh�wetiands. df Yes — Contact WNHP/WDNR and go to SC 2.4 No = Not a WHCV SC 2.4. Has WDNR identified the wetland within the S/T/R as a Wetland of High Conservation Value and listed it on their website? Yes = Category l No = Not a WHCV SC 3.0. Bogs Does the wetland (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the key below. If you answer YES you will still need to rate the wetland based on its functions. SC 3.1. Does an area within the wetland unit have organic soil horizons, either peats or mucks, that compose 16 in or more of the first 32 in of the soil profile? Yes — Go to SC 3.3 No — Go to SC 3.2 SC 3.2. Does an area within the wetland unit have organic soils, either peats or mucks, that are less than 16 in deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on top of a lake or pond? Yes — Go to SC 3.3 No = Is not a bog SC 3.3. Does an area with peats or mucks have more than 70% cover of mosses at ground level, AND at least a 30% cover of plant species listed in Table 4? Yes = Is a Category I bog No — Go to SC 3.4 NOTE: If you are uncertain about the extent of mosses in the understory, you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16 in deep. If the pH is less than 5.0 and the plant species in Table 4 are present, the wetland is a bog. Cat. I SC 3.4. Is an area with peats or mucks forested (> 30% cover) with Sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Engelmann spruce, or western white pine, AND any of the species (or combination of species) listed in Table 4 provide more than 30% of the cover under the canopy? Yes = Is a Category I bog No = Is not a bog Wetland Rating System for Western WA: 2014 Update 16 Rating Form — Effective January 1, 2015 Wetland name or number SC 4.0. Forested Wetlands Does the wetland have at least 1 contiguous acre of forest that meets one of these criteria for the WA Department of Fish and Wildlife's forests as priority habitats? If you answer YES you will still need to rate the wetland based on its functions. Old -growth forests (west of Cascade crest): Stands of at least two tree species, forming a multi -layered canopy with occasional small openings; with at least 8 trees/ac (20 trees/ha) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 in (81 cm) or more. Mature forests (west of the Cascade Crest): Stands where the largest trees are 80- 200 years old OR the species that make up the canopy have an average diameter (dbh) exceeding 21 in (53 cm). Yes = Category I No = Not a forested wetland for this section Cat. I SC 5.0. Wetlands in Coastal Lagoons Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks The lagoon in which the wetland is located contains ponded water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) Cat. I Yes — Go to SC 5.1 No = Not a wetland in a coastal lagoon SC 5.1. Does the wetland meet all of the following three conditions? The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of aggressive, opportunistic plant species (see list of species on p. 100). Cat. 11 At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un-grazed or un- mowed grassland. The wetland is larger than 1/10 ac (4350 ft2) Yes = Category I No = Category II SC 6.0. Interdunal Wetlands Is the wetland west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? If you answer yes you will still need to rate the wetland based on its habitat functions. In practical terms that means the following geographic areas: Long Beach Peninsula: Lands west of SR 103 Grayland-Westport: Lands west of SR 105 Cat I Ocean Shores-Copalis: Lands west of SR 115 and SR 109 Yes — Go to SC 6.1 No = not an interdunal wetland for rating SC 6.1. Is the wetland 1 ac or larger and scores an 8 or 9 for the habitat functions on the form (rates H,H,H or H,H,M Cat. 11 for the three aspects of function)? Yes = Category[ No — Go to SC 6.2 SC 6.2. Is the wetland 1 ac or larger, or is it in a mosaic of wetlands that is 1 ac or larger? Yes = Category II No — Go to SC 6.3 Cat. III SC 6.3. Is the unit between 0.1 and 1 ac, or is it in a mosaic of wetlands that is between 0.1 and 1 ac? Yes = Category III No = Category IV Cat. IV Category of wetland based on Special Characteristics If you answered No for all types, enter "Not Applicable' on Summary Form Wetland Rating System for Western WA: 2014 Update 17 Rating Form — Effective January 1, 2015 Ire ��ir� i� 1. i �I ri� Il ��irtc � Lwyataa°- rlua ttv I�n�o°. ement 7aate- i"LralP ?r =-,ve vent Feala:ama�- FBI a' 9 ar- mmamish; The following table lid overviews information For water quality improvement projects (including total maximum daily loeds, or TIVIDI-s) for this water resource... inventory area (4WRIA). Please use links (where available) for more mfr rmatiort an project.,: - Counties ® <inq . Snohomish Waterbodyr Name Pollutants Status' -fMDL Lead Ballinger Labe, Total Phecphorus ._ Approved by EPA - Tricia Shobinm --_ 42E 649 7288 Pear -Evans Greek Basin Fecal Colrfa..rm ----- Approved by EPA Jean Nolari:--- --- -- 4..2.5 649-4-435 Dissolved'iOxygen+ Approved by EPA, ----- Temperature - Cottage Lake Total Fhcsphorus Approved by EPA Tricia Shablom Has an implementation 4.15-549 7288 plan' Issaquah Creek Basin Fecal Cohl'orm Approved by EPA Joan Nralan 425 649-4,425 Little Bear Creek - Fecal Colifearm — Approved by EPA Reph Svricek -- Tributaries. 425-649 7036 Trout Stream: Great Danei . Creek Cutthroat Greek North Greek Fecal ColiFcrm Approved by EPA Ralph Svncelc Has an implementation 425 649-7036 plan Piaers Creek : Fecal C.olifarm.. ,approved by EPA Joan Nolan. 425-649-4425 Sammarnish River Dissolved Oxygen Field work starts' Ral h svr'tcek — Temperature summer 2015:.. 425 6,49 7036 S^vramo Creek Fecal ColiForm Approved by EPA Ptalch Svri ek Has an implementation 425 6,49 7036 Nefland C Rating Figure :. WRIA 8 TMDL Screen Shot SHANNON ILA APPENDIX D IMPORTANT INFORMATION ABOUT YOUR WETLAND DELINEATION/MITIGATION AND/OR STREAM CLASSIFICATION REPORT 21-1-22082-002 SHANNON & WILSON, INC. Attachment to and part of Report 21-1-20581-010 Geotechnical and Environmental Consultants Date: September 15, 2015 To: Ms. Taine Wilton Edmonds School District #15 AND/OR.MPORTANT INFORMATION ABOUT YOUR WETLAND DELINEATION/MITIGATION .M CLASSIFICATION REP• ■ /_1VITiAlw_1211%.]11:1A1T,I:1=1001AARN 4-111&114exel Z 1;J ZT0111x01f-ia=191II «lyl:91t011;I Wetland delineation/mitigation and stream classification reports are based on a unique set of project -specific factors. These typically include the general nature of the project and property involved, its size, and its configuration; historical use and practice; the location of the project on the site and its orientation; and the level of additional risk the client assumed by virtue of limitations imposed upon the exploratory program. The jurisdiction of any particular wetland/stream is determined by the regulatory authority(s) issuing the permit(s). As a result, one or more agencies will have jurisdiction over a particular wetland or stream with sometimes confusing regulations. It is necessary to involve a consultant who understands which agency(s) has jurisdiction over a particular wetland/stream and what the agency(s) permitting requirements are for that wetland/stream. To help reduce or avoid potential costly problems, have the consultant determine how any factors or regulations (which can change subsequent to the report) may affect the recommendations. Unless your consultant indicates otherwise, your report should not be used: ► If the size or configuration of the proposed project is altered. ► If the location or orientation of the proposed project is modified. ► If there is a change of ownership. ► For application to an adjacent site. P. For construction at an adjacent site or on site. ► Following floods, earthquakes, or other acts of nature. Wetland/stream consultants cannot accept responsibility for problems that may develop if they are not consulted after factors considered in their reports have changed. Therefore, it is incumbent upon you to notify your consultant of any factors that may have changed prior to submission of our final report. Wetland boundaries identified and stream classifications made by Shannon & Wilson are considered preliminary until validated by the U.S. Army Corps of Engineers (Corps) and/or the local jurisdictional agency. Validation by the regulating agency(s) provides a certification, usually written, that the wetland boundaries verified are the boundaries that will be regulated by the agency(s) until a specified date, or until the regulations are modified, and that the stream has been properly classified. Only the regulating agency(s) can provide this certification. MOST WETLAND/STREAM "FINDINGS" ARE PROFESSIONAL ESTIMATES. Site exploration identifies wetland/stream conditions at only those points where samples are taken and when they are taken, but the physical means of obtaining data preclude the determination of precise conditions. Consequently, the information obtained is intended to be sufficiently accurate for design, but is subject to interpretation. Additionally, data derived through sampling and subsequent laboratory testing are extrapolated by the consultant who then renders an opinion about overall conditions, the likely reaction to proposed construction activity, and/or appropriate design. Even under optimal circumstances, actual conditions may differ from those thought to exist because no consultant, no matter how qualified, and no exploration program, no matter how comprehensive, can reveal what is hidden by earth, rock, and time. Nothing can be done to prevent the unanticipated, but steps can be taken to help reduce their impacts. For this reason, most experienced owners retain their consultants through the construction or wetland mitigation/stream classification stage to identify variances, to conduct additional evaluations that may be needed, and to recommend solutions to problems encountered on site. Page 1 of 1/2015 Since natural systems are dynamic systems affected by both natural processes and human activities, changes in wetland boundaries and stream conditions may be expected. Therefore, delineated wetland boundaries and stream classifications cannot remain valid for an indefinite period of time. The Corps typically recognizes the validity of wetland delineations for a period of five years after completion. Some city and county agencies recognize the validity of wetland delineations for a period of two years. If a period of years have passed since the wetland/stream report was completed, the owner is advised to have the consultant reexamine the wetland/stream to determine if the classification is still accurate. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or water fluctuations may also affect conditions and, thus, the continuing adequacy of the wetland/stream report. The consultant should be kept apprised of any such events and should be consulted to determine if additional evaluation is necessary. THE WETLAND/STREAM REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when plans are developed based on misinterpretation of a wetland/stream report. To help avoid these problems, the consultant should be retained to work with other appropriate professionals to explain relevant wetland, stream, geological, and other findings, and to review the adequacy of plans and specifications relative to these issues. DATA FORMS SHOULD NOT BE SEPARATED FROM THE REPORT. Final data forms are developed by the consultant based on interpretation of field sheets (assembled by site personnel) and laboratory evaluation of field samples. Only final data forms customarily are included in a report. These data forms should not, under any circumstances, be drawn for inclusion in other drawings because drafters may commit errors or omissions in the transfer process. Although photographic reproduction eliminates this problem, it does nothing to reduce the possibility of misinterpreting the forms. When this occurs, delays, disputes, and unanticipated costs are frequently the result. To reduce the likelihood of data form misinterpretation, contractors, engineers, and planners should be given ready access to the complete report. Those who do not provide such access may proceed under the mistaken impression that simply disclaiming responsibility for the accuracy of information always insulates them from attendant liability. Providing the best available information to contractors, engineers, and planners helps prevent costly problems and the adversarial attitudes that aggravate them to a disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY. Because a wetland delineation/stream classification is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent this problem, consultants have developed a number of clauses for use in written transmittals. These are not exculpatory clauses designed to foist the consultant's liabilities onto someone else; rather, they are definitive clauses that identify where the consultant's responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of these definitive clauses are likely to appear in your report, and you are encouraged to read them closely. Your consultant will be pleased to give full and frank answers to your questions. THERE MAY BE OTHER STEPS YOU CAN TAKE TO REDUCE RISK. Your consultant will be pleased to discuss other techniques or designs that can be employed to mitigate the risk of delays and to provide a variety of alternatives that may be beneficial to your project. Contact your consultant for further information. Page 2 of 2 1/2015 VVefl8Od HVdrODe[iOd/\O@lVSiS ?/ Figure F1:Wetland BExisting Conditions Y Figure F2:Wetland BProposed Conditions Y HydnnpohndCa|ou|adona MadmnaSnhoo —EdmondsScboo District 0 50 100 200 O 1 inch = 100 feet Project Title MADRONA K-8 Client MAHLUM ARCHITECTS Drawing Title WETLAND B EXISTING CONDITIONS Drawing Reference F1 1" = 100' 1601 Sth Avenue, Suite 1600 Seattle, WA 98101 Dot; Drawn/Ck'd By 20662 5822 — . w.k . pff.co. 1/28/2016 SJ/CB p M: dap H � Y: ..o`"' ,y.g iµz�„N „pkm si 9 y t,� :� '%`a ,;a �r §r � . �p � R➢ r r� aSa; j R T'— ({A§ P 9, �pk�yx.��ppB X d 9; p E # }k, t # k ¢L i t r ,y. x i* 6 x r f ' f R �. � e a , � k p i , { a �- � R tm i� a t� "a �" r', ,xr' x r .,o , } ft t. r� �t I W *i F, $ � { r t � a :t £ t t �» r r s a t ' � s .a. >arr rrr.. { G ¢ " ' P ` Y m a . _ ^. ,: # ,e"', t .J z ;...:. ,.r s.m , € r`'t , , x e < r . �' .,". ° ,,,""` r rf a{ <Y ft � _�. r a ,,,,,, <.,, r, t{ g+n , :„ .a , , d :.f s .:,r y e rW; .x,ad ra.' mm ,.r•::...... ,. , ..,<. .,. a ;r = Y } , u , = a j_x" a. .n• .w „i,* ,.., µ :.,� ^^„° ,:.ar re, ., :.'� 'kt$+'=',r�%R:gi .x, ., Y ' S: b a v ="„ "-_'" -` .aw•_.«', _.t.,.,,»+�..:w'- ..::'�',v:' �,:h r x;- t ..0 ."r r .. , r A t.. , s." t ...<. , , ^ , Y ,, t , r:.. „x < ,., W •• ,.;,," , w, , Y,;li[Y e t. TM ,m. 8 x E , • '°: a »:; ,>' .z's,:+d'..xw, r`u ..>»:: ,_.: .,..,-'"r�.:..,. ,t .., ..... ''+' is'tw zL' v e t a' i• u :, . 4: x '� G 9 4 y[t*" r r F ¢j s ab `H i :i. # *. , ,.. tt a e„ .sft .s n ., n.. ,. .. <,,. :. ,+ }t. 1 r•, ,`✓, ;;at,n.. ,,. ,. .: :'4 r, s = a•• .�:YAW a , r , ' h rr � _ t s e „ta � t , , ." , � a,. ,�:: :.1 -« ,xe.I dr, n,.. ,:: B , ..,. x ,.:..-..,.,. ,x 7 x nr r, , :� a'... as �. ».. '1 ,::., , >m .,., .. , ,... , , , > rcP , „r. :.,, . +. f „ ., , ,+, ..... ,,..... ....,.., mr" ,r r • a " ,,, r: t _.. tYh # ,.. .. e ., . �� ;z s , ,. ,,. z e , s 9 d ,s r ° n, » s 3 r,� � t`: < r .. .. ., .. r t¢,.,..,»„, � . <,,.. �'. ,£ T •, ..,.. .zy, (z4 aS r 7 M„ .q f; x, , , .Cn,, ::. ... .. ;., �s ., ka i . €` f s "t -r ,wr' :P:r , ® .. ,, ', ., , ,., ,.. ,. °, , ..:. 'f a» f.,..:• •- `� : .;. �,rr. � �;..:, < , , ,. ,a ..<_. '»`• :,.. ,T n ,> . f• i1 rxi .,_. at ,xi. P,. .. ,„,. a. -.a.,:.». .,.. , :, ,✓ a ....t rs M , ,. ,.. ,.: ,r3 'i. C .. , . .. .....,. e. f "yvyn,,r. ,.... .. , ... <..: ,".. ,< _m... r y,.' ... •` ?, ,.. Sk_., � , 5.,., < .« ➢ .. „• ., a , .., �,, ..: 7x �, $ . µ r .. .Sw , .5 <,,....,.. .... _.,;, f „_,. J ,,:.. .7<,+ I k t ✓� ,.„„c . ,< ,. t,"r ,,.,, ..:.. +, ::,-a,,,<'i. .,, ..,.. Y 7 :::. » rnr t R t :a „ ,. ,,. -.. tr` , '".... .... .. ... .. ... ... ....� ,., ..,.....:: „ Ys" ;";', q,{•., t ,,,... t4a 4., ., ,:.: r,.. was,:v 'l�,a .,.I :, „. ,>,. ,. - ., .:. ..... ...... r.,,. .._, .. ... ..,, ,.:: ..... ,,,..,. ..., ,.., ,r-` ,xm .<,....: ,... ,., ... ...,,.. ' ,r , y_µ ,t-:xz , r, :Y r Sti °' _, ..:,.. ',t.,._.:.. . ..... ...... .:: ` a WETLAND B .r WETLAND B ♦ 1 { d ,1 NORTH BASIN ,§ SOUTH BASIN m a►,.,, 5 is Ms h ,.,,,,,.,. .,.. f if3,ft , ,'"., x, , ,,.„,,.,.. #r , "=2re;'",. ..,. t,..vr ry ,,, x f '} }, .Y a., n Y4';r D ., ..., r. 'i. ,. , „ ...r.... 7, ::rU, -., _.< ... ... ,. „,. }mft , to {.......,, 3 i, ,,. .,,. - f ,{ _ , bs s .S, .., ,1 .., », „§,., _. »„ ✓_ , .u, s+++;; =r; ', , .r ,Y, ...::,^ ... SY�' ..,k.r,„., „". ,.. 'fd s r ,.ff , ... x t ..x, n { r , < ,....,.. ......, L ,,,,.;:< rx .,.... ...,< . ..:::: .... ..._ , .. x .,7 „,... r ,., r .. ,, .. ,, r x, .. .;;f .. +.:.. .., ,. :-... x. a,. <, a "f. ., :.. i'.�•J., ,r, , r .,. .... rr.:.. '4€`tx _,, :.. .. ,.. ... ,..,, x. jY..- e..V„ ......: ...., ,,, t ,.1-,.., .�,...., ..�x%f t....... .. ,.., a r ,.,..,.,. ,, •+.,4 .4 ..,. t,.. , n.. s e ., .. _ :,.. ., .._..... ,. :x.ss». „} hYi `'r: k„ ,s wry h<. Ylt� ,r r }h n:..,n.. w>.. •, }, .,, _...._ d , x ...,., ,. .,... sK.* .... ".-xk.,. , t„t . ,+.,., ,a t .. f r ., a. , r man. �.nra,'. .. . °. ,.. ., i.: .•�. .,:^` f :#ti.. •- ,.,.,.. r ':; .,., , � <i . , �34 < "A" ., , , ,. r <, a, ,.<. .. , . ,t fu c. , 4a _..,dt.................. . f r , s. ,. ,r u:a >�,nxp.. ,➢:.1d. .. . .. . .. .. ., ..' Xn a. ��ftr €{ tt f.,. », ,. .,. t • r..rt§ 1A, JJ ✓. :r:r+n e x r., ,+ a „r m,. , ,. a. .°:a. .., }. .. ..' ,.. ,.......,., i. ..e , t fr r.,,. .., . , .. , r9. „.. �: ,,.., ... _ ,»..,rr. ,. -, , ... ...,. .. € , o ,+ ,, II , ( „ ,ra.,�.. ... � � :. .., .....•. �a`�,, t`}, �._,, Ill d' rr, � ,., .. ..... k ... rv:... :... .... .:... ,. � r{5 �,t a � i �r LIMITS OF WORK x. t, <. � .. �,. , .. � .. .... � : ;tt ....•r , ' �. rcs. r xi r, , #a ,.. I w.s x ,.,. ,, s .,'.:..•. z k,,a,i t o x r:P' r< e ra ,. a Y. ..•' Sf t �� t , c=... t ,. ,. , ?. ,>< . , , z,§ X ,..; r fi� r„ sY s .. r t t t zr°a 4r :.xxxxrrr,t - a r § , ., ,. , . _ <. z , `t r ., k ,.ns�:s+ mva.+:. +, �. m Y t x, ,7e:<~, '+t'rs. oe k r { a ,... .. , -.. r ,.f7.. ..<.{„..f,,.:'#rsk, '� ..S ., '!� ,., , €... ,. ..,, ..x. .:.:•. rl,e, ., €, .{ ,., 6'c " .r. 4. .... ,. ,. .. .,;:,......... ....... ? ` ';i`t .t :_!, ,..,,... .i'r -,,. .., i:..::. . , , i % h 1 ii , .. ,t r r f r.x t r # .k ,,. 1 t .._.,. _ r >> . , 1 � x _ . ...- ....s. , _. —, s.,l+• = 1 Y ' a ..., .. ,E i r Y». �, , ..as¢'•. , , . , ,. � , ,., f. ; , 2,.., , d. ,kr zr� s�,. x• ,, „§ .}»„i£ <., ., <.. , 1 F '.,.y t. ..;..:.. ., .� •.".,• toe <,,,,,� x. 8xt f. �,➢. � s.t ,,... ��. , � ,t a .. s r.. I �r +7 , ,,. ,.$I ..,.. .. ,. ,a•..•, r ,. ' '" �• x� 8,'" ,f €a.;, s, rf% , • <.... d � ;t:,, ..,,,_. ,. ,:,, :,..,,..,,>�, , s.. ,. , , ... t • • k a..3fr ,tr . ` (4 me t }, {## :.. k.. �,...............( »i5r s,< V'" tz kx, a, o„ Iv. ',; ",. � � r £,.. •, � r .. b f= � .2.. , �' i .. x.•. ,+v ... .... .. ' k. .:.,.:,:: s.,r,"fz rra, xi',t. u; « a , „ t .... �_➢ — -- � ., ,r,.. .. ax` - S • . • �z" _ r.. .,....r +x, r rw, i �`. �,x,,, ,.f.} � ,wu,,. ' '° ,. ,a k .Y#'k >. ;. �.t:'.•:°. L.i �r ,2: a. •.r-. tnf, +, xk .a. a r s:, ..-=o,•,. *r. a•.+,. +t ,. ,. ..:.:•. t : :�*r,:'d.•.I'.,...' t # k t _. ,.f ,. ,,, „a t. .., ..lit r. , »r,. r„} _. ,» < ., a 2,< .�• eM#.<& L.,... 5{. , , 'h az f#i� �, ,,i •,.. ', x' ,, 5a„ ,, '.. „ ,,.. '<, r... , ; : , a4 .-X,*:.2£s�t• ,_. ,�.tt,. .., i t )rct .... n, ,,v ,: „-,. .:". '� f ...,,,,:. ._. ., , �'t » _ .. •.3m ,»r ax � :caP,r. ,; t tf, ,h <., :e t§ , ,,. x � ,x t} i f to , w, .— " i , , h..- • - ,. � s a < r# ,... t,:.k „.,<.,, t .,7 r t. , },I : r. rr i . Y +. ,: =t v. >:...,,_ >., .,A , s ,. .o =. r{ »_" k a :,£ti.= d .p, .,r, •'... @QARfiRRS4 •b+ x1t � ,.,p,ir,� ..,.,. .,. , .< , ,. x€ '.: ,.:a», , .... »:,;,, ... • `,< ...:. {:>.. '.'i rr i t' . J.. .,,,il...r w : t ,a; tt'x. m. '','} ;r""•;.i , TMrs L .,,,,, a t .._..._..Q,➢.. ....... - ....,.. fie•. m ,. a >f. ! a,•. , , ,. #➢ e. {.. n{ nk to «mtttY z +,,, ., k ,� , ,.: . ,. .r .. _,.,.. ,. .... .. .....,,, ` }' + °. I, r , ,_ .':.:.y, =,r :: ,t,r' s: t r+,: � �: t �. ., r,. „ a,.,a.: '._^ ,s Y J:..x,jf rrk � � � �..+..,.:..-� � � � ��.'>. ,...... .... Aft^ f. `7/ty. +t f J ,: t ... .. ! ,,f„ f ,iS f ,rxa i s3Y.,, f' rc3e. ., ,u„ .,. •.... n , ? .... '�'f.aS€m,,:= F 4" :{.:.. ,,.., 3,..{§��':= a`�x, ...... Yu,r �} s„ ar:s:..{..... #'...:.t, ,,4s"...xt.�xtk; @ d,4,' a,Yrar 5 ,';t a 4 z x ..' J#�" r} 2� r. r Project Title Drawing Title ASI/RFI/CSK Number MADRONA K-8 WETLAND B F2 f=-- 0 50 100 200 PROPOSED CONDITIONS Drawing Reference Scale a [� 1 " = 100' O Client z 1 inch = 100 feet MAHLUM ARCHITECTS 16015th Avenue, Suite 1600 Seattle, Avenue, nue, Date Drawn/Ck'tl By 206.62w.kp822 11/28/2016 SJ/CB www.kpff.com PROPOSED SURFACE AREAS NORTH BASIN SOUTH BASIN IMPERVIOUS AREA 1.55 AC 1.20 AC PERVIOUS (FOREST) 2.57 AC 3.95 AC PERVIOUS (GRASS) 2.45 AC 0.99 AC TOTAL AREA 6.57 AC 6.14 AC MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.38 Program License Number: 200410007 Project Simulation Performed on: 11/21/2016 2:56 PM Report Generation Date: 11/21/2016 2:56 PM Input File Name: Wetland B.fld Project Name: Madrona Analysis Title: Wetland B Comments: PRECIPITATION INPUT Computational Time Step (Minutes): Extended Precipitation Time Series Selected Climatic Region Number: 13 Full Period of Record Available used for Routing Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097 Evaporation Station 961040 Puget East 40 in MAP Evaporation Scale Factor 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Total Subbasin Area (acres) 12.930 12.715 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 12.930 12.715 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 Subbasin Till Forest Till Pasture Till Grass Outwash Forest : South Subbasin -------Area(Acres) 3.955 0.000 2.156 0.000 Post Developed Page 1 of 31 Outwash Pasture Outwash Grass Wetland Green Roof User 2 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 2 Impervious Subbasin Total 6.764 : North Subbasin -------Area(Acres) 2.572 0.000 1.709 0.000 0.000 0.000 0.000 0.000 0.000 1.885 6.166 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 2 Impervious Subbasin Total Subbasin Till Forest Till Pasture Till Grass Outwash Forest Outwash Pasture Outwash Grass Wetland Green Roof User 2 : South Subbasin -------Area(Acres) 3.955 0.000 0.986 0.000 0.000 0.000 0.000 0.000 0.000 1.196 6.137 : North Subbasin -------Area(Acres) 2.572 0.000 2.455 0.000 0.000 0.000 0.000 0.000 0.000 Page 2 of 31 Impervious 1.551 Subbasin Total 6.578 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 2 Link Name: Wetland B - South Link Type: Structure Downstream Link: None User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 424.00 0. 425.00 359. 426.00 2395. 427.00 8143. 428.00 20539. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.03 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 1.00 Common Length (ft) : 0.000 Riser Crest Elevation : 430.00 ft Hydraulic Structure Geometry Number of Devices: ---Device Number 1 --- Device Type Circular Orifice Control Elevation (ft) 424.19 Diameter (in) 18.00 Orientation : Vertical Elbow : No Link Name: Wetland B - North Link Type: Structure Downstream Link Name: Wetland B - South User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 430.00 0. 431.00 1498. 432.00 7141. Page 3 of 31 433.00 17684. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.03 Riser Geometry Riser Structure Type Riser Diameter (in) Common Length (ft) Riser Crest Elevation Hydraulic Structure Geometry Number of Devices: Circular 1.00 0.000 435.00 ft --- Device Number 1 --- Device Type Trapezoidal Broad Crested Weir (Independent of Riser) Invert Elevation (ft) 431.64 Length (ft) 8.00 Side Slope (Z) (ft/ft) 9.70 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 2 Link Name: Wetland B - North Link Type: Structure Downstream Link Name: Wetland B - South User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 430.00 0. 431.00 1498. 432.00 7141. 433.00 17684. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.03 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 1.00 Common Length (ft) : 0.000 Riser Crest Elevation : 435.00 ft Hydraulic Structure Geometry Number of Devices: --- Device Number 1 --- Device Type Trapezoidal Broad Crested Weir (Independent of Riser) Invert Elevation (ft) 431.64 Page 4 of 31 Length (ft) 8.00 Side Slope (Z) (ft/ft) 9.70 Link Name: Wetland B - South Link Type: Structure Downstream Link: None User Specified Elevation Volume Table Used Elevation (ft) Pond Volume (cu-ft) 424.00 0. 425.00 359. 426.00 2395. 427.00 8143. 428.00 20539. Constant Infiltration Option Used Infiltration Rate (in/hr): 0.03 Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 1.00 Common Length (ft) : 0.000 Riser Crest Elevation : 430.00 ft Hydraulic Structure Geometry Number of Devices: ---Device Number 1 --- Device Type Circular Orifice Control Elevation (ft) 424.19 Diameter (in) 18.00 Orientation : Vertical Elbow : No **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 Number of Links: 2 ********** Subbasin: South Subbasin ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.589 5-Year 0.947 10-Year 1.168 25-Year 1.738 50-Year 2.218 100-Year 2.656 Page 5 of 31 200-Year 3.209 ********** Subbasin: North Subbasin ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 1.088 5-Year 1.503 10-Year 1.828 25-Year 2.376 50-Year 3.647 100-Year 4.093 200-Year 4.238 ********** Link: Wetland B - South ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 1.348 5-Year 1.925 10-Year 2.571 25-Year 3.260 50-Year 4.225 100-Year 5.580 200-Year 5.823 ********** Link: Wetland B - South ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) -------------------------------------- -------------------------------------- 1.05-Year 424.526 1.11-Year 424.554 1.25-Year 424.589 2.00-Year 424.706 3.33-Year 424.768 5-Year 424.815 10-Year 424.920 25-Year 425.015 50-Year 425.144 100-Year 425.283 ********** Link: Wetland B - North ********** Link Inflow Frequency Stats Page 6 of 31 Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 1.088 5-Year 1.503 10-Year 1.828 25-Year 2.376 50-Year 3.647 100-Year 4.093 200-Year 4.238 ********** Link: Wetland B - North ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.860 5-Year 1.188 10-Year 1.553 25-Year 1.906 50-Year 2.480 100-Year 3.177 200-Year 3.310 ********** Link: Wetland B - North ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) -------------------------------------- -------------------------------------- 1.05-Year 431.706 1.11-Year 431.711 1.25-Year 431.718 2.00-Year 431.745 3.33-Year 431.760 5-Year 431.770 10-Year 431.793 25-Year 431.814 50-Year 431.845 100-Year 431.880 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 2 Number of Links: 2 ********** Subbasin: South Subbasin ********** Flood Frequency Data(cfs) Page 7 of 31 (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.708 5-Year 0.974 10-Year 1.223 25-Year 1.587 50-Year 2.265 100-Year 2.668 200-Year 2.969 ********** Subbasin: North Subbasin ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.991 5-Year 1.430 10-Year 1.874 25-Year 2.473 50-Year 3.664 100-Year 4.269 200-Year 4.295 ********** Link: Wetland B - North ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.991 5-Year 1.430 10-Year 1.874 25-Year 2.473 50-Year 3.664 100-Year 4.269 200-Year 4.295 ********** Link: Wetland B - North ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 0.795 5-Year 1.134 10-Year 1.518 25-Year 1.884 50-Year 2.455 100-Year 3.380 Page 8 of 31 200-Year 3.428 ********** Link: Wetland B - North ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) -------------------------------------- -------------------------------------- 1.05-Year 431.700 1.11-Year 431.705 1.25-Year 431.712 2.00-Year 431.740 3.33-Year 431.756 5-Year 431.767 10-Year 431.791 25-Year 431.812 50-Year 431.844 100-Year 431.888 ********** Link: Wetland B - South ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) -------------------------------------- -------------------------------------- 2-Year 1.385 5-Year 1.940 10-Year 2.555 25-Year 3.202 50-Year 4.061 100-Year 5.505 200-Year 5.676 ********** Link: Wetland B - South ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) -------------------------------------- -------------------------------------- 1.05-Year 424.538 1.11-Year 424.566 1.25-Year 424.604 2.00-Year 424.709 3.33-Year 424.775 5-Year 424.817 10-Year 424.917 25-Year 425.008 50-Year 425.127 100-Year 425.279 Page 9 of 31 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perind Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: South Subbasin Subbasin: North Subbasin Link: Wetland B - South Link: Wetland B - North Total: 651.361 0.000 364.540 943.969 1959.870 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: South Subbasin 801.083 Subbasin: North Subbasin 742.467 Link: Wetland B - North 359.759 Link: Wetland B - South 0.000 Total: 1903.309 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 12.404 ac-ft/year, Post Developed: 12.046 ac-ft/year ***********Water Quality Facility Data ************* SCENARIO: PREDEVELOPED Number of Links: 2 ********** Link: Wetland B - South Basic Wet Pond Volume (91 % Exceedance): 23443. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 35165. cu-ft Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 2150.93 Inflow Volume Including PPT-Evap (ac-ft): 2150.93 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2156.17 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Wetland B - North Basic Wet Pond Volume (91 % Exceedance): 12484. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 18726. cu-ft ********** ********** Page 10 of 31 Time to Infiltrate 91 % Treatment Volume, (Hours): 4151.11 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 1424.67 Inflow Volume Including PPT-Evap (ac-ft): 1424.67 Total Runoff Infiltrated (ac-ft): 364.54, 25.59% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 1063.07 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 25.59% SCENARIO:POSTDEVELOPED Number of Links: 2 ********** Link: Wetland B - North Basic Wet Pond Volume (91 % Exceedance): 12298. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 18447. cu-ft Time to Infiltrate 91 % Treatment Volume, (Hours): 4166.12 Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 1424.80 Inflow Volume Including PPT-Evap (ac-ft): 1424.80 Total Runoff Infiltrated (ac-ft): 359.76, 25.25% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 1067.30 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 25.25% ********** Link: Wetland B - South Basic Wet Pond Volume (91 % Exceedance): 23291. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 34936. cu-ft Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 2163.57 Inflow Volume Including PPT-Evap (ac-ft): 2163.57 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2169.36 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: Wetland B - South Scenario Postdeveloped Compliance Link: Wetland B - South *** Point of Compliance Flow Frequency Data *** ********** ********** Page 11 of 31 Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ------------------------------------------------------------------------------------------------------------ 2-Year 1.331 2-Year 1.348 5-Year 1.900 5-Year 1.911 10-Year 2.523 10-Year 2.508 25-Year 3.165 25-Year 3.117 50-Year 4.020 50-Year 3.901 100-Year 5.002 100-Year 4.971 200-Year 5.166 200-Year 5.098 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals ***********Wetland Hydroperiod Analysis Results ************* Predeveloped Wetland Location: Wetland B - North Postdeveloped Wetland Location: Wetland B - North ***********Mean Water Level Fluctuation Results (ft) ************* Month Predeveloped Postdeveloped Oct 0.5300 0.5242 Nov 0.1175 0.1105 Dec 0.0946 0.0884 Jan 0.1155 0.1096 Feb 0.1048 0.0993 Mar 0.1194 0.1125 Apr 0.1334 0.1274 May 0.1813 0.1742 Jun 0.2064 0.1992 Jul 0.1996 0.1922 Aug 0.1963 0.1875 Sep 0.2352 0.2290 Ann 0.1862 0.1795 ***********Stage Excursion Results ************* Stage Excursions Threshold (ft): 0.500 Avg Number of Stage Excursions Per Year: 0.000 WY No. Excursions Max (ft) Max Dur (hrs) Avg Duration (hrs) ---------------------------------------------------------------------------------------------------------------------------- 1940 00 0.0000 0.0 0.0 1941 00 0.0000 0.0 0.0 1942 00 0.0000 0.0 0.0 1943 00 0.0000 0.0 0.0 1944 00 0.0000 0.0 0.0 1945 00 0.0000 0.0 0.0 1946 00 0.0000 0.0 0.0 1947 00 0.0000 0.0 0.0 1948 00 0.0000 0.0 0.0 1949 00 0.0000 0.0 0.0 1950 00 0.0000 0.0 0.0 1951 00 0.0000 0.0 0.0 1952 00 0.0000 0.0 0.0 Page 12 of 31 1953 00 0.0000 0.0 0.0 1954 00 0.0000 0.0 0.0 1955 00 0.0000 0.0 0.0 1956 00 0.0000 0.0 0.0 1957 00 0.0000 0.0 0.0 1958 00 0.0000 0.0 0.0 1959 00 0.0000 0.0 0.0 1960 00 0.0000 0.0 0.0 1961 00 0.0000 0.0 0.0 1962 00 0.0000 0.0 0.0 1963 00 0.0000 0.0 0.0 1964 00 0.0000 0.0 0.0 1965 00 0.0000 0.0 0.0 1966 00 0.0000 0.0 0.0 1967 00 0.0000 0.0 0.0 1968 00 0.0000 0.0 0.0 1969 00 0.0000 0.0 0.0 1970 00 0.0000 0.0 0.0 1971 00 0.0000 0.0 0.0 1972 00 0.0000 0.0 0.0 1973 00 0.0000 0.0 0.0 1974 00 0.0000 0.0 0.0 1975 00 0.0000 0.0 0.0 1976 00 0.0000 0.0 0.0 1977 00 0.0000 0.0 0.0 1978 00 0.0000 0.0 0.0 1979 00 0.0000 0.0 0.0 1980 00 0.0000 0.0 0.0 1981 00 0.0000 0.0 0.0 1982 00 0.0000 0.0 0.0 1983 00 0.0000 0.0 0.0 1984 00 0.0000 0.0 0.0 1985 00 0.0000 0.0 0.0 1986 00 0.0000 0.0 0.0 1987 00 0.0000 0.0 0.0 1988 00 0.0000 0.0 0.0 1989 00 0.0000 0.0 0.0 1990 00 0.0000 0.0 0.0 1991 00 0.0000 0.0 0.0 1992 00 0.0000 0.0 0.0 1993 00 0.0000 0.0 0.0 1994 00 0.0000 0.0 0.0 1995 00 0.0000 0.0 0.0 1996 00 0.0000 0.0 0.0 1997 00 0.0000 0.0 0.0 1998 00 0.0000 0.0 0.0 1999 00 0.0000 0.0 0.0 2000 00 0.0000 0.0 0.0 2001 00 0.0000 0.0 0.0 2002 00 0.0000 0.0 0.0 2003 00 0.0000 0.0 0.0 2004 00 0.0000 0.0 0.0 2005 00 0.0000 0.0 0.0 2006 00 0.0000 0.0 0.0 2007 00 0.0000 0.0 0.0 2008 00 0.0000 0.0 0.0 Page 13 of 31 2009 00 0.0000 0.0 0.0 2010 00 0.0000 0.0 0.0 2011 00 0.0000 0.0 0.0 2012 00 0.0000 0.0 0.0 2013 00 0.0000 0.0 0.0 2014 00 0.0000 0.0 0.0 2015 00 0.0000 0.0 0.0 2016 00 0.0000 0.0 0.0 2017 00 0.0000 0.0 0.0 2018 00 0.0000 0.0 0.0 2019 00 0.0000 0.0 0.0 2020 00 0.0000 0.0 0.0 2021 00 0.0000 0.0 0.0 2022 00 0.0000 0.0 0.0 2023 00 0.0000 0.0 0.0 2024 00 0.0000 0.0 0.0 2025 00 0.0000 0.0 0.0 2026 00 0.0000 0.0 0.0 2027 00 0.0000 0.0 0.0 2028 00 0.0000 0.0 0.0 2029 00 0.0000 0.0 0.0 2030 00 0.0000 0.0 0.0 2031 00 0.0000 0.0 0.0 2032 00 0.0000 0.0 0.0 2033 00 0.0000 0.0 0.0 2034 00 0.0000 0.0 0.0 2035 00 0.0000 0.0 0.0 2036 00 0.0000 0.0 0.0 2037 00 0.0000 0.0 0.0 2038 00 0.0000 0.0 0.0 2039 00 0.0000 0.0 0.0 2040 00 0.0000 0.0 0.0 2041 00 0.0000 0.0 0.0 2042 00 0.0000 0.0 0.0 2043 00 0.0000 0.0 0.0 2044 00 0.0000 0.0 0.0 2045 00 0.0000 0.0 0.0 2046 00 0.0000 0.0 0.0 2047 00 0.0000 0.0 0.0 2048 00 0.0000 0.0 0.0 2049 00 0.0000 0.0 0.0 2050 00 0.0000 0.0 0.0 2051 00 0.0000 0.0 0.0 2052 00 0.0000 0.0 0.0 2053 00 0.0000 0.0 0.0 2054 00 0.0000 0.0 0.0 2055 00 0.0000 0.0 0.0 2056 00 0.0000 0.0 0.0 2057 00 0.0000 0.0 0.0 2058 00 0.0000 0.0 0.0 2059 00 0.0000 0.0 0.0 2060 00 0.0000 0.0 0.0 2061 00 0.0000 0.0 0.0 2062 00 0.0000 0.0 0.0 2063 00 0.0000 0.0 0.0 2064 00 0.0000 0.0 0.0 Page 14 of 31 2065 00 0.0000 0.0 0.0 2066 00 0.0000 0.0 0.0 2067 00 0.0000 0.0 0.0 2068 00 0.0000 0.0 0.0 2069 00 0.0000 0.0 0.0 2070 00 0.0000 0.0 0.0 2071 00 0.0000 0.0 0.0 2072 00 0.0000 0.0 0.0 2073 00 0.0000 0.0 0.0 2074 00 0.0000 0.0 0.0 2075 00 0.0000 0.0 0.0 2076 00 0.0000 0.0 0.0 2077 00 0.0000 0.0 0.0 2078 00 0.0000 0.0 0.0 2079 00 0.0000 0.0 0.0 2080 00 0.0000 0.0 0.0 2081 00 0.0000 0.0 0.0 2082 00 0.0000 0.0 0.0 2083 00 0.0000 0.0 0.0 2084 00 0.0000 0.0 0.0 2085 00 0.0000 0.0 0.0 2086 00 0.0000 0.0 0.0 2087 00 0.0000 0.0 0.0 2088 00 0.0000 0.0 0.0 2089 00 0.0000 0.0 0.0 2090 00 0.0000 0.0 0.0 2091 00 0.0000 0.0 0.0 2092 00 0.0000 0.0 0.0 2093 00 0.0000 0.0 0.0 2094 00 0.0000 0.0 0.0 2095 00 0.0000 0.0 0.0 2096 00 0.0000 0.0 0.0 2097 00 0.0000 0.0 0.0 ***********No Water (Dry) Excursion Results ************* Wetland Dry when Stage Drops Below (ft): 0.010 Dry Excursion Duration (hrs) WY Predeveloped Postdeveloped 1940 460.8 460.9 1941 0.0 0.0 1942 0.0 0.0 1943 0.0 0.0 1944 0.0 0.0 1945 0.0 0.0 1946 78.5 98.3 1947 0.0 0.0 1948 0.0 0.0 1949 315.8 338.5 1950 0.0 0.0 1951 709.7 777.1 1952 0.0 0.0 1953 0.7 38.4 1954 0.0 0.0 1955 0.0 0.0 Page 15 of 31 1956 0.0 0.0 1957 0.0 0.0 1958 246.1 300.2 1959 0.0 0.0 1960 152.8 199.7 1961 0.0 0.0 1962 0.0 0.0 1963 0.0 0.0 1964 0.0 0.0 1965 0.0 0.0 1966 0.0 0.0 1967 370.1 361.9 1968 0.0 0.0 1969 0.0 0.0 1970 0.0 0.0 1971 0.0 0.0 1972 0.0 0.0 1973 0.0 0.0 1974 0.0 0.0 1975 85.6 125.3 1976 0.0 0.0 1977 0.0 0.0 1978 0.0 0.0 1979 0.0 0.0 1980 0.0 0.0 1981 0.0 0.0 1982 0.0 0.0 1983 0.0 0.0 1984 0.0 0.0 1985 0.0 0.0 1986 81.9 141.7 1987 0.0 0.0 1988 0.0 0.0 1989 0.0 0.0 1990 0.0 0.0 1991 0.0 0.0 1992 0.0 0.0 1993 181.2 177.3 1994 130.8 132.4 1995 0.0 0.0 1996 0.0 0.0 1997 0.0 0.0 1998 711.4 760.2 1999 0.0 0.0 2000 5.0 43.2 2001 0.0 0.0 2002 561.3 618.3 2003 251.9 252.1 2004 783.5 978.3 2005 0.0 0.0 2006 0.0 0.0 2007 0.0 0.0 2008 0.0 0.0 2009 0.0 0.0 2010 0.0 0.0 2011 339.3 374.7 Page 16 of 31 2012 296.4 283.9 2013 46.7 83.0 2014 0.0 0.0 2015 0.0 0.0 2016 0.0 0.0 2017 367.3 411.5 2018 318.1 306.3 2019 119.9 155.8 2020 355.2 390.4 2021 0.0 0.0 2022 68.6 69.2 2023 242.8 243.6 2024 0.0 15.2 2025 0.0 0.0 2026 35.3 93.8 2027 594.2 641.1 2028 0.0 0.0 2029 524.6 514.9 2030 587.6 622.7 2031 29.8 20.1 2032 33.6 58.0 2033 88.9 88.2 2034 0.0 0.0 2035 0.0 0.0 2036 0.0 0.0 2037 0.0 0.0 2038 0.0 0.0 2039 0.0 0.0 2040 268.5 295.4 2041 733.4 745.9 2042 0.0 0.0 2043 0.0 0.0 2044 276.9 267.6 2045 0.0 0.0 2046 325.3 327.3 2047 139.4 151.8 2048 1255.4 1347.9 2049 0.0 0.0 2050 0.0 0.0 2051 100.0 99.9 2052 58.9 114.5 2053 0.0 0.0 2054 939.3 993.0 2055 0.0 0.0 2056 0.0 0.0 2057 0.0 0.0 2058 676.8 692.5 2059 0.0 0.0 2060 0.0 0.0 2061 0.0 0.0 2062 0.0 0.0 2063 0.0 0.0 2064 0.0 0.0 2065 0.0 0.0 2066 0.0 0.0 2067 0.0 0.0 Page 17 of 31 2068 0.0 0.0 2069 0.0 0.0 2070 0.0 0.0 2071 0.0 0.0 2072 0.0 0.0 2073 0.0 0.0 2074 0.0 0.0 2075 0.0 0.0 2076 0.0 0.0 2077 0.0 0.0 2078 0.0 0.0 2079 0.0 0.0 2080 0.0 0.0 2081 0.0 0.0 2082 0.0 0.0 2083 0.0 0.0 2084 0.0 0.0 2085 0.0 0.0 2086 61.5 59.7 2087 0.0 0.0 2088 0.0 0.0 2089 0.0 0.0 2090 7.8 28.3 2091 0.0 0.0 2092 0.0 0.0 2093 0.0 0.0 2094 245.7 279.1 2095 0.0 0.0 2096 0.0 0.0 2097 6.0 6.0 ***********Amphibian Season Analysis************* Season Begins : 02/01 Season Ends : 05/31 Amphibian Stage Excursions Threshold (ft): 0.250 WY Max Excursion (ft) Max 30-Day Excursion (hrs) --------------------------------------------------------------------------------------------- 1940 0.000 ---------- 0.0 1941 0.000 0.0 1942 0.000 0.0 1943 0.000 0.0 1944 0.000 0.0 1945 0.000 0.0 1946 0.000 0.0 1947 0.000 0.0 1948 0.000 0.0 1949 0.000 0.0 1950 0.000 0.0 1951 0.000 0.0 1952 0.000 0.0 1953 0.000 0.0 1954 0.000 0.0 1955 0.000 0.0 1956 0.000 0.0 Page 18 of 31 1957 0.000 0.0 1958 0.000 0.0 1959 0.000 0.0 1960 0.000 0.0 1961 0.000 0.0 1962 0.000 0.0 1963 0.000 0.0 1964 0.000 0.0 1965 0.000 0.0 1966 0.000 0.0 1967 0.000 0.0 1968 0.000 0.0 1969 0.000 0.0 1970 0.000 0.0 1971 0.000 0.0 1972 0.000 0.0 1973 0.000 0.0 1974 0.000 0.0 1975 0.000 0.0 1976 0.000 0.0 1977 0.000 0.0 1978 0.000 0.0 1979 0.000 0.0 1980 0.000 0.0 1981 0.000 0.0 1982 0.000 0.0 1983 0.000 0.0 1984 0.000 0.0 1985 0.000 0.0 1986 0.000 0.0 1987 0.000 0.0 1988 0.000 0.0 1989 0.000 0.0 1990 0.000 0.0 1991 0.000 0.0 1992 0.000 0.0 1993 0.000 0.0 1994 0.000 0.0 1995 0.000 0.0 1996 0.000 0.0 1997 0.000 0.0 1998 0.000 0.0 1999 0.000 0.0 2000 0.000 0.0 2001 0.000 0.0 2002 0.000 0.0 2003 0.000 0.0 2004 0.000 0.0 2005 0.000 0.0 2006 0.000 0.0 2007 0.000 0.0 2008 0.000 0.0 2009 0.000 0.0 2010 0.000 0.0 2011 0.000 0.0 2012 0.000 0.0 Page 19 of 31 2013 0.000 0.0 2014 0.000 0.0 2015 0.000 0.0 2016 0.000 0.0 2017 0.000 0.0 2018 0.000 0.0 2019 0.000 0.0 2020 0.000 0.0 2021 0.000 0.0 2022 0.000 0.0 2023 0.000 0.0 2024 0.000 0.0 2025 0.000 0.0 2026 0.000 0.0 2027 0.000 0.0 2028 0.000 0.0 2029 0.000 0.0 2030 0.000 0.0 2031 0.000 0.0 2032 0.000 0.0 2033 0.000 0.0 2034 0.000 0.0 2035 0.000 0.0 2036 0.000 0.0 2037 0.000 0.0 2038 0.000 0.0 2039 0.000 0.0 2040 0.000 0.0 2041 0.000 0.0 2042 0.000 0.0 2043 0.000 0.0 2044 0.000 0.0 2045 0.000 0.0 2046 0.000 0.0 2047 0.000 0.0 2048 0.000 0.0 2049 0.000 0.0 2050 0.000 0.0 2051 0.000 0.0 2052 0.000 0.0 2053 0.000 0.0 2054 0.000 0.0 2055 0.000 0.0 2056 0.000 0.0 2057 0.000 0.0 2058 0.000 0.0 2059 0.000 0.0 2060 0.000 0.0 2061 0.000 0.0 2062 0.000 0.0 2063 0.000 0.0 2064 0.000 0.0 2065 0.000 0.0 2066 0.000 0.0 2067 0.000 0.0 2068 0.000 0.0 Page 20 of 31 2069 0.000 0.0 2070 0.000 0.0 2071 0.000 0.0 2072 0.000 0.0 2073 0.000 0.0 2074 0.000 0.0 2075 0.000 0.0 2076 0.000 0.0 2077 0.000 0.0 2078 0.000 0.0 2079 0.000 0.0 2080 0.000 0.0 2081 0.000 0.0 2082 0.000 0.0 2083 0.000 0.0 2084 0.000 0.0 2085 0.000 0.0 2086 0.000 0.0 2087 0.000 0.0 2088 0.000 0.0 2089 0.000 0.0 2090 0.000 0.0 2091 0.000 0.0 2092 0.000 0.0 2093 0.000 0.0 2094 0.000 0.0 2095 0.000 0.0 2096 0.000 0.0 2097 0.000 0.0 Page 21 of 31 ***********Wetland Hydroperiod Analysis Results ************* Predeveloped Wetland Location: Wetland B - South Postdeveloped Wetland Location: Wetland B - South ***********Mean Water Level Fluctuation Results (ft) ************* Month Predeveloped Postdeveloped Oct 0.4631 0.4730 Nov 0.1739 0.1835 Dec 0.1565 0.1642 Jan 0.1442 0.1507 Feb 0.1447 0.1516 Mar 0.1470 0.1540 Apr 0.1224 0.1324 May 0.0965 0.1086 Jun 0.0815 0.0925 Jul 0.0428 0.0507 Aug 0.0447 0.0538 Sep 0.0861 0.0977 Ann 0.1419 0.1511 ***********Stage Excursion Results ************* Stage Excursions Threshold (ft): 0.500 Avg Number of Stage Excursions Per Year: 0.000 WY No. Excursions Max (ft) Max Dur (hrs) Avg Duration (hrs) ---------------------------------------------------------------------------------------------------------------------------- 1940 00 0.0000 0.0 0.0 1941 00 0.0000 0.0 0.0 1942 00 0.0000 0.0 0.0 1943 00 0.0000 0.0 0.0 1944 00 0.0000 0.0 0.0 1945 00 0.0000 0.0 0.0 1946 00 0.0000 0.0 0.0 1947 00 0.0000 0.0 0.0 1948 00 0.0000 0.0 0.0 1949 00 0.0000 0.0 0.0 1950 00 0.0000 0.0 0.0 1951 00 0.0000 0.0 0.0 1952 00 0.0000 0.0 0.0 1953 00 0.0000 0.0 0.0 1954 00 0.0000 0.0 0.0 1955 00 0.0000 0.0 0.0 1956 00 0.0000 0.0 0.0 1957 00 0.0000 0.0 0.0 1958 00 0.0000 0.0 0.0 1959 00 0.0000 0.0 0.0 1960 00 0.0000 0.0 0.0 1961 00 0.0000 0.0 0.0 1962 00 0.0000 0.0 0.0 1963 00 0.0000 0.0 0.0 1964 00 0.0000 0.0 0.0 1965 00 0.0000 0.0 0.0 1966 00 0.0000 0.0 0.0 1967 00 0.0000 0.0 0.0 Page 22 of 31 1968 00 0.0000 0.0 0.0 1969 00 0.0000 0.0 0.0 1970 00 0.0000 0.0 0.0 1971 00 0.0000 0.0 0.0 1972 00 0.0000 0.0 0.0 1973 00 0.0000 0.0 0.0 1974 00 0.0000 0.0 0.0 1975 00 0.0000 0.0 0.0 1976 00 0.0000 0.0 0.0 1977 00 0.0000 0.0 0.0 1978 00 0.0000 0.0 0.0 1979 00 0.0000 0.0 0.0 1980 00 0.0000 0.0 0.0 1981 00 0.0000 0.0 0.0 1982 00 0.0000 0.0 0.0 1983 00 0.0000 0.0 0.0 1984 00 0.0000 0.0 0.0 1985 00 0.0000 0.0 0.0 1986 00 0.0000 0.0 0.0 1987 00 0.0000 0.0 0.0 1988 00 0.0000 0.0 0.0 1989 00 0.0000 0.0 0.0 1990 00 0.0000 0.0 0.0 1991 00 0.0000 0.0 0.0 1992 00 0.0000 0.0 0.0 1993 00 0.0000 0.0 0.0 1994 00 0.0000 0.0 0.0 1995 00 0.0000 0.0 0.0 1996 00 0.0000 0.0 0.0 1997 00 0.0000 0.0 0.0 1998 00 0.0000 0.0 0.0 1999 00 0.0000 0.0 0.0 2000 00 0.0000 0.0 0.0 2001 00 0.0000 0.0 0.0 2002 00 0.0000 0.0 0.0 2003 00 0.0000 0.0 0.0 2004 00 0.0000 0.0 0.0 2005 00 0.0000 0.0 0.0 2006 00 0.0000 0.0 0.0 2007 00 0.0000 0.0 0.0 2008 00 0.0000 0.0 0.0 2009 00 0.0000 0.0 0.0 2010 00 0.0000 0.0 0.0 2011 00 0.0000 0.0 0.0 2012 00 0.0000 0.0 0.0 2013 00 0.0000 0.0 0.0 2014 00 0.0000 0.0 0.0 2015 00 0.0000 0.0 0.0 2016 00 0.0000 0.0 0.0 2017 00 0.0000 0.0 0.0 2018 00 0.0000 0.0 0.0 2019 00 0.0000 0.0 0.0 2020 00 0.0000 0.0 0.0 2021 00 0.0000 0.0 0.0 2022 00 0.0000 0.0 0.0 2023 00 0.0000 0.0 0.0 Page 23 of 31 2024 00 0.0000 0.0 0.0 2025 00 0.0000 0.0 0.0 2026 00 0.0000 0.0 0.0 2027 00 0.0000 0.0 0.0 2028 00 0.0000 0.0 0.0 2029 00 0.0000 0.0 0.0 2030 00 0.0000 0.0 0.0 2031 00 0.0000 0.0 0.0 2032 00 0.0000 0.0 0.0 2033 00 0.0000 0.0 0.0 2034 00 0.0000 0.0 0.0 2035 00 0.0000 0.0 0.0 2036 00 0.0000 0.0 0.0 2037 00 0.0000 0.0 0.0 2038 00 0.0000 0.0 0.0 2039 00 0.0000 0.0 0.0 2040 00 0.0000 0.0 0.0 2041 00 0.0000 0.0 0.0 2042 00 0.0000 0.0 0.0 2043 00 0.0000 0.0 0.0 2044 00 0.0000 0.0 0.0 2045 00 0.0000 0.0 0.0 2046 00 0.0000 0.0 0.0 2047 00 0.0000 0.0 0.0 2048 00 0.0000 0.0 0.0 2049 00 0.0000 0.0 0.0 2050 00 0.0000 0.0 0.0 2051 00 0.0000 0.0 0.0 2052 00 0.0000 0.0 0.0 2053 00 0.0000 0.0 0.0 2054 00 0.0000 0.0 0.0 2055 00 0.0000 0.0 0.0 2056 00 0.0000 0.0 0.0 2057 00 0.0000 0.0 0.0 2058 00 0.0000 0.0 0.0 2059 00 0.0000 0.0 0.0 2060 00 0.0000 0.0 0.0 2061 00 0.0000 0.0 0.0 2062 00 0.0000 0.0 0.0 2063 00 0.0000 0.0 0.0 2064 00 0.0000 0.0 0.0 2065 00 0.0000 0.0 0.0 2066 00 0.0000 0.0 0.0 2067 00 0.0000 0.0 0.0 2068 00 0.0000 0.0 0.0 2069 00 0.0000 0.0 0.0 2070 00 0.0000 0.0 0.0 2071 00 0.0000 0.0 0.0 2072 00 0.0000 0.0 0.0 2073 00 0.0000 0.0 0.0 2074 00 0.0000 0.0 0.0 2075 00 0.0000 0.0 0.0 2076 00 0.0000 0.0 0.0 2077 00 0.0000 0.0 0.0 2078 00 0.0000 0.0 0.0 2079 00 0.0000 0.0 0.0 Page 24 of 31 2080 00 0.0000 0.0 0.0 2081 00 0.0000 0.0 0.0 2082 00 0.0000 0.0 0.0 2083 00 0.0000 0.0 0.0 2084 00 0.0000 0.0 0.0 2085 00 0.0000 0.0 0.0 2086 00 0.0000 0.0 0.0 2087 00 0.0000 0.0 0.0 2088 00 0.0000 0.0 0.0 2089 00 0.0000 0.0 0.0 2090 00 0.0000 0.0 0.0 2091 00 0.0000 0.0 0.0 2092 00 0.0000 0.0 0.0 2093 00 0.0000 0.0 0.0 2094 00 0.0000 0.0 0.0 2095 00 0.0000 0.0 0.0 2096 00 0.0000 0.0 0.0 2097 00 0.0000 0.0 0.0 ***********No Water (Dry) Excursion Results ************* Wetland Dry when Stage Drops Below (ft): 0.010 Dry Excursion Duration (hrs) WY Predeveloped Postdeveloped 1940 460.8 460.7 1941 0.0 0.0 1942 0.0 0.0 1943 0.0 0.0 1944 0.0 0.0 1945 0.0 0.0 1946 0.0 0.0 1947 0.0 0.0 1948 0.0 0.0 1949 0.0 0.0 1950 0.0 0.0 1951 0.0 0.0 1952 0.0 0.0 1953 0.0 0.0 1954 0.0 0.0 1955 0.0 0.0 1956 0.0 0.0 1957 0.0 0.0 1958 0.0 0.0 1959 0.0 0.0 1960 0.0 0.0 1961 0.0 0.0 1962 0.0 0.0 1963 0.0 0.0 1964 0.0 0.0 1965 0.0 0.0 1966 0.0 0.0 1967 0.0 0.0 1968 0.0 0.0 1969 0.0 0.0 1970 0.0 0.0 Page 25 of 31 1971 0.0 0.0 1972 0.0 0.0 1973 0.0 0.0 1974 0.0 0.0 1975 0.0 0.0 1976 0.0 0.0 1977 0.0 0.0 1978 0.0 0.0 1979 0.0 0.0 1980 0.0 0.0 1981 0.0 0.0 1982 0.0 0.0 1983 0.0 0.0 1984 0.0 0.0 1985 0.0 0.0 1986 0.0 0.0 1987 0.0 0.0 1988 0.0 0.0 1989 0.0 0.0 1990 0.0 0.0 1991 0.0 0.0 1992 0.0 0.0 1993 0.0 0.0 1994 0.0 0.0 1995 0.0 0.0 1996 0.0 0.0 1997 0.0 0.0 1998 0.0 0.0 1999 0.0 0.0 2000 0.0 0.0 2001 0.0 0.0 2002 0.0 0.0 2003 0.0 0.0 2004 0.0 0.0 2005 0.0 0.0 2006 0.0 0.0 2007 0.0 0.0 2008 0.0 0.0 2009 0.0 0.0 2010 0.0 0.0 2011 0.0 0.0 2012 0.0 0.0 2013 0.0 0.0 2014 0.0 0.0 2015 0.0 0.0 2016 0.0 0.0 2017 0.0 0.0 2018 0.0 0.0 2019 0.0 0.0 2020 0.0 0.0 2021 0.0 0.0 2022 0.0 0.0 2023 0.0 0.0 2024 0.0 0.0 2025 0.0 0.0 2026 0.0 0.0 Page 26 of 31 2027 0.0 0.0 2028 0.0 0.0 2029 0.0 0.0 2030 0.0 0.0 2031 0.0 0.0 2032 0.0 0.0 2033 0.0 0.0 2034 0.0 0.0 2035 0.0 0.0 2036 0.0 0.0 2037 0.0 0.0 2038 0.0 0.0 2039 0.0 0.0 2040 0.0 0.0 2041 0.0 0.0 2042 0.0 0.0 2043 0.0 0.0 2044 0.0 0.0 2045 0.0 0.0 2046 0.0 0.0 2047 0.0 0.0 2048 0.0 0.0 2049 0.0 0.0 2050 0.0 0.0 2051 0.0 0.0 2052 0.0 0.0 2053 0.0 0.0 2054 0.0 0.0 2055 0.0 0.0 2056 0.0 0.0 2057 0.0 0.0 2058 0.0 0.0 2059 0.0 0.0 2060 0.0 0.0 2061 0.0 0.0 2062 0.0 0.0 2063 0.0 0.0 2064 0.0 0.0 2065 0.0 0.0 2066 0.0 0.0 2067 0.0 0.0 2068 0.0 0.0 2069 0.0 0.0 2070 0.0 0.0 2071 0.0 0.0 2072 0.0 0.0 2073 0.0 0.0 2074 0.0 0.0 2075 0.0 0.0 2076 0.0 0.0 2077 0.0 0.0 2078 0.0 0.0 2079 0.0 0.0 2080 0.0 0.0 2081 0.0 0.0 2082 0.0 0.0 Page 27 of 31 2083 0.0 0.0 2084 0.0 0.0 2085 0.0 0.0 2086 0.0 0.0 2087 0.0 0.0 2088 0.0 0.0 2089 0.0 0.0 2090 0.0 0.0 2091 0.0 0.0 2092 0.0 0.0 2093 0.0 0.0 2094 0.0 0.0 2095 0.0 0.0 2096 0.0 0.0 2097 6.0 6.0 ***********Amphibian Season Analysis************* Season Begins : 02/01 Season Ends : 05/31 Amphibian Stage Excursions Threshold (ft): 0.250 WY Max Excursion (ft) Max 30-Day Excursion (hrs) •------------------------------------------------------------------------------------------------------ 1940 0.000 0.0 1941 0.000 0.0 1942 0.000 0.0 1943 0.000 0.0 1944 0.000 0.0 1945 0.000 0.0 1946 0.000 0.0 1947 0.000 0.0 1948 0.000 0.0 1949 0.000 0.0 1950 0.000 0.0 1951 0.000 0.0 1952 0.000 0.0 1953 0.000 0.0 1954 0.000 0.0 1955 0.000 0.0 1956 0.000 0.0 1957 0.000 0.0 1958 0.000 0.0 1959 0.000 0.0 1960 0.000 0.0 1961 0.000 0.0 1962 0.000 0.0 1963 0.000 0.0 1964 0.000 0.0 1965 0.000 0.0 1966 0.000 0.0 1967 0.000 0.0 1968 0.000 0.0 1969 0.000 0.0 1970 0.000 0.0 1971 0.000 0.0 Page 28 of 31 1972 0.000 0.0 1973 0.000 0.0 1974 0.000 0.0 1975 0.000 0.0 1976 0.000 0.0 1977 0.000 0.0 1978 0.000 0.0 1979 0.000 0.0 1980 0.000 0.0 1981 0.000 0.0 1982 0.000 0.0 1983 0.000 0.0 1984 0.000 0.0 1985 0.000 0.0 1986 0.000 0.0 1987 0.000 0.0 1988 0.000 0.0 1989 0.000 0.0 1990 0.000 0.0 1991 0.000 0.0 1992 0.000 0.0 1993 0.000 0.0 1994 0.000 0.0 1995 0.000 0.0 1996 0.000 0.0 1997 0.000 0.0 1998 0.000 0.0 1999 0.000 0.0 2000 0.000 0.0 2001 0.000 0.0 2002 0.000 0.0 2003 0.000 0.0 2004 0.000 0.0 2005 0.000 0.0 2006 0.000 0.0 2007 0.000 0.0 2008 0.000 0.0 2009 0.000 0.0 2010 0.000 0.0 2011 0.000 0.0 2012 0.000 0.0 2013 0.000 0.0 2014 0.000 0.0 2015 0.000 0.0 2016 0.000 0.0 2017 0.000 0.0 2018 0.000 0.0 2019 0.000 0.0 2020 0.000 0.0 2021 0.000 0.0 2022 0.000 0.0 2023 0.000 0.0 2024 0.000 0.0 2025 0.000 0.0 2026 0.000 0.0 2027 0.000 0.0 Page 29 of 31 2028 0.000 0.0 2029 0.000 0.0 2030 0.000 0.0 2031 0.000 0.0 2032 0.000 0.0 2033 0.000 0.0 2034 0.000 0.0 2035 0.000 0.0 2036 0.000 0.0 2037 0.000 0.0 2038 0.000 0.0 2039 0.000 0.0 2040 0.000 0.0 2041 0.000 0.0 2042 0.000 0.0 2043 0.000 0.0 2044 0.000 0.0 2045 0.000 0.0 2046 0.000 0.0 2047 0.000 0.0 2048 0.000 0.0 2049 0.000 0.0 2050 0.000 0.0 2051 0.000 0.0 2052 0.000 0.0 2053 0.000 0.0 2054 0.000 0.0 2055 0.000 0.0 2056 0.000 0.0 2057 0.000 0.0 2058 0.000 0.0 2059 0.000 0.0 2060 0.000 0.0 2061 0.000 0.0 2062 0.000 0.0 2063 0.000 0.0 2064 0.000 0.0 2065 0.000 0.0 2066 0.000 0.0 2067 0.000 0.0 2068 0.000 0.0 2069 0.000 0.0 2070 0.000 0.0 2071 0.000 0.0 2072 0.000 0.0 2073 0.000 0.0 2074 0.000 0.0 2075 0.000 0.0 2076 0.000 0.0 2077 0.000 0.0 2078 0.000 0.0 2079 0.000 0.0 2080 0.000 0.0 2081 0.000 0.0 2082 0.000 0.0 2083 0.000 0.0 Page 30 of 31 2084 0.000 0.0 2085 0.000 0.0 2086 0.000 0.0 2087 0.000 0.0 2088 0.000 0.0 2089 0.000 0.0 2090 0.000 0.0 2091 0.000 0.0 2092 0.000 0.0 2093 0.000 0.0 2094 0.000 0.0 2095 0.000 0.0 2096 0.000 0.0 2097 0.000 0.0 Page 31 of 31 Appendix G Stormwater Pollution Prevention (SWPP) Y SWPP Report (partially completed, pending contractor selection) Madrona School — Edmonds School District Construction Stormwater General Permit 1 1111111111, 11 lill I I � 11 IF 2IIUrIUff0M2• = for Madrona School Prepared for: The Washington State Department of Ecology Northwest Regional Office Permittee / Owner Developer Operator / Contractor Edmonds School District N/A TBD Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Christopher Borzio, PE KPFF Consulting Engineers (206) 622-5822 SWPPP Preparation Date 12/04/2016 Project Construction Dates Activity / Phase Start Date End Date Site Work 5/1/2017 10/10/2018 Table of Contents 1 Project Information .............................................................................................................. 4 1.1 Existing Conditions ...................................................................................................... 4 1.2 Proposed Construction Activities .................................................................................. 5 2 Construction S[Ornlvv8[erBest Management Practices (BMPm) ........................................... 0 2.1 The 13Elements .......................................................................................................... 0 2.11 Element 1:Preserve Vegetation / Mark Clearing Limits ........................................ 0 2.1.2 Element 2:Establish Construction Access ............................................................ 7 2.1.3 Element 3: Control Flow Rates ............................................................................. 8 2.1/4 0e[O8Oi 4: |OSt@U Sediment COD1n]|S ----------------------.. Q 2.1.5 Element 5:Stabilize Soils .................................................................................... 18 2.1.6 Element 6:Protect Slopes .................................................................................... 1U 2.1.7 Element 7:Protect Drain Inlets ............................................................................ 11 2.1.8 Element M:Stabilize Channels and Outlets .......................................................... 12 2.1.9 E|8[n8Ot9: Control Pollutants ............................................................................... 13 2.1]0 E|eDleD[1O: Control Oevv@tHhDg.......................................................................... 15 2.1.11 Element 11:Maintain BNYPS................................................................................. 10 2.113 Element 13:Manage the Project .......................................................................... 17 2.1.13 0gDlgOi 13: Protect Low Impact Development (L|[)) BK4PS................................. 1Q 3 Pollution Prevention Team ................................................................................................. 21 4 Monitoring and Sampling Requirements ............................................................................ 22 4] Site Inspection ------------------------------------22 4.2 8tO[nlvv@tHrQuality Sampling ...................................................................................... 22 4.2.1 Turbidity Sampling ............................................................................................... 22 4.2.2 p||Sampling ........................................................................................................ 24 5 Discharges U]303(d)OrTotal Maximum Daily Load [TMOL)VV8terbOdi8S......................... 25 5.1 303(d)Listed VV8tH[bOdi8S.......................................................................................... 25 52 TMK]LVVG1O[bOdks..................................................................................................... 25 6 Reportingand Record Keeping .......................................................................................... 2G 6.1 Record Keeping .......................................................................................................... 2G 5.1] Site Log Book ...................................................................................................... 2G 0.1.2 Records Retention ............................................................................................... 20 0.1.3 Updating the SVVPPP........................................................................................... 20 0.2 Reporting.................................................................................................................... 27 6.2.1 Discharge Monitoring Reports --------------------------27 List of Tables Table 1 — Summary of Site Pollutant Constituents..................................................................... 4 Table2 — Pollutants..................................................................................................................13 Table 3 — pH -Modifying Sources...............................................................................................13 Table4 — Dewatering BMPs......................................................................................................15 Table5 — Management.............................................................................................................17 Table 6 — BMP Implementation Schedule.................................................................................18 Table 7 — Team Information......................................................................................................21 Table 8 — Turbidity Sampling Method........................................................................................22 Table 9 — pH Sampling Method.................................................................................................24 List of Appendices Appendix/Glossary A. Site Map B. BMP Detail C. Correspondence D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303(d) List Waterbodies / TMDL Waterbodies Information G. Contaminated Site Information H. Engineering Calculations List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GUILD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model Page 13 I Project Information Project/Site Name: Madrona School Street/Location: 9300 236th St SW City: Edmonds State: WA Zip code: 98020 Subdivision: N/A Receiving waterbody: Edmonds Way Watershed — Puget Sound 1.1 Existing Conditions Total acreage (including support activities such as off -site equipment staging yards, material storage areas, borrow areas). Total acreage: Disturbed acreage Existing structures Landscape topography: 40 AC 15 AC 2.9 AC 6.4 AC (proposed) Drainage patterns: TDA #1 to 236th St SW, TDA 2 to the eastern wetland, TDA 3 to the western steep slope. See Appendix A. Existing Vegetation: Lawn, planters, and forest. Critical Areas (wetlands, streams, high erosion Wetland and steep slope east of site and risk, steep or difficult to stabilize slopes): steep slope west of site. List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: According to the Washington State Water Quality Atlas website, the Puget Sound is 303(d) listed for the following pollutants at the Edmonds Way outfall: Bacteria, Benzo(a)anthracene, Benzo(a)pyrene, Benzo(k)fluoranthene, Benzo(k)fluoranthene, Chrysene, and Polychlorinated Biphenyls (PCBs). Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. Table 1 — Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration Various Hazardous Building Materials Existing Buildings to be demolished See 2015 RBM Assessment Report See 2015 RBM Assessment Report Page 14 1.2 Proposed Construction Activities The existing Madrona Elementary School will be demolished and replaced with a new school. The proposed school consists of a larger gymnasium and administration unit and five smaller classroom units. Other site improvements include new sports fields, play equipment, a bus drop-off loop, and parking lots. The new school will be situated in the field south of the existing school to enable phased construction while the existing school is in session. Construction Activities include, clearing and grading, landscaping, utility installation, paving, and building construction. The existing site is part of the larger Edmonds Way Watershed as defined on figure B — 1 in the Edmonds Supplement. The site is comprised of three Threshold Discharge Areas (TDA). TDA 1 includes the eastern half of 236th st and adjacent forested area as well as the eastern half of the staff parking lot and east driveway. TDA 1 drains through catch basins and pipes to the piped system in 236th St SW heading East to Edmonds Way. TDA 2 includes the eastern half of the site including half of the existing school, the southeastern field, and the large wetland. Some offsite area from the neighboring residences also is included in TDA 2. Surface runoff either sheet flows directly to the wetland or is discharged via open pipe ends or dispersion trenches. Runoff in the wetland pools at the south end against the 240th St SW embankment until reaching the 18" culvert crossing the road. Downstream of the culvert, runoff is directed to the Edmonds Way system via open ditches and pipes. TDA 3 includes the western half of the site including the remaining half of 236th st and the existing school, parent parking lot, track, and south western field. TDA 3 either sheet flows or discharges via open pipe ends or dispersion trenches to the steep slope west of the site. Edmonds School District Maintenance staff has noted that during heavy rain, flowing water originating from the steep slope encroaches on the former Woodway Elementary school. The site will be fully stabilized in the final condition through paving, landscaping, seeding, and building construction. There is no evidence to suggest that there are any existing contaminated soils or groundwater onsite. 2 Construction Stormwater Best Management Practices (BMPs) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e., hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits Prior to earthmoving activities, the clearing limits will be staked and marked to ensure protection of native vegetation. List and describe BMPs: C101, C102, C103 Installation Schedules: Prior to earthmoving. Inspection and Maintenance plan: See Appendix B. Responsible Staff: TBD Page 16 2.1.2 Element 2: Establish Construction Access Construction access shall be stabilized by maintaining existing asphalt drives, paving new asphalt treated base construction access routes, or by providing new stabilized construction entrances. Dust shall be kept to a minimum by watering and temporary site stabilization. All sediment tracked offsite by construction activity shall be swept immediately. Flushing sediment from city streets into the storm drainage system is not acceptable. List and describe BMPs: C105, C107, C140 Installation Schedules: Prior to earthmoving activity and maintained throughout construction. Inspection and Maintenance plan: See Appendix B. Responsible Staff: TBD 2.1.3 Element 3: Control Flow Rates Flow rates shall be controlled using temporary portable sedimentation tanks discharging to existing outfalls. The permanent flow control facilities (Underground Injection Control Wells) shall not be used to control any construction phase runoff in order to protect the infiltrative capacity of the soil. All runoff prior to final site stabilization shall be directed to existing outfalls. Will you construct stormwater retention and/or detention facilities? ❑ Yes ® No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? ❑ Yes ® No List and describe BMPs: Temporary Portable Sedimentation Tanks Installation Schedules: Prior to earthmoving activity. Inspection and Maintenance plan: Wet Season: Weekly and after heavy rainfall, Dry Season: Monthly and after rainfall. Responsible Staff: TBD Page 18 2.1.4 Element 4: Install Sediment Controls BMPs, including silt fence, interceptor swales, straw wattles, check dams, catch basin protection, and Temporary Portable Sedimentation Tanks will minimize sediment discharge from the site. Each phase of construction activity shall utilize these BMPs to direct all site runoff to collection points where runoff can be pumped into the sedimentation tanks prior to discharge to existing outfalls. These elements will be upgraded if necessary to account for site conditions and rainfall. List and describe BMPs: C200, C201, C202, C207, C208, C209, C220, C233, C235. Installation Schedules: Prior to earthmoving activity and maintained throughout construction. Inspection and Maintenance plan: Wet Season: Weekly and after heavy rainfall, Dry Season: Monthly and after rainfall. See Appendix B. Responsible Staff: TBD Pegs 19 2.1.5 Element 5: Stabilize Soils Exposed soil will be stabilized using a combination of temporary and semi permanent BMPs including erosion control nets, plastic covering, early top soiling, and if necessary Polyacrylamide soil stabilization. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 — September 30 7 days During the Wet Season October 1 —April 30 2 days Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: 5/1/2017 End date: 10/10/2018 Will you construct during the wet season? ® Yes ❑ No List and describe BMPs: C122, C123, C125, C126, C130, Installation Schedules: During earthmoving activity and maintained throughout construction. Inspection and Maintenance plan: Wet Season: Weekly and after heavy rainfall, Dry Season: Monthly and after rainfall. See Appendix B. Responsible Staff: TBD 2.1.6 Element 6: Protect Slopes All runoff will be directed away from proposed slopes onsite and these slopes will be covered during construction with plastic or erosion control netting. Existing steep slopes to the east and west of the site will not be disturbed aside from outfall construction and stabilization. All construction discharge to the western steep slope will be through existing stabilized outfalls. Stockpile slopes will be covered with plastic while unused. Will steep slopes be present at the site during construction? ® Yes ❑ No List and describe BMPs: C122, C123 Installation Schedules: During earthmoving activity and maintained throughout construction. Page 110 Inspection and Maintenance plan: Wet Season: Weekly and after heavy rainfall, Dry Season: Monthly and after rainfall. See Appendix B Responsible Staff: TBD 2.1.7 Element 7: Protect Drain Inlets Storm drain inlets will be protected primarily by the onsite sediment control BMPs. All inlets onsite and in the vicinity of the site will be protected with catch basin inserts. List and describe BMPs: C220 Installation Schedules: Prior to earthmoving activity. Inspection and Maintenance plan: Wet Season: Weekly and daily during rainfall, Dry Season: Monthly and daily during rainfall. See Appendix B. Responsible Staff: TBD 2.1.8 Element 8: Stabilize Channels and Outlets Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. All proposed and temporary outlets will be inspected and upgraded where necessary to suit the phase of construction and weather conditions. Final outlet stabilization will be according to the site civil construction plans. Onsite permanent and temporary channels will be lined until fully stabilized. List and describe BMPs: C122, C209 Installation Schedules: Prior to earthmoving activity and maintained throughout construction Inspection and Maintenance plan: Wet Season: Weekly and after heavy rainfall, Dry Season: Monthly and after rainfall. See Appendix B. Responsible Staff: TBD 2.1.9 Element 9: Control Pollutants The following pollutants are anticipated to be present on -site: Table 2 — Pollutants Pollutant (List pollutants and source, if applicable) Concrete dust and slurry (Building Demolition and onsite concrete work) Various Hazardous Building Materials (Existing Buildings to be demolished) Slurry generated from concrete sawcutting will be collected separately and disposed of legally. Concrete trucks will be cleaned only in designated concrete washout areas. Building demolition debris will be covered in plastic while onsite and disposed of legally. See the See 2015 RBM Assessment Report for hazardous materials specific to the existing buildings. List and describe BMPs: C151, C152, C153 Installation Schedules: During demolition and concrete work. Inspection and Maintenance plan: Daily during demolition and concrete work. Responsible Staff: TBD Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on -site? ❑ Yes ® No Will wheel wash or tire bath system BMPs be used during construction? ❑ Yes ® No Will pH -modifying sources be present on -site? ❑ Yes ❑ No Table 3 — pH -Modifying Sources ❑ None ❑ Bulk cement ❑ Cement kiln dust ❑ Fly ash ❑ Other cementitious materials ❑ New concrete washing or curing waters ® Waste streams generated from concrete grinding and sawing ❑ Exposed aggregate processes ❑ Dewatering concrete vaults Pegs 113 ® Concrete pumping and mixer washout waters ❑ Recycled concrete ❑ Rec cled concrete stockpiles ❑ Other (i.e., calcium lignosulfate) [please describe: ] Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on -site, except in designated concrete washout areas with appropriate BMPs installed. Will uncontaminated water from water -only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? ❑ Yes ® No Fags 114 2.1.10 Element 10: Control Dewatering Large scale dewatering is not anticipated for this site; however, small amounts of perched groundwater water may require dewatering from utility trenches or other excavation activity. Turbid dewatering effluent will be routed to onsite stormwater management BMPs and discharged to existing stormwater outfalls. Table 4 — Dewatering BMPs ❑ Infiltration ❑ Transport off -site in a vehicle (vacuum truck for legal disposal) ❑ Ecology -approved on -site chemical treatment or other suitable treatment technologies ❑ Sanitary or combined sewer discharge with local sewer district approval (last resort) ® Use of sedimentation bag with discharge to ditch or swale (small volumes of localized dewatering) List and describe BMPs: See other elements for onsite stormwater management BMPs. Installation Schedules: During trenching activity. Inspection and Maintenance plan: Daily during trenching activity. Responsible Staff: TBD. Page 115 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume 1l of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on -site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles: Y Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. Y Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. Y Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 5 — Management ® Design the project to fit the existing topography, soils, and drainage patterns ® Emphasize erosion control rather than sediment control ® Minimize the extent and duration of the area exposed ® Keep runoff velocities low ® Retain sediment on -site ® Thoroughly monitor site and maintain all ESC measures ® Schedule major earthwork during the dry season ❑ Other (please describe) Table 6 — BMP Implementation Schedule Phase of Construction Project Stormwater BMPs Date Wet/Dry Season [Insert construction activity] [Insert BMP] [MM/DD/YYYY] [Insert Season] Phase of Construction Project Stormwater BMPs Date Wet/Dry Season Page 118 [Insert construction activity] [Insert BMP] [MM/DD/YYYY] [Insert Season] 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs The site employs bioretention, underground injection control well, and permeable pavements. These facilities are especially sensitive to sedimentation. Prior to installation, bioretention areas will be staked, marked, and fenced to prevent compaction by heavy construction equipment. After installation, Bioretention areas will be protected from foot and construction traffic. The side slopes will be protected from concentrated flow to prevent erosion of the biofiltration media. The UIC wells will remain offline until the site has been fully stabilized in order to maintain their infiltrative capacity. Temporary sediment controls will remain until the UIC wells are brought online. Permeable pavements will be protected from sediment by careful scheduling and protection from construction traffic. Permeable pavements and permeable base material will be installed after the surrounding earthwork is complete. Permeable pavements that are fouled by sedimentation will be cleaned via water jetting vacuum truck. P a g e 120 3 Pollution Prevention Team Table 7 — Team Information Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer TBD TBD Emergency Ecology Contact TBD TBD Emergency Permittee/ Owner Contact TBD TBD Non -Emergency Owner Contact TBD TBD Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office 425-649-7000 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on -site construction activities and will include: Y A record of the implementation of the SWPPP and other permit requirements Y Site inspections Y Stormwater sampling data See Appendix D for inspection form. The site log book must be maintained on -site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 8 — Turbidity Sampling Method ® Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) ❑ Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge's turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region's Environmental Report Tracking System (ERTS) within 24 hours. Y Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/CRO nerts online,htmi Y Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 or htt ://www.ec .wa. ov/ ro rarnsls ills/formslnerts online/ERO nerts online.html Y Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or htt ://www.ec .wa. ov/ ro rams/s illslforrns/Harts online/NWRO nerts online.html Y Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or htt ://www.ec .wa. ov/ ro rarr�s/s illslforms/Harts online/SWRO nerts online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: Y Turbidity is 25 NTU (or lower). Y Transparency is 33 cm (or greater). Y Compliance with the water quality limit for turbidity is achieved. 0 1 - 5 NTU over background turbidity, if background is less than 50 NTU 0 1 % - 10% over background turbidity, if background is 50 NTU or greater Y The discharge stops or is eliminated. P a g e 123 4.2.2 pH Sampling pH monitoring is required for "Significant concrete work" (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (COO sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Table 9 — pH Sampling Method ❑ H meter ❑ pH test kit ❑ Wide range pH indicator paper P a g e 124 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies Discharges to TMDL receiving waterbodies will meet in -stream water quality criteria at the point of discharge. The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water Body form is included in Appendix F. Page 125 6 Reporting and Record Keeping 6.1 Record Keeping 6.1.1 Site Log Book A site log book will be maintained for all on -site construction activities and will include: Y A record of the implementation of the SWPPP and other permit requirements Y Site inspections Y Sample logs 6.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.0 of the CSWGP. Permit documentation to be retained on -site: Y CSWGP Y Permit Coverage Letter Y SWPPP Y Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. 6.1.3 Updating the SWPPP The SWPPP will be modified if: Y Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. Y There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. 6.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting "No Discharge". The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology's WQWebDMR System. 6.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. Y Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County Y Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County Y Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Y Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum Include the following information: Page 127 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. Pegs 128 Appendix/Glossary A. Site Map B. BMP Detail C. Correspondence D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303(d) List Waterbodies / TMDL Waterbodies Information G. Contaminated Site Information H. Engineering Calculations Page 129 Appendix A - Site Map 9'L 93RD X • rQ .. ..... ... 1A me :--- ....... . .............. DOWNSTREAM SYSTEM .......... ... ... 'A --- -------- '5' 'r EDMONDS� WAY 1 9, . . . ..... . .. . ..... . 41� I - N, """'J v. t 3 1 ti Project Title MADRONA K-8 Client MAHLUM ARCHITECTS Drawing Title EXISTING THRESHOLD DISCHARGE AREAS 1601 5th Avenue, Suite 1600 Seattle, WA 98101 206.62 .5822 .ww.kpff.co. Drawing Reference scale ill = 60' Date Dram/Ck'd By 12/05/2016 CB/JCG 3 4 5 6 E A 'HAANUW IECURTY SECTION %, TOWNSHIP 27 NORTH, RANGE 3 EAST A rLIP- KT 3F WORK ltWOPAFY HAINLINK 0US111CCnC14 FENCE F� ELU ma ;F-TEN- F A FOAM HE D LOCAT N �il,',E I ry PL FLA& I EAST Of R'R[ PHASE I S011TH OF HERE NAl 2 VOFTH OF H-RE C'� U�o rr t)WE (Tep: 7 > FE(YEM11 E4CSED J CATCA EARN OiCek DAB 4TYF) pvorvl�; cm 'rEu =,it *L NOTES 1. SEE SHEET C-300 FOR GENERAL SWPPP NOTES 2. PROTECT EXISTING AND PROPDSID UIC WELLS IN PLACE DURING ALL CONSTRUCTION ACTIATlES, NO CONSTRUCTION STORMWATER aIALL BE DISCHARGED TO THE UIC WELLS AND THE SITE SHALL BE FULLY STABILIZED PRIOR TO BRINING THE BIG WELLS ONTNE, INSTALL THE TOP OF THE SURFACE CASING A MINIMUM 6" ABOVE GRADE PER DETAIL 1/C-121 UNTIL THE PERMANENT SDMH IS INSTALLED. fofATFucncN /k�)PPO\IiED FCR jl'0N5TRJIF,-loN UllY OF EUMUNDS 0 Q 33 60 DATE: Ciii E" all 11 E WIh.! p CITY ENGINEERING DIVISION boorayoudig mahlum 71 COL MNA I FLOOR 4 OFIKE E P*RrL%M lX, I e Ll I N c lqm-. r D PRELIMINARY B "t Edmcrcis �cflco- Instf-IC' EM10S scmoot asrRct MADCNA 92$C)OL(E&r) 9300 26-11 iT,SY%, E)MON)8,VoA 10020 MARP DOTE DESCkWMN mWE DATEe 05 DECEMBER 2016 ISSUE SITEP23MIT ?R�TWO'.- 150)129 DRAW4 ay, I CB CH90EW, JCGrTJE A STOW WATER P(RULUTXM p NriflN (SWPPI PLAN am 1 2 3 4 5 6 I 2 3 5 6 E D C 111111" ,"lIVIG' 56 01-Ct . AND Rhmp-C-0 TWOPART FW,5URE-- '-- DSL'4ATq, TO S:DWFtTftTLCl 'A All IHl- 11 HE. H"k , HFIE MUM low m AN Imis Am. SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST 1Wa QLALTY SWPIN, 01 'EW ORAF , V Y 3I?Vf"Y P NS�H.T IROA TANSlXblI4Q ',EJIHM TEMOCAFY #0EUl SIDIMEP-TAOGN TAN((.g 50,00 GkI-04 (BaKEL OR EWIVNLENT" FILL) LockTF TIJAfOrAF.Y INTVIRG-Pl0fi. DRAINAGE SNAI 7iED LOCATE (71) GCOtXTU CifD'K DAVI (M) I`w i9 `6 L30TE PR)POSE) BIG WEL owm(t SEAL SEE TEED LCCAJE (TV) T� 7'k E t "';k I ",st 2 W ?ERE. 'O-E tCHECK JAB �DYP) MI`MR' PRESSURE Fflb LX14E DIS(>AFP[ TG SrDIFF)TARON TANK(S) T4*10RARY A' ORE SRUNENT A 10M T94US) 23GOOGALLN (BAKE twIllAfy 101ILl ZZ11111tATI111 QUWALENT), n1t, LACITE. 'AW() °OXJC GAU-* (BIAM DR 9 EQUVA-BT) FIELD LOCATE, TEVp')RARY C$AMTY PRE3SkRE DY,. 1.13C mw TmK TZ Dooc,,— TI, TIWQIRti +a—fl E'MSTNO 09-9TE A,'OPM D&CfAFGF FFCIMI T,,NK TO E , USIN Ot_31TJ _TCRM NOTES 1. SEE SHEET C-300 FOR GENERAL SIMPER NOTES. 2. PROTECT FASTING AND PROPDSfD UIC WELLS IN PLACE DURING ALL CONSTRUCTION ACTIATlES, NO CONSTRUCTION STORMWATER SLIALL BE DISCHARGED TO THE UIC WELLS AND THE SITE SHALL BE FULLY STABILIZED PRIOR TO BRINING THE UIC WELLS ONUNE, INSTALL THE TOP OF THE SURFACE CASING A MINIMUM 6" ABOVE GRADE PER DETAIL 1/C-121 JNnL THE PERMANENT SDMH IS INSTALLED. KEY PLAN i4�1 ADPRO\�ED FCR -�ONSTRJC-10N Ul I Y Ul- EDMONDS DATE: Ewa" ilo lij BY.. CITY ENGINEERING DIVISION 1 inch X fc,,t b"youdig mahlum 71 COL AMA I FLOOR 4 1�11 E P*RrL%M :'�� 'I, ". �. "", � �-' le I 'l— AM INC D PRELIMINARY te Ecd, cmro c c i s VIST'VICT EM10S scmoot asrRct MADNCNA 92$OOL(E&r) 9300 29-11 ' T, SV%, E)WON)8, VoA 94020 C B MARR DATE DESCRprioN MIME DATEa 05 DECEMBER2016 ME, SITE PEIWIT PR�T 140— 150,"29 DRAW al; CB C119cup ", JCGr.E A STOIN WATER POWTh" P NriflN (SWPP) PLAN =A 1 2 4 6 PR)POSE) BIG WEL owm(t SEAL SEE TEED LCCAJE (TV) T� 7'k E t "';k I ",st 2 W ?ERE. 'O-E tCHECK JAB �DYP) MI`MR' PRESSURE Fflb LX14E DIS(>AFP[ TG SrDIFF)TARON TANK(S) T4*10RARY A' ORE SRUNENT A 10M T94US) 23GOOGALLN (BAKE twIllAfy 101ILl ZZ11111tATI111 QUWALENT), n1t, LACITE. 'AW() °OXJC GAU-* (BIAM DR 9 EQUVA-BT) FIELD LOCATE, TEVp')RARY C$AMTY PRE3SkRE DY,. 1.13C mw TmK TZ Dooc,,— TI, TIWQIRti +a—fl E'MSTNO 09-9TE A,'OPM D&CfAFGF FFCIMI T,,NK TO E , USIN Ot_31TJ _TCRM NOTES 1. SEE SHEET C-300 FOR GENERAL SIMPER NOTES. 2. PROTECT FASTING AND PROPDSfD UIC WELLS IN PLACE DURING ALL CONSTRUCTION ACTIATlES, NO CONSTRUCTION STORMWATER SLIALL BE DISCHARGED TO THE UIC WELLS AND THE SITE SHALL BE FULLY STABILIZED PRIOR TO BRINING THE UIC WELLS ONUNE, INSTALL THE TOP OF THE SURFACE CASING A MINIMUM 6" ABOVE GRADE PER DETAIL 1/C-121 JNnL THE PERMANENT SDMH IS INSTALLED. KEY PLAN i4�1 ADPRO\�ED FCR -�ONSTRJC-10N Ul I Y Ul- EDMONDS DATE: Ewa" ilo lij BY.. CITY ENGINEERING DIVISION 1 inch X fc,,t b"youdig mahlum 71 COL AMA I FLOOR 4 1�11 E P*RrL%M :'�� 'I, ". �. "", � �-' le I 'l— AM INC D PRELIMINARY te Ecd, cmro c c i s VIST'VICT EM10S scmoot asrRct MADNCNA 92$OOL(E&r) 9300 29-11 ' T, SV%, E)WON)8, VoA 94020 C B MARR DATE DESCRprioN MIME DATEa 05 DECEMBER2016 ME, SITE PEIWIT PR�T 140— 150,"29 DRAW al; CB C119cup ", JCGr.E A STOIN WATER POWTh" P NriflN (SWPP) PLAN =A 1 2 4 6 Appendix B - BMP Detail 4.1 Source Control BMPs BMP C101: Preserving Natural Vegetation Purpose The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting site disturbance is the single most effective method for reducing erosion. For example, conifers can hold up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this rain. may never reach the ground but is taken up by the tree or evaporates. Another benefit is that the rain held in the tree can be released slowly to the ground after the storm. Conditions of Use • Natural vegetation should be preserved on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. • As required by local governments. Design and Natural vegetation can be preserved in natural clumps or as individual Installation trees, shrubs and vines. Specifications The preservation of individual plants is more difficult because heavy equipment is generally used to remove unwanted vegetation. The points to remember when attempting to save individual plants are: • Is the plant worth saving? Consider the location, species, size, age, vigor, and the work involved. Local governments may also have ordinances to save natural vegetation and trees. • Fence or clearly mark areas around trees that are to be saved. It is preferable to keep ground disturbance away from the trees at least as far out as the dripline. Plants need protection from three kinds of injuries: Construction Equipment - This injury can be above or below the ground level. Damage results from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer zone around plants to be saved prior to construction can prevent construction equipment injuries. Grade Changes - Changing the natural ground level will alter grades, which affects the plant's ability to obtain the necessary air, water, and minerals. Minor fills usually do not cause problems although sensitivity between species does vary and should be checked. Trees can tolerate fill of 6 inches or less. For shrubs and other plants, the fill should be less. When there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be done by placing a layer of gravel and a the system over the roots before the fill is made. A the 4-2 Volume 11 — Construction Stormwater Pollution Prevention February 2005 system protects a tree from a raised grade. The the system should be laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered with small stones to allow air to circulate over the root area. Lowering the natural ground level can seriously damage trees and shrubs. The highest percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be necessary to terrace the immediate area around the plants to be saved. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants can also be preserved by leaving them on an undisturbed, gently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside the dripline of the plant. • Excavations - Protect trees and other plants when excavating for drainfields, power, water, and sewer lines. Where possible, the trenches should be routed around trees and large shrubs. When this is not possible, it is best to tunnel under them. This can be done with hand tools or with power augers. If it is not possible to route the trench around plants to be saved, then the following should be observed: Cut as few roots as possible. When you have to cut, cut clean. Paint cut root ends with a wood dressing like asphalt base paint. Backfill the trench as soon as possible. Tunnel beneath root systems as close to the center of the main trunk to preserve most of the important feeder roots. Some problems that can be encountered with a few specific trees are: • Maple, Dogwood, Red alder, Western hemlock, Western red cedar, and Douglas fir do not readily adjust to changes in environment and special care should be taken to protect these trees. • The windthrow hazard of Pacific silver fir and madronna is high, while that of Western hemlock is moderate. The danger of windthrow increases where dense stands have been thinned. Other species (unless they are on shallow, wet soils less than 20 inches deep) have a low windthrow hazard. • Cottonwoods, maples, and willows have water -seeking roots. These can cause trouble in sewer lines and infiltration fields. On the other hand, they thrive in high moisture conditions that other trees would not. • Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, Sitka spruce, Western red cedar, Western hemlock, February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-3 Pacific dogwood, and Red alder can cause serious disease problems. Disease can become established through damaged limbs, trunks, roots, and freshly cut stumps. Diseased and weakened trees are also susceptible to insect attack. Maintenance Inspect flagged and/or fenced areas regularly to make sure flagging or Standards fencing has not been removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. • If tree roots have been exposed or injured, "prune" cleanly with an. appropriate pruning saw or topers directly above the damaged roots and recover with native soils. Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. 4-4 Volume lI — Construction Stormwater Pollution Prevention February 2005 BMP C102: Buffer Zones Purpose An undisturbed area or strip of natural vegetation or an established suitable planting that will provide a living filter to reduce soil erosion and runoff velocities. Conditions of Use Natural buffer zones are used along streams, wetlands and other bodies of water that need protection from erosion and sedimentation. Vegetative buffer zones can be used to protect natural swales and can be incorporated into the natural landscaping of an area. Critical -areas buffer zones should not be used as sediment treatment areas. These areas shall remain completely undisturbed. The local permitting authority may expand the buffer widths temporarily to allow the use of the expanded area for removal of sediment. Design and • Preserving natural vegetation or plantings in clumps, blocks, or strips Installation is generally the easiest and most successful method. Specifications Leave all unstable steep slopes in natural vegetation. • Mark clearing limits and keep all equipment and construction debris out of the natural areas. Steel construction fencing is the most effective method in protecting sensitive areas and buffers. Alternatively, wire -backed silt fence on steel posts is marginally effective. Flagging alone is typically not effective. • Keep all excavations outside the dripline of trees and shrubs. • Do not push debris or extra soil into the buffer zone area because it will cause damage from burying and smothering. • Vegetative buffer zones for streams, lakes or other waterways shall be established by the local permitting authority or other state or federal permits or approvals. Maintenance Inspect the area frequently to make sure flagging remains in place Standards and the area remains undisturbed. February 2005 Volume ll — Construction Stormwater Pollution Prevention 4-5 BMP C103: High Visibility Plastic or Metal Fence Purpose Fencing is intended to: (1) restrict clearing to approved limits; (2) prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and, (4) protect areas where marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits, plastic or metal fence may be used: • At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared. As necessary to control vehicle access to and on the site. Design and High visibility plastic fence shall be composed of a high -density Installation polyethylene material and shall be at least four feet in height. Posts Specifications for the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to prevent sagging between posts. The fence color shall be high visibility orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM D4595 testing method. Metal fences shall be designed and installed according to the manufacturer's specifications. • Metal fences shall be at least 3 feet high and must be highly visible. • Fences shall not be wired or stapled to trees. Maintenance If the fence has been damaged or visibility reduced, it shall be Standards repaired or replaced immediately and visibility restored. 4-6 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C105: Stabilized Construction Entrance Purpose Construction entrances are stabilized to reduce the amount of sediment transported onto paved roads by vehicles or equipment by constructing a stabilized pad of quarry spalls at entrances to construction sites. Conditions of Use Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within 1,000 feet of the site. Design and Installation Specifications On large commercial, highway, and road projects, the designer should include enough extra materials in the contract to allow for additional stabilized entrances not shown in the initial Construction SWPPP. It is difficult to determine exactly where access to these projects will take place; additional materials will enable the contractor to install them where needed. See Figure 4.2 for details. Note: the 100' minimum length of the entrance shall be reduced to the maximum practicable size when the size or configuration of the site does not allow the full length (100'). • A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4751) 200 psi min. Grab Tensile Elongation (ASTM D4632) 30% max. Mullen Burst Strength (ASTM D3786-80a) 400 psi min. AOS (ASTM D4751) 20-45 (U.S. standard sieve size) • Consider early installation of the first lift of asphalt in areas that will paved; this can be used as a stabilized entrance. Also consider the installation of excess concrete as a stabilized entrance. During large concrete pours, excess concrete is often available for this purpose. • Hog fuel (wood -based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. Hog fuel is generally less effective at stabilizing construction entrances and should be used only at sites where the amount of traffic is very limited. Hog fuel is not recommended for entrance stabilization in urban areas. The effectiveness of hog fuel is highly variable and it generally requires more maintenance than quarry spalls. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause degradation of the subgrade support over time. • Fencing (see BMPs C103 and C104) shall be installed as necessary to restrict traffic to the construction entrance. 4-8 Volume 11 — Construction Stormwater Pollution Prevention February 2005 • Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance Quarry spalls (or hog fuel) shall be added if the pad is no longer in Standards accordance with the specifications. • If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. • Any sediment that is tracked onto pavement shall be removed by shoveling or street sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, the construction of a small sump shall be considered. The sediment would then be washed into the sump where it can be controlled. • Any quarry spalls that are loosened from the pad, which end up on the roadway shall be removed immediately. • If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see BMPs C 103 and C 104) shall be installed to control traffic. • Upon project completion and site stabilization, all construction accesses intended as permanent access for maintenance shall be permanently stabilized. Driveway shall meet the requirements of the permitting agency It is recommended that the entrance be crowned so that runoff oad drains off the pad i Install driveway culvert if there is a roadside ditch present 4"-8" quarry spalls Geotextile 12" min. thickness Provide full width of ingress/egress area Figure 4.2 — Stabilized Construction Entrance February 2005 Volume Il — Construction Stormwater Pollution Prevention 4-9 BMP C107: Construction Road/Parking Area Stabilization Purpose Stabilizing subdivision roads, parking areas, and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use ' Roads or parking areas shall be stabilized wherever they are constructed, whether permanent or temporary, for use by construction traffic. • Fencing (see BMPs C1.03 and C104) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and • On areas that will receive asphalt as part of the project, install the first Installation lift as soon as possible. Specifications A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is used for roadbase stabilization, pH monitoring and BMPs are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. • Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super -elevated section. Drainage ditches shall be directed to a sediment control BMP. Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet -flows into a heavily vegetated area with a well - developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include wetlands. If runoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. • Storm drain inlets shall be protected to prevent sediment -laden water entering the storm drain system (see BMP C220). Maintenance • Inspect stabilized areas regularly, especially after large storm events. Standards . Crushed rock, gravel base, hog fuel, etc. shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. Following construction, these areas shall be restored to pre -construction condition or better to prevent future erosion. 4-12 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C122: Nets and Blankets Purpose Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation. can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets (commonly called matting) are strands of material woven into an open, but high -tensile strength net (for example, coconut fiber matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: • To aid permanent vegetated stabilization of slopes 2H:1 V or greater and with more than 10 feet of vertical relief. For drainage ditches and swales (highly recommended). The application of appropriate netting or blanket to drainage ditches and swales can protect bare soil from channelized runoff while vegetation is established. Nets and blankets also can capture a great deal of sediment due to their open, porous structure. Synthetic nets and blankets can be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. 100 percent synthetic blankets manufactured for use in ditches may be easily reused as temporary ditch liners. Disadvantages of blankets include: • Surface preparation required; • On slopes steeper than 2.5:1, blanket installers may need to be roped and harnessed for safety; • They cost at least $4,000-6,000 per acre installed. Advantages of blankets include: • Can be installed without mobilizing special equipment; • Can be installed by anyone with minimal training; • Can be installed in stages or phases as the project progresses; • Seed and fertilizer can be hand -placed by the installers as they progress down the slope; • Can be installed in any weather; • There are numerous types of blankets that can be designed with various parameters in mind. Those parameters include: fiber blend, mesh strength, longevity, biodegradability, cost, and availability. 4-22 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Design and See Figure 4.4 and Figure 4.5 for typical orientation and installation of Installation blankets used in channels and as slope protection. Note: these are Specifications typical only; all blankets must be installed per manufacturer's installation instructions. • Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. • Installation of Blankets on Slopes: 1. Complete final grade and track walk up and down the slope. 2. Install hydromulch with seed and fertilizer. 3. Dig a small trench, approximately 12 inches wide by 6 inches deep along the top of the slope. 4. Install the leading edge of the blanket into the small trench and staple approximately every 18 inches. NOTE: Staples are metal,"U"-shaped, and a minimum of 6 inches long. Longer staples are used in sandy soils. Biodegradable stakes are also available. Roll the blanket slowly down the slope as installer walks backwards. NOTE: The blanket rests against the installer's legs. Staples are installed as the blanket is unrolled. It is critical that the proper staple pattern is used for the blanket being installed. The blanket is not to be allowed to roll down the slope on its own as this stretches the blanket making it impossible to maintain soil contact. In addition, no one is allowed to walk on the blanket after it is in place. 6. If the blanket is not long enough to cover the entire slope length, the trailing edge of the upper blanket should overlap the leading edge of the lower blanket and be stapled. On steeper slopes, this overlap should be installed in a small trench, stapled, and covered with soil. With the variety of products available, it is impossible to cover all the details of appropriate use and installation. Therefore, it is critical that the design engineer consults the manufacturer's information and that a site visit takes place in order to insure that the product specified is appropriate. Information is also available at the following web sites: 1. WSDOT: http://www.wsdot.wa.gov/eesc/environmental/ 2. Texas Transportation Institute: http://www. dot. state.tx.us/insdtdot/orgchart/cmd/erosion/contents. htm February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-23 • Jute matting must be used in conjunction with mulch (BMP C121). Excelsior, woven straw blankets and coir (coconut fiber) blankets may be installed without mulch. There are many other types of erosion control nets and blankets on the market that may be appropriate in certain circumstances. In general, most nets (e.g., jute matting) require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. • Extremely steep, unstable, wet, or rocky slopes are often appropriate candidates for use of synthetic blankets, as are riverbanks, beaches and other high-energy environments. If synthetic blankets are used, the soil should be hydromulched first. 100 percent biodegradable blankets are available for use in sensitive areas. These organic blankets are usually held together with a paper or fiber mesh and stitching which may last up to a year. • Most netting used with blankets is photodegradable, meaning they break down under sunlight (not UV stabilized). However, this process can take months or years even under bright sun. Once vegetation is established, sunlight does not reach the mesh. It is not uncommon to find non -degraded netting still in place several years after installation. This can be a problem if maintenance requires the use of mowers or ditch cleaning equipment. In addition, birds and small animals can become trapped in the netting. Maintenance Good contact with the ground must be maintained, and erosion must Standards not occur beneath the net or blanket. • Any areas of the net or blanket that are damaged or not in close contact with the ground shall be repaired and stapled. • If erosion occurs due to poorly controlled drainage, the problem shall be fixed and the eroded area protected. 4-24 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Longitudinal Anchor Trench Terminal Slope and Channel Anchor Trench Stake at T-5' 1-1.5m) intervals. _loll Check slot at 25' (7.6m) intervals Isometric View Initial Channel Anchor Trench Intermittent Check Slot NOTES: 1. Check slots to be constructed per manufacturers specifications. 2. Staking or stapling layout per manufacturers specifications. Figure 4.4 — Channel Installation Slope surface shall be smooth before placement for proper soil contact. Stapling pattern as per T+ I A f; -- If there is a berm at the upslope of the berm. top of slope, anchor manu urer s recommen a ions. Min. 2" Overlap i. I Anchor in 6"W' min. Trench and staple at 12" intervals. -T Min. 6" overlap. FT Staple overlaps ==—=—W I EI11 I11 I11 I1=1 max. 5"spacing.L�F—,F .LV1-1, Bring material down to a level area, turn Do not stretch blankets/mattings tight - the end under 4" and staple at 12" intervals. allow the rolls to mold to any irregularities. For slopes less than 3HAV, rolls Lime, fertilize, and seed before installation. may be placed in horizontal strips. Planting of shrubs, trees, etc. Should occur after installation. Figure 4.5 — Slope Installation February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-25 BMP C123: Plastic Covering Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Plastic covering may be used on disturbed areas that require cover Use measures for less than 30 days, except as stated below. Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term (greater than six months) applications. Clear plastic sheeting can be used over newly -seeded areas to create a greenhouse effect and encourage grass growth if the hydroseed was installed too late in the season to establish 75 percent grass cover, or if the wet season started earlier than normal. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass. • Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. • While plastic is inexpensive to purchase, the added cost of installation, maintenance, removal, and disposal make this an expensive material, up to $1.50-2.00 per square yard. Whenever plastic is used to protect slopes, water collection measures must be installed at the base of the slope. These measures include plastic -covered berms, channels, and pipes used to covey clean rainwater away from bare soil and disturbed areas. At no time is clean runoff from a plastic covered slope to be mixed with dirty runoff from a project. • Other uses for plastic include: 1. Temporary ditch liner; 2. Pond liner in temporary sediment pond; 3. Liner for bermed temporary fuel storage area if plastic is not reactive to the type of fuel being stored; 4. Emergency slope protection during heavy rains; and, 5. Temporary drainpipe ("elephant trunk") used to direct water. 4-26 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Design and Installation Specifications Maintenance Standards • Plastic slope cover must be installed as follows: 1. Run plastic up and down slope, not across slope; 2. Plastic may be installed perpendicular to a slope if the slope length is less than 10 feet; 3. Minimum of 8-inch overlap at seams; 4. On long or wide slopes, or slopes subject to wind, all seams should be taped; 5. Place plastic into a small (12-inch wide by 6-inch deep) slot trench at the top of the slope and backfill with soil to keep water from flowing underneath; 6. Place sand filled burlap or geotextile bags every 3 to 6 feet along seams and pound a wooden stake through each to hold them in place; 7. Inspect plastic for rips, tears, and open seams regularly and repair immediately. This prevents high velocity runoff from contacting bare soil which causes extreme erosion; 8. Sandbags may be lowered into place tied to ropes. However, all sandbags must be staked in place. • Plastic sheeting shall have a minimum thickness of 0.06 millimeters. • If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. • Torn sheets must be replaced and open seams repaired. • If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced. When the plastic is no longer needed, it shall be completely removed. Dispose of old tires appropriately. February 2005 Volume /I — Construction Stormwater Pollution Prevention 4-27 BMP C125: Topsoiling Purpose To provide a suitable growth medium for final site stabilization with vegetation. While not a permanent cover practice in itself, topsoiling is an integral component of providing permanent cover in those areas where there is an unsuitable soil surface for plant growth. Native soils and disturbed soils that have been organically amended not only retain much more stormwater, but they also serve as effective biofilters for urban pollutants and, by supporting more vigorous plant growth, reduce the water, fertilizer and pesticides needed to support installed landscapes. Topsoil does not include any subsoils but only the material from the top several inches including organic debris. Conditions of Native soils should be left undisturbed to the maximum extent Use practicable. Native soils disturbed during clearing and grading should be restored, to the maximum extent practicable, to a condition where moisture -holding capacity is equal to or better than the original site conditions. This criterion can be met by using on -site native topsoil, incorporating amendments into on -site soil, or importing blended topsoil. • Topsoiling is a required procedure when establishing vegetation on shallow soils, and soils of critically low pH (high acid) levels. • Stripping of existing, properly functioning soil system and vegetation for the purpose of topsoiling during construction is not acceptable. If an existing soil system is functioning properly it shall be preserved in its undisturbed and uncompacted condition. • Depending on where the topsoil comes from, or what vegetation was on site before disturbance, invasive plant seeds may be included and could cause problems for establishing native plants, landscaped areas, or grasses. • Topsoil from the site will contain mycorrhizal bacteria that are necessary for healthy root growth and nutrient transfer. These native mycorrhiza are acclimated to the site and will provide optimum conditions for establishing grasses. Commercially available mycorrhiza products should be used when topsoil is brought in from off -site. Design and If topsoiling is to be done, the following items should be considered: Installation Maximize the depth of the topsoil wherever possible to provide the Specifications maximum possible infiltration capacity and beneficial growth medium. Topsoil depth shall be at least 8 inches with a minimum organic content of 10 percent dry weight and pH between 6.0 and 8.0 or matching the pH of the undisturbed soil. This can be accomplished either by returning native topsoil to the site and/or incorporating organic amendments. Organic amendments should be incorporated to a minimum 8-inch depth except where tree roots or other natural February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-29 features limit the depth of incorporation. Subsoils below the 12-inch depth should be scarified at least 2 inches to avoid stratified layers, where feasible. The decision to either layer topsoil over a subgrade or incorporate topsoil into the underlying layer may vary depending on the planting specified. • If blended topsoil is imported, then fines should be limited to 25 percent passing through a 200 sieve. • The final composition and construction of the soil system will result in a natural selection or favoring of certain plant species over time. For example, recent practices have shown that incorporation of topsoil may favor grasses, while layering with mildly acidic, high -carbon amendments may favor more woody vegetation. • Locate the topsoil stockpile so that it meets specifications and does not interfere with work on the site. It may be possible to locate more than one pile in proximity to areas where topsoil will be used. • Allow sufficient time in scheduling for topsoil to be spread prior to seeding, sodding, or planting. • Care must be taken not to apply to subsoil if the two soils have contrasting textures. Sandy topsoil over clayey subsoil is a particularly poor combination, as water creeps along the junction between the soil layers and causes the topsoil to slough. • If topsoil and subsoil are not properly bonded, water will not infiltrate the soil profile evenly and it will be difficult to establish vegetation. The best method to prevent a lack of bonding is to actually work the topsoil into the layer below for a depth of at least 6 inches. • Ripping or re -structuring the subgrade may also provide additional benefits regarding the overall infiltration and interflow dynamics of the soil system. • Field exploration of the site shall be made to determine if there is surface soil of sufficient quantity and quality to justify stripping. Topsoil shall be friable and loamy (loam, sandy loam, silt loam, sandy clay loam, clay loam). Areas of natural ground water recharge should be avoided. • Stripping shall be confined to the immediate construction area. A 4- to 6- inch stripping depth is common, but depth may vary depending on the particular soil. All surface runoff control structures shall be in place prior to stripping. Stockpiling of topsoil shall occur in the following manner: • Side slopes of the stockpile shall not exceed 2:1. • An interceptor dike with gravel outlet and silt fence shall surround all topsoil stockpiles between October 1 and April 30. Between May 1 4-30 Volume 11 — Construction Stormwater Pollution Prevention February 2005 and September 30, an interceptor dike with gravel outlet and silt fence shall be installed if the stockpile will remain in place for a longer period of time than active construction grading. • Erosion control seeding or covering with clear plastic or other mulching materials of stockpiles shall be completed within 2 days (October 1 through April 30) or 7 days (May 1 through September 30) of the formation of the stockpile. Native topsoil stockpiles shall not be covered with plastic. • Topsoil shall not be placed while in a frozen or muddy condition, when the subgrade is excessively wet, or when conditions exist that may otherwise be detrimental to proper grading or proposed sodding or seeding. • Previously established grades on the areas to be topsoiled shall be maintained according to the approved plan. • When native topsoil is to be stockpiled and reused the following should apply to ensure that the mycorrhizal bacterial, earthworms, and other beneficial organisms will not be destroyed: 1. Topsoil is to be re -installed within 4 to 6 weeks; 2. Topsoil is not to become saturated with water; 3. Plastic cover is not allowed. Maintenance Inspect stockpiles regularly, especially after large storm events. Standards Stabilize any areas that have eroded. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-31 BMP C126: Polyacrylamide for Soil Erosion Protection Purpose Polyacrylamide (PAM) is used on construction sites to prevent soil erosion. Applying PAM to bare soil in advance of a rain event significantly reduces erosion and controls sediment in two ways. First, PAM increases the soil's available pore volume, thus increasing infiltration through flocculation and reducing the quantity of sormwater runoff. Second, it increases flocculation of suspended particles and aids in their deposition, thus reducing sormwater runoff turbidity and improving water quality. Conditions of Use PAM shall not be directly applied to water or allowed to enter a water body. In areas that drain to a sediment pond, PAM can be applied to bare soil under the following conditions: • During rough grading operations. • Staging areas. • Balanced cut and fill earthwork. • Haul roads prior to placement of crushed rock surfacing. • Compacted soil roadbase. • Stockpiles. • After final grade and before paving or final seeding and planting. • Pit sites. • Sites having a winter shut down. In the case of winter shut down, or where soil will remain unworked for several months, PAM should be used together with mulch. Design and PAM may be applied in dissolved form with water, or it may be applied in Installation dry, granular or powdered form. The preferred application method is the Specifications dissolved form. PAM is to be applied at a maximum rate of 2/3 pound PAM per 1000 gallons water (80 mg/L) per 1 acre of bare soil. Table 4.8 can be used to determine the PAM and water application rate for a disturbed soil area. Higher concentrations of PAM do not provide any additional effectiveness. Table 4.8 PAM and Water Application Rates Disturbed Area (ac) PAM Ibs Water al 0.50 0.33 500 1.00 0.66 1,000 1.50 1.00 1,500 2.00 1.32 2,000 2.50 1.65 2,500 3.00 2.00 3,000 3.50 2.33 3,500 4.00 2.65 4,000 4.50 3.00 4,500 5.00 3.33 5,000 4-32 Volume 11 — Construction Stormwater Pollution Prevention February 2005 The Preferred Method: • Pre -measure the area where PAM is to be applied and calculate the amount of product and water necessary to provide coverage at the specified application rate (2/3 pound PAM/1000 gallons/acre). • PAM has infinite solubility in water, but dissolves very slowly. Dissolve pre -measured dry granular PAM with a known quantity of clean water in a bucket several hours or overnight. Mechanical mixing will help dissolve the PAM. Always add PAM to water - not water to PAM. • Pre -fill the water truck about 1/8 full with water. The water does not have to be potable, but it must have relatively low turbidity — in the range of 20 NTU or less. • Add PAM /Water mixture to the truck • Completely fill the water truck to specified volume. • Spray PAM/Water mixture onto dry soil until the soil surface is uniformly and completely wetted. An Alternate Method: PAM may also be applied as a powder at the rate of 5 lbs. per acre. This must be applied on a day that is dry. For areas less than 5-10 acres, a hand-held "organ grinder" fertilizer spreader set to the smallest setting will work. Tractor -mounted spreaders will work for larger areas. The following shall be used for application of PAM: • PAM shall be used in conjunction with other BMPs and not in place of other BMPs. • Do not use PAM on a slope that flows directly into a stream or wetland. The stormwater runoff shall pass through a sediment control BMP prior to discharging to surface waters. • Do not add PAM to water discharging from site. • When the total drainage area is greater than or equal to 5 acres, PAM treated areas shall drain to a sediment pond. • Areas less than 5 acres shall drain to sediment control BMPs, such as a minimum of 3 check dams per acre. The total number of check dams used shall be maximized to achieve the greatest amount of settlement of sediment prior to discharging from the site. Each check dam shall be spaced evenly in the drainage channel through which stormwater flows are discharged off -site. • On all sites, the use of silt fence shall be maximized to limit the discharges of sediment from the site. • All areas not being actively worked shall be covered and protected from rainfall. PAM shall not be the only cover BMP used. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-33 • PAM can be applied to wet soil, but dry soil is preferred due to less sediment loss. • PAM will work when applied to saturated soil but is not as effective as applications to dry or damp soil. • Keep the granular PAM supply out of the sun. Granular PAM loses its effectiveness in three months after exposure to sunlight and air. • Proper application and re -application plans are necessary to ensure total effectiveness of PAM usage. • PAM, combined with water, is very slippery and can be a safety hazard. Care must be taken to prevent spills of PAM powder onto paved surfaces. During an application of PAM, prevent over -spray from reaching pavement as pavement will become slippery. If PAM powder gets on skin or clothing, wipe it off with a rough towel rather than washing with water -this only makes cleanup messier and take longer. • Some PAMs are more toxic and carcinogenic than others. Only the most environmentally safe PAM products should be used. The specific PAM copolymer formulation must be anionic. Cationic PAM shall not be used in any application because of known aquatic toxicity problems. Only the highest drinking water grade PAM, certified for compliance with ANSI/NSF Standard 60 for drinking water treatment, will be used for soil applications. Recent media attention and high interest in PAM has resulted in some entrepreneurial exploitation of the term "polymer." All PAM are polymers, but not all polymers are PAM, and not all PAM products comply with ANSI/NSF Standard 60. PAM use shall be reviewed and approved by the local permitting authority. The Washington State Department of Transportation (WSDOT) has listed approved PAM products on their web page. • PAM designated for these uses should be "water soluble" or "linear" or "non-crosslinked". Cross -linked or water absorbent PAM, polymerized in highly acidic (pH<2) conditions, are used to maintain soil moisture content. • The PAM anionic charge density may vary from 2-30 percent; a value of 18 percent is typical. Studies conducted by the United States Department of Agriculture (USDA)/ARS demonstrated that soil stabilization was optimized by using very high molecular weight (12- 15 mg/mole), highly anionic (>20% hydrolysis) PAM. • PAM tackifiers are available and being used in place of guar and alpha plantago. Typically, PAM tackifiers should be used at a rate of no more than 0.5-1 lb. per 1000 gallons of water in a hydromulch machine. Some tackifier product instructions say to use at a rate of 3 — 4-34 Volume 11 — Construction Stormwater Pollution Prevention February 2005 5 lbs. per acre, which can be too much. In addition, pump problems can occur at higher rates due to increased viscosity. Maintenance PAM may be reapplied on actively worked areas after a 48-hour Standards period. Reapplication is not required unless PAM treated soil is disturbed or unless turbidity levels show the need for an additional application. If PAM treated soil is left undisturbed a reapplication may be necessary after two months. More PAM applications may be required for steep slopes, silty and clayey soils (USDA Classification Type "C" and "D" soils), long grades, and high precipitation areas. When PAM is applied first to bare soil and then covered with straw, a reapplication may not be necessary for several months. • Loss of sediment and PAM may be a basis for penalties per RCW 90.48.080. February 2005 Volume /I — Construction Stormwater Pollution Prevention 4-35 BMP C130: Surface Roughening Purpose Surface roughening aids in the establishment of vegetative cover, reduces runoff velocity, increases infiltration, and provides for sediment trapping through the provision of a rough soil surface. Horizontal depressions are created by operating a tiller or other suitable equipment on the contour or by leaving slopes in a roughened condition by not fine grading them. Conditions for All slopes steeper than 3:1 and greater than 5 vertical feet require Use surface roughening. • Areas with grades steeper than 3:1 should be roughened to a depth of 2 to 4 inches prior to seeding. • Areas that will not be stabilized immediately may be roughened to reduce runoff velocity until seeding takes place. • Slopes with a stable rock face do not require roughening. • Slopes where mowing is planned should not be excessively roughened. Design and There are different methods for achieving a roughened soil surface on a Installation slope, and the selection of an appropriate method depends upon the type of Specifications slope. Roughening methods include stair -step grading, grooving, contour furrows, and tracking. See Figure 4.6 for tracking and contour furrows. Factors to be considered in choosing a method are slope steepness, mowing requirements, and whether the slope is formed by cutting or filling. • Disturbed areas that will not require mowing may be stair -step graded, grooved, or left rough after filling. • Stair -step grading is particularly appropriate in soils containing large amounts of soft rock. Each "step" catches material that sloughs from above, and provides a level site where vegetation can become established. Stairs should be wide enough to work with standard earth moving equipment. Stair steps must be on contour or gullies will form on the slope. • Areas that will be mowed (these areas should have slopes less steep than 3:1) may have small furrows left by disking, harrowing, raking, or seed -planting machinery operated on the contour. • Graded areas with slopes greater than 3:1 but less than 2:1 should be roughened before seeding. This can be accomplished in a variety of ways, including "track walking," or driving a crawler tractor up and down the slope, leaving a pattern of cleat imprints parallel to slope contours. • Tracking is done by operating equipment up and down the slope to leave horizontal depressions in the soil. Maintenance • Areas that are graded in this manner should be seeded as quickly as Standards possible. • Regular inspections should be made of the area. If rills appear, they should be re -graded and re -seeded immediately. 4-36 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Figure 4.6 — Surface Roughening by Tracking and Contour Furrows February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-37 BMP C140: Dust Control Purpose Dust control prevents wind transport of dust from disturbed soil surfaces onto roadways, drainage ways, and surface waters. Conditions of Use In areas (including roadways) subject to surface and air movement of dust where on -site and off -site impacts to roadways, drainage ways, or surface waters are likely. Design and • Vegetate or mulch areas that will not receive vehicle traffic. In areas Installation where planting, mulching, or paving is impractical, apply gravel or Specifications landscaping rock. • Limit dust generation by clearing only those areas where immediate activity will take place, leaving the remaining area(s) in the original condition, if stable. Maintain the original ground cover as long as practical. • Construct natural or artificial windbreaks or windscreens. These may be designed as enclosures for small dust sources. • Sprinkle the site with water until surface is wet. Repeat as needed. To prevent carryout of mud onto street, refer to Stabilized Construction Entrance (BMP C105). • Irrigation water can be used for dust control. Irrigation systems should be installed as a first step on sites where dust control is a concern. • Spray exposed soil areas with a dust palliative, following the manufacturer's instructions and cautions regarding handling and application. Used oil is prohibited from use as a dust suppressant. Local governments may approve other dust palliatives such as calcium chloride or PAM. • PAM (BMP C126) added to water at a rate of 0.5 lbs. per 1,000 gallons of water per acre and applied from a water truck is more effective than water alone. This is due to the increased infiltration of water into the soil and reduced evaporation. In addition, small soil particles are bonded together and are not as easily transported by wind. Adding PAM may actually reduce the quantity of water needed for dust control, especially in eastern Washington. Since the wholesale cost of PAM is about $ 4.00 per pound, this is an extremely cost- effective dust control method. Techniques that can be used for unpaved roads and lots include: Lower speed limits. High vehicle speed increases the amount of dust stirred up from unpaved roads and lots. • Upgrade the road surface strength by improving particle size, shape, and mineral types that make up the surface and base materials. 4-40 Volume 11 — Construction Stormwater Pollution Prevention February 2005 • Add surface gravel to reduce the source of dust emission. Limit the amount of fine particles (those smaller than .075 mm) to 10 to 20 percent. • Use geotextile fabrics to increase the strength of new roads or roads undergoing reconstruction. • Encourage the use of alternate, paved routes, if available. • Restrict use by tracked vehicles and heavy trucks to prevent damage to road surface and base. • Apply chemical dust suppressants using the admix method, blending the product with the top few inches of surface material. Suppressants may also be applied as surface treatments. • Pave unpaved permanent roads and other trafficked areas. • Use vacuum street sweepers. • Remove mud and other dirt promptly so it does not dry and then turn into dust. • Limit dust -causing work on windy days. • Contact your local Air Pollution Control Authority for guidance and training on other dust control measures. Compliance with the local Air Pollution Control Authority constitutes compliance with this BMP. Maintenance Respray area as necessary to keep dust to a minimum. Standards February 2005 Volume 11— Construction Stormwater Pollution Prevention 4-41 BMP C151: Concrete Handling Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. This BMP is intended to minimize and eliminate concrete process water and slurry from entering waters of the state. Conditions of Use Any time concrete is used, these management practices shall be utilized. Concrete construction projects include, but are not limited to, the following: • Curbs • Sidewalks • Roads Bridges • Foundations • Floors • Runways Design and • Concrete truck chutes, pumps, and internals shall be washed out only Installation into formed areas awaiting installation of concrete or asphalt. Specifications Unused concrete remaining in the truck and pump shall be returned to the originating batch plant for recycling. Hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels shall be washed off only into formed areas awaiting installation of concrete or asphalt. • Equipment that cannot be easily moved, such as concrete pavers, shall only be washed in areas that do not directly drain to natural or constructed stormwater conveyances. • Washdown from areas such as concrete aggregate driveways shall not drain directly to natural or constructed stormwater conveyances. When no formed areas are available, washwater and leftover product shall be contained in a lined container. Contained concrete shall be disposed of in a manner that does not violate groundwater or surface water quality standards. Maintenance Containers shall be checked for holes in the liner daily during concrete Standards pours and repaired the same day. February 2005 Volume /I — Construction Stormwater Pollution Prevention 4-43 BMP C152: Sawcutting and Surfacing Pollution Prevention Purpose Sawcutting and surfacing operations generate slurry and process water that contains fine particles and high pH (concrete cutting), both of which can violate the water quality standards in the receiving water. This BMP is intended to minimize and eliminate process water and slurry from entering waters of the State. Conditions of Use Anytime sawcutting or surfacing operations take place, these management practices shall be utilized. Sawcutting and surfacing operations include, but are not limited to, the following: • Sawing • Coring • Grinding • Roughening • Hydro -demolition • Bridge and road surfacing Design and • Slurry and cuttings shall be vacuumed during cutting and surfacing Installation operations. Specifications • Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. • Slurry and cuttings shall not drain to any natural or constructed drainage conveyance. • Collected slurry and cuttings shall be disposed of in a manner that does not violate groundwater or surface water quality standards. • Process water that is generated during hydro -demolition, surface roughening or similar operations shall not drain to any natural or constructed drainage conveyance and shall be disposed of in a manner that does not violate groundwater or surface water quality standards. • Cleaning waste material and demolition debris shall be handled and disposed of in a manner that does not cause contamination of water. If the area is swept with a pick-up sweeper, the material must be hauled out of the area to an appropriate disposal site. Maintenance Continually monitor operations to determine whether slurry, cuttings, or Standards process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. 4-44 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C153: Material Delivery, Storage and Containment Purpose Prevent, reduce, or eliminate the discharge of pollutants from material delivery and storage to the sormwater system or watercourses by minimizing the storage of hazardous materials onsite, storing materials in a designated area, and installing secondary containment. Conditions of Use These procedures are suitable for use at all construction sites with delivery and storage of the following materials: • Petroleum products such as fuel, oil and grease • Soil stabilizers and binders (e.g. Polyacrylamide) • Fertilizers, pesticides and herbicides • Detergents • Asphalt and concrete compounds • Hazardous chemicals such as acids, lime, adhesives, paints, solvents and curing compounds • Any other material that may be detrimental if released to the environment Design and The following steps should be taken to minimize risk: Installation Temporary storage area should be located away from vehicular traffic, Specifications near the construction entrance(s), and away from waterways or storm drains. • Material Safety Data Sheets (MSDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. • Hazardous material storage on -site should be minimized. • Hazardous materials should be handled as infrequently as possible. • During the wet weather season (Oct 1 — April 30), consider storing materials in a covered area. • Materials should be stored in secondary containments, such as earthen dike, horse trough, or even a children's wading pool for non -reactive materials such as detergents, oil, grease, and paints. Small amounts of material may be secondarily contained in "bus boy" trays or concrete mixing trays. • Do not store chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet and, when possible, in secondary containment. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-45 • If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of drums, preventing water from collecting. Material Storage Areas and Secondary Containment Practices: • Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be stored in approved containers and drums and shall not be overfilled. Containers and drums shall be stored in temporary secondary containment facilities. • Temporary secondary containment facilities shall provide for a spill containment volume able to contain precipitation from a 25 year, 24 hour storm event, plus 10% of the total enclosed container volume of all containers, or 110% of the capacity of the largest container within. its boundary, whichever is greater. • Secondary containment facilities shall be impervious to the materials stored therein for a minimum contact time of 72 hours. • Secondary containment facilities shall be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed into drums. These liquids shall be handled as hazardous waste unless testing determines them to be non -hazardous. • Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. • During the wet weather season (Oct 1— April 30), each secondary containment facility shall be covered during non -working days, prior to and during rain events. • Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). • The spill kit should include, at a minimum: • 1-Water Resistant Nylon Bag • 3-Oil Absorbent Socks 3"x 4' 2-Oil Absorbent Socks 3"x 10' • 12-Oil Absorbent Pads 17"x19" • 1-Pair Splash Resistant Goggles • 3-Pair Nitrile Gloves 10-Disposable Bags with Ties • Instructions 4-46 Volume 11 — Construction Stormwater Pollution Prevention February 2005 4.2 Runoff Conveyance and Treatment BMPs BMP C200: Interceptor Dike and Swale Purpose Provide a ridge of compacted soil, or a ridge with an upslope swale, at the top or base of a disturbed slope or along the perimeter of a disturbed construction area to convey stormwater. Use the dike and/or swale to intercept the runoff from unprotected areas and direct it to areas where erosion can be controlled. This can prevent storm runoff from entering the work area or sediment -laden runoff from leaving the construction site. Conditions of Use Where the runoff from an exposed site or disturbed slope must be conveyed to an erosion control facility which can safely convey the stormwater. • Locate upslope of a construction site to prevent runoff from entering disturbed area. • When placed horizontally across a disturbed slope, it reduces the amount and velocity of runoff flowing down the slope. • Locate downslope to collect runoff from a disturbed area and direct it to a sediment basin. Design and • Dike and/or swale and channel must be stabilized with temporary or Installation permanent vegetation or other channel protection during construction. Specifications . Channel requires a positive grade for drainage; steeper grades require channel protection and check dams. • Review construction for areas where overtopping may occur. • Can be used at top of new fill before vegetation is established. • May be used as a permanent diversion channel to carry the runoff. • Sub -basin tributary area should be one acre or less. • Design capacity for the peak flow from a 10-year, 24-hour storm, assuming a Type I rainfall distribution, for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. For facilities that will also serve on a permanent basis, consult the local government's drainage requirements. Interceptor dikes shall meet the following criteria: Top Width 2 feet minimum. Height 1.5 feet minimum on berm. Side Slope 2:1 or flatter. Grade Depends on topography, however, dike system minimum is 0.5%, maximum is 1%. Compaction Minimum of 90 percent ASTM D698 standard proctor. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-57 Horizontal Spacing of Interceptor Dikes: Average Slope Slope Percent 20H:1 V or less 3-5% (10 to 20)H:1V 5-10% (4 to 1.0)H:1V 10-25% (2 to 4)H:1 V 25-50% Stabilization depends on velocity and reach Flowpath Length 300 feet 200 feet 100 feet 50 feet Slopes <5% Seed and mulch applied within 5 days of dike construction (see BMP C121, Mulching). Slopes 5 - 40% Dependent on runoff velocities and dike materials. Stabilization should be done immediately using either sod or riprap or other measures to avoid erosion. • The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion shall occur at the outlet. Provide energy dissipation measures as necessary. Sediment -laden runoff must be released through a sediment trapping facility. Minimize construction traffic over temporary dikes. Use temporary cross culverts for channel crossing. Interceptor swales shall meet the following criteria: Bottom Width 2 feet minimum; the bottom shall be level. Depth 1-foot minimum. Side Slope 2:1 or flatter. Grade Maximum 5 percent, with positive drainage to a suitable outlet (such as a sediment pond). Stabilization Seed as per BMP C120, Temporary and Permanent Seeding, or BMP C202, Channel Lining, 12 inches thick of riprap pressed into the bank and extending at least 8 inches vertical from the bottom. • Inspect diversion dikes and interceptor swales once a week and after every rainfall. Immediately remove sediment from the flow area. Damage caused by construction traffic or other activity must be repaired before the end of each working day. Check outlets and make timely repairs as needed to avoid gully formation. When the area below the temporary diversion dike is permanently stabilized, remove the dike and fill and stabilize the channel to blend with the natural surface. 4-58 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C201: Grass -Lined Channels Purpose To provide a channel with a vegetative lining for conveyance of runoff. See Figure 4.7 for typical grass -lined channels. Conditions of Use This practice applies to construction sites where concentrated runoff need; to be contained to prevent erosion or flooding. When a vegetative lining can provide sufficient stability for the channel cross section and at lower velocities of water (normally dependent on grade). This means that the channel slopes are generally less than 5 percent and space is available for a relatively large cross section. • Typical uses include roadside ditches, channels at property boundaries, outlets for diversions, and other channels and drainage ditches in low areas. Channels that will be vegetated should be installed before major earthwork and hydroseeded with a bonded fiber matrix (.BFM). The vegetation should be well established (i.e., 75 percent cover) before water is allowed to flow in the ditch. With channels that will have high flows, erosion control blankets should be installed over the hydroseed. If vegetation cannot be established from seed before water is allowed in the ditch, sod should be installed in the bottom of the ditch in lieu of hydromulch and blankets. Design and Locate the channel where it can conform to the topography and other Installation features such as roads. Specifications Locate them to use natural drainage systems to the greatest extent possible. • Avoid sharp changes in alignment or bends and changes in grade. • Do not reshape the landscape to fit the drainage channel. • The maximum design velocity shall be based on soil conditions, type of vegetation, and method of revegetation, but at no times shall velocity exceed 5 feet/second. The channel shall not be overtopped by the peak runoff from a 10-year, 24-hour storm, assuming a Type I rainfall distribution." Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model to determine a flow rate which the channel must contain. Where the grass -lined channel will also function as a permanent stormwater conveyance facility, consultant the drainage conveyance requirements of the local government with jurisdiction. An established grass or vegetated lining is required before the channel can be used to convey stormwater, unless stabilized with nets or blankets. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-59 • If design velocity of a channel to be vegetated by seeding exceeds 2 ft/sec, a temporary channel liner is required. Geotextile or special mulch protection such as fiberglass roving or straw and netting provide stability until the vegetation is fully established. See Figure 4.9. • Check dams shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. • If vegetation is established by sodding, the permissible velocity for established vegetation may be used and no temporary liner is needed. • Do not subject grass -lined channel to sedimentation from disturbed areas. Use sediment -trapping BMPs upstream of the channel. • V-shaped grass channels generally apply where the quantity of water is small, such as in short reaches along roadsides. The V-shaped cross section is least desirable because it is difficult to stabilize the bottom where velocities may be high. • Trapezoidal grass channels are used where runoff volumes are large and slope is low so that velocities are nonerosive to vegetated linings. (Note: it is difficult to construct small parabolic shaped channels.) • Subsurface drainage, or riprap channel bottoms, may be necessary on sites that are subject to prolonged wet conditions due to long duration flows or a high water table. • Provide outlet protection at culvert ends and at channel intersections. • Grass channels, at a minimum, should carry peak runoff for temporary construction drainage facilities from the 10-year, 24-hour storm without eroding. Where flood hazard exists, increase the capacity according to the potential damage. • Grassed channel side slopes generally are constructed 3:1 or flatter to aid in the establishment of vegetation and for maintenance. • Construct channels a minimum of 0.2 foot larger around the periphery to allow for soil bulking during seedbed preparations and sod buildup. Maintenance During the establishment period, check grass -lined channels after every Standards rainfall. • After grass is established, periodically check the channel; check it after every heavy rainfall event. Immediately make repairs. • It is particularly important to check the channel outlet and all road crossings for bank stability and evidence of piping or scour holes. • Remove all significant sediment accumulations to maintain the designed carrying capacity. Keep the grass in a healthy, vigorous condition at all times, since it is the primary erosion protection for the channel. 4-60 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Filter Fabric / With Rock Center 6-9 (150-225mm) Key in Fabric Typicalic Channel Cross-Secti �, \(50 Key In Fabric \// / `/\�------ Filter Fabric With Channel Liner With Rock Center for Base Flow Typicalr i tCross-Section 'M//// Design Depth \iv / Gi vercut channel 2" (50mm)/ to allow bulking during seedbed preparation and growth of vegetation. / Filter ----- With Rock Center For Base Flow _/ Fabric Figure 4.8 — Typical Grass -Lined Channels February 2005 Volume II — Construction Stormwater Pollution Prevention 4-61 Overlap 6" (1 50mm) minimum 'X, Excavate Channel to Design Grade and Cross Section Design Depth OVERCUTCHANA(H z Longitudinal 2-(90mm) TOALLOW \'W� Ai ,`fitanchor trench 914L I(ING DURING SEF09ED PREPARATION TYPICAL INSTALLATION WITH EROSION CONTROL BLANKETS OR TURF REINFORCEMENT MATS Intermittent Check Slot Shingle -lap spliced ends or begin new roll in an intermittent check slot Prepare soil and apply seed before installing blankets, mats or other temporary channel liner system 0 UL Y YY \X/� < 'X X/Y NOTES: 1. Design velocities exceeding 2 ft/sec (0.5m/sec) require temporary blankets, mats or similar liners to protect seed and soil until vegetation becomes established. 2. Grass -lined channels with design velocities exceeding 6 ft/sec (2m/sec) should include turf reinforcement mats. Figure 4.9 — Temporary Channel Liners 4-62 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C202: Channel Lining Purpose To protect erodible channels by providing a channel liner using either blankets or riprap. Conditions of Use When natural soils or vegetated stabilized soils in a channel are not adequate to prevent channel erosion. • When a permanent ditch or pipe system is to be installed and a temporary measure is needed. In almost all cases, synthetic and organic coconut blankets are more effective than riprap for protecting channels from erosion. Blankets can be used with and without vegetation. Blanketed channels can be designed to handle any expected flow and longevity requirement. Some synthetic blankets have a predicted life span of 50 years or more, even in sunlight. Other reasons why blankets are better than rock include the availability of blankets over rock. In many areas of the state, rock is not easily obtainable or is very expensive to haul to a site. Blankets can be delivered anywhere. Rock requires the use of dump trucks to haul and heavy equipment to place. Blankets usually only require laborers with hand tools, and sometimes a backhoe. • The Federal Highway Administration recommends not using flexible liners whenever the slope exceeds 10 percent or the shear stress exceeds 81bs/ft2. Design and See BMP C1.22 for information on blankets. Installation Since riprap is used where erosion potential is high, construction must be Specifications sequenced so that the riprap is put in place with the minimum possible delay. • Disturbance of areas where riprap is to be placed should be undertaken only when final preparation and placement of the riprap can follow immediately behind the initial disturbance. Where riprap is used for outlet protection, the riprap should be placed before or in conjunction with the construction of the pipe or channel so that it is in place when the pipe or channel begins to operate. • The designer, after determining the riprap size that will be stable under the flow conditions, shall consider that size to be a minimum size and then, based on riprap gradations actually available in the area, select the size or sizes that equal or exceed the minimum size. The possibility of drainage structure damage by children shall be considered in selecting a riprap size, especially if there is nearby water or a gully in which to toss the stones. • Stone for riprap shall consist of Feld stone or quarry stone of approximately rectangular shape. The stone shall be hard and angular and of such quality that it will not disintegrate on exposure to water or February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-63 weathering and it shall be suitable in all respects for the purpose intended. • Rubble concrete may be used provided it has a density of at least 150 pounds per cubic foot, and otherwise meets the requirement of this standard and specification. • A lining of engineering filter fabric (geotextile) shall be placed between the riprap and the underlying soil surface to prevent soil movement into or through the riprap. The geotextile should be keyed in at the top of the bank. • Filter fabric shall not be used on slopes greater than 1-1 /2:1 as slippage may occur. It should be used in conjunction with a layer of coarse aggregate (granular filter blanket) when the riprap to be placed is 12 inches and larger. 4-64 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C207: Check Dams Purpose Construction of small dams across a swale or ditch reduces the velocity of concentrated flow and dissipates energy at the check dam. Conditions of Use Where temporary channels or permanent channels are not yet vegetated, channel lining is infeasible, and velocity checks are required. • Check dams may not be placed in streams unless approved by the State Department of Fish and Wildlife. Check dams may not be placed in wetlands without approval from a permitting agency. • Check dams shall not be placed below the expected backwater from any salmonid bearing water between October 1 and May 31 to ensure that there is no loss of high flow refuge habitat for overwintering juvenile salmonids and emergent salmonid fry. Design and Whatever material is used, the dam should form a triangle when viewed Installation from the side. This prevents undercutting as water flows over the face of Specifications the dam rather than falling directly onto the ditch bottom. Check dams in association with sumps work more effectively at slowing flow and retaining sediment than just a check dam alone. A deep sump should be provided immediately upstream of the check dam. • In some cases, if carefully located and designed, check dams can remain as permanent installations with very minor regrading. They may be left as either spillways, in which case accumulated sediment would be graded and seeded, or as check dams to prevent further sediment from leaving the site. • Check dams can be constructed of either rock or pea -gravel filled bags. Numerous new products are also available for this purpose. They tend to be re -usable, quick and easy to install, effective, and cost efficient. • Check dams should be placed perpendicular to the flow of water. • The maximum spacing between the dams shall be such that the toe of the upstream dam is at the same elevation as the top of the downstream dam. • Keep the maximum height at 2 feet at the center of the dam. • Keep the center of the check dam at least 12 inches lower than the outer edges at natural ground elevation. • Keep the side slopes of the check dam at 2:1 or flatter. • Key the stone into the ditch banks and extend it beyond the abutments a minimum of 18 inches to avoid washouts from overflow around the dam. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-75 Use filter fabric foundation under a rock or sand bag check dam. If a blanket ditch liner is used, this is not necessary. A piece of organic or synthetic blanket cut to fit will also work for this purpose. Rock check dams shall be constructed of appropriately sized rock. The rock must be placed by hand or by mechanical means (no dumping of rock to form dam) to achieve complete coverage of the ditch or swale and to ensure that the center of the dam is lower than the edges. The rock used must be large enough to stay in place given the expected design flow through the channel. In the case of grass -lined ditches and swales, all check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale - unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. • Ensure that channel appurtenances, such as culvert entrances below check dams, are not subject to damage or blockage from displaced stones. Figure 4.13 depicts a typical rock check dam. Maintenance Check dams shall be monitored for performance and sediment Standards accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the sump depth. • Anticipate submergence and deposition above the check dam and erosion from high flows around the edges of the dam. • If significant erosion occurs between dams, install a protective riprap liner in that portion of the channel. 4-76 Volume 11— Construction Stormwater Pollution Prevention February 2005 NOTE: Key stone into channel banks and extend it beyond the abutments a minimum of 18" (0.5m) to prevent flow around dam. Section FI r)1A1 U 18" (0.5m) �- 12" (150mm) Spacing Between Check Dams 'L' = the distance such that points Wand 'B' are of equal elevation. L' Qo, , oao o O Qo �0000 0 00 0o POINT 'A' Figure 4.13 — Check Dams 0 Qo _ (10.6m) 1 101101101.1 NOT TO SCALE February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-77 BMP C208: Triangular Silt Dike (Geotextile-Encased Check Dam) Purpose Triangular silt dikes may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Conditions of use May be used in place of straw bales for temporary check dams in ditches of any dimension. • May be used on soil or pavement with adhesive or staples. • TSDs have been used to build temporary: 1. sediment ponds; 2. diversion ditches; 3. concrete wash out facilities; 4. curbing; 5. water bars; 6. level spreaders; and, 7. berms. Design and Made of urethane foam sewn into a woven geosynthetic fabric. Installation It is triangular, 10 inches to 14 inches high in the center, with a 20-inch to Specifications 28-inch base. A 2—foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed. • Install with ends curved up to prevent water from flowing around the ends. • The fabric flaps and check dam units are attached to the ground with wire staples. Wire staples should be No. 11 gauge wire and should be 200 mm to 300 mm in length. • When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. • Check dams should be located and installed as soon as construction will allow. • Check dams should be placed perpendicular to the flow of water. • When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. • In the case of grass -lined ditches and swales, check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. Maintenance • Triangular silt dams shall be monitored for performance and sediment Standards accumulation during and after each runoff producing rainfall. 4-78 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Sediment shall be removed when it reaches one half the height of the dam. • Anticipate submergence and deposition above the triangular silt dam and erosion from high flows around the edges of the dam. Immediately repair any damage or any undercutting of the dam. February 2005 Volume ll — Construction Stormwater Pollution Prevention 4-79 BMP C209: Outlet Protection Purpose Outlet protection prevents scour at conveyance outlets and minimizes the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. Conditions of use Outlet protection is required at the outlets of all ponds, pipes, ditches, or other conveyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, wetland, lake, or ditch. Design and The receiving channel at the outlet of a culvert shall be protected from Installation erosion by rock lining a minimum of 6 feet downstream and extending up Specifications the channel sides a minimum of 1—foot above the maximum tailwater elevation or 1-foot above the crown, whichever is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to four times the diameter of the culvert. • Standard wingwalls, and tapered outlets and paved channels should also be considered when appropriate for permanent culvert outlet protection. (See WSDOT Hydraulic Manual, available through WSDOT Engineering Publications). • Organic or synthetic erosion blankets, with or without vegetation, are usually more effective than rock, cheaper, and easier to install. Materials can be chosen using manufacturer product specifications. ASTM test results are available for most products and the designer can choose the correct material for the expected flow. • With low flows, vegetation (including sod) can be effective. • The following guidelines shall be used for riprap outlet protection: If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot. 2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3 percent), use 24-inch to 4-foot riprap. Minimum thickness is 2 feet. 3. For outlets at the base of steep slope pipes (pipe slope greater than 10 percent), an engineered energy dissipater shall be used. Filter fabric or erosion control blankets should always be used under riprap to prevent scour and channel erosion. New pipe outfalls can provide an opportunity for low-cost fish habitat improvements. For example, an alcove of low -velocity water can be created by constructing the pipe outfall and associated energy dissipater back from the stream edge and digging a channel, over - widened to the upstream side, from the outfall. Overwintering juvenile and migrating adult salmonids may use the alcove as shelter during 4-80 Volume 11 — Construction Stormwater Pollution Prevention February 2005 high flows. :Bank stabilization, bioengineering, and habitat features may be required for disturbed areas. See Volume V for more information on outfall system design. Maintenance . Inspect and repair as needed. Standards • Add rock as needed to maintain the intended function. • Clean energy dissipater if sediment builds up. February 2005 Volume 11— Construction Stormwater Pollution Prevention 4-81 BMP C220: Storm Drain Inlet Protection Purpose To prevent coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Conditions of Use Where storm drain inlets are to be made operational before permanent stabilization of the disturbed drainage area. Protection should be provided for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. Inlet protection may be used anywhere to protect the drainage system. It is likely that the drainage system will still require cleaning. Table 4.9 lists several options for inlet protection. All of the methods for storm drain inlet protection are prone to plugging and require a high frequency of maintenance. Drainage areas should be limited to 1 acre or less. Emergency overflows may be required where stormwater ponding would cause a hazard. If an emergency overflow is provided, additional end -of -pipe treatment may be required. Table 4.9 Storm Drain Inlet Protetion Applicable for Type of Inlet Emergency Paved/ Earthen Protection Overflow Surfaces Conditions of Use Drop Inlet Protection Excavated drop inlet Yes, Earthen Applicable for heavy flows. Easy protection temporary to maintain. Large area flooding will Requirement: 30' X 30'/acre occur Block and gravel drop Yes Paved or Earthen Applicable for heavy concentrated inlet protection flows. Will not pond. Gravel and wire drop No Applicable for heavy concentrated inlet protection flows. Will pond. Can withstand traffic. Catch basin filters Yes Paved or Earthen Frequent maintenance required. Curb Inlet Protection Curb inlet protection Small capacity Paved Used for sturdy, more compact with a wooden weir overflow installation. Block and gravel curb Yes Paved Sturdy, but limited filtration. inlet protection Culvert Inlet Protection Culvert inlet sediment 18 month expected life. trap 4-82 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Design and Excavated Drop Inlet Protection - An excavated impoundment around the Installation storm drain. Sediment settles out of the stormwater prior to entering the Specifications storm drain. • Depth 1-2 ft as measured from the crest of the inlet structure. • Side Slopes of excavation no steeper than 2:1. • Minimum volume of excavation 35 cubic yards. • Shape basin to fit site with longest dimension oriented toward the longest inflow area. • Install provisions for draining to prevent standing water problems. • Clear the area of all debris. • Grade the approach to the inlet uniformly. • Drill weep holes into the side of the inlet. • Protect weep holes with screen wire and washed aggregate. • Seal weep holes when removing structure and stabilizing area. • It may be necessary to build a temporary dike to the down slope side of the structure to prevent bypass flow. Block and Gravel Filter - A barrier formed around the storm drain inlet with standard concrete blocks and gravel. See Figure 4.14. • Height 1 to 2 feet above inlet. • Recess the first row 2 inches into the ground for stability. • Support subsequent courses by placing a 2x4 through the block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pool. • Place hardware cloth or comparable wire mesh with 1/2-inch openings over all block openings. • Place gravel just below the top of blocks on slopes of 2:1 or flatter. • An alternative design is a gravel donut. • Inlet slope of 3:1. • Outlet slope of 2:1. • 1-foot wide level stone area between the structure and the inlet. • Inlet slope stones 3 inches in diameter or larger. • Outlet slope use gravel'/z- to 3/4-inch at a minimum thickness of 1-foot. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-83 Plan View,q Drain o /� °��°c�G�%G O/\ ° °oar, `✓ o `o Grate o� 0 v o o°J �T� Co 0°° J x0 �o n` o ° o `'f ° �° 000 ��Oo _off �nCO oo �o o° 0�°o Concrete �\J ° O�' LI L.�<�_�°� o oBlock a ��, O Jo0<.���-- Gravel U L�aOo°� "'�� )o Backfill �(5(� OHO°ao40 00 �oo o and �n o 0 0 0 o Uaoo J� � 0- o ,OOa ra �, A Section A - A Concrete Block Wire Screen or Filter Fabric Gravel Backfill Overflow Water Ponding Height o°o , ° o OG°O Water UoC��° Jo. /VA/VA/VA jAjj\y Drop Inlet \\//\ \ j \ \\\//\j/ Notes: 1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less than 5%) 2. Excavate a basin of sufficient size adjacent to the drop inlet. 3. The top of the structure (ponding height) must be well below the ground elevation downslope to prevent runoff from bypassing the inlet. A temporary dike may be necessary on the dowslope side of the structure. Figure 4.14 — Block and Gravel Filter Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This structure does not provide an overflow. • Hardware cloth or comparable wire mesh with 1/z-inch openings. • Coarse aggregate. • Height 1-foot or more, 18 inches wider than inlet on all sides. • Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond each side of the inlet structure. • If more than one strip of mesh is necessary, overlap the strips. • Place coarse aggregate over the wire mesh. • The depth of the gravel should be at least 12 inches over the entire inlet opening and extend at least 18 inches on all sides. 4-84 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Cacchbasin Filters - Inserts should be designed by the manufacturer for use at construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required, which may be daily for heavy sediment loads. The maintenance requirements can be reduced by combining a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflow and therefore may be a better method for inlets located along active rights -of - way. • 5 cubic feet of storage. • Dewatering provisions. • High -flow bypass that will not clog under normal use at a construction site. • The catchbasin filter is inserted in the catchbasin just below the grating. Curb Inlet Protection with Wooden Weir — Barrier formed around a curb inlet with a wooden frame and gravel. • Wire mesh with 1/2-inch openings. • Extra strength filter cloth. • Construct a frame. • Attach the wire and filter fabric to the frame. • Pile coarse washed aggregate against wire/fabric. • Place weight on frame anchors. Block and Gravel Curb Inlet Protection — Barrier formed around an inlet with concrete blocks and gravel. See Figure 4.14. • Wire mesh with 1/2-inch openings. • Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks. • Place a 2x4 stud through the outer holes of each spacer block to align the front blocks. • Place blocks on their sides across the front of the inlet and abutting the spacer blocks. • Place wire mesh over the outside vertical face. • Pile coarse aggregate against the wire to the top of the barrier. Curb and Gutter Sediment Barrier — Sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See Figure 4.16. • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-85 Maintenance Catch basin filters should be inspected frequently, especially after Standards storm events. If the insert becomes clogged, it should be cleaned or replaced. • For systems using stone filters: If the stone filter becomes clogged with sediment, the stones must be pulled away from the inlet and cleaned or replaced. Since cleaning of gravel at a construction site may be difficult, an alternative approach would be to use the clogged stone as fill and put fresh stone around the inlet. Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate. 4-86 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Plan View Back of Sidewalk A Catch Basin 2x4 Wood Stud Back of Curb Concrete Block Curb Inlet o� ° ooao 92 vow oo� o >oQo o' o �° ------------- o 0 o� o.000g. o�°C o o0a °000 °o ao0° ° o 0 0 . �opOa.�ooa°o c�o�°�a O� o�J �go°ogo°oog°o°oo°o°oo o° 0 0 �R> g.°� o��4oppo op�o°o; rJ�O oo .00 Qo oa......... � Qon oo�O.,d`�p�°otS��°°S� Cog° a0°o° oCY °o `Oo aoG'� `oo ° od)a °o `Oo ao o Cno °Oo °oo a°off oo �ao09 ooa "Oo °ori oC>�O0000� o°oo� op o�op o0 0� n�>.°° 00 ope ° o°ao�° �e�Q. bo�Oo°o`�°oo0 j°o oo ° �a°�� °o �o 00 oa Sao 0 ��,� 00 0 Q - °a o4,.o 0a�o C7° Si CJ� Wire Screen r Filter Fabric A . Concrete Block Section A - A ( Drain Gravel 20mm) %" Drain Gravel (20mm) Ponding Height Concrete Block Overrfffoow _ Curb Inlet Wire Screen or Filter Fabric Catch Basin 4 Wood Stud / (100x50 Timber Stud) V� NOTES: 1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shall allow for overflow from severe storm event. 3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. Figure 4.15 — Block and Gravel Curb Inlet Protection February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-87 1:2 Back of Sidewalk r`n+nh D—;i NOTES: 1. Place curb type sediment barriers on gently sloping street segments, where water can pond and allow sediment to separate from runoff. 2. Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered and packed tightly. 3. Leave a one sandbag gap in the top row to provide a spillway for overflow. 4. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. 4-88 Volume 11 — Construction Stormwater Pollution Prevention February 2005 BMP C233: Silt Fence Purpose Conditions of Use Design and Installation Specifications Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. See Figure 4.19 for details on silt fence construction. Silt fence may be used downslope of all disturbed areas. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a silt fence, rather than by a sediment pond, is when the area draining to the fence is one acre or less and flow rates are less than 0.5 cfs. Silt fences should not be constructed in streams or used in V-shaped ditches. They are not an adequate method of silt control for anything deeper than sheet or overland flow. Joints in filter fabric shall be spliced at posts. Use staples, wire rings or 2" x2' by 14 Ga. wire or equivalent to attach fabric to posts equivalent, if standard 7-7--- z------------------ - - strength fabric used Filter fabric — N ------------ 6 max Minimum 4" x4" trench 1J1 Backfill trench with native soil Post spacing may be increased or 3/4"-1.5" washed gravel to 8' if wire backing is used 2' x2" wood posts, steel fence posts, or equivalent Figure 4.19 — Silt Fence • Drainage area of 1 acre or less or in combination with sediment basin in a larger site. • Maximum slope steepness (normal (perpendicular) to fence line) 1:1. Maximum sheet or overland flow path length to the fence of 100 feet. • No flows greater than 0.5 cfs. • The geotextile used shall meet the following standards. All geotextile properties listed below are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or exceed the values shown in Table 4.10): 4-94 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Table 4.10 Geotextile Standards Polymeric Mesh AOS 0.60 mm maximum for slit film wovens (#30 sieve). 0.30 (ASTM D4751) mm maximum for all other geotextile types (#50 sieve). 0.15 mm minimum for all fabric types (#100 sieve). Water Permittivity 0.02 sec' minimum (ASTM D4491) Grab Tensile Strength 1.80 lbs. Minimum for extra strength fabric. (ASTM D4632) 100 lbs minimum for standard strength fabric. Grab Tensile Strength 30% maximum (ASTM D4632) Ultraviolet Resistance 70% minimum (ASTM D4355) • Standard strength fabrics shall be supported with wire mesh, chicken wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the strength of the fabric. Silt fence materials are available that have synthetic mesh backing attached. • Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. • 100 percent biodegradable silt fence is available that is strong, long lasting, and can be left in place after the project is completed, if permitted by local regulations. • Standard Notes for construction plans and specifications follow. Refer to Figure 4.19 for standard silt fence details. The contractor shall install and maintain temporary silt fences at the locations shown in the Plans. The silt fences shall be constructed in the areas of clearing, grading, or drainage prior to starting those activities. A silt fence shall not be considered temporary if the silt fence must function beyond the life of the contract. The silt fence shall prevent soil carried by runoff water from going beneath, through, or over the top of the silt fence, but shall allow the water to pass through the fence. The minimum height of the top of silt fence shall be 2 feet and the maximum height shall be 2'/z feet above the original ground surface. The geotextile shall be sewn together at the point of manufacture, or at an approved location as determined by the Engineer, to form geotextile lengths as required. All sewn seams shall be located at a support post. Alternatively, two sections of silt fence can be overlapped, provided the Contractor can demonstrate, to the satisfaction of the Engineer, that the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap. February 2005 Volume lI — Construction Stormwater Pollution Prevention 4-95 The geotextile shall be attached on the up -slope side of the posts and support system with staples, wire, or in accordance with the manufacturer's recommendations. The geotextile shall be attached to the posts in a manner that reduces the potential for geotextile tearing at the staples, wire, or other connection device. Silt fence back-up support for the geotextile in the form of a wire or plastic mesh is dependent on the properties of the geotextile selected for use. If wire or plastic back-up mesh is used, the mesh shall be fastened securely to the up -slope of the posts with the geotextile being up -slope of the mesh back-up support. The geotextile at the bottom of the fence shall be buried in a trench to a minimum depth of 4 inches below the ground surface. The trench shall be backFilled and the soil tamped in place over the buried portion of the geotextile, such that no flow can pass beneath the fence and scouring can not occur. When wire or polymeric back-up support mesh is used, the wire or polymeric mesh shall extend into the trench a minimum of 3 inches. The fence posts shall be placed or driven a minimum of 18 inches. A minimum depth of 12 inches is allowed if topsoil or other soft subgrade soil is not present and a minimum depth of 18 inches cannot be reached. Fence post depths shall be increased by 6 inches if the fence is located on slopes of 3:1 or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading. Silt fences shall be located on contour as much as possible, except at the ends of the fence, where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water from flowing around the end of the fence. If the fence must cross contours, with the exception of the ends of the fence, gravel check dams placed perpendicular to the back of the fence shall be used to minimize concentrated flow and erosion along the back of the fence. The gravel check dams shall be approximately 1- foot deep at the back of the fence. It shall be continued perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. The gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. The gravel check dams shall be located every 10 feet along the fence where the fence must cross contours. The slope of the fence line where contours must be crossed shall not be steeper than 3:1. Wood, steel or equivalent posts shall be used. Wood posts shall have minimum dimensions of 2 inches by 2 inches by 3 feet minimum length, and shall be free of defects such as knots, splits, or gouges. 4-96 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Steel posts shall consist of either size No. 6 rebar or larger, AST.M A 120 steel pipe with a minimum diameter of 1-inch, U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. or other steel posts having equivalent strength and bending resistance to the post sizes listed. The spacing of the support posts shall be a maximum of 6 feet. Fence back-up support, if used, shall consist of steel wire with a maximum mesh spacing of 2 inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 1801bs. grab tensile strength. The polymeric mesh must be as resistant to ultraviolet radiation as the geotextile it supports. • Silt fence installation using the slicing method specification details follow. Refer to Figure 4.20 for slicing method details. The base of both end posts must be at least 2 to 4 inches above the top of the silt fence fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation. Install posts 3 to 4 feet apart in critical retention areas and 6 to 7 feet apart in standard applications. Install posts 24 inches deep on the downstream side of the silt fence, and as close as possible to the fabric, enabling posts to support the fabric from upstream water pressure. Install posts with the nipples facing away from the silt fence fabric. Attach the fabric to each post with three ties, all spaced within the top 8 inches of the fabric. Attach each tie diagonally 45 degrees through the fabric, with each puncture at least 1 inch vertically apart. In addition, each tie should be positioned to hang on a post nipple when tightening to prevent sagging. Wrap approximately 6 inches of fabric around the end posts and secure with 3 ties. No more than 24 inches of a 36-inch fabric is allowed above ground level. The rope lock system must be used in all ditch check applications. The installation should be checked and corrected for any deviation before compaction. Use a flat -bladed shovel to tuck fabric deeper into the ground if necessary. Compaction is vitally important for effective results. Compact the soil immediately next to the silt fence fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. February 2005 Volume /I — Construction Stormwater Pollution Prevention 4-97 • Any damage shall be repaired immediately. Maintenance If concentrated flows are evident uphill of the fence, they must be Standards intercepted and conveyed to a sediment pond. • It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. • Sediment deposits shall either be removed when the deposit reaches approximately one-third the height of the silt fence, or a second silt fence shall be installed. • If the filter fabric (geotextile) has deteriorated due to ultraviolet it shall be Pending height POST SPACING, mow. 24, T max, on: open runs P max. on Poounv area• r Aieh was to upstremin into of Part FLOW- adv. erg each *440 of POST O PTHi sat hsseca S to 4r1 dawaceexoolug As mouth below ground 60 P..2.1. tr greater.. as retuic above ground 1..0 compot id• 1:. Convection No more than 2•o `c is allamd above ground 10 OWation Ad A of A tend Fabde Fence l '^�sarayarca�a�.�r,rc rear<a # 4 f'• _-' 141a�i 1 pr_ 4-98 Volume 11— Construction Stormwater Pollution Prevention February 2005 BMP C235: Straw Wattles Purpose Straw wattles are temporary erosion and sediment control barriers consisting of straw that is wrapped in biodegradable tubular plastic or similar encasing material. They reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Straw wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. The wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. See Figure 4.21 for typical construction details. Conditions of Use • Disturbed areas that require immediate erosion protection. • Exposed soils during the period of short construction delays, or over winter months. • On slopes requiring stabilization until permanent vegetation can be established. • Straw wattles are effective for one to two seasons. • If conditions are appropriate, wattles can be staked to the ground using willow cuttings for added revegetation. • Rilling can occur beneath wattles if not properly entrenched and water can pass between wattles if not tightly abutted together. Design Criteria • It is critical that wattles are installed perpendicular to the flow direction and parallel to the slope contour. • Narrow trenches should be dug across the slope on contour to a depth of 3 to 5 inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and areas with high rainfall, the trenches should be dug to a depth of 5 to 7 inches, or 1/2 to 2/3 of the thickness of the wattle. • Start building trenches and installing wattles from the base of the slope and work up. Excavated material should be spread evenly along the uphill slope and compacted using hand tamping or other methods. • Construct trenches at contour intervals of 3 to 30 feet apart depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches. • Install the wattles snugly into the trenches and abut tightly end to end. Do not overlap the ends. • Install stakes at each end of the wattle, and at 4-foot centers along entire length of wattle. • If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. • At a minimum, wooden stakes should be approximately 3/4 x 3/4 x 24 inches. Willow cuttings or 3/8-inch rebar can also be used for stakes. 4-100 Volume 11 — Construction Stormwater Pollution Prevention February 2005 Maintenance • Stakes should be driven through the middle of the wattle, leaving 2 to 3 Standards inches of the stake protruding above the wattle. • Wattles may require maintenance to ensure they are in contact with soil and thoroughly entrenched, especially after significant rainfall on steep sandy soils. • Inspect the slope after significant storms and repair any areas where wattles are not tightly abutted or water has scoured beneath the wattles. 3'-4' (1.2m) / \ f ", Straw Rolls Must X Be Placed Along Slope Contours / j Adjacent rolls shall tightly abut \ / y A�;, / f \VAS 10'-25' (3-8m) /, Spacing Depends on Soil Type and Sediment, organic matter, Slope Steepness \���\ and native seeds are >11 captured behind the rolls. 3%5" (75-125mm) / %\-� 8"-10" DIA. (200 250mm) Live Stake \ / 1 RP "Stake not to scale (25 x 25mm) NOTE: 1. Straw roll installation requires the placement and secure staking of the roll in a trench, 3%5" (75-125mm) deep, dug on contour. runoff must not be allowed to run under or around roll. Figure 4.21 — Straw Wattles February 2005 Volume 11 — Construction Stormwater Pollution Prevention 4-101 Appendix C - Correspondence File Future Correspondence Here Appendix D - Site Inspection Form Construction Stormwater Site Inspection Form Project Name Permit # Inspection Date Time Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre Print Name: Approximate rainfall amount since the last inspection (in inches): Approximate rainfall amount in the last 24 hours (in inches): Current Weather Clear Cloudy ❑ Mist ❑ Rain Wind ❑ Fog ❑ A. Type of inspection: Weekly ❑ Post Storm Event 0 Other ❑ B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/roads Concrete pours Vertical Construction/buildings Utilities Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected? Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No 3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & SS) Yes No 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?* Yes No 5. If yes to #4 was it reported to Ecology? Yes No 6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken, and when. *If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparency is 33 cm or greater. Sampling Results: Date: Parameter; Method (circle one) Result other/Note NTU cm pH Turbidity tube, meter, laboratory pH Paper, kit, meter Page 1 Construction Stormwater Site Inspection Form D. Check the observed status of all items. Provide "Action Required "details and dates. Element # Inspection BMPs BMP needs BMP Action Inspected maintenance failed required (describe in yes no n/a section F) 1 Before beginning land disturbing Clearing activities are all clearing limits, Limits natural resource areas (streams, wetlands, buffers, trees) protected with barriers or similar BMPs? (high visibility recommended) 2 Construction access is stabilized Construction with quarry spalls or equivalent Access BMP to prevent sediment from being tracked onto roads? Sediment tracked onto the road way was cleaned thoroughly at the end of the day or more frequent as necessary. 3 Are flow control measures installed Control Flow to control stormwater volumes and Rates velocity during construction and do they protect downstream properties and waterways from erosion? If permanent infiltration ponds are used for flow control during construction, are they protected from siltation? 4 All perimeter sediment controls Sediment (e.g. silt fence, wattles, compost Controls socks, berms, etc.) installed, and maintained in accordance with the Stormwater Pollution Prevention Plan (SWPPP). Sediment control BMPs (sediment ponds, traps, filters etc.) have been constructed and functional as the first step of grading. Stormwater runoff from disturbed areas is directed to sediment removal BMP. S Have exposed un-worked soils Stabilize been stabilized with effective BMP Soils to prevent erosion and sediment deposition? Page 2 Construction Stormwater Site Inspection Form Element # Inspection BMPs BMP needs BMP Action Inspected maintenance failed required (describe in yes no n/a section F) 5 Are stockpiles stabilized from erosion, Stabilize Soils protected with sediment trapping Cont. measures and located away from drain inlet, waterways, and drainage channels? Have soils been stabilized at the end of the shift, before a holiday or weekend if needed based on the weather forecast? Has stormwater and ground water 6 been diverted away from slopes and Protect disturbed areas with interceptor dikes, Slopes pipes and or swales? Is off -site storm water managed separately from stormwater generated on the site? Is excavated material placed on uphill side of trenches consistent with safety and space considerations? Have check dams been placed at regular intervals within constructed channels that are cut down a slope? 7 Storm drain inlets made operable Drain Inlets during construction are protected. Are existing storm drains within the influence of the project protected? 8 Have all on -site conveyance channels Stabilize been designed, constructed and Channel and stabilized to prevent erosion from Outlets expected peak flows? Is stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream conveyance systems? 9 Are waste materials and demolition Control debris handled and disposed of to Pollutants prevent contamination of stormwater? Has cover been provided for all chemicals, liquid products, petroleum products, and other material? Has secondary containment been provided capable of containing 110% of the volume? Were contaminated surfaces cleaned immediately after a spill incident? Were BMPs used to prevent contamination of stormwater by a pH modifying sources? Page 3 Construction Stormwater Site Inspection Form Element # Inspection BMPs BMP needs BMP Action Inspected maintenance failed required (describe in yes no n/a section F) 9 Wheel wash wastewater is handled Cont. and disposed of properly. 10 Concrete washout in designated areas. Control No washout or excess concrete on the Dewatering ground. Dewatering has been done to an approved source and in compliance with the SWPPP. Were there any clean non turbid dewatering discharges? 11 Are all temporary and permanent Maintain erosion and sediment control BMPs BMP maintained to perform as intended? 12 Has the project been phased to the Manage the maximum degree practicable? Project Has regular inspection, monitoring and maintenance been performed as required by the permit? Has the SWPPP been updated, implemented and records maintained? 13 Is all Bioretention and Rain Garden Protect LID Facilities protected from sedimentation with appropriate BMPs? Is the Bioretention and Rain Garden protected against over compaction of construction equipment and foot traffic to retain its infiltration capabilities? Permeable pavements are clean and free of sediment and sediment laden - water runoff. Muddy construction equipment has not been on the base material or pavement. Have soiled permeable pavements been cleaned of sediments and pass infiltration test as required by stormwater manual methodology? Heavy equipment has been kept off existing soils under LID facilities to retain infiltration rate. E. Check all areas that have been inspected. All in place BMPs F-] All disturbed soils All concrete wash out area 7 All material storage areas All discharge locations [:] All equipment storage areas All construction entrances/exits 1-1 Page 4 Construction Stormwater Site Inspection Form F. Elements checked "Action Required" (section D) describe corrective action to be taken. List the element number; be specific on location and work needed. Document, initial, and date when the corrective action has been completed and inspected. Element # Description and Location Action Required Completion Date Initials Attach additional page if needed Sign the following certification: "1 certify that this report is true, accurate, and complete, to the best of my knowledge and belief" Inspected by: (print) Title/Qualification of Inspector: (Signature) Date: Page 5 Appendix E - Construction Stormwater General Permit (CSWGP) Issuance hate: November 18, 2015 Effective Date; January 1, 2016 Expiration Date: December 31, 2020 GENE,!\ AL PERMIT National Polhoam Discharge Elimination System (NPDES) and State Waste Discharge General Permit lot Stornovater Discharges Associated with Construction Activity State of Washington Department of Ecology Olympia, Washington:9850d In compliance with the provisions of Chapter: 90.48 Revised Code of Washington: (State of Washington Water Pollution Control Act) and Tula 33 United States Code, Section 1251 at seq, The Frost al Water Pollution Control Act (The Clean Water Act) Until this permit expires, is modified, or revoked, Permittees that have property obtained coverage under this general permit arc authorized to discharge in accordance with the special and .general conditions that follow. Heather R Bat dett Wata• duality Program Manager Washington State Department of Ecology LIST {)FTABLES ........................................................................................................................... 3 SUMMARY ()FPERMIT REPORT SUBMITTALS -----------------------4 SPECIAL CONDITIONS -------------------------------------. 5 Sl. PERMIT COVERAGE ----------------------------------..5 S2. APPLICATION REQUIREMENTS ---------------------------'8 S3. COMPLIANCE WITH STANDARDS............................................................................. |2 S4. MONITORING REQUIREMENTS, BENCHMARKS, AND REPORTINGTRIGGERS ................................................................................................ l3 95. REPORTING AND RECORDKEEPING REQUIREMENTS -------------..20 S6. PERMIT FEES ................................................................................................................... 23 S7. SOLID AND LIQUID WASTE DISPOSAL .................................................................... 23 S8. DISCHARGES TO 303(d)ORTMDLWATE0BODlES................................................ 23 S9. STORMWATER POLLUTION PREVENTION PLAN ................................................... 27 Sl0. NOTICE OF TERMINATION -----------------------------..37 GENERALCONDITIONS........................................................................................................... 3A (}l. DISCHARGE VIOLATIONS ------------------------------.38 G2. SIGNATORY REQUIREMENTS ----------------------------.38 G3. RIGHT OF INSPECTION AND ENTRY ......................................................................... 3g G4. GENERAL PERMIT MODIFICATION AND REVOCATION ------------..3P G5. REVOCATION OF COVERAGE UNDER THE PERMIT ............................................. ]9 Gh. REPORTING ACAUSE FOR MODIFICATION ............................................................ 40 G7. COMPLIANCE WITH OTHER LAWS AND STATUTES ............................................. 4A G8. DUTY I()REAPPLY ....................................................................................................... 40 G9. TRANSFER (}FGENERAL PERMIT COVERAGE ....................................................... 4] G/0. REMOVED SUBSTANCES ............................................................................................. 4l Gll. DUTY T(JPROVIDE INFORMATION -------------------------4l G12. OTHER REQUIREMENTSOF4ACFRL........................................................................... 4l {}13. ADDITIONAL MONITORING -----------------------------/4l G/4. PENALTIES FOR VIOLATING PERMIT CONDITIONS --------------..'4l {}15. lJPSET------------------------------------------. 42 [000trnclion Sforlmvater General Perinif G17. DUTY TO COMPLY........................................................................................................42 G18. TOXIC POLLUTANTS.....................................................................................................42 G19. PENALTIES FOR TAMPERING.....................................................................................43 G20. REPORTING PLANNED CHANGES.............................................................................43 G21. REPORTING OTHER INFORMATION..........................................................................43 G22. REPORTING ANTICIPATED NON-COMPLIANCE.....................................................43 G23. REQUESTS TO BE EXCLUDED FROM COVERAGE UNDER THE PERMIT ..........44 G24. APPEALS..........................................................................................................................44 G25. SEVERABILITY...............................................................................................................44 G26. BYPASS PROHIBITED....................................................................................................44 APPENDIX A — DEFINITIONS...................................................................................................47 APPENDIX B — ACRONYMS.....................................................................................................55 LIST OF TABLES Table 1: Summary of Required Submittals................................................................................... 4 Table 2: Summary of Required On -site Documentation............................................................... 4 Table 3: Summary of Primary Monitoring Requirements.......................................................... 15 Table 4: Monitoring and Reporting Requirements..................................................................... 17 Table 5: Turbidity, Fine Sediment & Phosphorus Sampling and Limits for 303(d)-Listed Waters.................................................................................................... 25 Table 6: pH Sampling and Limits for 303(d)-Listed Waters ...................................................... 26 `()t2strztc,tion , 1orn,iit>eiter Grnca`rd Permit Page 3 VUV IUV K1 WAIM 0 U DUAL] I 1111111 ti 0103 tA NNIM '6104 119 Refer to the Special and General Conditions within this permit for additional submittal requirements. Appendix A provides a list of definitions. Appendix B provides a list of acronyms. Table 1: Summary of Required Submittals Permit Submittal Frequency First Submittal Date Section S5.A and High Turbidity/Transparency Phone As Necessary Within 24 hours S8 Reporting S5.B Discharge Monitoring Report Monthly* Within 15 days following the end of each month S55 and Noncompliance Notification — As necessary Within 24-hours S8 Telephone Notification S55 Noncompliance Notification — As necessary Within 5 Days of non - Written Report compliance S9.0 Request for Chemical Treatment As necessary Written approval from Form Ecology is required prior to using chemical treatment (with the exception of dry ice or CO2 to adjust pH) G2 Notice of Change in Authorization As necessary G6 Permit Application for Substantive As necessary Changes to the Discharge G8 Application for Permit Renewal 1 /permit cycle No later than 180 days before expiration G9 Notice of Permit Transfer As necessary G20 Notice of Planned Changes As necessary G22 Reporting Anticipated Non- As necessary compliance SPECIAL NOTE: *Permittees must submit electronic Discharge Monitoring Reports (DMRs) to the Washington State Department of Ecology monthly, regardless of site discharge, for the full duration of permit coverage. Refer to Section S5.13 of this General Permit for more specific information regarding DMRs. Table 2: Summary of Required On -site Documentation Document Title Permit Conditions Permit Coverage Letter See Conditions S2, S5 Construction Stormwater General Permit See Conditions S2, S5 Site Log Book See Conditions S4, S5 Stormwater Pollution Prevention Plan (SWPPP) See Conditions S9, S5 Consh'tiction Sloi-nnvaler General 1'ei-rnil Page 4 SPECIAL CONDITIONS St. PERMIT COVERAGE A. Permit Area This Construction Stormwater General Permit (CSWGP) covers all areas of Washington State, except for federal operators and Indian Country as specified in Special Condition S 1.E.3. B. Operators Required to Seek Coverage Under this General Permit: Operators of the following construction activities are required to seek coverage under this CSWGP: a. Clearing, grading and/or excavation that results in the disturbance of one or more acres (including off -site disturbance acreage authorized in S1.C.2) and discharges stormwater to surface waters of the State; and clearing, grading and/or excavation on sites smaller than one acre that are part of a larger common plan of development or sale, if the common plan of development or sale will ultimately disturb one acre or more and discharge stormwater to surface waters of the State. i. This includes forest practices (including, but not limited to, class IV conversions) that are part of a construction activity that will result in the disturbance of one or more acres, and discharge to surface waters of the State (that is, forest practices that prepare a site for construction activities); and b. Any size construction activity discharging stormwater to waters of the State that the Washington State Department of Ecology (Ecology): i. Determines to be a significant contributor of pollutants to waters of the State of Washington. ii. Reasonably expects to cause a violation of any water quality standard. 2. Operators of the following activities are not required to seek coverage under this CSWGP (unless specifically required under Special Condition S I.B. I.b. above): a. Construction activities that discharge all stormwater and non-stormwater to ground water, sanitary sewer, or combined sewer, and have no point source discharge to either surface water or a storm sewer system that drains to surface waters of the State. b. Construction activities covered under an Erosivity Waiver (Special Condition S2.C). c. Routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of a facility. Gen ral Permit Page 5 C. Authorized Discharges: Stormwater Associated with Construction Activity. Subject to compliance with the terms and conditions of this permit, Permittees are authorized to discharge stormwater associated with construction activity to surface waters of the State or to a storm sewer system that drains to surface waters of the State. (Note that "surface waters of the State" may exist on a construction site as well as off site; for example, a creek running through a site.) 2. Stormwater Associated with Construction Support Activity. This permit also authorizes stormwater discharge from support activities related to the permitted construction site (for example, an on -site portable rock crusher, off -site equipment staging yards, material storage areas, borrow areas, etc.) provided: a. The support activity relates directly to the permitted construction site that is required to have an NPDES permit; and b. The support activity is not a commercial operation serving multiple unrelated construction projects, and does not operate beyond the completion of the construction activity; and c. Appropriate controls and measures are identified in the Stormwater Pollution Prevention Plan (SWPPP) for the discharges from the support activity areas. 3. Non-Stormwater Discharges. The categories and sources of non-stormwater discharges identified below are authorized conditionally, provided the discharge is consistent with the terms and conditions of this permit: a. Discharges from fire -fighting activities. b. Fire hydrant system flushing. c. Potable water, including uncontaminated water line flushing. d. Hydrostatic test water. e. Uncontaminated air conditioning or compressor condensate. £ Uncontaminated ground water or spring water. g. Uncontaminated excavation dewatering water (in accordance with S9.D.10). h. Uncontaminated discharges from foundation or footing drains. i. Uncontaminated water used to control dust. Permittees must minimize the amount of dust control water used. j. Routine external building wash down that does not use detergents. k. Landscape irrigation water. The SWPPP must adequately address all authorized non-Stormwater discharges, except for discharges from fire -fighting activities, and must comply with Special Condition S3. ada to°tic°tr �r �, rax >� rca°General Perna t Page 6 At a minimum, discharges from potable water (including water line flushing), fire hydrant system flushing, and pipeline hydrostatic test water must undergo the following: dechlorination to a concentration of 0.1 parts per million (ppm) or less, and pH adjustment to within 6.5 — 8.5 standard units (su), if necessary. D. Prohibited Discharges: The following discharges to waters of the State, including ground water, are prohibited. Concrete wastewater. 2. Wastewater from washout and clean-up of stucco, paint, form release oils, curing compounds and other construction materials. 3. Process wastewater as defined by 40 Code of Federal Regulations (CFR) 122.2 (see Appendix A of this permit). 4. Slurry materials and waste from shaft drilling, including process wastewater from shaft drilling for construction of building, road, and bridge foundations unless managed according to Special Condition S9.D.9.j. 5. Fuels, oils, or other pollutants used in vehicle and equipment operation and maintenance. 6. Soaps or solvents used in vehicle and equipment washing. 7. Wheel wash wastewater, unless managed according to Special Condition S9.13.9. 8. Discharges from dewatering activities, including discharges from dewatering of trenches and excavations, unless managed according to Special Condition. S9.D.10. E. Limits on. Coverage Ecology may require any discharger to apply for and obtain coverage under an. individual permit or another more specific general permit. Such alternative coverage will be required when Ecology determines that this CSWGP does not provide adequate assurance that water quality will be protected, or there is a reasonable potential for the project to cause or contribute to a violation of water quality standards. The following stormwater discharges are not covered by this permit: Post -construction stormwater discharges that originate from the site after completion of construction activities and the site has undergone final stabilization. 2. Non -point source silvicultural activities such as nursery operations, site preparation, reforestation and subsequent cultural treatment, thinning, prescribed burning, pest and fire control, harvesting operations, surface drainage, or road construction and maintenance, from which there is natural runoff as excluded in 40 CFR Subpart 122. 3. Stormwater from any federal operator. Tarr, to c t r�rt �S ��r°rrr. a> >r Gerieral.Per idt d.3aaage 7 4. Stormwater from facilities located on "Indian Country" as defined in 18 U.S.C.§1151, except portions of the Puyallup Reservation as noted below. Indian Country includes: a. All land within any Indian Reservation notwithstanding the issuance of any patent, and, including rights -of -way running through the reservation. This includes all federal, tribal, and Indian and non -Indian privately owned land within the reservation. b. All off -reservation Indian allotments, the Indian titles to which have not been extinguished, including rights -of -way running through the same. c. All off -reservation federal trust lands held for Native American Tribes. Puyallup Exception: Following the Puyallup Tribes of Indians Land Settlement Act of 1989, 25 U.S.C. § 1773; the permit does apply to land within the Puyallup Reservation except for discharges to surface water on land held in trust by the federal government. 5. Stormwater from any site covered under an existing NPDES individual permit in which stormwater management and/or treatment requirements are included for all stormwater discharges associated with construction activity. 6. Stormwater from a site where an applicable Total Maximum Daily Load (TMDL) requirement specifically precludes or prohibits discharges from construction activity. S2. APPLICATION REQUIREMENTS A. Permit Application Forms Notice of Intent Form/Timeline a. Operators of new or previously unpermitted construction activities must submit a complete and accurate permit application (Notice of Intent, or NOI) to Ecology. b. Operators must apply using the electronic application form (NOI) available on. Ecology's website http://www.ecy,wa. ov/programs/wc�lstormwater/ constction/index.html. Permittees unable to submit electronically (for example, those who do not have an internet connection) must contact Ecology to request a waiver and obtain instructions on how to obtain a paper NOI. Department of Ecology Water Quality Program - Construction Stormwater PO Box 47696 Olympia, Washington 98504-7696 Construction ,. torai waler General Perinil Page 8 c. The operator must submit the NOT at least 60 days before discharging stormwater from construction activities and must submit it on or before the date of the first public notice (see Special Condition S2.13 below for details). The 30- day public comment period begins on the publication date of the second public notice. Unless Ecology responds to the complete application in writing, based on public comments, or any other relevant factors, coverage under the general permit will automatically commence on the thirty-first day following receipt by Ecology of a completed NOI, or the issuance date of this permit, whichever is later; unless Ecology specifies a later date in writing as required by WAC173- 226-200(2). d. If an applicant intends to use a Best Management Practice (BMP) selected on the basis of Special Condition S9.C.4 ("demonstrably equivalent" BMPs), the applicant must notify Ecology of its selection as part of the NOI. In the event the applicant selects BMPs after submission of the NOI, it must provide notice of the selection of an equivalent BMP to Ecology at least 60 days before intended use of the equivalent BMP. Permittees must notify Ecology regarding any changes to the information provided on the NOI by submitting an updated NOI. Examples of such changes include, but are not limited to: i. Changes to the Permittee's mailing address, ii. Changes to the on -site contact person information, and iii. Changes to the area/acreage affected by construction activity. £ Applicants must notify Ecology if they are aware of contaminated soils and/or groundwater associated with the construction activity. Provide detailed information with the NOI (as known and readily available) on the nature and extent of the contamination (concentrations, locations, and depth), as well as pollution prevention and/or treatment BMPs proposed to control the discharge of soil and/or groundwater contaminants in stormwater. Examples of such detail may include, but are not limited to: i. List or table of all known contaminants with laboratory test results showing concentration and depth, ii. Map with sample locations, iii. Temporary Erosion and Sediment Control (TESC) plans, iv. Related portions of the Stormwater Pollution Prevention Plan (SWPPP) that address the management of contaminated and potentially contaminated construction stormwater and dewatering water, V. Dewatering plan and/or dewatering contingency plan. C ei; ier l Permit 2. Transfer of Coverage Form The Permittee can transfer current coverage under this permit to one or more new operators, including operators of sites within a Common Plan of Development, provided the Permittee submits a Transfer of Coverage Form in accordance with General Condition G9. Transfers do not require public notice. B. Public Notice For new or previously unpermitted construction activities, the applicant must publish a public notice at least one time each week for two consecutive weeks, at least 7 days apart, in a newspaper with general circulation in the county where the construction is to take place. The notice must contain: 1. A statement that "The applicant is seeking coverage under the Washington State Department of Ecology's Construction Stormwater NPDES and State Waste Discharge General Permit". 2. The name, address and location of the construction site. 3. The name and address of the applicant. 4. The type of construction activity that will result in a discharge (for example, residential construction, commercial construction, etc.), and the number of acres to be disturbed. 5. The name of the receiving water(s) (that is, the surface water(s) to which the site will discharge), or, if the discharge is through a storm sewer system, the name of the operator of the system. 6. The statement: "Any persons desiring to present their views to the Washington State Department of Ecology regarding this application, or interested in Ecology's action on this application, may notify Ecology in writing no later than 30 days of the last date of publication of this notice. Ecology reviews public comments and considers whether discharges from this project would cause a measurable change in receiving water quality, and, if so, whether the project is necessary and in the overriding public interest according to Tier II antidegradation requirements under WAC 173-201A-320. Comments can be submitted to: Department of Ecology, PO Box 47696, Olympia, Washington 98504-7696 Attn: Water Quality Program, Construction. Stormwater." ada to°tic°tr �r �, rax >� rca°Geircxral Perna t Pa'-)e 10 C. Erosivity Waiver Construction site operators may qualify for an erosivity waiver from the CSWGP if the following conditions are met: The site will result in the disturbance of fewer than 5 acres and the site is not a portion of a common plan of development or sale that will disturb 5 acres or greater. 2. Calculation of Erosivity "R" Factor and Regional Timeframe: a. The project's rainfall erosivity factor ("R" Factor) must be less than 5 during the period of construction activity, as calculated (see the CSWGP homepage ttp://wwwaecynwa.gov/pramslwglstormwater/co nstruction/index.html for a link to the EPA's calculator and step by step instructions on computing the "R" Factor in the EPA Erosivity Waiver Fact Sheet). The period of construction activity starts when the land is first disturbed and ends with final stabilization. In addition: b. The entire period of construction activity must fall within the following timeframes: i. For sites west of the Cascades Crest: June 15 — September 15. ii. For sites east of the Cascades Crest, excluding the Central Basin: June 15 — October 15. iii. For sites east of the Cascades Crest, within the Central Basin: no additional timeframe restrictions apply. The Central Basin is defined as the portions of Eastern. Washington with mean annual precipitation of less than 12 inches. For a map of the Central Basin (Average Annual Precipitation Region 2), refer to htlp://www.ecy.wa.gov/programs/wq/stormwater/ construction/resource s guidance ehtml. 3. Construction site operators must submit a complete Erosivity Waiver certification form at least one week before disturbing the land. Certification must include statements that the operator will: a. Comply with applicable local stormwater requirements; and b. Implement appropriate erosion and sediment control BMPs to prevent violations of water quality standards. 4. This waiver is not available for facilities declared significant contributors of pollutants as defined in Special Condition S 1.B.1.b. or for any size construction activity that could reasonably expect to cause a violation of any water quality standard as defined in Special Condition S1.B.l.b.ii. 5. This waiver does not apply to construction activities which include non- stormwater discharges listed in Special Condition S1.C.3. Geiwr l Permit P,Ig I 6. If construction activity extends beyond the certified waiver period for any reason, the operator must either: a. Recalculate the rainfall erosivity "R" factor using the original start date and a new projected ending date and, if the "R" factor is still under 5 and the entire project falls within the applicable regional timeframe in Special Condition S2.C.2.b, complete and submit an amended waiver certification form before the original waiver expires; or b. Submit a complete permit application to Ecology in accordance with Special Condition S2.A and B before the end of the certified waiver period. S3. COMPLIANCE WITH STANDARDS A. Discharges must not cause or contribute to a violation of surface water quality standards (Chapter 173-201A WAC), ground water quality standards (Chapter 173-200 WAC), sediment management standards (Chapter 173-204 WAC), and human health -based criteria in the National Toxics Rule (40 CFR Part 131.36). Discharges not in compliance with these standards are not authorized. B. Prior to the discharge of stormwater and non-stormwater to waters of the State, the Permittee must apply all known, available, and reasonable methods of prevention, control, and treatment (AKART). This includes the preparation and implementation of an adequate SWPPP, with all appropriate BMPs installed and maintained in accordance with the SWPPP and the terms and conditions of this permit. C. Ecology presumes that a Permittee complies with water quality standards unless discharge monitoring data or other site -specific information demonstrates that a discharge causes or contributes to a violation of water quality standards, when the Permittee complies with the following conditions. The Permittee must fully: 1. Comply with all permit conditions, including planning, sampling, monitoring, reporting, and recordkeeping conditions. 2. Implement stormwater BMPs contained in stormwater management manuals published or approved by Ecology, or BMPs that are demonstrably equivalent to BMPs contained in stormwater technical manuals published or approved by Ecology, including the proper selection, implementation, and maintenance of all applicable and appropriate BMPs for on -site pollution control. (For purposes of this section, the stormwater manuals listed in Appendix 10 of the Phase I Municipal Stormwater Permit are approved by Ecology.) D. Where construction sites also discharge to ground water, the ground water discharges must also meet the terms and conditions of this CSWGP. Permittees who discharge to ground water through an injection well must also comply with any applicable requirements of the Underground Injection Control (UIC) regulations, Chapter 173-218 WAC. General Permit P age 121 S4. MONITORING REQUIREMENTS, BENCHMARKS, AND REPORTING TRIGGERS A. Site Log Book The Permittee must maintain a site log book that contains a record of the implementation of the SWPPP and other permit requirements, including the installation and maintenance of BMPs, site inspections, and stormwater monitoring. B. Site Inspections The Permittee's site inspections must include all areas disturbed by construction activities, all BMPs, and all stormwater discharge points under the Permittee's operational control. (See Special Conditions S4.13.3 and B.4 below for detailed requirements of the Permittee's Certified Erosion and Sediment Control Lead [CESCL].) Construction sites one acre or larger that discharge stormwater to surface waters of the State must have site inspections conducted by a certified CESCL. Sites less than one acre may have a person without CESCL certification conduct inspections. 1. The Permittee must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. The Permittee must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. Based on the results of the inspection, the Permittee must correct the problems identified by: a. Reviewing the SWPPP for compliance with Special Condition S9 and making appropriate revisions within 7 days of the inspection. b. Immediately beginning the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems no later than within 10 days of the inspection. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when an extension is requested by a Permittee within the initial 10-day response period. c. Documenting BMP implementation and maintenance in the site log book. 2. The Permittee must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.) The Permittee may reduce the inspection frequency for temporarily stabilized, inactive sites to once every calendar month. bra 7struc Lion Storwrr.wrafer General Permit Page 13 3. The Permittee must have staff knowledgeable in the principles and practices of erosion and sediment control. The CESCL (sites one acre or more) or inspector (sites less than one acre) must have the skills to assess the: a. Site conditions and construction activities that could impact the quality of stormwater, and b. Effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. 4. The SWPPP must identify the CESCL or inspector, who must be present on site or on -call at all times. The CESCL must obtain this certification through an approved erosion and sediment control training program that meets the minimum training standards established by Ecology (see BMP C160 in the manual referred to in Special Condition S9.C.1 and 2). 5. The Permittee must summarize the results of each inspection in an inspection report or checklist and enter the report/checklist into, or attach it to, the site log book. At a minimum, each inspection report or checklist must include: a. Inspection date and time. b. Weather information, the general conditions during inspection and the approximate amount of precipitation since the last inspection, and precipitation within the last 24 hours. c. A summary or list of all implemented BMPs, including observations of all erosion/sediment control structures or practices. d. A description of the locations: i. Of BMPs inspected; ii. Of BMPs that need maintenance and why; iii. Of BMPs that failed to operate as designed or intended; and iv. Where additional or different BMPs are needed, and why. e. A description of stormwater discharged from the site. The Permittee must note the presence of suspended sediment, turbidity, discoloration, and oil sheen, as applicable. f. Any water quality monitoring performed during inspection. g. General comments and notes, including a brief description of any BMP repairs, maintenance or installations made following the inspection. h. A summary report and a schedule of implementation of the remedial actions that the Permittee plans to take if the site inspection indicates that the site is out of compliance. The remedial actions taken must meet the requirements of the SWPPP and the permit. arr, t °zit llr rt ,. r rr. v r General Permit The name, title, and signature of the person conducting the site inspection, a phone number or other reliable method to reach this person, and the following statement: "I certify that this report is true, accurate, and complete to the best of my knowledge and belief." Table 3: Summary of Primary Monitoring Requirements Size of Soil Weekly Site Weekly Weekly Weekly PH CELL Disturbancel Inspections Sampling w/ Sampling wl Sampling2 Required for Turbidity Transparency Inspections? Meter Tube Sites that disturb Required Not Required Not Required Not Required No less than 1 acre, but are part of a larger Common Plan of Development Sites that disturb 1 Required Sampling Required — Required Yes acre or more, but either method3 fewer than 5 acres Sites that disturb 5 Required Required Not Required' Required Yes acres or more ' Soil disturbance is calculated by adding together all areas that will be affected by construction activity. Construction activity means clearing, grading, excavation, and any other activity that disturbs the surface of the land, including ingress/egress from the site. ' If construction activity results in the disturbance of I acre or more, and involves significant concrete work (1,000 cubic yards of poured over the life of a project) or the use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln dust [CKD], or fly ash), and stormwater from the affected area drains to surface waters of the State or to a storm sewer stormwater collection system that drains to other surface waters of the State, the Permittee must conduct pH sampling in accordance with Special Condition S4.D. ' Sites with one or more acres, but fewer than 5 acres of soil disturbance, must conduct turbidity or transparency sampling in accordance with Special Condition S4.C. 4 Sites equal to or greater than 5 acres of soil disturbance must conduct turbidity sampling using a turbidity meter in accordance with Special Condition S4.C. Construction Stortn waler General Permit Page 15 C. Turbidity/Transparency Sampling Requirements 1. Sampling Methods a. If construction activity involves the disturbance of 5 acres or more, the Permittee must conduct turbidity sampling per Special Condition S4.C. b. If construction activity involves 1 acre or more but fewer than 5 acres of soil disturbance, the Permittee must conduct either transparency sampling or turbidity sampling per Special Condition S4.C. 2. Sampling Frequency a. The Permittee must sample all discharge points at least once every calendar week when stormwater (or authorized non-stormwater) discharges from the site or enters any on -site surface waters of the state (for example, a creek running through a site); sampling is not required on sites that disturb less than an acre. b. Samples must be representative of the flow and characteristics of the discharge. c. Sampling is not required when there is no discharge during a calendar week. d. Sampling is not required outside of normal working hours or during unsafe conditions. e. If the Permittee is unable to sample during a monitoring period, the Permittee must include a brief explanation in the monthly Discharge Monitoring Report (DMR). £ Sampling is not required before construction activity begins. g. The Permittee may reduce the sampling frequency for temporarily stabilized, inactive sites to once every calendar month. 3. Sampling Locations a. Sampling is required at all points where stormwater associated with construction activity (or authorized non-stormwater) is discharged off site, including where it enters any on -site surface waters of the state (for example, a creek running through a site). b. The Permittee may discontinue sampling at discharge points that drain areas of the project that are fully stabilized to prevent erosion. c. The Permittee must identify all sampling point(s) on the SWPPP site map and clearly mark these points in the field with a flag, tape, stake or other visible marker. d. Sampling is not required for discharge that is sent directly to sanitary or combined sewer systems. ada to°tic°tr �r �, rax >� rca°Gorcxral Perna t Pa,_)e 16 e. The Permittee may discontinue sampling at discharge points in areas of the project where the Permittee no longer has operational control of the construction activity. 4. Sampling and Analysis Methods a. The Permittee performs turbidity analysis with a calibrated turbidity meter (turbidimeter) either on site or at an accredited lab. The Permittee must record the results in the site log book in nephelometric turbidity units (NTUs). b. The Permittee performs transparency analysis on site with a 13/4-inch-diameter, 60-centimeter (cm) -long transparency tube. The Permittee will record the results in the site log book in centimeters (cm). Table 4: Monitoring and Reporting Requirements Parameter Unit Analytical Method Sampling Benchmark Phone Frequency Value Reporting Trigger Value Turbidity NTU SM2130 Weekly, if 25 NTUs 250 NTUs discharging Transparency cm Manufacturer Weekly, if 33 cm 6 cm instructions, or discharging Ecology guidance 5. Turbidity/Transparency Benchmark Values and Reporting Triggers The benchmark value for turbidity is 25 NTUs or less. The benchmark value for transparency is 33 centimeters (cm). Note: Benchmark values do not apply to discharges to segments of water bodies on. Washington. State's 303(d) list (Category 5) for turbidity, fine sediment, or phosphorus; these discharges are subject to a numeric effluent limit for turbidity. Refer to Special Condition S8 for more information. a. Turbidity 26 — 249 NTUs, or Transparency 32 — 7 cm: If the discharge turbidity is 26 to 249 NTUs; or if discharge transparency is less than 33 cm, but equal to or greater than 6 cm, the Permittee must: i. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. ii. .Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. Gc=nerad.Permit Page 17 iii. Document BM:P implementation and maintenance in the site log book. b. Turbidity 250 NTUs or greater, or Transparency 6 cm or less: If a discharge point's turbidity is 250 NTUs or greater, or if discharge transparency is less than or equal to 6 cm, the Permittee must complete the reporting and adaptive management process described below. i. Telephone or submit an electronic report to the applicable Ecology Region's Environmental Report Tracking System (ERTS) number (or through Ecology's Water Quality Permitting Portal [WQWebPortal] — Permit Submittals when the form is available) within 24 hours, in accordance with Special Condition S5.A. Central Region (Okanogan, Chelan, Douglas, Kittitas, Yakima, Klickitat, Benton): (509) 575-2490 Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 Northwest Region (Kitsap, Snohomish, Island, King, San Juan, Skagit, Whatcom): (425) 649-7000 Southwest Region (Grays Harbor, Lewis, Mason, Thurston, Pierce, Clark, Cowlitz, Skamania, Wahkiakum, Clallam, Jefferson, Pacific): (360) 407-6300 Links to these numbers and the ERTS reporting page are located on the following web site: htt�a://www.ecy.v? a.gov(programs/wq/stormwaterlconstruction/index.html. ii. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. iii. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. iv. Document BMP implementation and maintenance in the site log book. V. Sample discharges daily until: a) Turbidity is 25 NTUs (or lower); or b) Transparency is 33 cm (or greater); or ada to°tic°tr �r �, rax >� rca°Gencxral Perinit PLq-)e 1 c) The Permittee has demonstrated compliance with the water quality limit for turbidity: 1) No more than 5 NTUs over background turbidity, if background is less than 50 NTUs, or 2) No more than 10% over background turbidity, if background is 50 NTUs or greater; or d) The discharge stops or is eliminated. D. pH Sampling Requirements — Significant Concrete Work or Engineered Soils If construction activity results in the disturbance of 1 acre or more, and involves significant concrete work (significant concrete work means greater than 1000 cubic yards poured concrete used over the life of a project ) or the use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln dust [CKD], or fly ash), and stormwater from the affected area drains to surface waters of the State or to a storm sewer system that drains to surface waters of the State, the Permittee must conduct pH sampling as set forth below. Note: In addition, discharges to segments of water bodies on Washington State's 303(d) list (Category 5) for high pH are subject to a numeric effluent limit for pH; refer to Special Condition S8. For sites with significant concrete work, the Permittee must begin the pH sampling period when the concrete is first poured and exposed to precipitation, and continue weekly throughout and after the concrete pour and curing period, until stormwater pH is in the range of 6.5 to 8.5 (su). 2. For sites with recycled concrete, the Permittee must begin the weekly pH sampling period when the recycled concrete is first exposed to precipitation and must continue until the recycled concrete is fully stabilized and stormwater pH is in the range of 6.5 to 8.5 (su). 3. For sites with engineered soils, the Permittee must begin the pH sampling period when the soil amendments are first exposed to precipitation and must continue until the area of engineered soils is fully stabilized. 4. During the applicable pH monitoring period defined above, the Permittee must obtain a representative sample of stormwater and conduct pH analysis at least once per week. 5. The Permittee must sample pH in the sediment trap/pond(s) or other locations that receive stormwater runoff from the area of significant concrete work or engineered soils before the stormwater discharges to surface waters. 6. The benchmark value for pH is 8.5 standard units. Anytime sampling indicates that pH is 8.5 or greater, the Permittee must either: Pm)e 19 a. Prevent the high pH water (8.5 or above) from entering storm sewer systems or surface waters; or b. If necessary, adjust or neutralize the high pH water until it is in the range of pH 6.5 to 8.5 (su) using an appropriate treatment BMP such as carbon dioxide (CO2) sparging or dry ice. The Permittee must obtain written approval from Ecology before using any form of chemical treatment other than CO2 sparging or dry ice. 7. The Permittee must perform pH analysis on site with a calibrated pH meter, pH test kit, or wide range pH indicator paper. The Permittee must record pH sampling results in the site log book. S5. REPORTING AND RECORDKEEPING REQUIREMENTS A. High Turbidity Reporting Anytime sampling performed in accordance with Special Condition S4.0 indicates turbidity has reached the 250 NTUs or more (or transparency less than or equal to 6 cm) high turbidity reporting level, the Permittee must either call the applicable Ecology Region's Environmental Report Tracking System (ERTS) number by phone within 24 hours of analysis or submit an electronic ERTS report (or submit an electronic report through Ecology's Water Quality Permitting Portal (WQWebPortal) — Permit Submittals when the form is available). See the CSWGP web site for links to ERTS and the WQWebPortal: nstruction/ index.html. Also, see phone numbers in Special Condition S4.C.5.b.i. B. Discharge Monitoring Reports (DMRs) Permittees required to conduct water quality sampling in accordance with Special Conditions S4.0 (Turbidity/Transparency), S4.D (pH), S8 (303[d]/TMDL sampling), and/or G13 (Additional Sampling) must submit the results to Ecology. Permittees must submit monitoring data using Ecology's WQWebDMR web application accessed through Ecology's Water Quality Permitting Portal. To find out more information and to sign up for WQWebDMR go to: http,//www.ecy.wa.gov/Trogams/ 3y /taermits/paris/portal,html. Permittees unable to submit electronically (for example, those who do not have an internet connection) must contact Ecology to request a waiver and obtain instructions on how to obtain a paper copy DMR at: Department of Ecology Water Quality Program - Construction. Stormwater PO Box 47696 Olympia, Washington 98504-7696 Permittees who obtain a waiver not to use WQWebDMR must use the forms provided to them by Ecology; submittals must be mailed to the address above. Permittees shall arr, t °zit llr rt ,. r rr. v r Geiiicral Permit P'lg o submit DMR forms to be received by Ecology within 15 days following the end of each month. If there was no discharge during a given monitoring period, all Permittees must submit a DMR as required with "no discharge" entered in place of the monitoring results. DMRs are required for the full duration of permit coverage (from issuance date to termination). For more information, contact Ecology staff using information provided at the following web site: www.ecy,wa.goil rams/:; Dermitsloaris/contacts.html. C. Records Retention The Permittee must retain records of all monitoring information (site log book, sampling results, inspection reports/checklists, etc.), Stormwater Pollution Prevention Plan, copy of the permit coverage letter (including Transfer of Coverage documentation), and any other documentation of compliance with permit requirements for the entire life of the construction project and for a minimum of three years following the termination of permit coverage. Such information must include all calibration and maintenance records, and records of all data used to complete the application for this permit. This period of retention must be extended during the course of any unresolved litigation regarding the discharge of pollutants by the Permittee or when requested by Ecology. D. Recording Results For each measurement or sample taken, the Permittee must record the following information: Date, place, method, and time of sampling or measurement. 2. The first and last name of the individual who performed the sampling or measurement. 3. The date(s) the analyses were performed. 4. The first and last name of the individual who performed the analyses. 5. The analytical techniques or methods used. 6. The results of all analyses. E. Additional Monitoring by the Permittee If the Permittee monitors any pollutant more frequently than required by this permit using test procedures specified by Special Condition S4 of this permit, the results of this monitoring must be included in the calculation and reporting of the data submitted in the Permittee's DMR. F. Noncompliance Notification In the event the Permittee is unable to comply with any part of the terms and conditions of this permit, and the resulting noncompliance may cause a threat to human health or the environment (such as but not limited to spills of fuels or other materials, catastrophic pond or slope failure, and discharges that violate water quality standards), or exceed ara, to°zit lr��rr , ear rr.v�>r � rGeneral Permit Page 21 numeric effluent limitations (see S8. Discharges to 303(d) or TMDL Waterbodies), the Permittee must, upon becoming aware of the circumstance: 1. Notify Ecology within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (refer to Special Condition S4.C.5.b.i. or www.ec gov/ rogra� slwcl/sto waterlconst ctioniturbidity,html for Regional ERTS phone numbers). 2. Immediately take action to prevent the discharge/pollution, or otherwise stop or correct the noncompliance, and, if applicable, repeat sampling and analysis of any noncompliance immediately and submit the results to Ecology within five (5) days of becoming aware of the violation. 3. Submit a detailed written report to Ecology within five (5) days, of the time the Permittee becomes aware of the circumstances, unless requested earlier by Ecology. The report must be submitted using Ecology's Water Quality Permitting Portal (WQWebPortal) - Permit Submittals, unless a waiver from electronic reporting has been granted according to S5.13. The report must contain a description of the noncompliance, including exact dates and times, and if the noncompliance has not been corrected, the anticipated time it is expected to continue; and the steps taken or planned to reduce, eliminate, and prevent reoccurrence of the noncompliance. The Permittee must report any unanticipated bypass and/or upset that exceeds any effluent limit in the permit in accordance with the 24-hour reporting requirement contained in 40 C.F.R. 122.41(1)(6). Compliance with these requirements does not relieve the Permittee from responsibility to maintain continuous compliance with the terms and conditions of this permit or the resulting liability for failure to comply. Upon request of the Permittee, Ecology may waive the requirement for a written report on a case -by - case basis, if the immediate notification is received by Ecology within 24 hours. G. Access to Plans and Records The Permittee must retain the following permit documentation (plans and records) on site, or within reasonable access to the site, for use by the operator or for on -site review by Ecology or the local jurisdiction: a. General Permit b. Permit Coverage Letter c. Stormwater Pollution Prevention Plan (SWPPP) d. Site Log Book 2. The Permittee must address written requests for plans and records listed above (Special Condition S5.G.1) as follows: Construction Swrai water General Perinit 1'age 2 a. The Permittee must provide a copy of plans and records to Ecology within 14 days of receipt of a written request from Ecology. b. The Permittee must provide a copy of plans and records to the public when requested in writing. Upon receiving a written request from the public for the Permittee's plans and records, the Permittee must either: i. Provide a copy of the plans and records to the requester within 14 days of a receipt of the written request; or ii. Notify the requester within 10 days of receipt of the written request of the location and times within normal business hours when the plans and records may be viewed; and provide access to the plans and records within 14 days of receipt of the written request; or iii. Within 14 days of receipt of the written request, the Permittee may submit a copy of the plans and records to Ecology for viewing and/or copying by the requester at an Ecology office, or a mutually agreed location. If plans and records are viewed and/or copied at a location other than at an Ecology office, the Permittee will provide reasonable access to copying services for which a reasonable fee may be charged. The Permittee must notify the requester within 10 days of receipt of the request where the plans and records may be viewed and/or copied. S6. PERMIT FEES The Permittee must pay permit fees assessed by Ecology. Fees for stormwater discharges covered under this permit are established by Chapter 173-224 WAC. Ecology continues to assess permit fees until the permit is terminated in accordance with Special Condition S 10 or revoked in accordance with General Condition G5. S7. SOLID AND LIQUID WASTE DISPOSAL The Permittee must handle and dispose of solid and liquid wastes generated by construction activity, such as demolition debris, construction materials, contaminated materials, and waste materials from maintenance activities, including liquids and solids from cleaning catch basins and other stormwater facilities, in accordance with: A. Special Condition S3, Compliance with Standards B. WAC 173-216-1.10 C. Other applicable regulations S8. DISCHARGES TO 303(d) OR TMDL WATERBODIES A. Sampling and Numeric Effluent Limits For Certain Discharges to 303(d)-listed Waterbodies Permittees who discharge to segments of waterbodies listed as impaired by the State of Washington under Section 303(d) of the Clean Water Act for turbidity, fine sediment, high pH, or phosphorus, must conduct water quality sampling according to the requirements of this section, and Special Conditions S4.C.2.b-f and S4.C.3.b-d, and must comply with the applicable numeric effluent limitations in S8.0 and S8.D. 2. All references and requirements associated with Section 303(d) of the Clean Water Act mean the most current listing by Ecology of impaired waters (Category 5) that exists on January 1, 2016, or the date when the operator's complete permit application is received by Ecology, whichever is later. B. Limits on Coverage for New Discharges to TMDL or 303(d)-listed Waters Operators of construction sites that discharge to a TMDL or 303(d)-listed waterbody are not eligible for coverage under this permit unless the operator: Prevents exposing stormwater to pollutants for which the waterbody is impaired, and retains documentation in the SWPPP that details procedures taken to prevent exposure on site; or 2. Documents that the pollutants for which the waterbody is impaired are not present at the site, and retains documentation of this finding within the SWPPP; or 3. Provides Ecology with data indicating the discharge is not expected to cause or contribute to an exceedance of a water quality standard, and retains such data on site with the SWPPP. The operator must provide data and other technical information to Ecology that sufficiently demonstrate: a. For discharges to waters without an EPA -approved or -established TMDL, that the discharge of the pollutant for which the water is impaired will meet in - stream water quality criteria at the point of discharge to the waterbody; or b. For discharges to waters with an EPA -approved or -established TMDL, that there is sufficient remaining wasteload allocation in the TMDL to allow construction stormwater discharge and that existing dischargers to the waterbody are subject to compliance schedules designed to bring the waterbody into attainment with water quality standards. Operators of construction sites are eligible for coverage under this permit if Ecology issues permit coverage based upon an affirmative determination that the discharge will not cause or contribute to the existing impairment. C. Sampling and Numeric Effluent Limits for Discharges to Water Bodies on the 303(d) List for Turbidity, Fine Sediment, or Phosphorus Permittees who discharge to segments of water bodies on the 303(d) list (Category 5) for turbidity, fine sediment, or phosphorus must conduct turbidity sampling in accordance with Special Condition S4.C.2 and comply with either of the numeric effluent limits noted in Table 5 below. General Perniii 1'A e 24 2. As an alternative to the 25 NTUs effluent limit noted in Table 5 below (applied at the point where stormwater [or authorized non-stormwater] is discharged off -site), Permittees may choose to comply with the surface water quality standard for turbidity. The standard is: no more than 5 NTUs over background turbidity when the background turbidity is 50 NTUs or less, or no more than a 10% increase in turbidity when the background turbidity is more than 50 NTUs. In order to use the water quality standard requirement, the sampling must take place at the following locations: a. Background turbidity in the 303(d)-listed receiving water immediately upstream (upgradient) or outside the area of influence of the discharge. b. Turbidity at the point of discharge into the 303(d)-listed receiving water, inside the area of influence of the discharge. 3. Discharges that exceed the numeric effluent limit for turbidity constitute a violation of this permit. 4. Permittees whose discharges exceed the numeric effluent limit shall sample discharges daily until the violation is corrected and comply with the non- compliance notification requirements in Special Condition S5.17. Table 5: Turbidity, Fine Sediment & Phosphorus Sampling and Limits for 303(d)-Listed Waters Parameter identified in 303(d) listing Parameter Sampled Unit Analytical Method Sampling Frequency Numeric Effluent Limit' Turbidity Turbidity NTU SM2130 Weekly, if 25 NTUs, at the Fine Sediment discharging point where Phosphorus stormwater is discharged from the site; OR In compliance with the surface water quality standard for turbidity (S8.C.2.a) 'Permittees subject to a numeric effluent limit for turbidity may, at their discretion, choose either numeric effluent limitation based on site -specific considerations including, but not limited to, safety, access and convenience. D. Discharges to Water Bodies on the 303(d) List for High pH Permittees who discharge to segments of water bodies on the 303(d) list (Category 5) for high pH must conduct pH sampling in accordance with the table below, and comply with the numeric effluent limit of pH 6.5 to 8.5 su (Table 6). �vafer General Permit Pa—e Table 6: pH Sampling and Limits for 303(d)-Listed Waters Parameter identified in Parameter Analytical Sampling Numeric Effluent 303(d) listing Sampled/Units Method Frequency Limit High pH pH /Standard pH meter Weekly, if In the range of 6.5 Units discharging — 8.5 2. At the Permittee's discretion, compliance with the limit shall be assessed at one of the following locations: a. Directly in the 303(d)-listed waterbody segment, inside the immediate area of influence of the discharge; or b. Alternatively, the Permittee may measure pH at the point where the discharge leaves the construction site, rather than in the receiving water. 3. Discharges that exceed the numeric effluent limit for pH (outside the range of 6.5 — 8.5 su) constitute a violation of this permit. 4. Permittees whose discharges exceed the numeric effluent limit shall sample discharges daily until the violation is corrected and comply with the non- compliance notification requirements in Special Condition S5.17. E. Sampling and Limits for Sites Discharging to Waters Covered by a TMDL or Another Pollution Control Plan 1. Discharges to a waterbody that is subject to a Total Maximum Daily Load (TMDL) for turbidity, fine sediment, high pH, or phosphorus must be consistent with the TMDL. Refer to http //www.ecy.wa.gov/Trogams/wq/tmdl/ TMDLsbyWria/TMDLbyWria,ht l for more information on TMDLs. a. Where an applicable TMDL sets specific waste load allocations or requirements for discharges covered by this permit, discharges must be consistent with any specific waste load allocations or requirements established by the applicable TMDL. i. The Permittee must sample discharges weekly or as otherwise specified by the TMDL to evaluate compliance with the specific waste load allocations or requirements. ii. Analytical methods used to meet the monitoring requirements must conform to the latest revision of the Guidelines Establishing Test Procedures for the Analysis of Pollutants contained in 40 CFR Part 136. Turbidity and pH methods need not be accredited or registered unless conducted at a laboratory which must otherwise be accredited or registered. b. Where an applicable TMDL has established a general waste load allocation for construction stormwater discharges, but has not identified specific requirements, `(.)Ii trztc,tion , 1ornr.vt>riter Genci`cd Permit compliance with Special Conditions S4 (Monitoring) and S9 (SWPPPs) will constitute compliance with the approved TMDL. c. Where an applicable TMDL has not specified a waste load allocation for construction stormwater discharges, but has not excluded these discharges, compliance with Special Conditions S4 (Monitoring) and S9 (SWPPPs) will constitute compliance with the approved TMDL. d. Where an applicable TMDL specifically precludes or prohibits discharges from construction activity, the operator is not eligible for coverage under this permit. 2. Applicable TMDL means a TMDL for turbidity, fine sediment, high pH, or phosphorus that is completed and approved by EPA before January 1, 2016,.or before the date the operator's complete permit application is received by Ecology, whichever is later. TMDLs completed after the operator's complete permit application is received by Ecology become applicable to the Permittee only if they are imposed through an administrative order by Ecology, or through a modification of permit coverage. The Permittee must prepare and properly implement an adequate Stormwater Pollution Prevention Plan (SWPPP) for construction activity in accordance with the requirements of this permit beginning with initial soil disturbance and until final stabilization. A. The Permittee's SWPPP must meet the following objectives: To implement best management practices (BMPs) to prevent erosion and sedimentation, and to identify, reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. To prevent violations of surface water quality, ground water quality, or sediment management standards. 3. To control peak volumetric flow rates and velocities of stormwater discharges. B. General Requirements 1. The SWPPP must include a narrative and drawings. All BMPs must be clearly referenced in the narrative and marked on the drawings. The SWPPP narrative must include documentation to explain and justify the pollution prevention decisions made for the project. Documentation must include: a. Information about existing site conditions (topography, drainage, soils, vegetation, etc.). b. Potential erosion problem areas. The 13 elements of a SWPPP in Special Condition S9.D.1-13, including BMPs used to address each element. ada to°tic°tr �r �, rax >� rca°Gencxral Permit d. Construction phasing/sequence and general BMP implementation schedule. e. The actions to be taken if BMP performance goals are not achieved —for example, a contingency plan for additional treatment and/or storage of stormwater that would violate the water quality standards if discharged. f. Engineering calculations for ponds, treatment systems, and any other designed structures. 2. The Permittee must modify the SWPPP if, during inspections or investigations conducted by the owner/operator, or the applicable local or state regulatory authority, it is determined that the SWPPP is, or would be, ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. The Permittee must then: a. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within 7 days of the inspection or investigation. b. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible, addressing the problems no later than 10 days from the inspection or investigation. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when an extension is requested by a Permittee within the initial 10-day response period. c. Document BMP implementation and maintenance in the site log book. The Permittee must modify the SWPPP whenever there is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. C. Stormwater Best Management Practices (BMPs) BMPs must be consistent with: Stormwater Management Manual for Western Washington (most current approved edition at the time this permit was issued), for sites west of the crest of the Cascade Mountains; or 2. Stormwater Management Manual for Eastern Washington (most current approved edition at the time this permit was issued), for sites east of the crest of the Cascade Mountains; or 3. Revisions to the manuals listed in Special Condition S9.C.1. & 2., or other Stormwater management guidance documents or manuals which provide an equivalent level of pollution prevention, that are approved by Ecology and incorporated into this permit in accordance with the permit modification requirements of WAC 173-226-230; or ara, to°zit lr��rr , ear rr.v�>r � r erieral Permit Page 28 4. Documentation in the SWPPP that the BMPs selected provide an equivalent level of pollution prevention, compared to the applicable Stormwater Management Manuals, including: a. The technical basis for the selection of all stormwater BMPs (scientific, technical studies, and/or modeling) that support the performance claims for the BMPs being selected. b. An assessment of how the selected BMP will satisfy AKART requirements and the applicable federal technology -based treatment requirements under 40 CFR part 125.3. D. SWPPP — Narrative Contents and Requirements The Permittee must include each of the 13 elements below in Special Condition S9.D.1-13 in the narrative of the SWPPP and implement them unless site conditions render the element unnecessary and the exemption from that element is clearly justified in the SWPPP. Preserve Vegetation/Mark Clearing Limits a. Before beginning land -disturbing activities, including clearing and grading, clearly mark all clearing limits, sensitive areas and their buffers, and trees that are to be preserved within the construction area. b. Retain the duff layer, native topsoil, and natural vegetation in an undisturbed state to the maximum degree practicable. 2. Establish Construction Access a. Limit construction vehicle access and exit to one route, if possible. b. Stabilize access points with a pad of quarry spalls, crushed rock, or other equivalent BMPs, to minimize tracking sediment onto roads. c. Locate wheel wash or tire baths on site, if the stabilized construction entrance is not effective in preventing tracking sediment onto roads. d. If sediment is tracked off site, clean the affected roadway thoroughly at the end of each day, or more frequently as necessary (for example, during wet weather). Remove sediment from roads by shoveling, sweeping, or pickup and transport of the sediment to a controlled sediment disposal area. Conduct street washing only after sediment removal in accordance with Special Condition S9.D.2.d. Control street wash wastewater by pumping back on site or otherwise preventing it from discharging into systems tributary to waters of the State. 3. Control Flow Rates a. Protect properties and waterways downstream of development sites from erosion and the associated discharge of turbid waters due to increases in the `onstruction Slortrx.wtvfer General Permit )age, ' 9 velocity and peak volumetric flow rate of stormwater runoff from the project site, as required by local plan approval authority. b. Where necessary to comply with Special Condition S9.D.3.a, construct stormwater retention or detention facilities as one of the first steps in grading. Assure that detention facilities function properly before constructing site improvements (for example, impervious surfaces). c. If permanent infiltration ponds are used for flow control during construction, protect these facilities from siltation during the construction phase. 4. Install Sediment Controls The Permittee must design, install and maintain effective erosion controls and sediment controls to minimize the discharge of pollutants. At a minimum, the Permittee must design, install and maintain such controls to: a. Construct sediment control BMPs (sediment ponds, traps, filters, infiltration facilities, etc.) as one of the first steps in grading. These BMPs must be functional before other land disturbing activities take place. b. Minimize sediment discharges from the site. The design, installation and maintenance of erosion and sediment controls must address factors such as the amount, frequency, intensity and duration of precipitation, the nature of resulting stormwater runoff, and soil characteristics, including the range of soil particle sizes expected to be present on the site. c. Direct stormwater runoff from disturbed areas through a sediment pond or other appropriate sediment removal BMP, before the runoff leaves a construction site or before discharge to an infiltration facility. Runoff from fully stabilized areas may be discharged without a sediment removal BMP, but must meet the flow control performance standard of Special Condition S9.D.3.a. d. Locate BMPs intended to trap sediment on site in a manner to avoid interference with the movement of juvenile salmonids attempting to enter off -channel areas or drainages. e. Provide and maintain natural buffers around surface waters, direct stormwater to vegetated areas to increase sediment removal and maximize stormwater infiltration, unless infeasible. f. Where feasible, design outlet structures that withdraw impounded stormwater from the surface to avoid discharging sediment that is still suspended lower in the water column. 5. Stabilize Soils a. The Permittee must stabilize exposed and unworked soils by application of effective BMPs that prevent erosion. Applicable BMPs include, but are not limited to: temporary and permanent seeding, sodding, mulching, plastic covering, erosion control fabrics and matting, soil application of polyacrylamide `(.)Ii trztc,tion , 1orn,iit>eiter Grnca`cd Permit 'A y 30 (PAM), the early application of gravel base on areas to be paved, and dust control. b. The Permittee must control stormwater volume and velocity within the site to minimize soil erosion. The Permittee must control stormwater discharges, including both peak flow rates and total stormwater volume, to minimize erosion at outlets and to minimize downstream channel and stream bank erosion. d. Depending on the geographic location of the project, the Permittee must not allow soils to remain exposed and unworked for more than the time periods set forth below to prevent erosion: West of the Cascade Mountains Crest During the dry season (May 1 - September 30): 7 days During the wet season (October 1 - April 30): 2 days East of the Cascade Mountains Crest, except for Central Basin* During the dry season (July 1 - September 30): 10 days During the wet season (October 1 - June 30): 5 days The Central Basin*, East of the Cascade Mountains Crest During the dry season (July 1 - September 30): 30 days During the wet season (October 1 - June 30): 15 days *Note: The Central Basin is defined as the portions of Eastern Washington with mean annual precipitation of less than 12 inches. The Permittee must stabilize soils at the end of the shift before a holiday or weekend if needed based on the weather forecast. f. The Permittee must stabilize soil stockpiles from erosion, protected with. sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. g. The Permittee must minimize the amount of soil exposed during construction activity. h. The Permittee must minimize the disturbance of steep slopes. The Permittee must minimize soil compaction and, unless infeasible, preserve topsoil. 6. Protect Slopes a. The Permittee must design and construct cut -and -fill slopes in a manner to minimize erosion. Applicable practices include, but are not limited to, reducing continuous length of slope with terracing and diversions, reducing slope steepness, and roughening slope surfaces (for example, track walking). ara, to°zit lr��rr , ear rr.v�>r � r erieral Pertitit Page 31 b. The Permittee must divert off -site stormwater (run-on) or ground water away from slopes and disturbed areas with interceptor dikes, pipes, and/or swales. Off -site stormwater should be managed separately from stormwater generated on the site. c. At the top of slopes, collect drainage in pipe slope drains or protected channels to prevent erosion. i. West of the Cascade Mountains Crest: Temporary pipe slope drains must handle the peak 10-minute flow rate from a Type IA, 10-year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate predicted by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the Western Washington Hydrology Model (WWHM) to predict flows, bare soil areas should be modeled as "landscaped area." ii. East of the Cascade Mountains Crest: Temporary pipe slope drains must handle the expected peak flow rate from a 6-month, 3-hour storm for the developed condition, referred to as the short duration storm. d. Place excavated material on the uphill side of trenches, consistent with safety and space considerations. Place check dams at regular intervals within constructed channels that are cut down a slope. 7. Protect Drain Inlets a. Protect all storm drain inlets made operable during construction so that stormwater runoff does not enter the conveyance system without first being filtered or treated to remove sediment. b. Clean or remove and replace inlet protection devices when sediment has filled one-third of the available storage (unless a different standard is specified by the product manufacturer). 8. Stabilize Channels and Outlets a. Design, construct and stabilize all on -site conveyance channels to prevent erosion from the following expected peak flows: i. West of the Cascade Mountains Crest: Channels must handle the peak 10-minute flow rate from a Type IA, 10-year, 24-hour frequency storm for the developed condition. Alternatively, the 10-year, 1-hour flow rate indicated by an approved continuous runoff model, increased by a factor of 1.6, may be used. The hydrologic analysis must use the existing land C'nistruelion Stonrr.wtvter General Perinif )age 3Z cover condition for predicting flow rates from tributary areas outside the project limits. For tributary areas on the project site, the analysis must use the temporary or permanent project land cover condition, whichever will produce the highest flow rates. If using the WWHM to predict flows, bare soil areas should be modeled as "landscaped area." ii. East of the Cascade Mountains Crest: Channels must handle the expected peak flow rate from a 6-month, 3-hour storm for the developed condition, referred to as the short duration storm. b. Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches at the outlets of all conveyance systems. 9. Control Pollutants Design, install, implement and maintain effective pollution prevention measures to minimize the discharge of pollutants. The Permittee must: a. Handle and dispose of all pollutants, including waste materials and demolition debris that occur on site in a manner that does not cause contamination of stormwater. b. Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum products, and other materials that have the potential to pose a threat to human health or the environment. On -site fueling tanks must include secondary containment. Secondary containment means placing tanks or containers within an impervious structure capable of containing 110% of the volume contained in the largest tank within the containment structure. Double - walled tanks do not require additional secondary containment. c. Conduct maintenance, fueling, and repair of heavy equipment and vehicles using spill prevention and control measures. Clean contaminated surfaces immediately following any spill incident. d. Discharge wheel wash or tire bath wastewater to a separate on -site treatment system that prevents discharge to surface water, such as closed -loop recirculation or upland land application, or to the sanitary sewer with local sewer district approval. e. Apply fertilizers and pesticides in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Follow manufacturers' label. requirements for application rates and procedures. f. Use BMPs to prevent contamination of stormwater runoff by pH -modifying sources. The sources for this contamination include, but are not limited to: bulk cement, cement kiln dust, fly ash, new concrete washing and curing waters, recycled concrete stockpiles, waste streams generated from concrete grinding and sawing, exposed aggregate processes, dewatering concrete vaults, concrete Pm)e 33 pumping and mixer washout waters. (Also refer to the definition for "concrete wastewater" in Appendix A --Definitions.) g. Adjust the pH of stormwater or authorized non-stormwater if necessary to prevent an exceedance of groundwater and/or surface water quality standards. h. Assure that washout of concrete trucks is performed off -site or in designated concrete washout areas only. Do not wash out concrete trucks or concrete handling equipment onto the ground, or into storm drains, open ditches, streets, or streams. Do not dump excess concrete on site, except in designated concrete washout areas. Concrete spillage or concrete discharge to surface waters of the State is prohibited. i. Obtain written approval from Ecology before using any chemical treatment, with the exception of COa or dry ice used to adjust pH. Uncontaminated water from water -only based shaft drilling for construction of building, road, and bridge foundations may be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters. Prior to infiltration, water from water -only based shaft drilling that comes into contact with curing concrete must be neutralized until pH is in the range of 6.5 to 8.5 (su). 10. Control Dewatering a. Permittees must discharge foundation, vault, and trench dewatering water, which have characteristics similar to stormwater runoff at the site, into a controlled conveyance system before discharge to a sediment trap or sediment pond. b. Permittees may discharge clean, non -turbid dewatering water, such as well - point ground water, to systems tributary to, or directly into surface waters of the State, as specified in Special Condition S9.D.8, provided the dewatering flow does not cause erosion or flooding of receiving waters. Do not route clean dewatering water through stormwater sediment ponds. Note that "surface waters of the State" may exist on a construction site as well as off site; for example, a creek running through a site. c. Other dewatering treatment or disposal options may include: i. Infiltration. ii. Transport off site in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute state waters. iii. Ecology -approved on -site chemical treatment or other suitable treatment technologies (see S9.D.9.i. regarding chemical treatment written approval). iv. Sanitary or combined sewer discharge with local sewer district approval, if there is no other option. Construction Storwrr.wrafer General Permit t'ri V. Use of a sedimentation bag with discharge to a ditch or swale for small volumes of localized dewatering. d. Permittees must handle highly turbid or contaminated dewatering water separately from stormwater. 11. Maintain BMPs a. Permittees must maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to assure continued performance of their intended function in accordance with BMP specifications. b. Permittees must remove all temporary erosion and sediment control BMPs within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. 12. Manage the Project a. Phase development projects to the maximum degree practicable and take into account seasonal work limitations. b. Inspection and monitoring — Inspect, maintain and repair all BMPs as needed to assure continued performance of their intended function. Conduct site inspections and monitoring in accordance with Special Condition S4. c. Maintaining an updated construction SWPPP — Maintain, update, and implement the SWPPP in accordance with Special Conditions S3, S4 and S9. 13. Protect Low Impact Development (LID) BMPs The primary purpose of LID BMPs/On-site LID Stormwater Management BMPs is to reduce the disruption of the natural site hydrology. LID BMPs are permanent facilities. a. Permittees must protect all Bioretention and Rain Garden facilities from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the Bioretention and/or Rain Garden facilities. Restore the facilities to their fully functioning condition if they accumulate sediment during construction. Restoring the facility must include removal of sediment and any sediment -laden Bioretention/Rain Garden soils, and replacing the removed soils with soils meeting the design specification. b. Permittees must maintain the infiltration capabilities of Bioretention and Rain Garden facilities by protecting against compaction by construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. Permittees must control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy `(.)Ii trztc,tion , 1orn,iit>eiter Grnca`rd Permit 'A cy 3 construction equipment on the base material or pavement. Do not allow sediment -laden runoff onto permeable pavements. d. Permittees must clean permeable pavements fouled with sediments or no longer passing an initial infiltration test using local stormwater manual methodology or the manufacturer's procedures. e. Permittees must keep all heavy equipment off existing soils under LID facilities that have been excavated to final grade to retain the infiltration rate of the soils. E. SWPPP — Map Contents and Requirements The Permittee's SWPPP must also include a vicinity map or general location map (for example, a USGS quadrangle map, a portion of a county or city map, or other appropriate map) with enough detail to identify the location of the construction site and receiving waters within one mile of the site. The SWPPP must also include a legible site map (or maps) showing the entire construction site. The following features must be identified, unless not applicable due to site conditions: 1. The direction of north, property lines, and existing structures and roads. 2. Cut and fill slopes indicating the top and bottom of slope catch lines. 3. Approximate slopes, contours, and direction of stormwater flow before and after major grading activities. 4. Areas of soil disturbance and areas that will not be disturbed. 5. Locations of structural and nonstructural controls (BMPs) identified in the SWPPP. 6. Locations of off -site material, stockpiles, waste storage, borrow areas, and vehicle/equipment storage areas. 7. Locations of all surface water bodies, including wetlands. 8. Locations where stormwater or non-stormwater discharges off -site and/or to a surface waterbody, including wetlands. 9. Location of water quality sampling station(s), if sampling is required by state or local permitting authority. 10. Areas where final stabilization has been accomplished and no further construction - phase permit requirements apply. 11. Location or proposed location of LID facilities. ada to°tic°tr �r �, rax >� rca°Gencxral Permit L_)e36 SIO. NOTICE OF TERMINATION A. The site is eligible for termination of coverage when it has met any of the following conditions: The site has undergone final stabilization, the Permittee has removed all temporary BMPs (except biodegradable BMPs clearly manufactured with the intention for the material to be left in place and not interfere with maintenance or land use), and all stormwater discharges associated with construction activity have been eliminated; or 2. All portions of the site that have not undergone final stabilization per Special Condition S 10.A.1 have been sold and/or transferred (per General Condition G9), and the Permittee no longer has operational control of the construction activity; or 3. For residential construction only, the Permittee has completed temporary stabilization and the homeowners have taken possession of the residences. B. When the site is eligible for termination, the Permittee must submit a complete and accurate Notice of Termination (NOT) form, signed in accordance with General Condition G2, to: Department of Ecology Water Quality Program — Construction Stormwater PO Box 47696 Olympia, Washington 98504-7696 When an electronic termination form is available, the Permittee may choose to submit a complete and accurate Notice of Termination (NOT) form through the Water Quality Permitting Portal rather than mailing a hardcopy as noted above. The termination is effective on the thirty-first calendar day following the date Ecology receives a complete NOT form, unless Ecology notifies the Permittee that the termination request is denied because the Permittee has not met the eligibility requirements in Special. Condition S 1 O.A. Permittees are required to comply with all conditions and effluent limitations in the permit until the permit has been terminated. Permittees transferring the property to a new property owner or operator/Permittee are required to complete and submit the Notice of Transfer form to Ecology, but are not required to submit a Notice of Termination form for this type of transaction. `(.)Ii trztc,tion , 1orn,iit>eiter Geiricrcd Pertittt ,age 37 GENERAL CONDITIONS GI. DISCHARGE VIOLATIONS All discharges and activities authorized by this general permit must be consistent with the terms and conditions of this general permit. Any discharge of any pollutant more frequent than or at a level in excess of that identified and authorized by the general permit must constitute a violation of the terms and conditions of this permit. G2. SIGNATORY REQUIREMENTS A. All permit applications must bear a certification of correctness to be signed: In the case of corporations, by a responsible corporate officer; 2. In the case of a partnership, by a general partner of a partnership; 3. In the case of sole proprietorship, by the proprietor; or 4. In the case of a municipal, state, or other public facility, by either a principal executive officer or ranking elected official. B. All reports required by this permit and other information requested by Ecology (including NOIs, NOTs, and Transfer of Coverage forms) must be signed by a person described above or by a duly authorized representative of that person. A person is a duly authorized representative only if: 1. The authorization is made in writing by a person described above and submitted to Ecology. 2. The authorization specifies either an individual or a position having responsibility for the overall operation of the regulated facility, such as the position of plant manager, superintendent, position of equivalent responsibility, or an individual or position having overall responsibility for environmental matters. C. Changes to authorization. If an authorization under paragraph G2.13.2 above is no longer accurate because a different individual or position has responsibility for the overall operation of the facility, a new authorization satisfying the requirements of paragraph G2.13.2 above must be submitted to Ecology prior to or together with any reports, information, or applications to be signed by an authorized representative. D. Certification. Any person signing a document under this section must make the following certification: "I certify under penalty of law, that this document and all attachments were prepared under my direction or supervision in accordance with a system designed to assure that qualified personnel properly gathered and evaluated the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering information, the information submitted is, to the best of my General Permit age 3 knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations." G3. RIGHT OF INSPECTION AND ENTRY The Permittee must allow an authorized representative of Ecology, upon the presentation of credentials and such other documents as may be required by law: A. To enter upon the premises where a discharge is located or where any records are kept under the terms and conditions of this permit. B. To have access to and copy — at reasonable times and at reasonable cost — any records required to be kept under the terms and conditions of this permit. C. To inspect — at reasonable times — any facilities, equipment (including monitoring and control equipment), practices, methods, or operations regulated or required under this permit. D. To sample or monitor — at reasonable times — any substances or parameters at any location for purposes of assuring permit compliance or as otherwise authorized by the Clean Water Act. 111141 M W This permit may be modified, revoked and reissued, or terminated in accordance with the provisions of Chapter 173-226 WAC. Grounds for modification, revocation and reissuance, or termination include, but are not limited to, the following: A. When a change occurs in the technology or practices for control or abatement of pollutants applicable to the category of dischargers covered under this permit. B. When effluent limitation guidelines or standards are promulgated pursuant to the CWA or Chapter 90.48 RCW, for the category of dischargers covered under this permit. C. When a water quality management plan containing requirements applicable to the category of dischargers covered under this permit is approved, or D. When information is obtained that indicates cumulative effects on the environment from dischargers covered under this permit are unacceptable. G5. REVOCATION OF COVERAGE UNDER THE PERMIT Pursuant to Chapter 43.21 B RCW and Chapter 173-226 WAC, the Director may terminate coverage for any discharger under this permit for cause. Cases where coverage may be terminated include, but are not limited to, the following: A. Violation of any term or condition of this permit. B. Obtaining coverage under this permit by misrepresentation or failure to disclose fully all relevant facts. `(.)Ii trztc,tion , 1orn,iit>eiter Grnca`cd Perinit 'A cy 39 C. A change in any condition that requires either a temporary or permanent reduction or elimination of the permitted discharge. D. Failure or refusal of the Permittee to allow entry as required in RCW 90.48.090. E. A determination that the permitted activity endangers human health or the environment, or contributes to water quality standards violations. F. Nonpayment of permit fees or penalties assessed pursuant to RCW 90.48.465 and Chapter 173-224 WAC. G. Failure of the Permittee to satisfy the public notice requirements of WAC 173-226- 130(5), when applicable. The Director may require any discharger under this permit to apply for and obtain coverage under an individual permit or another more specific general permit. Permittees who have their coverage revoked for cause according to WAC 173-226-240 may request temporary coverage under this permit during the time an individual permit is being developed, provided the request is made within ninety (90) days from the time of revocation and is submitted along with a complete individual permit application form. G6. REPORTING A CAUSE FOR MODIFICATION The Permittee must submit a new application, or a supplement to the previous application, whenever a material change to the construction activity or in the quantity or type of discharge is anticipated which is not specifically authorized by this permit. This application must be submitted at least sixty (60) days prior to any proposed changes. Filing a request for a permit modification, revocation and reissuance, or termination, or a notification of planned changes or anticipated noncompliance does not relieve the Permittee of the duty to comply with the existing permit until it is modified or reissued. G7. COMPLIANCE WITH OTHER LAWS AND STATUTES Nothing in this permit will be construed as excusing the Permittee from compliance with. any applicable federal, state, or local statutes, ordinances, or regulations. no Ira 11111114 WMIJ The Permittee must apply for permit renewal at least 180 days prior to the specified expiration date of this permit. The Permittee must reapply using the electronic application form (NOI) available on Ecology's website. Permittees unable to submit electronically (for example, those who do not have an internet connection) must contact Ecology to request a waiver and obtain instructions on how to obtain a paper NOI. Department of Ecology Water Quality Program - Construction Stormwater PO Box 47696 Olympia, Washington 98504-7696 ara, tr°zit lr��rr , �r rr.v�>r � rGen ral Permit Page 40 G9. TRANSFER OF GENERAL PERMIT COVERAGE Coverage under this general permit is automatically transferred to a new discharger, including operators of lots/parcels within a common plan of development or sale, if: A. A written agreement (Transfer of Coverage Form) between the current discharger (Permittee) and new discharger, signed by both parties and containing a specific date for transfer of permit responsibility, coverage, and liability (including any Administrative Orders associated with the Permit) is submitted to the Director; and B. The Director does not notify the current discharger and new discharger of the Director's intent to revoke coverage under the general permit. If this notice is not given, the transfer is effective on the date specified in the written agreement. When a current discharger (Permittee) transfers a portion of a permitted site, the current discharger must also submit an updated application form (NOI) to the Director indicating the remaining permitted acreage after the transfer. G10. REMOVED SUBSTANCES The Permittee must not re -suspend or reintroduce collected screenings, grit, solids, sludges, filter backwash, or other pollutants removed in the course of treatment or control of stormwater to the final effluent stream for discharge to state waters. The Permittee must submit to Ecology, within a reasonable time, all information that Ecology may request to determine whether cause exists for modifying, revoking and reissuing, or terminating this permit or to determine compliance with this permit. The Permittee must also submit to Ecology, upon request, copies of records required to be kept by this permit [40 CFR 122.41(h)]. Clf6 mY:1ifta.7!L11111.7NLTA111alk-101X.,uro101a All other requirements of 40 CFR 122.41 and 122.42 are incorporated in this permit by reference. G13. ADDITIONAL MONITORING Ecology may establish specific monitoring requirements in addition to those contained in this permit by administrative order or permit modification. G14. PENALTIES FOR VIOLATING PERMIT CONDITIONS Any person who is found guilty of willfully violating the terms and conditions of this permit shall be deemed guilty of a crime, and upon conviction thereof shall be punished by a fine of up to ten thousand dollars ($10,000) and costs of prosecution, or by imprisonment at the discretion of the court. Each day upon which a willful violation occurs may be deemed a separate and additional violation. bra 7struc Lion Storaiwraler General Permit Page 41 Any person who violates the terms and conditions of a waste discharge permit shall incur, in addition to any other penalty as provided by law, a civil penalty in the amount of up to ten thousand dollars ($10,000) for every such violation. Each and every such violation shall be a separate and distinct offense, and in case of a continuing violation, every day's continuance shall be deemed to be a separate and distinct violation. G15. UPSET Definition — "Upset" means an exceptional incident in which there is unintentional and temporary noncompliance with technology -based permit effluent limitations because of factors beyond the reasonable control of the Permittee. An upset does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation. An upset constitutes an affirmative defense to an action brought for noncompliance with such technology -based permit effluent limitations if the requirements of the following paragraph are met. A Permittee who wishes to establish the affirmative defense of upset must demonstrate, through properly signed, contemporaneous operating logs or other relevant evidence that: 1) an upset occurred and that the Permittee can identify the cause(s) of the upset; 2) the permitted facility was being properly operated at the time of the upset; 3) the Permittee submitted notice of the upset as required in Special Condition S5.17, and; 4) the Permittee complied with any remedial measures required under this permit. In any enforcement proceeding, the Permittee seeking to establish the occurrence of an upset has the burden of proof. G16. PROPERTY RIGHTS This permit does not convey any property rights of any sort, or any exclusive privilege. G17. DUTY TO COMPLY The Permittee must comply with all conditions of this permit. Any permit noncompliance constitutes a violation of the Clean Water Act and is grounds for enforcement action; for permit termination, revocation and reissuance, or modification; or denial of a permit renewal application. G1.8. TOXIC POLLUTANTS The Permittee must comply with effluent standards or prohibitions established under Section 307(a) of the Clean Water Act for toxic pollutants within the time provided in the regulations that establish those standards or prohibitions, even if this permit has not yet been modified to incorporate the requirement. C(a istruc1r'on Storlii.wtvter General Perinit Page 42 G19. PENALTIES FOR TAMPERING The Clean Water Act provides that any person who falsifies, tampers with, or knowingly renders inaccurate any monitoring device or method required to be maintained under this permit shall, upon conviction, be punished by a fine of not more than $10,000 per violation, or by imprisonment for not more than two years per violation, or by both. If a conviction of a person is for a violation committed after a first conviction of such person under this condition, punishment shall be a fine of not more than $20,000 per day of violation, or imprisonment of not more than four (4) years, or both. G20. REPORTING PLANNED CHANGES The Permittee must, as soon as possible, give notice to Ecology of planned physical alterations, modifications or additions to the permitted construction activity. The Permittee should be aware that, depending on the nature and size of the changes to the original permit, a new public notice and other permit process requirements may be required. Changes in activities that require reporting to Ecology include those that will result in: A. The permitted facility being determined to be a new source pursuant to 40 CFR 122.29(b). B. A significant change in the nature or an increase in quantity of pollutants discharged, including but not limited to: for sites 5 acres or larger, a 20% or greater increase in acreage disturbed by construction activity. C. A change in or addition of surface water(s) receiving stormwater or non-stormwater from the construction activity. D. A change in the construction plans and/or activity that affects the Permittee's monitoring requirements in Special Condition S4. Following such notice, permit coverage may be modified, or revoked and reissued pursuant to 40 CFR 122.62(a) to specify and limit any pollutants not previously limited. Until such modification is effective, any new or increased discharge in excess of permit limits or not specifically authorized by this permit constitutes a violation. G21. REPORTING OTHER INFORMATION Where the Permittee becomes aware that it failed to submit any relevant facts in a permit application, or submitted incorrect information in a permit application or in any report to Ecology, it must promptly submit such facts or information. G22. REPORTING ANTICIPATED NON-COMPLIANCE The Permittee must give advance notice to Ecology by submission of a new application or supplement thereto at least forty-five (45) days prior to commencement of such discharges, of any facility expansions, production increases, or other planned changes, such as process modifications, in the permitted facility or activity which may result in noncompliance with permit limits or conditions. Any maintenance of facilities, which might necessitate `(a istructimi Storax.vs ales Geri real Periiiit oe 4. unavoidable interruption of operation and degradation of effluent quality, must be scheduled during non -critical water quality periods and carried out in a manner approved by Ecology. G23. REQUESTS TO BE EXCLUDED FROM COVERAGE UNDER THE PERMIT Any discharger authorized by this permit may request to be excluded from coverage under the general permit by applying for an individual permit. The discharger must submit to the Director an application as described in WAC 173-220-040 or WAC 173-216-070, whichever is applicable, with reasons supporting the request. These reasons will fully document how an individual permit will apply to the applicant in a way that the general permit cannot. Ecology may make specific requests for information to support the request. The Director will either issue an individual permit or deny the request with a statement explaining the reason for the denial. When an individual permit is issued to a discharger otherwise subject to the construction stormwater general permit, the applicability of the construction stormwater general permit to that Permittee is automatically terminated on the effective date of the individual permit. G24. APPEALS A. The terms and conditions of this general permit, as they apply to the appropriate class of dischargers, are subject to appeal by any person within 30 days of issuance of this general permit, in accordance with Chapter 43.21B RCW, and Chapter 173-226 WAC. B. The terms and conditions of this general permit, as they apply to an individual discharger, are appealable in accordance with Chapter 43.2113 RCW within 30 days of the effective date of coverage of that discharger. Consideration of an appeal of general permit coverage of an individual discharger is limited to the general permit's applicability or non applicability to that individual discharger. C. The appeal of general permit coverage of an individual discharger does not affect any other dischargers covered under this general permit. If the terms and conditions of this general permit are found to be inapplicable to any individual discharger(s), the matter shall be remanded to Ecology for consideration of issuance of an individual permit or permits. Cli►•1:�_,10i,I117\:3101111'1 The provisions of this permit are severable, and if any provision of this permit, or application of any provision of this permit to any circumstance, is held invalid, the application of such provision to other circumstances, and the remainder of this permit shall not be affected thereby. A. Bypass Procedures Bypass, which is the intentional diversion of waste streams from any portion of a treatment facility, is prohibited for stormwater events below the design criteria for Geriera1.Per idt I)ag stormwater management. Ecology may take enforcement action against a Permittee for bypass unless one of the following circumstances (1, 2, 3 or 4) is applicable. Bypass of stormwater is consistent with the design criteria and part of an approved management practice in the applicable stormwater management manual. 2. Bypass for essential maintenance without the potential to cause violation of permit limits or conditions. Bypass is authorized if it is for essential maintenance and does not have the potential to cause violations of limitations or other conditions of this permit, or adversely impact public health. 3. Bypass of stormwater is unavoidable, unanticipated, and results in noncompliance of this permit. This bypass is permitted only if: a. Bypass is unavoidable to prevent loss of life, personal injury, or severe property damage. "Severe property damage" means substantial physical damage to property, damage to the treatment facilities which would cause them to become inoperable, or substantial and permanent loss of natural resources which can reasonably be expected to occur in the absence of a bypass. b. There are no feasible alternatives to the bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, maintenance during normal periods of equipment downtime (but not if adequate backup equipment should have been installed in the exercise of reasonable engineering judgment to prevent a bypass which occurred during normal periods of equipment downtime or preventative maintenance), or transport of untreated wastes to another treatment facility. c. Ecology is properly notified of the bypass as required in Special Condition S5.17 of this permit. 4. A planned action that would cause bypass of stormwater and has the potential to result in noncompliance of this permit during a storm event. The Permittee must notify Ecology at least thirty (30) days before the planned date of bypass. The notice must contain: a. A description of the bypass and its cause. b. An analysis of all known alternatives which would eliminate, reduce, or mitigate the need for bypassing. c. A cost-effectiveness analysis of alternatives including comparative resource damage assessment. d. The minimum and maximum duration of bypass under each alternative. e. A recommendation as to the preferred alternative for conducting the bypass. a istruction Storax.vs ales Geri real Periiiit oe 4. f. The projected date of bypass initiation. g. A statement of compliance with SEPA. h. A request for modification of water quality standards as provided for in WAC 173-201A-110, if an exceedance of any water quality standard is anticipated. i. Steps taken or planned to reduce, eliminate, and prevent reoccurrence of the bypass. 5. For probable construction bypasses, the need to bypass is to be identified as early in the planning process as possible. The analysis required above must be considered during preparation of the Stormwater Pollution Prevention Plan (SWPPP) and must be included to the extent practical. In cases where the probable need to bypass is determined early, continued analysis is necessary up to and including the construction period in an effort to minimize or eliminate the bypass. Ecology will consider the following before issuing an administrative order for this type bypass: a. If the bypass is necessary to perform construction or maintenance -related activities essential to meet the requirements of this permit. b. If there are feasible alternatives to bypass, such as the use of auxiliary treatment facilities, retention of untreated wastes, stopping production, maintenance during normal periods of equipment down time, or transport of untreated wastes to another treatment facility. c. If the bypass is planned and scheduled to minimize adverse effects on the public and the environment. After consideration of the above and the adverse effects of the proposed bypass and any other relevant factors, Ecology will approve, conditionally approve, or deny the request. The public must be notified and given an opportunity to comment on bypass incidents of significant duration, to the extent feasible. Approval of a request to bypass will be by administrative order issued by Ecology under RCW 90.48.120. B. Duty to Mitigate The Permittee is required to take all reasonable steps to minimize or prevent any discharge or sludge use or disposal in violation of this permit that has a reasonable likelihood of adversely affecting human health or the environment. `onstruction Slortrx.wtvfer General Permit Noe 4. AKART is an acronym for "all known, available, and reasonable methods of prevention, control, and treatment." AKART represents the most current methodology that can be reasonably required for preventing, controlling, or abating the pollutants and controlling pollution associated with a discharge. Applicable TMDL means a TMDL for turbidity, fine sediment, high pH, or phosphorus, which was completed and approved by EPA before January 1, 2016, or before the date the operator's complete permit application is received by Ecology, whichever is later. Applicant means an operator seeking coverage under this permit. Benchmark means a pollutant concentration used as a permit threshold, below which a pollutant is considered unlikely to cause a water quality violation, and above which it may. When pollutant concentrations exceed benchmarks, corrective action requirements take effect. Benchmark values are not water quality standards and are not numeric effluent limitations; they are indicator values. Best Management Practices (BMPs) means schedules of activities, prohibitions of practices, maintenance procedures, and other physical, structural and/or managerial practices to prevent or reduce the pollution of waters of the State. BMPs include treatment systems, operating procedures, and practices to control: stormwater associated with construction activity, spillage or leaks, sludge or waste disposal, or drainage from raw material storage. Buffer means an area designated by a local jurisdiction that is contiguous to and intended to protect a sensitive area. Bypass means the intentional diversion of waste streams from any portion of a treatment facility. Calendar Day A period of 24 consecutive hours starting at 12:00 midnight and ending the following 12:00 midnight. Calendar Week (same as Week) means a period of seven consecutive days starting at 12:01 a.m. (0:01 hours) on. Sunday. Certified Erosion and Sediment Control Lead (CESCL) means a person who has current certification through an approved erosion and sediment control training program that meets the minimum training standards established by Ecology (see BMP C160 in the SWMM). Chemical Treatment means the addition of chemicals to stormwater and/or authorized non- stormwater prior to filtration and discharge to surface waters. Clean Water Act (CWA) means the Federal Water Pollution Control Act enacted by Public Law 92-500, as amended by Public Laws 95-217, 95-576, 96-483, and 97-117; USC 1251 et seq. Combined Sewer means a sewer which has been designed to serve as a sanitary sewer and a storm sewer, and into which inflow is allowed by local ordinance. Construction Swrai water Geri >ral Perinit Page 47 Common Plan of Development or Sale means a site where multiple separate and distinct construction activities may be taking place at different times on different schedules and/or by different contractors, but still under a single plan. Examples include: 1) phased projects and projects with multiple filings or lots, even if the separate phases or filings/lots will be constructed under separate contract or by separate owners (e.g., a development where lots are sold to separate builders); 2) a development plan that may be phased over multiple years, but is still under a consistent plan for long-term development; 3) projects in a contiguous area that may be unrelated but still under the same contract, such as construction of a building extension and a new parking lot at the same facility; and 4) linear projects such as roads, pipelines, or utilities. If the project is part of a common plan of development or sale, the disturbed area of the entire plan must be used in determining permit requirements. Composite Sample means a mixture of grab samples collected at the same sampling point at different times, formed either by continuous sampling or by mixing discrete samples. May be "time -composite" (collected at constant time intervals) or "flow -proportional" (collected either as a constant sample volume at time intervals proportional to stream flow, or collected by increasing the volume of each aliquot as the flow increases while maintaining a constant time interval between the aliquots. Concrete Wastewater means any water used in the production, pouring and/or clean-up of concrete or concrete products, and any water used to cut, grind, wash, or otherwise modify concrete or concrete products. Examples include water used for or resulting from concrete truck/mixer/pumper/tool/chute rinsing or washing, concrete saw cutting and surfacing (sawing, coring, grinding, roughening, hydro -demolition, bridge and road surfacing). When stormwater comingles with concrete wastewater, the resulting water is considered concrete wastewater and must be managed to prevent discharge to waters of the State, including ground water. Construction Activity means land disturbing operations including clearing, grading or excavation which disturbs the surface of the land. Such activities may include road construction, construction of residential houses, office buildings, or industrial buildings, site preparation, soil compaction, movement and stockpiling of topsoils, and demolition activity. Contaminant means any hazardous substance that does not occur naturally or occurs at greater than natural background levels. See definition of "hazardous substance" and WAC 173-340-200. Contaminated Groundwater means groundwater which contains contaminants, pollutants, or hazardous substances that do not occur naturally or occur at levels greater than natural background. Contaminated Soil means soil which contains contaminants, pollutants, or hazardous substances that do not occur naturally or occur at levels greater than natural background. Demonstrably Equivalent means that the technical basis for the selection of all stormwater BMPs is documented within a SWPPP, including: 1. The method and reasons for choosing the stormwater BMPs selected. C'anstruelion Stornr.wtvter General C'erinif 'age 4 2. The pollutant removal performance expected from the BMPs selected. 3. The technical basis supporting the performance claims for the BMPs selected, including any available data concerning field performance of the BMPs selected. 4. An assessment of how the selected BMPs will comply with state water quality standards. 5. An assessment of how the selected BMPs will satisfy both applicable federal technology - based treatment requirements and state requirements to use all known, available, and reasonable methods of prevention, control, and treatment (AKART). Department means the Washington State Department of Ecology. Detention means the temporary storage of stormwater to improve quality and/or to reduce the mass flow rate of discharge. Dewatering means the act of pumping ground water or stormwater away from an active construction site. Director means the Director of the Washington State Department of Ecology or his/her authorized representative. Discharger means an owner or operator of any facility or activity subject to regulation under Chapter 90.48 RCW or the Federal Clean Water Act. Domestic Wastewater means water carrying human wastes, including kitchen, bath, and laundry wastes from residences, buildings, industrial establishments, or other places, together with such ground water infiltration or surface waters as may be present. Ecology means the Washington State Department of Ecology. Engineered Soils means the use of soil amendments including, but not limited, to Portland cement treated base (CTB), cement kiln dust (CKD), or fly ash to achieve certain desirable soil characteristics. Equivalent BMPs means operational, source control, treatment, or innovative BMPs which result in equal or better quality of stormwater discharge to surface water or to ground water than BMPs selected from the SWMM. Erosion means the wearing away of the land surface by running water, wind, ice, or other geological agents, including such processes as gravitational creep. Erosion and Sediment Control BMPs means BMPs intended to prevent erosion and sedimentation, such as preserving natural vegetation, seeding, mulching and matting, plastic covering, filter fences, sediment traps, and ponds. Erosion and sediment control BMPs are synonymous with stabilization and structural BMPs. Federal Operator is an entity that meets the definition of "Operator" in this permit and is either any department, agency or instrumentality of the executive, legislative, and judicial branches of `(.)Ii trztc,tion , 1orn,iit�eiter Grnca`cd Perinit 'A cy 49 the Federal government of the United States, or another entity, such as a private contractor, performing construction activity for any such department, agency, or instrumentality. Final Stabilization (same as fully stabilized or full stabilization) means the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (examples of permanent non -vegetative stabilization methods include, but are not limited to riprap, gabions or geotextiles) which prevents erosion. Ground Water means water in a saturated zone or stratum beneath the land surface or a surface waterbody. Hazardous Substance means any dangerous or extremely hazardous waste as defined in RCW 70.105.010 (5) and (6), or any dangerous or extremely dangerous waste as designated by rule under chapter 70.105 RCW; any hazardous substance as defined in RCW 70.105.010(10) or any hazardous substance as defined by rule under chapter 70.105 RCW; any substance that, on the effective date of this section, is a hazardous substance under section 101(14) of the federal cleanup law, 42 U.S.C., Sec. 9601(14); petroleum or petroleum products; and any substance or category of substances, including solid waste decomposition products, determined by the director by rule to present a threat to human health or the environment if released into the environment. The term hazardous substance does not include any of the following when contained in an underground storage tank from which there is not a release: crude oil or any fraction thereof or petroleum, if the tank is in compliance with all applicable federal, state, and local law. Injection Well means a well that is used for the subsurface emplacement of fluids. (See Well.) Jurisdiction means a political unit such as a city, town or county; incorporated for local self- government. National Pollutant Discharge Elimination System (NPDES) means the national program for issuing, modifying, revoking and reissuing, terminating, monitoring, and enforcing permits, and imposing and enforcing pretreatment requirements, under sections 307, 402, 318, and 405 of the Federal Clean Water Act, for the discharge of pollutants to surface waters of the State from point sources. These permits are referred to as NPDES permits and, in Washington State, are administered by the Washington State Department of Ecology. Notice of Intent (NOI) means the application for, or a request for coverage under this general permit pursuant to WAC 173-226-200. Notice of Termination (NOT) means a request for termination of coverage under this general permit as specified by Special Condition S 10 of this permit. Operator means any party associated with a construction project that meets either of the following two criteria: The party has operational control over construction plans and specifications, including the ability to make modifications to those plans and specifications; or ara, to°zit lr��rr , ear rr.v�>r � r erieral Pertitit Page 50 The party has day-to-day operational control of those activities at a project that are necessary to ensure compliance with a SWPPP for the site or other permit conditions (e.g., they are authorized to direct workers at a site to carry out activities required by the SWPPP or comply with other permit conditions). Permittee means individual or entity that receives notice of coverage under this general permit. pH means a liquid's measure of acidity or alkalinity. A pH of 7 is defined as neutral. Large variations above or below this value are considered harmful to most aquatic life. pH Monitoring Period means the time period in which the pH of stormwater runoff from a site must be tested a minimum of once every seven days to determine if stormwater pH is between 6.5 and 8.5. Point Source means any discernible, confined, and discrete conveyance, including but not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, and container from which pollutants are or may be discharged to surface waters of the State. This term does not include return flows from irrigated agriculture. (See Fact Sheet for further explanation.) Pollutant means dredged spoil, solid waste, incinerator residue, filter backwash, sewage, garbage, domestic sewage sludge (biosolids), munitions, chemical wastes, biological materials, radioactive materials, heat, wrecked or discarded equipment, rock, sand, cellar dirt, and industrial, municipal, and agricultural waste. This term does not include sewage from vessels within the meaning of section 312 of the CWA, nor does it include dredged or fill material discharged in accordance with a permit issued under section 404 of the CWA. Pollution means contamination or other alteration of the physical, chemical, or biological properties of waters of the State; including change in temperature, taste, color, turbidity, or odor of the waters; or such discharge of any liquid, gaseous, solid, radioactive or other substance into any waters of the State as will or is likely to create a nuisance or render such waters harmful, detrimental or injurious to the public health, safety or welfare; or to domestic, commercial, industrial, agricultural, recreational, or other legitimate beneficial uses; or to livestock, wild animals, birds, fish or other aquatic life. Process Wastewater means any water which, during manufacturing or processing, comes into direct contact with or results from the production or use of any raw material, intermediate product, finished product, byproduct, or waste product. If stormwater commingles with process wastewater, the commingled water is considered process wastewater. Receiving Water means the waterbody at the point of discharge. If the discharge is to a storm sewer system, either surface or subsurface, the receiving water is the waterbody to which the storm system discharges. Systems designed primarily for other purposes such as for ground water drainage, redirecting stream natural flows, or for conveyance of irrigation water/return flows that coincidentally convey stormwater are considered the receiving water. FILi- > 51 Representative means a stormwater or wastewater sample which represents the flow and characteristics of the discharge. Representative samples may be a grab sample, a time - proportionate composite sample, or a flow proportionate sample. Ecology's Construction Stormwater Monitoring Manual provides guidance on representative sampling. Responsible Corporate Officer for the purpose of signatory authority means: (i) a president, secretary, treasurer, or vice-president of the corporation in charge of a principal business function, or any other person who performs similar policy- or decision -making functions for the corporation, or (ii) the manager of one or more manufacturing, production, or operating facilities, provided, the manager is authorized to make management decisions which govern the operation of the regulated facility including having the explicit or implicit duty of making major capital investment recommendations, and initiating and directing other comprehensive measures to assure long term environmental compliance with environmental laws and regulations; the manager can ensure that the necessary systems are established or actions taken to gather complete and accurate information for permit application requirements; and where authority to sign documents has been assigned or delegated to the manager in accordance with corporate procedures (40 CFR 122.22). Sanitary Sewer means a sewer which is designed to convey domestic wastewater. Sediment means the fragmented material that originates from the weathering and erosion of rocks or unconsolidated deposits, and is transported by, suspended in, or deposited by water. Sedimentation means the depositing or formation of sediment. Sensitive Area means a waterbody, wetland, stream, aquifer recharge area, or channel migration zone. SEPA (State Environmental Policy Act) means the Washington State Law, RCW 43.21C.020, intended to prevent or eliminate damage to the environment. Significant Amount means an amount of a pollutant in a discharge that is amenable to available and reasonable methods of prevention or treatment; or an amount of a pollutant that has a reasonable potential to cause a violation of surface or ground water quality or sediment management standards. Significant Concrete Work means greater than 1000 cubic yards poured concrete used over the life of a project. Significant Contributor of Pollutants means a facility determined by Ecology to be a contributor of a significant amount(s) of a pollutant(s) to waters of the State of Washington. Site means the land or water area where any "facility or activity" is physically located or conducted. Source Control BMPs means physical, structural or mechanical devices or facilities that are intended to prevent pollutants from entering stormwater. A few examples of source control General .Perinit Page 52 BMPs are erosion control practices, maintenance of stormwater facilities, constructing roofs over storage and working areas, and directing wash water and similar discharges to the sanitary sewer or a dead end sump. Stabilization means the application of appropriate BMPs to prevent the erosion of soils, such as, temporary and permanent seeding, vegetative covers, mulching and matting, plastic covering and sodding. See also the definition of Erosion and Sediment Control BMPs. Storm Drain means any drain which drains directly into a storm sewer system, usually found along roadways or in parking lots. Storm Sewer System means a means a conveyance, or system of conveyances (including roads with drainage systems, municipal streets, catch basins, curbs, gutters, ditches, manmade channels, or storm drains designed or used for collecting or conveying stormwater. This does not include systems which are part of a combined sewer or Publicly Owned Treatment Works (POTW) as defined at 40 CFR 122.2. Stormwater means that portion of precipitation that does not naturally percolate into the ground or evaporate, but flows via overland flow, interflow, pipes, and other features of a stormwater drainage system into a defined surface waterbody, or a constructed infiltration facility. Stormwater Management Manual (SWMM) or Manual means the technical Manual published by Ecology for use by local governments that contain descriptions of and design criteria for BMPs to prevent, control, or treat pollutants in stormwater. Stormwater Pollution Prevention Plan (SWPPP) means a documented plan to implement measures to identify, prevent, and control the contamination of point source discharges of stormwater. Surface Waters of the State includes lakes, rivers, ponds, streams, inland waters, salt waters, and all other surface waters and water courses within the jurisdiction of the State of Washington. Temporary Stabilization means the exposed ground surface has been covered with appropriate materials to provide temporary stabilization of the surface from water or wind erosion. Materials include, but are not limited to, mulch, riprap, erosion control mats or blankets and temporary cover crops. Seeding alone is not considered stabilization. Temporary stabilization is not a substitute for the more permanent "final stabilization." Total Maximum Daily Load (TMDL) means a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet state water quality standards. Percentages of the total maximum daily load are allocated to the various pollutant sources. A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and nonpoint sources. The TMDL calculations must include a "margin of safety" to ensure that the waterbody can be protected in case there are unforeseen events or unknown sources of the pollutant. The calculation must also account for seasonable variation in water quality. ada to°tic°tr �r �, rax >� rca°Gencxral Perna t PLq-) y 53 Transfer of Coverage (TOC) means a request for transfer of coverage under this general permit as specified by General Condition G9 of this permit. Treatment BMPs means BMPs that are intended to remove pollutants from stormwater. A few examples of treatment BMPs are detention ponds, oil/water separators, biofiltration, and constructed wetlands. Transparency means a measurement of water clarity in centimeters (cm), using a 60 cm transparency tube. The transparency tube is used to estimate the relative clarity or transparency of water by noting the depth at which a black and white Secchi disc becomes visible when water is released from a value in the bottom of the tube. A transparency tube is sometimes referred to as a "turbidity tube." Turbidity means the clarity of water expressed as nephelometric turbidity units (NTUs) and measured with a calibrated turbidimeter. Uncontaminated means free from any contaminant. See definition of "contaminant" and WAC 173-340-200. Waste Load Allocation (WLA) means the portion of a receiving water's loading capacity that is allocated to one of its existing or future point sources of pollution. WLAs constitute a type of water quality based effluent limitation (40 CFR 130.2[h]). Water -only Based Shaft Drilling is a shaft drilling process that uses water only and no additives are involved in the drilling of shafts for construction of building, road, or bridge foundations. Water quality means the chemical, physical, and biological characteristics of water, usually with respect to its suitability for a particular purpose. Waters of the State includes those waters as defined as "waters of the United States" in 40 CFR Subpart 122.2 within the geographic boundaries of Washington. State and "waters of the State" as defined in Chapter 90.48 RCW, which include lakes, rivers, ponds, streams, inland waters, underground waters, salt waters, and all other surface waters and water courses within the jurisdiction of the state of Washington. Well means a bored, drilled or driven shaft, or dug hole whose depth is greater than the largest surface dimension. (See Injection well.) Wheel Wash Wastewater means any water used in, or resulting from the operation of, a tire bath or wheel wash (BMP C106: Wheel Wash), or other structure or practice that uses water to physically remove mud and debris from vehicles leaving a construction site and prevent track - out onto roads. When stormwater comingles with wheel wash wastewater, the resulting water is considered wheel wash wastewater and must be managed according to Special Condition S9.D.9. `(.)Ii trztc,tion , 1ornr.writer Grnca`cd Perinit ,,,ige 54 F-11 W W NO , lVe 11 I • AKART All Known, Available, and Reasonable Methods of Prevention, Control, and Treatment BMP Best Management Practice CESCL Certified Erosion and Sediment Control Lead CFR Code of Federal Regulations CKD Cement Kiln Dust CM Centimeters CTB Cement -Treated Base CWA Clean Water Act DMR Discharge Monitoring Report EPA Environmental Protection Agency ERTS Environmental Report Tracking System ESC Erosion and Sediment Control FR Federal Register LID Low Impact Development NOI Notice of Intent NOT Notice of Termination NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Unit RCW Revised Code of Washington SEPA State Environmental Policy Act SWMM Stormwater Management Manual SWPPP Stormwater Pollution Prevention Plan TMDL Total Maximum Daily Load UIC Underground Injection Control USC United States Code USEPA United States Environmental Protection. Agency WAC Washington Administrative Code WQ Water Quality WWHM Western Washington Hydrology Model ada to°tic°tr �r �, rax >� rca°Gorcxral Perna t fla _)e 55 Appendix F - 303(d) List Waterbodies / TMDL Waterbodies Information Listing ID: 63207 Main Listing Information Listing ID: 63207 Waterbody Name: PUGET SOUND (NORTH - CENTRAL) Medium: Tissue Parameter: Polychlorinated Biphenyls (PCBs) WQI Project: None Assigned Designated Use: None Assigned Assessment Unit Assessment Unit ID: 4712213138 2014 Category: 5 2012 Category: 5 2008 Category: 3 2004 Category: 3 On 1998 303(d) List?: N On 1996 303(d) List?: N Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Total PCB congeners. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Total PCB congeners. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Total PCB congeners. Remarks Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 63192 Main Listing Information Listing ID: 63192 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Tissue 2008 Category: 3 Parameter: Chrysene 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213138 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Chrysene. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Chrysene. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Chrysene. Remarks .................................................................................................................................................................... Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 63191 Main Listing Information Listing ID: 63191 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Tissue 2008 Category: 3 Parameter: Benzo(k)fluoranthene 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213138 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[k]fluoranthene. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[k]fluoranthene. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[k]fluoranthene. Remarks Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 63190 Main Listing Information Listing ID: 63190 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Tissue 2008 Category: 3 Parameter: Benzo(b)fluoranthene 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213138 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[b]fluoranthene. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[b]fluoranthene. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[b]fluoranthene. Remarks .................................................................................................................................................................... Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 63189 Main Listing Information Listing ID: 63189 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Tissue 2008 Category: 3 Parameter: Benzo(a)pyrene 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213138 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[a]pyrene. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[a]pyrene. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benzo[a]pyrene. Remarks .................................................................................................................................................................... Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 63188 Main Listing Information Listing ID: 63188 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Tissue 2008 Category: 3 Parameter: Benzo(a)anthracene 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213138 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammarnish Waterbody ID (WBID): None Assigned Waterbody Class: None Assigned Town/Range/Section (Legacy): None Assigned Basis Location ID [PSEF] - In 2009, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benz[a]a nth race n e. Location ID [PSEF] - In 2008, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benz[a]a nth race n e. Location ID [PSEF] - In 2006, a composite tissue sample of mussel (Mytilus sp.) exceeded the National Toxics Rule criterion for Benz[a]a nth race n e. Remarks Remark Modified By Modified On Visibility This listing contains data not in EIM. Data from NOAA's National Brandee Era- 12/22/2010 Public Mussel Watch Program station: PSEF Miller EIM No EIM Records Entered MMMMM Listing ID: 42487 Main Listing Information Listing ID: 42487 2014 Category: 5 Waterbody Name: PUGET SOUND (NORTH- 2012 Category: 5 CENTRAL) Medium: Water 2008 Category: 5 Parameter: Bacteria 2004 Category: 5 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 4712213B8 Location Identification Counties: Snohomish WRIA: 8 - Cedar-Sammamish Waterbody ID (WBID): WA-08-0230 Waterbody Class: EAA Town/Range/Section (Legacy): None Assigned Basis Location ID [SNO029A] -- 1 of 1 (100.0%) of sample collected in 2006 exceeded the percent criterion (43 col/100mL) Location ID [SNO029A] -- Fewer than five samples were available in 2006, therefore a geometric mean was not calculated for this period Location ID [SNO029B] -- 1 of 1 (100.0%) of sample collected in 2006 exceeded the percent criterion (43 col/100mL) Location ID [SNO029B] -- Fewer than five samples were available in 2006, therefore a geometric mean was not calculated for this period Location ID [SNO029C] -- 0 of 1 (0.0%) of samples collected in 2006 exceed the percent criterion (43 col/100mL) Location ID [SNO029C] -- Fewer than five samples were available in 2006, therefore a geometric mean was not calculated for this period King County data (submitted by Kimberle Stark on 4/15/04) station ITBRACKETT (Brackett's Landing) shows 2 of 10 samples (20.0%) exceeded the percentile criterion in year 2002. BEACH ID [WA928351] -- In 2009, 1 out of 16 (6.3%) sample events exceeded the enterococcus percent criterion (208 col/100 mL). The geometric mean of 15.3 col/100 mL did not exceed the enterococcus geometric mean criterion (70 col/100 mL). BEACH ID [WA928351 ] -- In 2008, 1 out of 14 (7.1 %) sample events exceeded the enterococcus percent criterion (208 col/100 mL). The geometric mean of 21.5 col/100 mL did not exceed the enterococcus geometric mean criterion (70 col/100 mL). BEACH ID [WA928351] -- In 2007, 0 out of 15 (0%) sample events exceeded the enterococcus percent criterion (208 col/100 mQ. The geometric mean of 11.7 col/100 mL did not exceed the enterococcus geometric mean criterion (70 col/100 mL). BEACH ID [WA928351] -- In 2006, 2 out of 22 (9.1 %) sample events exceeded the enterococcus percent criterion (208 col/100 mL). The geometric mean of 29.9 col/100 mL did not exceed the enterococcus geometric mean criterion (70 col/1 00 mL). BEACH ID [WA928351] -- In 2005, 0 out of 17 (0%) sample events exceeded the enterococcus percent criterion (208 col/100 mL). The geometric mean of 14.3 col/100 mL did not exceed the enterococcus geometric mean criterion (70 col/1 00 mL). BEACH ID [WA928351] -- In 2004, 0 out of 12 (0%) sample events exceeded the enterococcus percent criterion (208 col/1 00 mL). The geometric mean of 12 col/1 00 mL did not exceed the enterococcus geometric mean criterion (70 col/1 00 mL). Remarks Remark Modified By Modified On Visibility Combined Listing: Listing lDs 45269, 46737, 46669, 46668, 52956 Chad Brown 9/24/2015 Public were rolled into this listing This listing contains both enterococcus and fecal coliform bacteria Jessica 1/20/2011 Public data. Bennett Category was determined by an exceedance of: the fecal coliform percent criteria. [Data collection period(s) -- 2006: Location ID -- Chad Brown 12/5/2007 Public SNO029A], the fecal coliform percent criteria. [Data collection period(s) -- 2006: Location ID -- SNO029B]. ----------------------------- EIM User Study ID: User Location ID: BEACH SNO029C BEACH SNO029B BEACH SNO029A EPABEACH SNO029A EPABEACH SNO029B EPABEACH SNO029C EPABEACH SNO029D EPABEACH SNO029E Appendix G - Contaminated Site Information No contaminated soils or groundwater expected - update as necessary. See 2015 RBM Assessment Report for various hazardous materials present in buildings to be demolished. Appendix H - Engineering Calculations Update as necessary to support phase specific erosion control measures. Operation and Maintenance Manual Madrona School — Edmonds School District Appendix H Applicable Operational BMPs: • Eliminate unpermitted wastewater discharges to storm sewer, ground water, or surface water. • Convey unpermitted discharges to a sanitary sewer if allowed by the local sewer authority, or to other approved treatment. • Obtain appropriate state and local permits for these discharges. Recommended Additional Operational BMPs: At commercial and industrial facilities, conduct a survey of wastewater discharge connections to storm drains and to surface water as follows: • Conduct a field survey of buildings, particularly older buildings, and other industrial areas to locate storm drains from buildings and paved surfaces. Note where these join the public storm drain(s). During non-stormwater conditions inspect each storm drain for non- stormwater discharges. Record the locations of all non-stormwater discharges. Include all permitted discharges. If useful, prepare a map of each area. Show on the map the known location of storm sewers, sanitary sewers, and permitted and unpermitted discharges. Aerial photos may be useful. Check records such as piping schematics to identify known side sewer connections and show these on the map. Consider using smoke, dye, or chemical analysis tests to detect connections between two conveyance systems (e.g., process water and stormwater). If desirable, conduct TV inspections of the storm drains and record the footage on videotape. • Compare the observed locations of connections with the information on the map and revise the map accordingly. Note suspect connections that are inconsistent with the field survey. Identify all connections to storm sewers or to surface water and take the actions specified above as applicable BMPs. S411 BMPs for Landscaping and Lawn/ Vegetation Management Description of Pollutant Sources: Landscaping can include grading, soil transfer, vegetation removal, pesticide and fertilizer applications, and watering. Stormwater contaminants include toxic organic compounds, heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and pesticides. Lawn and vegetation management can include control of objectionable weeds, insects, mold, bacteria, and other pests with pesticides. Examples include weed control on golf course lawns, access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs; rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential lawn/plant care. It is possible to Volume IV - Source Control BMPs — December 2014 2-21 release toxic pesticides such as pentachlorophenol, carbamates, and organometallics to the environment by leaching and dripping from treated parts, container leaks, product misuse, and outside storage of pesticide contaminated materials and equipment. Poor management of the vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater contamination. Pollutant Control Approach: Control of fertilizer and pesticide applications, soil erosion, and site debris to prevent contamination of stormwater. Develop and implement an Integrated Pest Management Plan (IPM) and use pesticides only as a last resort. Carefully apply pesticides/ herbicides, in accordance with label instructions. Maintain appropriate vegetation, with proper fertilizer application where practicable, to control erosion and the discharge of stormwater pollutants. Where practicable grow plant species appropriate for the site, or adjust the soil properties of the subject site to grow desired plant species. Applicable Operational BMPs for Landscaping: • Install engineered soil/landscape systems to improve the infiltration and regulation of stormwater in landscaped areas. Do not dispose of collected vegetation into waterways or storm sewer systems. Recommended Additional Operational BMPs for Landscaping: • Conduct mulch -mowing whenever practicable • Dispose of grass clippings, leaves, sticks, or other collected vegetation, by composting, if feasible. • Use mulch or other erosion control measures on soils exposed for more than one week during the dry season or two days during the rainy season. • Store and maintain appropriate oil and chemical spill cleanup materials in readily accessible locations when using oil or other chemicals. Ensure that employees are familiar with proper spill cleanup procedures. • Till fertilizers into the soil rather than dumping or broadcasting onto the surface. Determine the proper fertilizer application rate for the types of soil and vegetation encountered. • Till a topsoil mix or composted organic material into the soil to create a well -mixed transition layer that encourages deeper root systems and drought -resistant plants. • Use manual and/or mechanical methods of vegetation removal rather than applying herbicides, where practical. Volume IV - Source Control BMPs — December 2014 2-22 Applicable Operational BMPs for the Use of Pesticides: • Develop and implement an IPM (See section on IPM in Applicable p erataonal B Ps car Ve etation Management and use pesticides only as a last resort. • Implement a pesticide -use plan and include at a minimum: a list of selected pesticides and their specific uses; brands, formulations, application methods and quantities to be used; equipment use and maintenance procedures; safety, storage, and disposal methods; and monitoring, record keeping, and public notice procedures. All procedures shall conform to the requirements of Chapter 17.21 RCW and Chapter 16-228 WAC (Appendix IV-D P.7). • Choose the least toxic pesticide available that is capable of reducing the infestation to acceptable levels. The pesticide should readily degrade in the environment and/or have properties that strongly bind it to the soil. Conduct any pest control activity at the life stage when the pest is most vulnerable. For example, if it is necessary to use a Bacillus thurin ig ens application to control tent caterpillars, apply it to the material before the caterpillars cocoon or it will be ineffective. Any method used should be site -specific and not used wholesale over a wide area. • Apply the pesticide according to label directions. Do not apply pesticides in quantities that exceed manufacturer's instructions. • Mix the pesticides and clean the application equipment in an area where accidental spills will not enter surface or ground waters, and will not contaminate the soil. • Store pesticides in enclosed areas or in covered impervious containment. Do not discharge pesticide contaminated stormwater or spills/leaks of pesticides to storm sewers. Do not hose down the paved areas to a storm sewer or conveyance ditch. Store and maintain appropriate spill cleanup materials in a location known to all near the storage area. • Clean up any spilled pesticides. Keep pesticide contaminated waste materials in designated covered and contained areas. • The pesticide application equipment must be capable of immediate shutoff in the event of an emergency. • Spraying pesticides within 100 feet of open waters including wetlands, ponds, and rivers, streams, creeks, sloughs and any drainage ditch or channel that leads to open water may have additional regulatory requirements beyond just following the pesticide product label. Additional requirements may include: • Obtaining a discharge permit from Ecology. • Obtaining a permit from the local jurisdiction. • Using an aquatic labeled pesticide. Volume IV - Source Control BNIPs — December 2014 2-23 Flag all sensitive areas including wells, creeks, and wetlands prior to spraying. • Post notices and delineate the spray area prior to the application, as required by the local jurisdiction or by Ecology. Conduct spray applications during weather conditions as specified in the label direction and applicable local and state regulations. Do not apply during rain or immediately before expected rain. Recommended Additional Operational BMPs for the use of pesticides: Consider alternatives to the use of pesticides such as covering or harvesting weeds, substitute vegetative growth, and manual weed control/moss removal. • Consider the use of soil amendments, such as compost, that are known to control some common diseases in plants, such as Pythium root rot, ashy stem blight, and parasitic nematodes. The following are three possible mechanisms for disease control by compost addition (USEPA Publication 530-F-9-044): 1. Successful competition for nutrients by antibiotic production; 2. Successful predation against pathogens by beneficial microorganism; and 3. Activation of disease -resistant genes in plants by composts. Installing an amended soil/landscape system can preserve both the plant system and the soil system more effectively. This type of approach provides a soil/landscape system with adequate depth, permeability, and organic matter to sustain itself and continue working as an effective stormwater infiltration system and a sustainable nutrient cycle. • Once a pesticide is applied, evaluate its effectiveness for possible improvement. Records should be kept showing the effectiveness of the pesticides considered. Develop an annual evaluation procedure including a review of the effectiveness of pesticide applications, impact on buffers and sensitive areas (including potable wells), public concerns, and recent toxicological information on pesticides used/proposed for use. If individual or public potable wells are located in the proximity of commercial pesticide applications, contact the regional Ecology hydrogeologist to determine if additional pesticide application control measures are necessary. • Rinseate from equipment cleaning and/or triple -rinsing of pesticide containers should be used as product or recycled into product. For more information, contact the Washington State University (WSU) Extension Home -Assist Program, (253) 445-4556, or Bio-Integral Resource Center (BIRC), P.O. Box 7414, Berkeley, CA.94707, or EPA to Volume IF - Source Control BHPs — December 2014 2-24 obtain a publication entitled "Suspended, Canceled, and Restricted Pesticides " which lists all restricted pesticides and the specific uses that are allowed. Applicable Operational BMPs for Vegetation Management: Use at least an eight -inch "topsoil" layer with at least 8 percent organic matter to provide a sufficient vegetation -growing medium. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can substantially improve the permeability of the soil, the disease and drought resistance of the vegetation, and reduce fertilizer demand. This reduces the demand for fertilizers, herbicides, and pesticides. Organic matter is the least water-soluble form of nutrients that can be added to the soil. Composted organic matter generally releases only between 2 and 10 percent of its total nitrogen annually, and this release corresponds closely to the plant growth cycle. Return natural plant debris and mulch to the soil, to continue recycling nutrients indefinitely. Select the appropriate turfgrass mixture for the climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endophytic fungi found naturally in their tissues repel or kill common leaf and stem -eating lawn insects. However, they do not, repel root -feeding lawn pests such as Crane Fly larvae, and are toxic to ruminants such as cattle and sheep. The fungus causes no known adverse effects to the host plant or to humans. Endophytic grasses are commercially available; use them in areas such as parks or golf courses where grazing does not occur. Local agricultural or gardening resources such as Washington State University Extension office can offer advice on which types of grass are best suited to the area and soil type. • Use the following seeding and planting BMPs, or equivalent BMPs to obtain information on grass mixtures, temporary and permanent seeding procedures, maintenance of a recently planted area, and fertilizer application rates: Temporary and Permanent Seeding, Mulching, Plastic Covering, and Sodding as described in Volume II. Adjusting the soil properties of the subject site can assist in selection of desired plant species. For example, design a constructed wetland to resist the invasion of reed canary grass by layering specific strata of organic matters (e.g., composted forest product residuals) and creating a mildly acidic pH and carbon -rich soil medium. Consult a soil restoration specialist for site -specific conditions. • Aerate lawns regularly in areas of heavy use where the soil tends to become compacted. Conduct aeration while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than 3/4-inch deep. Volume IV - Source Control BMPs — December 2014 2-25 Mowing is a stress -creating activity for turfgrass. Grass decreases its productivity when mown too short and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses, more disease prone and more reliant on outside means such as pesticides, fertilizers, and irrigation to remain healthy. Set the mowing height at the highest acceptable level and mow at times and intervals designed to minimize stress on the turf. Generally mowing only 1/3 of the grass blade height will prevent stressing the turf. Irrigation: The depth from which a plant normally extracts water depends on the rooting depth of the plant. Appropriately irrigated lawn grasses normally root in the top 6 to 12 inches of soil; lawns irrigated on a daily basis often root only in the top 1 inch of soil. Improper irrigation can encourage pest problems, leach nutrients, and make a lawn completely dependent on artificial watering. The amount of water applied depends on the normal rooting depth of the turfgrass species used, the available water holding capacity of the soil, and the efficiency of the irrigation system. Consult with the local water utility, Conservation District, or Cooperative Extension office to help determine optimum irrigation practices. Fertilizer Management: Turfgrass is most responsive to nitrogen fertilization, followed by potassium and phosphorus. Fertilization needs vary by site depending on plant, soil, and climatic conditions. Evaluation of soil nutrient levels through regular testing ensures the best possible efficiency and economy of fertilization. For details on soils testing, contact the local Conservation District, a soils testing professional, or a Washington State University Extension office. Apply fertilizers in amounts appropriate for the target vegetation and at the time of year that minimizes losses to surface and ground waters. Do not fertilize when the soil is dry. Alternatively, do not apply fertilizers within three days prior to predicted rainfall. The longer the period between fertilizer application and either rainfall or irrigation, the less fertilizer runoff occurs. Use slow release fertilizers such as methylene urea, IDBU, or resin coated fertilizers when appropriate, generally in the spring. Use of slow release fertilizers is especially important in areas with sandy or gravelly soils. Time the fertilizer application to periods of maximum plant uptake. Ecology generally recommends application in the fall and spring, although Washington State University turf specialists recommend four fertilizer applications per year. Volume IV - Source Control BMPs — December 2014 2-26 • Properly trained persons should apply all fertilizers. Apply no fertilizer at commercial and industrial facilities, to grass swales, filter strips, or buffer areas that drain to sensitive water bodies unless approved by the local jurisdiction. Integrated Pest Management An IPM program might consist of the following steps: Step 1: Correctly identify problem pests and understand their life cycle Step 2: Establish tolerance thresholds for pests. Step 3: Monitor to detect and prevent pest problems. Step 4: Modify the maintenance program to promote healthy plants and discourage pests. Step 5: Use cultural, physical, mechanical or biological controls first if pests exceed the tolerance thresholds. Step 6: Evaluate and record the effectiveness of the control and modify maintenance practices to support lawn or landscape recovery and prevent recurrence. For an elaboration of these steps, refer to Appendix ITT-F. S412 BMPs for Loading and Unloading Areas for Liquid or Solid Material Description of Pollutant Sources: Operators typically conduct loading/unloading of liquid and solid materials at industrial and commercial facilities at shipping and receiving, outside storage, fueling areas, etc. Materials transferred can include products, raw materials, intermediate products, waste materials, fuels, scrap metals, etc. Leaks and spills of fuels, oils, powders, organics, heavy metals, salts, acids, alkalis, etc. during transfer may cause stormwater contamination. Spills from hydraulic line breaks are a common problem at loading docks. Pollutant Control Approach: Cover and contain the loading/unloading area where necessary to prevent run-on of stormwater and runoff of contaminated stormwater. Applicable Operational BMPs: At All Loading/ Unloading Areas: • A significant amount of debris can accumulate at outside, uncovered loading/unloading areas. Sweep these surfaces frequently to remove loose material that could contaminate stormwater. Sweep areas temporarily covered after removal of the containers, logs, or other material covering the ground. • Place drip pans, or other appropriate temporary containment device, at locations where leaks or spills may occur such as hose connections, hose reels and filler nozzles. Always use drip pans when making and Volume IV - Source Control BMPs — December 2014 2-2 7 Recommended Treatment BMPs: Install biofiltration swales and filter strips — (See Chapter 9, Volume V) to treat roadside runoff wherever practicable and use engineered topsoils wherever necessary to maintain adequate vegetation. These systems can improve infiltration and stormwater pollutant control upstream of roadside ditches. S417 BMPs for Maintenance of Stormwater Drainage and Treatment Systems Description of Pollutant Sources: Facilities include roadside catch basins on arterials and within residential areas, conveyance systems, detention facilities such as ponds and vaults, oil/water separators, biofilters, settling basins, infiltration systems, and all other types of stormwater treatment systems presented in Volume V. Oil and grease, hydrocarbons, debris, heavy metals, sediments and contaminated water are found in catch basins, oil and water separators, settling basins, etc. Pollutant Control Approach: Provide maintenance and cleaning of debris, sediments, and oil from stormwater collection, conveyance, and treatment systems to obtain proper operation. Applicable Operational BMPs: Maintain stormwater treatment facilities per the operations and maintenance (O&M) procedures presented in Section 4.6 of Volume V in addition to the following BMPs: • Inspect and clean treatment BMPs, conveyance systems, and catch basins as needed, and determine necessary O&M improvements. • Promptly repair any deterioration threatening the structural integrity of stormwater facilities. These include replacement of clean -out gates, catch basin lids, and rock in emergency spillways. • Ensure adequacy of storm sewer capacities and prevent heavy sediment discharges to the sewer system. • Regularly remove debris and sludge from BMPs used for peak -rate control, treatment, etc. and discharge to a sanitary sewer if approved by the sewer authority, or truck to an appropriate local or state government approved disposal site. • Clean catch basins when the depth of deposits reaches 60 percent of the sump depth as measured from the bottom of basin to the invert of the lowest pipe into or out of the basin. However, in no case should there be less than six inches clearance from the debris surface to the invert of the lowest pipe. Some catch basins (for example, WSDOT Type 1 L basins) may have as little as 12 inches sediment storage below the invert. These catch basins need frequent inspection and cleaning to prevent scouring. Where these catch basins are part of a stormwater collection and treatment system, the system Volume IV - Source Control BMPs — December 2014 2-3 7 owner/operator may choose to concentrate maintenance efforts on downstream control devices as part of a systems approach. Clean woody debris in a catch basin as frequently as needed to ensure proper operation of the catchbasin. Post warning signs; "Dump No Waste - Drains to Ground Water," "Streams," "Lakes," or emboss on or adjacent to all storm drain inlets where possible. • Disposal of sediments and liquids from the catch basins must comply with "Recommendations for Management of Street Wastes" described in Appendix IV-G of this volume. Additional Applicable BMPs: Select additional applicable BMPs from this chapter depending on the pollutant sources and activities conducted at the facility. Those BMPs include: • S425 BMPs for Soil Erosion and Sediment Control at Industrial Sites • S427 BMPs for Storage of Liquid, Food Waste or Dangerous Waste Containers • S406 BMPs for Spills of Coil and Hazardous Substances • 5410 BMPs for Illicit Connections to Storm Drains • S430 BMPs for Urban Streets S418 BMPs for Manufacturing Activities - Outside Description of Pollutant Sources: Manufacturing pollutant sources include outside process areas, stack emissions, and areas where manufacturing activity has taken place in the past and significant exposed pollutant materials remain. Pollution Control Approach: Cover and contain outside manufacturing and prevent stormwater run-on and contamination, where feasible. Applicable Operational BMP: • Sweep paved areas regularly, as needed, to prevent contamination of stormwater. • Alter the activity by eliminating or minimizing the contamination of stormwater. • Applicable Structural Source Control BMPs: Enclose the activity (see Fi ure 2A2.6): If possible, enclose the manufacturing activity in a building. • Cover the activity and connect floor drains to a sanitary sewer, if approved by the local sewer authority. Berm or slope the floor as needed to prevent drainage of pollutants to outside areas. (f� igure 2.2.7) Volume IV - Source Control BMPs — December 2014 2-38 Stock cleanup materials, such as brooms, dustpans, and vacuum sweepers near the storage area. S430 BMPs for Urban Streets Description of Pollutant Sources: Urban streets can be the source of vegetative debris, paper, fine dust, vehicle liquids, tire and brake wear residues, heavy metals (lead and zinc), soil particles, ice control salts, domestic wastes, lawn chemicals, and vehicle combustion products. Street surface contaminants contain significant concentrations of particle sizes less than 250 microns (Sartor and Boyd, 1972). Pollutant Control Approach: Conduct efficient street sweeping where and when appropriate to minimize the contamination of stormwater. Do not wash street debris into storm drains. Facilities not covered under the Industrial Stormwater General Permit may consider a minimum amount of water washing of streets. All facilities must comply with their local stormwater requirements for discharging to storm sewers. Municipal NPDES permittees are required to limit street wash water discharges and may have special conditions or treatment requirements. Recommended BMPs: For maximum stormwater pollutant reductions on curbed streets and high volume parking lots, use efficient vacuum sweepers. Note: High -efficiency street sweepers utilize strong vacuums and the mechanical action of main and gutter brooms combined with an air filtration system that only returns clean air to the atmosphere (i.e., filters very fine particulates). They sweep dry and use no water since they do not emit any dust. High-eff ciency vacuum sweepers have the capability of removing, 80 percent or more of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and reasonably expected accumulation conditions. For moderate stormwater pollutant reductions on curbed streets use regenerative air sweepers or tandem sweeping operations. Note: A tandem sweeping operation involves a single pass of a mechanical sweeper followed immediately by a single pass of a vacuum sweeper or regenerative air sweeper. - A regenerative air sweeper blows air down on the pavement to entrain particles and uses a return vacuum to transport the material to the hopper. Volume IV - Source Control BMPs — December 2014 2-57 - These operations usually use water to control dust. This reduces their ability to pick up fine particulates. These types of sweepers have the capability of removing approximately 25 to 50 percent of the accumulated street dirt particles whose diameters are less than 250 microns. (Sutherland, 1998). This assumes pavements under good conditions and typical accumulation conditions. For minimal stormwater pollutant reductions on curbed streets use mechanical sweepers. - Note: The industry refers to mechanical sweepers as broom sweepers and uses the mechanical action of main and gutter brooms to throw material on a conveyor belt that transports it to the hopper. - These sweepers usually use water to control dust. This reduces their ability to pick up fine particulates. Mechanical sweepers have the capability of removing only 10 to 20 percent of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and the most favorable accumulation conditions. • Conduct vacuum sweeping at optimal frequencies. Optimal frequencies are those scheduled sweeping intervals that produce the most cost-effective annual reduction of pollutants normally found in stormwater and can vary depending on land use, traffic volume and rainfall patterns. • Train operators in those factors that result in optimal pollutant removal. These factors include sweeper speed, brush adjustment and rotation rate, sweeping pattern, maneuvering around parked vehicles, and interim storage and disposal methods. • Consider the use of periodic parking restrictions in low to medium density single-family residential areas to ensure the sweeper's ability to sweep along the curb. • Establish programs for prompt vacuum sweeping, removal, and disposal of debris from special events that will generate higher than normal loadings. • Disposal of street sweeping solids must comply with "Recommendations for Management of Street Wastes" described in Appendix IV-G of this volume. • Inform citizens about eliminating yard debris, oil and other wastes in street gutters to reduce street pollutant sources. Volume IF - Source Control BAIPs - December 2014 2-58 For design on projects subject to Minimum Requirement #5, and choosing to use List #1 of that requirement, rain gardens shall have a horizontally projected surface area below the overflow which is at least 5% of the total impervious surface area draining to it. If lawn/landscape area will also be draining to the rain garden, Ecology recommends that the rain garden's horizontally projected surface area below the overflow be increased by 2% of the lawn/landscape area. Underdrains Ecology does not recommend the use of underdrains for rain gardens. Design and construction of an underdrain system likely requires professional expertise. Where a municipality intends to require or allow underdrained rain gardens in areas with initial infiltration rates between 0.3 and 0.6 inches per hour, the invert of the underdrain shall be 6 inches above the bottom of the aggregate bedding for the underdrain. A larger distance between the underdrain and the bottom of the aggregate bedding is desirable, but cannot be used to trigger infeasibility due to inadequate vertical separation to the seasonal high water table, bedrock, or other impermeable layer. Ecology recommends that the municipality establish standard design specifications and drawings. Maintenance Please refer to the Rain Garden Handbook for Western Washington (2013) for tips on mulching, watering, weeding, pruning, and soil management. The "Western Washington Low Impact Development (LID) Operation and Maintenance (O&M) Guidance Doucment" may be consulted for more detailed guidance. BMP T5.14B: Bioretention Purpose and Bioretention areas are shallow landscaped depressions, with a designed Definition soil mix and plants adapted to the local climate and soil moisture conditions, that receive stormwater from a contributing area. Bioretention provides effective removal of many stormwater pollutants by passing stormwater through a soil profile that meets specified characteristics. Bioretention can also reduce stormwater runoff quantity and surface runoff flow rates significantly where the exfiltrate from the design soil is allowed to infiltrate into the surrounding native soils. Bioretention can be used as a primary or supplemental detention/retention system. Where the native soils have low infiltration rates, underdrain systems can be installed and the facility used to filter pollutants and detain flows. However, designs utilizing underdrains provide less flow control benefits. Volume V—Runoff Treatment BMPs — December 2014 5-13 Applications and Bioretention facilities are an On -site BMP option for projects that only Limitations have to comply with Minimum Requirements #1 - #5. For projects electing to use Mandatory List #2 of Minimum Requirement #5, bioretention facilities are to be used to the extent feasible for runoff from roofs and other hard surfaces unless a higher priority BMP is feasible. Use of bioretention can be restricted by site limitations. Please see Bioretention infeasibility criteria in BMP 'T7.30 of this Volume. Design Refer to BMP 'T7.30 in Chapter 7 of this Volume for detailed design Guidelines guidelines. For design on projects subject to Minimum Requirement #5, and choosing to use List #1 or List #2 of that requirement, a bioretention facility shall have a horizontally projected surface area below the overflow which is at least 5% of the total impervious surface area draining to it. If lawn/landscape area will also be draining to the bioretention facility, Ecology recommends that the bioretention facility's horizontally projected surface area below the overflow be increased by 2% of the lawn/landscape area. Maintenance Refer to BMP 'T7.30 and Section 4.6 of this Volume for maintenance guidelines. Volume V —Runoff Treatment BMPs — December 2014 5-14 No. 21 - Maintenance Standards and Procedures for Bioretention Facilities. Note that the inspection and routine maintenance frequencies listed below are recommended by Ecology. They do not supersede or replace the municipal stormwater permit requirements for inspection frequency required of municipal stormwater permittees for "stormwater treatment and flow control BMPs/facilities." Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance Facility Footprint Earthen side slopes B, S Erosion (gullies/ rills) greater than 2 inches deep around . Eliminate cause of erosion and stabilize damaged area (regrade, rock, vegetation, erosion control matting) and berms inlets, outlet, and alongside slopes . For deep channels or cuts (over 3 inches in ponding depth), temporary erosion control measures should be put in place until permanent repairs can be made. . Properly designed, constructed and established facilities with appropriate flow velocities should not have erosion problems except perhaps in extreme events. If erosion problems persist, the following should be reassessed: (1) flow volumes from contributing areas and bioretention facility sizing; (2) flow velocities and gradients within the facility; and (3) flow dissipation and erosion protection strategies at the facility inlet. A Erosion of sides causes slope to become a hazard Take actions to eliminate the hazard and stabilize slopes A, S Settlement greater than 3 inches (relative to undisturbed Restore to design height sections of berm) A, S Downstream face of berm wet, seeps or leaks evident Plug any holes and compact berm (may require consultation with engineer, particularly for larger berms) A Any evidence of rodent holes or water piping in berm . Eradicate rodents (see "Pest control') • Fill holes and compact (may require consultation with engineer, particularly for larger berms) Concrete sidewalls A Cracks or failure of concrete sidewalls . Repair/ seal cracks • Replace if repair is insufficient Rockery sidewalls A Rockery side walls are insecure Stabilize rockery sidewalls (may require consultation with engineer, particularly for walls 4 feet or greater in height) Facility area All maintenance Trash and debris present Clean out trash and debris visits (at least biannually) Facility bottom area A, S Accumulated sediment to extent that infiltration rate is . Remove excess sediment reduced (see "Ponded water") or surface storage capacity . Replace any vegetation damaged or destroyed by sediment accumulation and removal significantly impacted . Mulch newly planted vegetation . Identify and control the sediment source (if feasible) • If accumulated sediment is recurrent, consider adding presettlement or installing berms to create a forebay at the inlet During/after fall leaf Accumulated leaves in facility Remove leaves if there is a risk to clogging outlet structure or water flow is impeded drop Low permeability A, S Sediment, vegetation, or debris accumulated at or blocking Clear the blockage check dams and (or having the potential to block) check dam, flow control weirs weir or orifice A, S Erosion and/or undercutting present Repair and take preventative measures to prevent future erosion and/or undercutting A Grade board or top of weir damaged or not level Restore to level position a Frequency: A = Annually; B = Biannually (twice per year); M = Monthty; W = At least one visit should occur during the wet season (for debris/clog related maintenance, this inspection/maintenance visit should occur in the early fall, after deciduous trees have lost their leaves); S = Perform inspections after major storm events (24-hour storm event with a 10-year or greater recurrence interval). IPM - Integrated Pest Management ISA - International Society of Arboriculture Volume V —Runoff Treatment BMPs — December 2014 4-54 No. 21 (continued) - Maintenance Standards and Procedures for Bioretention Facilities. Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance Facility Footprint (cont d) Ponded water B, S Excessive ponding water: Water overflows during storms Determine cause and resolve in the following order: smaller than the design event or ponded water remains in 1) Confirm leaf or debris buildup in the bottom of the facility is not impeding infiltration. If necessary, remove leaf litter/debris. the basin 48 hours or longer after the end of a storm. 2) Ensure that underdrain (if present) is not clogged. If necessary, clear underdrain. 3) Check for other water inputs (e.g., groundwater, illicit connections). 4) Verify that the facility is sized appropriately for the contributing area. Confirm that the contributing area has not increas ed. If steps #1-4 do not solve the problem, the bioretention soil is likely clogged by sediment accumulation at the surface or has become overly compacted. Dig a small hole to observe soil profile and identify compaction depth or clogging front to help determine the soil depth to be removed or otherwise rehabilitated (e.g., tilled). Consultation with an engineer is recommended. Bioretention soil As needed Bioretention soil media protection is needed when . Minimize all loading in the facility footprint (foot traffic and other loads) to the degree feasible in order to prevent compaction media performing maintenance requiring entrance into the facility of bioretention soils. footprint • Never drive equipment or apply heavy loads in facility footprint. • Because the risk of compaction is higher during saturated soil conditions, any type of loading in the cell (including foot traffic) should be minimized during wet conditions. • Consider measures to distribute loading if heavy foot traffic is required or equipment must be placed in facility. As an example, boards may be placed across soil to distribute loads and minimize compaction. • If compaction occurs, soil must be loosened or otherwise rehabilitated to original design state. lnletslOutletslPipes Splash block inlet A Water is not being directed properly to the facility and Reconfigure/ repair blocks to direct water to facility and away from structure away from the inlet structure Curb cut inlet/outlet M during the Weekly during fall Accumulated leaves at curb cuts Clear leaves (particularly important for key inlets and low points along long, linear facilities) wet season leaf drop and before severe storm is forecasted Pipe inlet/outlet A Pipe is damaged Repair/ replace W Pipe is clogged Remove roots or debris A, S Sediment, debris, trash, or mulch reducing capacity of . Clear the blockage inlet/outlet . Identify the source of the blockage and take actions to prevent future blockages Weekly during fall Accumulated leaves at inlets/outlets Clear leaves (particularly important for key inlets and low points along long, linear facilities) leaf drop A Maintain access for inspections . Clear vegetation (transplant vegetation when possible) within 1 foot of inlets and outlets, maintain access pathways • Consultation with a landscape architect is recommended for removal, transplant, or substitution of plants Erosion control at A Concentrated flows are causing erosion Maintain a cover of rock or cobbles or other erosion protection measure (e.g., matting) to protect the ground where inlet concentrated water enters the facility (e.g., a pipe, curb cut or swale) Volume V —Runoff Treatment BMPs — December 2014 4-SS No. 21 (continued) - Maintenance Standards and Procedures for Bioretention Facilities. Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance InletslOutlets/Pipes (cont'd) Trash rack S Trash or other debris present on trash rack Remove/dispose A Bar screen damaged or missing Repair/replace Overflow A, S Capacity reduced by sediment or debris Remove sediment or debris/dispose Underdrain pipe Clean pipe as Clean orifice at least . Plant roots, sediment or debris reducing capacity of • Jet clean or rotary cut debris/roots from underdrain(s) needed biannually (may underdrain . If underdrains are equipped with a flow restrictor (e.g., orifice) to attenuate flows, the orifice must be cleaned regularly. need more frequent • Prolonged surface ponding (see "Ponded water") cleaning during wet season) Vegetation Facility bottom area Fall and Vegetation survival rate falls below 75% within first two . Determine cause of poor vegetation growth and correct condition and upland slope Spring years of establishment (unless project O&M manual or • Replant as necessary to obtain 75% survival rate or greater. Refer to original planting plan, or approved jurisdictional vegetation record drawing stipulates more or less than 75% survival species list for appropriate plant replacements (See Appendix 3 - Bioretention Plant List, in the LID Technical Guidance rate). Manual for Puget Sound). • Confirm that plant selection is appropriate for site growing conditions • Consultation with a landscape architect is recommended for removal, transplant, or substitution of plants Vegetation (general) As needed Presence of diseased plants and plant material • Remove any diseased plants or plant parts and dispose of in an approved location (e.g., commercial landfill) to avoid risk of spreading the disease to other plants • Disinfect gardening tools after pruning to prevent the spread of disease • See Pacific Northwest Plant Disease Management Handbook for information on disease recognition and for additional resources . Replant as necessary according to recommendations provided for "facility bottom area and upland slope vegetation". Trees and shrubs All pruning seasons Pruning as needed • Prune trees and shrubs in a manner appropriate for each species. Pruning should be performed by landscape professionals (timing varies by familiar with proper pruning techniques species) • All pruning of mature trees should be performed by or under the direct guidance of an ISA certified arborist A Large trees and shrubs interfere with operation of the • Prune trees and shrubs using most current ANSI A300 standards and ISA BMPs. facility or access for maintenance . Remove trees and shrubs, if necessary. Fall and Standing dead vegetation is present • Remove standing dead vegetation Spring . Replace dead vegetation within 30 days of reported dead and dying plants (as practical depending on weather/planting season) . If vegetation replacement is not feasible within 30 days, and absence of vegetation may result in erosion problems, temporary erosion control measures should be put in place immediately. • Determine cause of dead vegetation and address issue, if possible • If specific plants have a high mortality rate, assess the cause and replace with appropriate species. Consultation with a landscape architect is recommended. Fall and Planting beneath mature trees . When working around and below mature trees, follow the most current ANSI A300 standards and ISA BMPs to the extent Spring practicable (e.g., take care to minimize any damage to tree roots and avoid compaction of soil). • Planting of small shrubs or groundcovers beneath mature trees may be desirable in some cases; such plantings should use mainly plants that come as bulbs, bare root or in 4-inch pots; plants should be in no larger than 1-gallon containers. Volume V —Runoff Treatment BMPs — December 2014 4-56 No. 21 (continued) - Maintenance Standards and Procedures for Bioretention Facilities. Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance Vegetation (cont'd) Trees and shrubs Fall and Planting beneath mature trees . When working around and below mature trees, follow the most current ANSI A300 standards and ISA BMPs to the extent (cont'd) Spring practicable (e.g., take care to minimize any damage to tree roots and avoid compaction of soil). • Planting of small shrubs or groundcovers beneath mature trees may be desirable in some cases; such plantings should use mainly plants that come as bulbs, bare root or in 4-inch pots; plants should be in no larger than 1-gallon containers. Fall and Presence of or need for stakes and guys (tree growth, . Verify location of facility liners and underdrain (if any) prior to stake installation in order to prevent liner puncture or pipe Spring maturation, and support needs) damage • Monitor tree support systems: Repair and adjust as needed to provide support and prevent damage to tree. • Remove tree supports (stakes, guys, etc.) after one growing season or maximum of 1 year. • Backfill stake holes after removal. Trees and shrubs A Vegetation causes some visibility (line of sight) or driver . Maintain appropriate height for sight clearance adjacent to vehicle safety issues • When continued, regular pruning (more than one time/ growing season) is required to maintain visual sight lines for safety or travel areas (or clearance along a walk or drive, consider relocating the plant to a more appropriate location. areas where visibility • Remove or transplant if continual safety hazard needs to be • Consultation with a landscape architect is recommended for removal, transplant, or substitution of plants maintained) Flowering plants A Dead or spent flowers present Remove spent flowers (deadhead) Perennials Fall Spent plants Cut back dying or dead and fallen foliage and stems Emergent vegetation Spring Vegetation compromises conveyance . Hand rake sedges and rushes with a small rake or fingers to remove dead foliage before new growth emerges in spring or earlier only if the foliage is blocking water flow (sedges and rushes do not respond well to pruning) Ornamental grasses Winter and Spring Dead material from previous year's growing cycle or dead . Leave dry foliage for winter interest (perennial) collapsed foliage . Hand rake with a small rake or fingers to remove dead foliage back to within several inches from the soil before new growth emerges in spring or earlier if the foliage collapses and is blocking water flow Ornamental grasses Fall and Spring Dead growth present in spring • Hand rake with a small rake or fingers to remove dead growth before new growth emerges in spring (evergreen) • Clean, rake, and comb grasses when they become too tall • Cut back to ground or thin every 2-3 years as needed Noxious weeds M Listed noxious vegetation is present (refer to current . By law, class A & B noxious weeds must be removed, bagged and disposed as garbage immediately (March - October, county noxious weed list) . Reasonable attempts must be made to remove and dispose of class C noxious weeds preceding seed • It is strongly encouraged that herbicides and pesticides not be used in order to protect water quality; use of herbicides and dispersal) pesticides may be prohibited in some jurisdictions • Apply mulch after weed removal (see "Mulch") a Frequency: A = Annually; B = Biannually (twice per year); M = Monthly; W = At least one visit should occur during the wet season (for debris/clog related maintenance, this inspection/maintenance visit should occur in the early fall, after deciduous trees have lost their leaves); S = Perform inspections after major storm events (24-hour storm event with a 10-year or greater recurrence interval). IPM - Integrated Pest Management ISA - International Society of Arboriculture Volume V —Runoff Treatment BMPs — December 2014 4-5 7 No. 21 (continued) - Maintenance Standards and Procedures for Bioretention Facilities. Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance Vegetation (cont'd) Weeds M Weeds are present Remove weeds with their roots manually with pincer -type weeding tools, flame weeders, or hot water weeders as (March — October, appropriate preceding seed . Follow IPM protocols for weed management (see "Additional Maintenance Resources" section for more information on IPM dispersal) protocols) Excessive vegetation Once in early to mid- Low-lying vegetation growing beyond facility edge onto . Edge or trim groundcovers and shrubs at facility edge May and once in sidewalks, paths, or street edge poses pedestrian safety . Avoid mechanical blade -type edger and do not use edger or trimmer within 2 feet of tree trunks early- to mid- hazard or may clog adjacent permeable pavement . While some clippings can be left in the facility to replenish organic material in the soil, excessive leaf litter can cause surface September surfaces due to associated leaf litter, mulch, and soil soil clogging As needed Excessive vegetation density inhibits stormwater flow . Determine whether pruning or other routine maintenance is adequate to maintain proper plant density and aesthetics beyond design ponding or becomes a hazard for . Determine if planting type should be replaced to avoid ongoing maintenance issues (an aggressive grower under perfect pedestrian and vehicular circulation and safety growing conditions should be transplanted to a location where it will not impact flow) • Remove plants that are weak, broken or not true to form; replace in -kind • Thin grass or plants impacting facility function without leaving visual holes or bare soil areas • Consultation with a landscape architect is recommended for removal, transplant, or substitution of plants As needed Vegetation blocking curb cuts, causing excessive sediment . Remove vegetation and sediment buildup buildup and flow bypass Mulch Mulch Following weeding Bare spots (without mulch cover) are present or mulch • Supplement mulch with hand tools to a depth of 2 to 3 inches depth less than 2 inches . Replenish mulch per O&M manual. Often coarse compost is used in the bottom of the facility and arborist wood chips are used on side slopes and rim (above typical water levels) • Keep all mulch away from woody stems Watering Irrigation system (if Based on Irrigation system present . Follow manufacturer's instructions for O&M any) manufacturer's instructions A Sprinklers or drip irrigation not directed/located to properly . Redirect sprinklers or move drip irrigation to desired areas water plants Summer watering Once every 1-2 Trees, shrubs and groundcovers in first year of . 10 to 15 gallons per tree (first year) weeks or as needed establishment period . 3 to 5 gallons per shrub during prolonged dry . 2 gallons water per square foot for groundcover areas periods . Water deeply, but infrequently, so that the top 6 to 12 inches of the root zone is moist • Use soaker hoses or spot water with a shower type wand when irrigation system is not present o Pulse water to enhance soil absorption, when feasible o Pre -moisten soil to break surface tension of dry or hydrophobic soils/mulch, followed by several more passes. With this method , each pass increases soil absorption and allows more water to infiltrate prior to runoff • Add a tree bag or slow -release watering device (e.g., bucket with a perforated bottom) for watering newly installed trees when irrigation system is not present a Frequency: A = Annually; B = Biannually (twice per year); M = Monthly; W = At least one visit should occur during the wet season (for debris/clog related maintenance, this inspection/maintenance visit should occur in the early fall, after deciduous trees have lost their leaves); S = Perform inspections after major storm events (24-hour storm event with a 10-year or greater recurrence interval). IPM - Integrated Pest Management ISA - International Society of Arboriculture Volume V —Runoff Treatment BMPs — December 2014 4-58 No. 21 (continued) - Maintenance Standards and Procedures for Bioretention Facilities. Maintenance Recommended Frequency a Condition when Maintenance is Needed Action Needed Inspection Routine Component (Standards) (Procedures) Maintenance Watering (cont'd) Summer watering Once every 2-4 Trees, shrubs and groundcovers in second or third year of . 10 to 15 gallons per tree (second and third weeks or as needed establishment period . 3 to 5 gallons per shrub years) during prolonged dry . 2 gallons water per square foot for groundcover areas periods . Water deeply, but infrequently, so that the top 6 to 12 inches of the root zone is moist • Use soaker hoses or spot water with a shower type wand when irrigation system is not present o Pulse water to enhance soil absorption, when feasible o Pre -moisten soil to break surface tension of dry or hydrophobic soils/mulch, followed by several more passes. With this method , each pass increases soil absorption and allows more water to infiltrate prior to runoff Summer watering As needed Established vegetation (after 3 years) . Plants are typically selected to be drought tolerant and not require regular watering after establishment; however, trees may (after establishment) take up to 5 years of watering to become fully established . Identify trigger mechanisms for drought -stress (e.g., leaf wilt, leaf senescence, etc.) of different species and water immediately after initial signs of stress appear • Water during drought conditions or more often if necessary to maintain plant cover Pest Control Mosquitoes B, S Standing water remains for more than 3 days after the end . Identify the cause of the standing water and take appropriate actions to address the problem (see " Ponded water") of a storm . To facilitate maintenance, manually remove standing water and direct to the storm drainage system (if runoff is from non pollution -generating surfaces) or sanitary sewer system (if runoff is from pollution -generating surfaces) after getting approval from sanitary sewer authority. • Use of pesticides or Bacillus thuringiensis israelensis (Bti)may be considered only as a temporary measure while addressing the standing water cause. If overflow to a surface water will occur within 2 weeks after pesticide use, apply for coverage under the Aquatic Mosquito Control NPDES General Permit. Nuisance animals As needed Nuisance animals causing erosion, damaging plants, or . Reduce site conditions that attract nuisance species where possible (e.g., plant shrubs and tall grasses to reduce open depositing large volumes of feces areas for geese, etc.) . Place predator decoys . Follow IPM protocols for specific nuisance animal issues (see "Additional Maintenance Resources" section for more information on IPM protocols) . Remove pet waste regularly . For public and right-of-way sites consider adding garbage cans with dog bags for picking up pet waste. Insect pests Every site Signs of pests, such as wilting leaves, chewed leaves and . Reduce hiding places for pests by removing diseased and dead plants visit bark, spotting or other indicators . For infestations, follow IPM protocols (see "Additional Maintenance Resources" section for more information on IPM associated protocols) with vegetation management a Frequency: A = Annually; B = Biannually (twice per year); M = Monthly; W = At least one visit should occur during the wet season (for debris/clog related maintenance, this inspection/maintenance visit should occur in the early fall, after deciduous trees have lost their leaves); S = Perform inspections after major storm events (24-hour storm event with a 10-year or greater recurrence interval). IPM - Integrated Pest Management ISA - International Society of Arboriculture Volume V —Runoff Treatment BMPs — December 2014 4-59 No. 5 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash & Trash or debris which is located immediately No Trash or debris located Debris in front of the catch basin opening or is immediately in front of blocking inletting capacity of the basin by catch basin or on grate more than 10%. opening. Trash or debris (in the basin) that exceeds 60 No trash or debris in the percent of the sump depth as measured from catch basin. the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free blocking more than 1/3 of its height. of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present within or dangerous gases (e.g., methane). the catch basin. Sediment Sediment (in the basin) that exceeds 60 No sediment in the catch percent of the sump depth as measured from basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Top slab has holes larger than 2 square Top slab is free of holes Damage to inches or cracks wider than 1/4 inch and cracks. Frame and/or Top Slab (intent is to make sure no material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sifting flush on separation of more than 3/4 inch of the frame the riser rings or top slab from the top slab. Frame not securely and firmly attached. attached Fractures or Maintenance person judges that structure is Basin replaced or repaired Cracks in unsound. to design standards. Basin Walls/ Bottom Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ If failure of basin has created a safety, Basin replaced or repaired Misalignment function, or design problem. to design standards. Vegetation Vegetation growing across and blocking more No vegetation blocking than 10% of the basin opening. opening to basin. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present. six inches apart. Contamination See "Detention Ponds" (No. 1). No pollution present. and Pollution Volume V — Runof .f Treatment BMPs — December 2014 4-38 No. 5 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is Cover Place Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. Bolts proper tools. Not Working into frame have less than 1/2 inch of thread. Cover Difficult One maintenance person cannot remove lid Cover can be removed by to Remove after applying normal lifting pressure. one maintenance person. (Intent is keep cover from sealing off access to maintenance.) Ladder Ladder Rungs Ladder is unsafe due to missing rungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Trash and debris that is blocking more than Grate free of trash and Debris 20% of grate surface inletting capacity. debris. Damaged or Grate missing or broken member(s) of the Grate is in place and Missing. I grate. meets design standards. No. 6 — Debris Barriers (e.g., Trash Racks) Maintenance Defect Condition When Maintenance is Results Expected When Components Needed Maintenance is Performed General Trash and Trash or debris that is plugging more Barrier cleared to design flow Debris than 20% of the openings in the barrier. capacity. Metal Damaged/ Bars are bent out of shape more than 3 Bars in place with no bends more Missing inches. than 3/4 inch. Bars. Bars are missing or entire barrier Bars in place according to design. missing. Bars are loose and rust is causing 50% Barrier replaced or repaired to deterioration to any part of barrier. design standards. Inlet/Outlet Debris barrier missing or not attached to Barrier firmly attached to pipe Pipe pipe Volume V —Runoff Treatment BMPs — December 2014 4-39 BMP C101: Preserving Natural Vegetation Purpose The purpose of preserving natural vegetation is to reduce erosion wherever practicable. Limiting site disturbance is the single most effective method for reducing erosion. For example, conifers can hold up to about 50 percent of all rain that falls during a storm. Up to 20-30 percent of this rain may never reach the ground but is taken up by the tree or evaporates. Another benefit is that the rain held in the tree can be released slowly to the ground after the storm. Conditions of Use Natural vegetation should be preserved on steep slopes, near perennial and intermittent watercourses or swales, and on building sites in wooded areas. • As required by local governments. • Phase construction to preserve natural vegetation on the project site for as long as possible during the construction period. Design and Natural vegetation can be preserved in natural clumps or as individual Installation trees, shrubs and vines. Specifications The preservation of individual plants is more difficult because heavy equipment is generally used to remove unwanted vegetation. The points to remember when attempting to save individual plants are: • Is the plant worth saving? Consider the location, species, size, age, vigor, and the work involved. Local governments may also have ordinances to save natural vegetation and trees. • Fence or clearly mark areas around trees that are to be saved. It is preferable to keep ground disturbance away from the trees at least as far out as the dripline. Plants need protection from three kinds of injuries: • Construction Equipment - This injury can be above or below the ground level. Damage results from scarring, cutting of roots, and compaction of the soil. Placing a fenced buffer zone around plants to be saved prior to construction can prevent construction equipment injuries. • Grade Changes - Changing the natural ground level will alter grades, which affects the plant's ability to obtain the necessary air, water, and minerals. Minor fills usually do not cause problems although sensitivity between species does vary and should be checked. Trees can typically tolerate fill of 6 inches or less. For shrubs and other plants, the fill should be less. When there are major changes in grade, it may become necessary to supply air to the roots of plants. This can be done by placing a layer of gravel and a the system over the roots before the fill is made. A the Volume II — Construction Stormwater Pollution Prevention - December 2014 4-3 system protects a tree from a raised grade. The the system should be laid out on the original grade leading from a dry well around the tree trunk. The system should then be covered with small stones to allow air to circulate over the root area. Lowering the natural ground level can seriously damage trees and shrubs. The highest percentage of the plant roots are in the upper 12 inches of the soil and cuts of only 2-3 inches can cause serious injury. To protect the roots it may be necessary to terrace the immediate area around the plants to be saved. If roots are exposed, construction of retaining walls may be needed to keep the soil in place. Plants can also be preserved by leaving them on an undisturbed, gently sloping mound. To increase the chances for survival, it is best to limit grade changes and other soil disturbances to areas outside the dripline of the plant. Excavations - Protect trees and other plants when excavating for drainfields, power, water, and sewer lines. Where possible, the trenches should be routed around trees and large shrubs. When this is not possible, it is best to tunnel under them. This can be done with hand tools or with power augers. If it is not possible to route the trench around plants to be saved, then the following should be observed: Cut as few roots as possible. When you have to cut, cut clean. Paint cut root ends with a wood dressing like asphalt base paint if roots will be exposed for more than 24-hours. Backfill the trench as soon as possible. Tunnel beneath root systems as close to the center of the main trunk to preserve most of the important feeder roots. Some problems that can be encountered with a few specific trees are: • Maple, Dogwood, Red alder, Western hemlock, Western red cedar, and Douglas fir do not readily adjust to changes in environment and special care should be taken to protect these trees. • The windthrow hazard of Pacific silver fir and madrona is high, while that of Western hemlock is moderate. The danger of windthrow increases where dense stands have been thinned. Other species (unless they are on shallow, wet soils less than 20 inches deep) have a low windthrow hazard. • Cottonwoods, maples, and willows have water -seeking roots. These can cause trouble in sewer lines and infiltration fields. On the other hand, they thrive in high moisture conditions that other trees would not. • Thinning operations in pure or mixed stands of Grand fir, Pacific silver fir, Noble fir, Sitka spruce, Western red cedar, Western hemlock, Pacific dogwood, and Red alder can cause serious disease problems. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-4 Disease can become established through damaged limbs, trunks, roots, and freshly cut stumps. Diseased and weakened trees are also susceptible to insect attack. Maintenance Inspect flagged and/or fenced areas regularly to make sure flagging or Standards fencing has not been removed or damaged. If the flagging or fencing has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. • If tree roots have been exposed or injured, "prune" cleanly with an appropriate pruning saw or toppers directly above the damaged roots and recover with native soils. Treatment of sap flowing trees (fir, hemlock, pine, soft maples) is not advised as sap forms a natural healing barrier. BM C102: Buffer Zones Purpose Creation of an undisturbed area or strip of natural vegetation or an established suitable planting that will provide a living filter to reduce soil erosion and runoff velocities. Conditions of Use Natural buffer zones are used along streams, wetlands and other bodies of water that need protection from erosion and sedimentation. Vegetative buffer zones can be used to protect natural swales and can be incorporated into the natural landscaping of an area. Critical -areas buffer zones should not be used as sediment treatment areas. These areas shall remain completely undisturbed. The local permitting authority may expand the buffer widths temporarily to allow the use of the expanded area for removal of sediment. Design and Preserving natural vegetation or plantings in clumps, blocks, or strips Installation is generally the easiest and most successful method. Specifications Leave all unstable steep slopes in natural vegetation. • Mark clearing limits and keep all equipment and construction debris out of the natural areas and buffer zones. Steel construction fencing is the most effective method in protecting sensitive areas and buffers. Alternatively, wire -backed silt fence on steel posts is marginally effective. Flagging alone is typically not effective. Keep all excavations outside the dripline of trees and shrubs. • Do not push debris or extra soil into the buffer zone area because it will cause damage from burying and smothering. • Vegetative buffer zones for streams, lakes or other waterways shall be established by the local permitting authority or other state or federal permits or approvals. Maintenance Inspect the area frequently to make sure flagging remains in place and the Standards area remains undisturbed. Replace all damaged flagging immediately. Volume II — Construction Stormwater Pollution Prevention - December 2014 M BMP C103: High Visibility Fence Purpose Fencing is intended to: 1. Restrict clearing to approved limits. 2. Prevent disturbance of sensitive areas, their buffers, and other areas required to be left undisturbed. 3. Limit construction traffic to designated construction entrances, exits, or internal roads. 4. Protect areas where marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits plastic, fabric, or metal fence may be used: • At the boundary of sensitive areas, their buffers, and other areas required to be left uncleared. • As necessary to control vehicle access to and on the site. Design and High visibility plastic fence shall be composed of a high -density Installation polyethylene material and shall be at least four feet in height. Posts for Specifications the fencing shall be steel or wood and placed every 6 feet on center (maximum) or as needed to ensure rigidity. The fencing shall be fastened to the post every six inches with a polyethylene tie. On long continuous lengths of fencing, a tension wire or rope shall be used as a top stringer to prevent sagging between posts. The fence color shall be high visibility orange. The fence tensile strength shall be 360 lbs./ft. using the ASTM D4595 testing method. If appropriate install fabric silt fence in accordance with BMP C233 to act as high visibility fence. Silt fence shall be at least 3 feet high and must be highly visible to meet the requirements of this BMP. Metal fences shall be designed and installed according to the manufacturer's specifications. Metal fences shall be at least 3 feet high and must be highly visible. Fences shall not be wired or stapled to trees. Maintenance If the fence has been damaged or visibility reduced, it shall be repaired or Standards replaced immediately and visibility restored. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-6 BMP C107: Construction Road/Parking Area Stabilization Purpose Stabilizing subdivision roads, parking areas, and other on -site vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use Roads or parking areas shall be stabilized wherever they are constructed, whether permanent or temporary, for use by construction traffic. High Visibility Fencing (see BMP C103) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and • On areas that will receive asphalt as part of the project, install the first Installation lift as soon as possible. Specifications A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If cement or cement kiln dust is used for roadbase stabilization, pH monitoring and BMPs (BMPs C252 and C253) are necessary to evaluate and minimize the effects on stormwater. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super -elevated section. Drainage ditches shall be directed to a sediment control BMP. Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet -flows into a heavily vegetated area with a well -developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation that water can flow through, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include wetlands or their buffers. If runoff is allowed to sheetflow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. • Storm drain inlets shall be protected to prevent sediment -laden water entering the storm drain system (see BMP C220). Maintenance Inspect stabilized areas regularly, especially after large storm events. Standards Crushed rock, gravel base, etc., shall be added as required to maintain a Volume II — Construction Stormwater Pollution Prevention - December 2014 4-12 stable driving surface and to stabilize any areas that have eroded. Following construction, these areas shall be restored to pre -construction condition or better to prevent future erosion. Perform street cleaning at the end of each day or more often if necessary. BMP C120: Temporary and Permanent Seeding Purpose Seeding reduces erosion by stabilizing exposed soils. A well -established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use Use seeding throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. The optimum seeding windows for western Washington are April 1 through June 30 and September 1 through October 1. Between July 1 and August 30 seeding requires irrigation until 75 percent grass cover is established. Between October 1 and March 30 seeding requires a cover of mulch with straw or an erosion control blanket until 75 percent grass cover is established. Review all disturbed areas in late August to early September and complete all seeding by the end of September. Otherwise, vegetation will not establish itself enough to provide more than average protection. • Mulch is required at all times for seeding because it protects seeds from heat, moisture loss, and transport due to runoff. Mulch can be applied on top of the seed or simultaneously by hydroseeding. See BMP C 121: Mulching for specifications. • Seed and mulch, all disturbed areas not otherwise vegetated at final site stabilization. Final stabilization means the completion of all soil disturbing activities at the site and the establishment of a permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement, riprap, gabions, or geotextiles) which will prevent erosion. Design and Seed retention/detention ponds as required. Installation Install channels intended for vegetation before starting major Specifications earthwork and hydroseed with a Bonded Fiber Matrix. For vegetated channels that will have high flows, install erosion control blankets over hydroseed. Before allowing water to flow in vegetated channels, establish 75 percent vegetation cover. If vegetated channels cannot be established by seed before water flow; install sod in the channel bottom —over hydromulch and erosion control blankets. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-13 BMP C250: Construction Stormwater Chemical Treatment BMP C251: Construction Stormwater Filtration BMP C252: High pH Neutralization Using COz BMP C253: pH Control for High pH Water BMP C200: Interceptor Dike and Swale Purpose Provide a ridge of compacted soil, or a ridge with an upslope swale, at the top or base of a disturbed slope or along the perimeter of a disturbed construction area to convey stormwater. Use the dike and/or swale to intercept the runoff from unprotected areas and direct it to areas where erosion can be controlled. This can prevent storm runoff from entering the work area or sediment -laden runoff from leaving the construction site. Conditions of Use Where the runoff from an exposed site or disturbed slope must be conveyed to an erosion control facility which can safely convey the stormwater. Locate upslope of a construction site to prevent runoff from entering disturbed area. • When placed horizontally across a disturbed slope, it reduces the amount and velocity of runoff flowing down the slope. Locate downslope to collect runoff from a disturbed area and direct water to a sediment basin. Design and • Dike and/or swale and channel must be stabilized with temporary or Installation permanent vegetation or other channel protection during construction. Specifications • Channel requires a positive grade for drainage; steeper grades require channel protection and check dams. Review construction for areas where overtopping may occur. • Can be used at top of new fill before vegetation is established. May be used as a permanent diversion channel to carry the runoff. • Sub -basin tributary area should be one acre or less. • Design capacity for the peak volumetric flow rate calculated using a 10-minute time step from a 10-year, 24-hour storm, assuming a Type 1 A rainfall distribution, for temporary facilities. Alternatively, use 1.6 times the 10-year, 1-hour flow indicated by an approved continuous runoff model. For facilities that will also serve on a permanent basis, consult the local government's drainage requirements. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-5 7 Interceptor dikes shall meet the following criteria: Top Width 2 feet minimum. Height 1.5 feet minimum on berm. Side Slope 2H:1 V or flatter. Grade Depends on topography, however, dike system minimum is 0.5%, and maximum is 1%. Compaction Minimum of 90 percent ASTM D698 standard proctor. Horizontal Spacing of Interceptor Dikes: Average Slope Slope Percent Flowpath Length 20H: IV or less 3-5% 300 feet (10 to 20)H:1 V 5-10% 200 feet (4 to 10)H:1 V 10-25% 100 feet (2 to 4)H:1 V 25-50% 50 feet Stabilization depends on velocity and reach Slopes <5% Seed and mulch applied within 5 days of dike construction (see BMP C 121 Mulching). Slopes 5 - 40% Dependent on runoff velocities and dike materials. Stabilization should be done immediately using either sod or riprap or other measures to avoid erosion. • The upslope side of the dike shall provide positive drainage to the dike outlet. No erosion shall occur at the outlet. Provide energy dissipation measures as necessary. Sediment -laden runoff must be released through a sediment trapping facility. • Minimize construction traffic over temporary dikes. Use temporary cross culverts for channel crossing. Interceptor swales shall meet the following criteria: Bottom Width 2 feet minimum; the cross-section bottom shall be level. Depth 1-foot minimum. Side Slope 2H:1 V or flatter. Grade Maximum 5 percent, with positive drainage to a suitable outlet (such as a sediment pond). Stabilization Seed as per BMP C 120, Temporary and Permanent Seeding, or BMP C202, Channel Lining, 12 inches thick riprap pressed into the bank and extending at least 8 inches vertical from the bottom. • Inspect diversion dikes and interceptor swales once a week and after every rainfall. Immediately remove sediment from the flow area. Volume H — Construction Stormwater Pollution Prevention - December 2014 4-58 Damage caused by construction traffic or other activity must be repaired before the end of each working day. Check outlets and make timely repairs as needed to avoid gully formation. When the area below the temporary diversion dike is permanently stabilized, remove the dike and fill and stabilize the channel to blend with the natural surface. BMP C201: Grass -Lined Channels Purpose To provide a channel with a vegetative lining for conveyance of runoff. See Figure for typical grass -lined channels. Conditions of Use This practice applies to construction sites where concentrated runoff needs to be contained to prevent erosion or flooding. When a vegetative lining can provide sufficient stability for the channel cross section and at lower velocities of water (normally dependent on grade). This means that the channel slopes are generally less than 5 percent and space is available for a relatively large cross section. • Typical uses include roadside ditches, channels at property boundaries, outlets for diversions, and other channels and drainage ditches in low areas. Channels that will be vegetated should be installed before major earthwork and hydroseeded with a bonded fiber matrix (BFM). The vegetation should be well established (i.e., 75 percent cover) before water is allowed to flow in the ditch. With channels that will have high flows, erosion control blankets should be installed over the hydroseed. If vegetation cannot be established from seed before water is allowed in the ditch, sod should be installed in the bottom of the ditch in lieu of hydromulch and blankets. Design and Locate the channel where it can conform to the topography and other Installation features such as roads. Specifications . Locate them to use natural drainage systems to the greatest extent possible. • Avoid sharp changes in alignment or bends and changes in grade. • Do not reshape the landscape to fit the drainage channel. • The maximum design velocity shall be based on soil conditions, type of vegetation, and method of revegetation, but at no times shall velocity exceed 5 feet/second. The channel shall not be overtopped by the peak volumetric flow rate calculated using a 10-minute time step from a 10-year, 24-hour storm, assuming a Type 1 A rainfall distribution. Alternatively, use 1.6 times the 10-year, I -hour flow indicated by an approved continuous runoff model to determine a flow rate which the channel must contain. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-59 BMP C208: Triangular Silt Dike (TSD) (Geotextile-Encased Check Dam) Purpose Triangular silt dikes may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Conditions of use ' May be used on soil or pavement with adhesive or staples. • TSDs have been used to build temporary: 1. sediment ponds; 2. diversion ditches; 3. concrete wash out facilities; 4. curbing; 5. water bars; 6. level spreaders; and, 7. berms. Design and Made of urethane foam sewn into a woven geosynthetic fabric. Installation It is triangular, 10 inches to 14 inches high in the center, with a 20-inch to Specifications 28-inch base. A 2—foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed. • Install with ends curved up to prevent water from flowing around the ends. • The fabric flaps and check dam units are attached to the ground with wire staples. Wire staples should be No. 11 gauge wire and should be 200 min to 300 mm in length. • When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. • Check dams should be located and installed as soon as construction will allow. • Check dams should be placed perpendicular to the flow of water. • When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. • In the case of grass -lined ditches and swples, check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the check dams shall be seeded and mulched immediately after dam removal. Maintenance • Triangular silt dams shall be inspected for performance and sediment Volume II — Construction Stormwater Pollution Prevention - December 2014 4-78 Standards accumulation during and after each runoff producing rainfall. Sediment shall be removed when it reaches one half the height of the dam. • Anticipate submergence and deposition above the triangular silt dam and erosion from high flows around the edges of the dam. Immediately repair any damage or any undercutting of the dam. BMP C209: Outlet Protection Purpose Outlet protection prevents scour at conveyance outlets and minimizes the potential for downstream erosion by reducing the velocity of concentrated stormwater flows. Conditions of use Outlet protection is required at the outlets of all ponds, pipes, ditches, or other conveyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, wetland, lake, or ditch. Design and The receiving channel at the outlet of a culvert shall be protected from Installation erosion by rock lining a minimum of 6 feet downstream and extending up Specifications the channel sides a minimum of 1—foot above the maximum tailwater elevation or 1-foot above the crown, whichever is higher. For large pipes (more than 18 inches in diameter), the outlet protection lining of the channel is lengthened to four times the diameter of the culvert. • Standard wingwalls, and tapered outlets and paved channels should also be considered when appropriate for permanent culvert outlet protection. (See WSDOT Hydraulic Manual, available through WSDOT Engineering Publications). • Organic or synthetic erosion blankets, with or without vegetation, are usually more effective than rock, cheaper, and easier to install. Materials can be chosen using manufacturer product specifications. ASTM test results are available for most products and the designer can choose the correct material for the expected flow. • With low flows, vegetation (including sod) can be effective. • The following guidelines shall be used for riprap outlet protection: 1. If the discharge velocity at the outlet is less than 5 fps (pipe slope less than 1 percent), use 2-inch to 8-inch riprap. Minimum thickness is 1-foot. 2. For 5 to 10 fps discharge velocity at the outlet (pipe slope less than 3 percent), use 24-inch to 48-inch riprap. Minimum thickness is 2 feet. 3. For outlets at the base of steep slope pipes (pipe slope greater than 10 percent), an engineered energy dissipater shall be used. Filter fabric or erosion control blankets should always be used under riprap to prevent scour and channel erosion. Volume II — Construction Stormwater Pollution Prevention - December 2014 4- 79 New pipe outfalls can provide an opportunity for low-cost fish habitat improvements. For example, an alcove of low -velocity water can be created by constructing the pipe outfall and associated energy dissipater back from the stream edge and digging a channel, over - widened to the upstream side, from the outfall. Overwintering juvenile and migrating adult salmonids may use the alcove as shelter during high flows. Bank stabilization, bioengineering, and habitat features may be required for disturbed areas. This work may require a HPA. See Volume V for more information on outfall system design. Maintenance • Inspect and repair as needed. Standards . Add rock as needed to maintain the intended function. • Clean energy dissipater if sediment builds up. BMP C220: Storm Drain Inlet Protection Purpose Storm drain inlet protection prevents coarse sediment from entering drainage systems prior to permanent stabilization of the disturbed area. Conditions of Use Use storm drain inlet protection at inlets that are operational before permanent stabilization of the disturbed drainage area. Provide protection for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless conveying runoff entering catch basins to a sediment pond or trap. Also consider inlet protection for lawn and yard drains on new home construction. These small and numerous drains coupled with lack of gutters in new home construction can add significant amounts of sediment into the roof drain system. If possible delay installing lawn and yard drains until just before landscaping or cap these drains to prevent sediment from entering the system until completion of landscaping. Provide 18-inches of sod around each finished lawn and yard drain. Table 4.2.2 lists several options for inlet protection. All of the methods for storm drain inlet protection tend to plug and require a high frequency of maintenance. Limit drainage areas to one acre or less. Possibly provide emergency overflows with additional end -of -pipe treatment where stormwater ponding would cause a hazard. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-80 Table 4.2.2 Storm Drain Inlet Protection Applicable for Type of Inlet Emergency Paved/ Earthen Protection Overflow Surfaces Conditions of Use Drop Inlet Protection Excavated drop inlet Yes, Earthen Applicable for heavy flows. Easy protection temporary to maintain. Large area flooding will Requirement: 30' X 307acre occur Block and gravel drop Yes Paved or Earthen Applicable for heavy concentrated inlet protection flows. Will not pond. Gravel and wire drop No Applicable for heavy concentrated inlet protection flows. Will pond. Can withstand traffic. Catch basin filters Yes Paved or Earthen Frequent maintenance required'. Curb Inlet Protection Curb inlet protection Small capacity Paved Used for sturdy, more compact with a wooden weir overflow installation. Block and gravel curb Yes Paved Sturdy, but limited filtration. inlet protection Culvert Inlet Protection Culvert inlet sediment 18 month expected life. trap Design and Excavated Drop Inlet Protection - An excavated impoundment around the Installation storm drain. Sediment settles out of the stormwater prior to entering the Specifications storm drain. • Provide a depth of 1-2 ft as measured from the crest of the inlet structure. • Slope sides of excavation no steeper than 2H:IV. • Minimum volume of excavation 35 cubic yards. • Shape basin to fit site with longest dimension oriented toward the longest inflow area. • Install provisions for draining to prevent standing water problems. • Clear the area of all debris. • Grade the approach to the inlet uniformly. • Drill weep holes into the side of the inlet. • Protect weep holes with screen wire and washed aggregate. • Seal weep holes when removing structure and stabilizing area. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-81 • Build a temporary dike, if necessary, to the down slope side of the structure to prevent bypass flow. Block and Gravel Filter - A barrier formed around the storm drain inlet with standard concrete blocks and gravel. See fuse� Provide a height of 1 to 2 feet above inlet. • Recess the first row 2-inches into the ground for stability. • Support subsequent courses by placing a 2x4 through the block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pool. • Place hardware cloth or comparable wire mesh with 1/2-inch openings over all block openings. • Place gravel just below the top of blocks on slopes of 2H:1 V or flatter. • An alternative design is a gravel donut. • Provide an inlet slope of 3H:IV. • Provide an outlet slope of 2H:IV. • Provide al -foot wide level stone area between the structure and the inlet. • Use inlet slope stones 3 inches in diameter or larger. • Use gravel %- to 3/4-inch at a minimum thickness of 1-foot for the outlet slope. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-82 Plan View A Drain Grate �o �Ooo° Pq 0j Oo �°° oo �ao °ooD30 oZAPaO�ZI0 o O °� ° a LJ 0 °o°�o °DO nOovO °o' ° o QO°o Q000�J C>'o 0`� Concrete 0 o O 0 0��0000ao° o Block QoO00o -00 o°o <: 00 ° oo O°o°o �o � ° o o°oo a0°° °oo° Gravel oo °�°a§o O Backfill O O o0 0 [-5 --�oo o �oCO o O �°°o��% ° �00 0�o as o�oa � °° oQ0 0�°° oo°°0000'oo�o°�O °ao°0"d,(—° 81' oO°O � o o°O r A Section A — A Concrete Block Wire Screen or Filter Fabric Gravel Backfill Overflow I Water Ponding Height O°DSo Water ��Goa°�°oo� 0 0 o o Drop Inlet j/ \x j Notes: 1. Drop inlet sediment barriers are to be used for small, nearly level drainage areas. (less than 5%) 2. Excavate a basin of sufficient size adjacent to the drop inlet. 3. The top of the structure (pending height) must be well below the ground elevation downslope to prevent runoff from bypassing the inlet. A temporary dike may be necessary on the downslope side of the structure. 00 Ilnnll Figure 4.2.8 — Block and Gravel Filter Gravel and Wire Mesh Filter - A gravel barrier placed over the top of the inlet. This structure does not provide an overflow. • Use a hardware cloth or comparable wire mesh with t/z-inch openings. • Use coarse aggregate. • Provide a height 1-foot or more, 18-inches wider than inlet on all sides. • Place wire mesh over the drop inlet so that the wire extends a minimum of 1-foot beyond each side of the inlet structure. • Overlap the strips if more than one strip of mesh is necessary. Volume II —Construction Stormwater Pollution Prevention -December 2014 4-83 • Place coarse aggregate over the wire mesh. • Provide at least a 12-inch depth of gravel over the entire inlet opening and extend at least 18-inches on all sides. Catchbasin Filters — Use inserts designed by manufacturers for construction sites. The limited sediment storage capacity increases the amount of inspection and maintenance required, which may be daily for heavy sediment loads. To reduce maintenance requirements combine a catchbasin filter with another type of inlet protection. This type of inlet protection provides flow bypass without overflow and therefore may be a better method for inlets located along active rights -of -way. • Provides 5 cubic feet of storage. • Requires dewatering provisions. • Provides a high -flow bypass that will not clog under normal use at a construction site. • Insert the catchbasin filter in the catchbasin just below the grating. Curb Inlet Protection with Wooden Weir — Barrier formed around a curb inlet with a wooden frame and gravel. • Use wire mesh with 1/2-inch openings. • Use extra strength filter cloth. • Construct a frame. • Attach the wire and filter fabric to the frame. • Pile coarse washed aggregate against wire/fabric. • Place weight on frame anchors. Block and Gravel Curb Inlet Protection — Barrier formed around a curb inlet with concrete blocks and gravel. See Pyre 4.2.9. • Use wire mesh with 1/z-inch openings. • Place two concrete blocks on their sides abutting the curb at either side of the inlet opening. These are spacer blocks. • Place a 2x4 stud through the outer holes of each spacer block to align the front blocks. • Place blocks on their sides across the front of the inlet and abutting the spacer blocks. • Place wire mesh over the outside vertical face. • Pile coarse aggregate against the wire to the top of the barrier. Curb and Gutter Sediment Barrier — Sandbag or rock berm (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape. See f i ure 4.110. Volume H — Construction Stormwater Pollution Prevention - December 2014 4-84 • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 feet high and 3 feet wide, at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm sized to sediment trap standards for protecting a culvert inlet. Maintenance • Inspect catch basin filters frequently, especially after storm events. Standards Clean and replace clogged inserts. For systems with clogged stone filters: pull away the stones from the inlet and clean or replace. An alternative approach would be to use the clogged stone as fill and put fresh stone around the inlet. • Do not wash sediment into storm drains while cleaning. Spread all excavated material evenly over the surrounding land area or stockpile and stabilize as appropriate. Approved as Ecology has approved products as able to meet the requirements of BMP Equivalent C220. The products did not pass through the Technology Assessment Protocol — Ecology (TAPE) process. Local jurisdictions may choose not to accept this product approved as equivalent, or may require additional testing prior to consideration for local use. The products are available for review on Ecology's website at htt ://w ,ec A a, oy/ ro rams/w /stormwater/ne ech/e uivalent.html Volume II — Construction Stormwater Pollution Prevention - December 2014 4-85 Plan View Back of Sidewalk A Catch Basin 2x4 Wood Stud Back of Curb Concrete Block Curb Inlet _._r --------------------------------------------------------------------- K�—' -- ------------ --------------------------------------------------------- t °0 °° Oa a0° o°o o 0 00�0 ��G�o�000 o°o Oa�Jooa° ��°Oo°ate a°Oo0MObP, joae°"ooo� O�r000 °off° ° 0o aJo . . `Oo mo°o " ne° q°' od`°° ��,�qg• o°°' o°`O` O0 o oa o.bJn� Wire Screen or Filter Fabric A Concrete Block Section A — A (2 Drain Gravel 0mm) %" Drain Gravel (20mm) Ponding Height Concrete Block Overflow ° �AV/ -- —_ Curb Inlet Wire Screen or Filter Fabric ice_ Catch Basin Vim' 4 Wood Stud ' (100x50 Timber Stud) NOTES: 1. Use block and gravel type sediment barrier when curb inlet is located in gently sloping street segment, where water can pond and allow sediment to separate from runoff. 2. Barrier shall allow for overflow from severe storm event. 3. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. Figure 4.2.9 — Block and Gravel Curb Inlet Protection Volume II — Construction Stormwater Pollution Prevention - December 2014 4-86 Plan View Back of Sidewalk NOTES: 1. Place curb type sediment barriers on gently sloping street segments, where water can pond and allow sediment to separate from runoff. 2. Sandbags of either burlap or woven 'geotextile' fabric, are filled with gravel, layered and packed tightly. 3. Leave a one sandbag gap in the top row to provide a spillway for overflow. 4. Inspect barriers and remove sediment after each storm event. Sediment and gravel must be removed from the traveled way immediately. Figure 4.2.10 — Curb and Gutter Barrier Volume II — Construction Stormwater Pollution Prevention - December 2014 4-87 BMP C232: Gravel Filter Berm Purpose A gravel filter berm is constructed on rights -of -way or traffic areas within a construction site to retain sediment by using a filter berm of gravel or crushed rock. Conditions of Use Where a temporary measure is needed to retain sediment from rights -of - way or in traffic areas on construction sites. Design and • Berm material shall be 3/4 to 3 inches in size, washed well -grade gravel Installation or crushed rock with less than 5 percent fines. Specifications Spacing of berms: — Every 300 feet on slopes less than 5 percent — Every 200 feet on slopes between 5 percent and 10 percent — Every 100 feet on slopes greater than 10 percent • Berm dimensions: — 1 foot high with 3H:1 V side slopes — 8 linear feet per 1 cfs runoff based on the 10-year, 24-hour design storm Maintenance • Regular inspection is required. Sediment shall be removed and filter Standards material replaced as needed. BMP C233: Silt Fence Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. See Figure 4.2.12 for details on silt fence construction. Conditions of Use Silt fence may be used downslope of all disturbed areas. • Silt fence shall prevent soil carried by runoff water from going beneath, through, or over the top of the silt fence, but shall allow the water to pass through the fence. • Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Convey any concentrated flows through the drainage system to a sediment pond. • Do not construct silt fences in streams or use in V-shaped ditches. Silt fences do not provide an adequate method of silt control for anything deeper than sheet or overland flow. Volume H — Construction Stormwater Pollution Prevention - December 2014 4-89 Joints in filter fabric shall be spliced at posts. Use staples, ware rings or equivalent to attach fabric to posts .k _ 6' max M€nimum 4"'x4" trench �I ,y Baekfill trench with native soil' Post spacing may be increased or 814"-1.5" washed gravel to 8` if ware backing is used "x2" wood posts, steel fence posts, or € quivalent Figure 4.2.12 — Silt Fence E N s E Design and • Use in combination with sediment basins or other BMPs. Installation Maximum slope steepness (normal (perpendicular) to fence line) Specifications 1PI:1V. Maximum sheet or overland flow path length to the fence of 100 feet. Do not allow flows greater than 0.5 cfs. • The geotextile used shall meet the following standards. All geotextile properties listed below are minimum average roll values (i.e., the test result for any sampled roll in a lot shall meet or exceed the values shown in `fable 4.2.3): Polymeric Mesh AOS (ASTM D4751) Water Permittivity (ASTM D4491) Grab Tensile Strength (ASTM D4632) Table 4.2.3 Geotextile Standards 0.60 mm maximum for slit film woven (#30 sieve). 0.30 mm maximum for all other geotextile types (#50 sieve). 0.15 mm minimum for all fabric types (#100 sieve). 0.02 see-' minimum 180 lbs. Minimum for extra strength fabric. 100 lbs minimum for standard strength fabric. Grab Tensile Strength 30% maximum (ASTM D4632) Ultraviolet Resistance 70% minimum (ASTM D4355) Support standard strength fabrics with wire mesh, chicken wire, 2-inch x 2-inch wire, safety fence, or jute mesh to increase the strength of the fabric. Silt fence materials are available that have synthetic mesh backing attached. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-90 Filter fabric material shall contain ultraviolet ray inhibitors and stabilizers to provide a minimum of six months of expected usable construction life at a temperature range of 0°F. to 120°F. One -hundred percent biodegradable silt fence is available that is strong, long lasting, and can be left in place after the project is completed, if permitted by local regulations. • Refer to Figure for standard silt fence details. Include the following standard Notes for silt fence on construction plans and specifications: 1. The contractor shall install and maintain temporary silt fences at the locations shown in the Plans. 2. Construct silt fences in areas of clearing, grading, or drainage prior to starting those activities. 3. The silt fence shall have a 2-feet min. and a 21/z-feet max. height above the original ground surface. 4. The filter fabric shall be sewn together at the point of manufacture to form filter fabric lengths as required. Locate all sewn seams at support posts. Alternatively, two sections of silt fence can be overlapped, provided the Contractor can demonstrate, to the satisfaction of the Engineer, that the overlap is long enough and that the adjacent fence sections are close enough together to prevent silt laden water from escaping through the fence at the overlap. 5. Attach the filter fabric on the up -slope side of the posts and secure with staples, wire, or in accordance with the manufacturer's recommendations. Attach the filter fabric to the posts in a manner that reduces the potential for tearing. 6. Support the filter fabric with wire or plastic mesh, dependent on the properties of the geotextile selected for use. If wire or plastic mesh is used, fasten the mesh securely to the up -slope side of the posts with the filter fabric up -slope of the mesh. 7. Mesh support, if used, shall consist of steel wire with a maximum mesh spacing of 2-inches, or a prefabricated polymeric mesh. The strength of the wire or polymeric mesh shall be equivalent to or greater than 1801bs. grab tensile strength. The polymeric mesh must be as resistant to the same level of ultraviolet radiation as the filter fabric it supports. 8. Bury the bottom of the filter fabric 4-inches min. below the ground surface. Backfill and tamp soil in place over the buried portion of the filter fabric, so that no flow can pass beneath the fence and scouring cannot occur. When wire or polymeric back-up support Volume II — Construction Stormwater Pollution Prevention - December 2014 4-91 mesh is used, the wire or polymeric mesh shall extend into the ground 3-inches min. 9. Drive or place the fence posts into the ground 18-inches min. A 12—inch min. depth is allowed if topsoil or other soft subgrade soil is not present and 18-inches cannot be reached. Increase fence post min. depths by 6 inches if the fence is located on slopes of 3H:1 V or steeper and the slope is perpendicular to the fence. If required post depths cannot be obtained, the posts shall be adequately secured by bracing or guying to prevent overturning of the fence due to sediment loading. 10. Use wood, steel or equivalent posts. The spacing of the support posts shall be a maximum of 6-feet. Posts shall consist of either: • Wood with dimensions of 2-inches by 2-inches wide min. and a 3-feet min. length. Wood posts shall be free of defects such as knots, splits, or gouges. • No. 6 steel rebar or larger. • ASTM A 120 steel pipe with a minimum diameter of 1-inch. • U, T, L, or C shape steel posts with a minimum weight of 1.35 lbs./ft. • Other steel posts having equivalent strength and bending resistance to the post sizes listed above. 11. Locate silt fences on contour as much as possible, except at the ends of the fence, where the fence shall be turned uphill such that the silt fence captures the runoff water and prevents water from flowing around the end of the fence. 12. If the fence must cross contours, with the exception of the ends of the fence, place gravel check dams perpendicular to the back of the fence to minimize concentrated flow and erosion. The slope of the fence line where contours must be crossed shall not be steeper than 3H: I V. • Gravel check dams shall be approximately 1-foot deep at the back of the fence. Gravel check dams shall be continued perpendicular to the fence at the same elevation until the top of the check dam intercepts the ground surface behind the fence. • Gravel check dams shall consist of crushed surfacing base course, gravel backfill for walls, or shoulder ballast. Gravel check dams shall be located every 10 feet along the fence where the fence must cross contours. • Refer to Figure 442.13 for slicing method details. Silt fence installation using the slicing method specifications: Volume H — Construction Stormwater Pollution Prevention - December 2014 4-92 The base of both end posts must be at least 2- to 4-inches above the top of the filter fabric on the middle posts for ditch checks to drain properly. Use a hand level or string level, if necessary, to mark base points before installation. 2. Install posts 3- to 4-feet apart in critical retention areas and 6- to 7- feet apart in standard applications. 3. Install posts 24-inches deep on the downstream side of the silt fence, and as close as possible to the filter fabric, enabling posts to support the filter fabric from upstream water pressure. 4. Install posts with the nipples facing away from the Ater fabric. 5. Attach the filter fabric to each post with three ties, all spaced within the top 8-inches of the filter fabric. Attach each tie diagonally 45 degrees through the filter fabric, with each puncture at least 1-inch vertically apart. Each tie should be positioned to hang on a post nipple when tightening to prevent sagging. 6. Wrap approximately 6-inches of fabric around the end posts and secure with 3 ties. 7. No more than 24-inches of a 36-inch filter fabric is allowed above ground level. Compact the soil immediately next to the filter fabric with the front wheel of the tractor, skid steer, or roller exerting at least 60 pounds per square inch. Compact the upstream side first and then each side twice for a total of four trips. Check and correct the silt fence installation for any deviation before compaction. Use a flat -bladed shovel to tuck fabric deeper into the ground if necessary. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-93 Maintenance Standards Fording hsigtlt POST SPACING: max 2A' 1* max. on open runs 4 max. on posting areas Attack fabric to *' upstream aide at Peat FLOW - Drive owr each side of alit fence 2 tod times '. arm deviee exsrda• t POST DEPTH: As f each below ground as fabric above ground Go P,a,r, or greater 1 1%compactic" 100 Compaction No more than 24' of a a fabric is allowed above ground. = ropoffebric Belt doubles 7�gonai aatachrrvxrrt . h W AnACHMW DETAKS- e Gather fabdc at peas.. I needed. • Wiite three ties per per. as within top 8" of fabric. • Pteftion each tie Sagonally, puncluM9 hoW verticaRy a rrJrJrnum of V apart. • hang each tie an a post nipple end tighten : (be caus tiers or Sot w%. Fabric above Silt Fence oftund Horizontal chiew pown Slicing blade fie (18 nrim width) Vibratory plow Is not acceptable because of hodwintal compaction Post 4MMed afar cta rnpaction completed kiotirlaton Figure 4.2.13 — Silt Fence Installation by Slicing Method • Repair any damage immediately. • Intercept and convey all evident concentrated flows uphill of the silt fence to a sediment pond. • Check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. Volume II — Construction Stormwater Pollution Prevention - December 2014 4-94 • Remove sediment deposits when the deposit reaches approximately one-third the height of the silt fence, or install a second silt fence. • Replace filter fabric that has deteriorated due to ultraviolet breakdown. BMP C234: Vegetated Strip Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use • Vegetated strips may be used downslope of all disturbed areas. Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment pond. The only circumstance in which overland flow can be treated solely by a strip, rather than by a sediment pond, is when the following criteria are met (see Table 4.2.4): Table 4.2.4 Contributing Drainage Area for Vegetated Strips Average Contributing Average Contributing area Max Contributing area Slope ___ Percent Slope _______ --- - area Flowpath Length -_ _ 1.5H:1 V or flatter 67% or flatter 100 feet 2H:1 V or flatter 50% or flatter 115 feet 4H:1 V or flatter 25 /o or flatter 150 feet 6H:1 V or flatter 16.7% or flatter 200 feet 1 OH:1 V or flatter 10% or flatter 250 feet Design and The vegetated strip shall consist of a minimum of a 25-foot flowpath Installation length continuous strip of dense vegetation with topsoil. Grass - Specifications covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well -developed soil that allows for infiltration of runoff. • The slope within the strip shall not exceed 4H:IV. • The uphill boundary of the vegetated strip shall be delineated with clearing limits. Maintenance Any areas damaged by erosion or construction activity shall be Standards seeded immediately and protected by mulch. • If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed. • If there are indications that concentrated flows are traveling across the buffer, surface water controls must be installed to reduce the flows Volume II — Construction Stormwater Pollution Prevention - December 2014 4-95 1 ( 2 3 4 5 ( 6 SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST 1: i rrr r ® .: y • r r i r yri i. ry •a ! . 0116 ■1 r ll'll rh C_ 1[# r i .r � ri A r i 2 4 D SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST MATCHLINE: SEE SHEET C-401 aa0 SDAD -. � -- BEEHIVE GRATE SDAD #111 BIORETENTION OVERFLOW - STA 104+03,54, 173.92' RT in SDCB 1120 �°---STA 102+51 71 174.13' RT' - �� s STA ID1+9524, 160.16' RT 6" IE IN 43989 (N) - -- =--- - i � SDCB #121 DUTFALL -- -- - - -- 0I �. STA 101+3830 16945-RT \ 4" STREAMS D COBBLES UIC WELL UIC WELL 8 r \ TA 102+463 , 174.05' RT STA 703+0621, 215.00' RT �,2 J SEE STORM DRAIN UIC WELL RIM-445.75 (TYP) C-421 STA 103+66.27, 215.00' RT UIC #100 12" IE IN-434.89 N RIM-445.49 M C 4ID.PROFILE 120 TA ID2+76 ifi50D"R� - (} 12" IE 34.89 (W) STA 103+96.21, M I r �R6 RIM=445.45 ggs 34 LF 12" SD ®-2A0% 16 LF 12" SD ® -6,95% g 215.00' R7 I 1 w , 12 �- 34 1E 12" SD ®-3.31% 5� M STAG I BEEHIVE GRATE 16 LF 12" SO ® -4.18% ':... BIORETENTION OVERFLOW ORS--� �_-.--- rNN STA 101+929Q, 262:18' RT 5 DRAIN 3 SDM RIM 442,56 C-41Q PROFILE 140 (TY') C-42 STA 102+76 2 1.25' RT 51 6- IF IN 43858 (W) pa5 r N" 6" IE OUT 438.58 (S) —,-so-- UIC WELL sD 0 ATER SDMH G101 i SDAD #140 Sp STA 103+36.21, 275.00 RT �� EaSSEPARATOR STA 703+66 21 ... -. eSTA 101+4801, 256.77 RT \. \ \ RIM=445.79 `'(,,P) 23125' RT M, C-420 72 IF 1N 434:89 (SW) a - 6A SEE STORM DRAI�yn-- 15 LF 12 SD �g0.T • C 410 FIR LE 110 00.50% w ---__w- (TYP. C-420 STA +92.90, 274.50' RT • ' S 10 6.21 . 5' T " IE=438.64 — SDAD #104 STA 103+66.20, 263.74' RT STA SDM 03.54 256.8 STREAMBED ES \ d- + e$EE STORM DRAIN bph STA. 101+ H, 27450' RT SDAD C 410 PROFILE 110 g .._BEEHIVE ' BIORETENTION OVERFLOW (.1yp) - 8 v> SAT $IM=443.66- � (TYP.) � ( IE IN=438.13 NE) __M 5.. U 420 IE OUT=438.13 (S) �- 420 F- ._ I i 4T SEE THE C-800 SERIES FOR WATER DETAILS (TYP) - v� 4 SEE STORM DRAIN A SDI 1 I C 410 PROFILE 130 STA ID2+8087, 330.77--RT eSEE STORM DRAIN I q55 SDCB #130 C-410 PROFILE 100 _ SDAD #10S �, _ STA. 103+66.21 336.68' RT i (TYP.).. 42 STp102+01.76, 332.18 RT SDCO — — - STA 102+19,39, 334.68' RT -�__ " 6' IE=439.10 --- —7 ., _. SDAD BEEHIVE GRATE I BIORETENTION. OVERFLOW STA 102+81,96, 33668' RT i RIM=442.52 6" IE IN=438.73 (NE) ' ,. 6" IF OUT=438.73 (S) , - I 94TN AVE W 5 NOTES MANIFOLD1. i ! STRUCTURES SHOULD BE INSPECTED EVERY MONTHDURING FIRST . OF OPERATION AND EVERY • MONTHS THEREAFTER O" SEDIMENT BUILDUP. SEDIMENT2. IF ANY i r DURING INSPECTION, SHOULD! r REMOVED, 3. DURING MANIFOLD MAINTENANCE JETTING � i • LEGEND fo UIC WELL imum MANIFOLD PIPE to 2 SDCQ o p o o ST 70 7. 7, 157.96' RT Ra�< 109 LF SDAD BEEHIVE GRATE - BIORETENTION OVERT �sqs .� STA 105+1893. . 0' RTe SDAD E GRATE D • 1 3 1 1 SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST MATCHLINE: SEE SHEET C-402 y SEE THE CR WA 6" ROOT LEADER SDCO FFE = 453 so SERIES FOR WATER COLLECTOR 6" 1107+58.}0, 755.93' RT (�-� DETAILS (T1P) 0.5% MIN 6' IE=447.56 1 7 / 57 F 4"AD IN 12" =447 % //% ��� SDaD o � �� 1I1iu.1t111! o 4" I 450.2 SDAD w m —_ 114h I 21" SD ®T.5% ELF 1i06+I!i71. SD o, SDCQ RIM- 48 <n SDC0 STA JO8+7238;136M. RT— �. 6" IF OUT (TYP) o SDCO �303 C - ---- 'r`' STA 707+5810._t9"a 4° IE 44839 DAD. ST 007+58 70, 203.43 RT 72"-1E 4qi 5g --{B" 1E-g4$;89-. IM 45 0 SDMH #302 - 52 STA 107+58. , "T _ 450 SDMH #301 _ - - - 5 1071+2RT `ll3"fZ`SD�= 90%— 6-iE-44B-30 = .i 447 w-TO-EFTY-PT-9-U6��: 72 !E w44763 SDCO yiz 10 PAVEMENT +7649 20," 16RT ( C D DRAIN ��� UIC WELL -UIC WELL ,) : 72 IE�h'LD6- STA 107+3551, 212.12' RT STA 707+65.43, 208.09' RTe(TYP.) / RIM 444.84 C-421 12" IF IN=439.91 NE RIM=444.77 SDCQ UIC #300 ( ) 12" IE IN 439.91 (N) STA 108+88.49, 20306 RT �,✓ STA. 107+07.25, 22275' R 12" IE 44205 SDCO '' 178LF 8" LD ®077 - STA ID7 60, - 23997 RT SEES OR AI :8" IE-439.81 ' PRRII SDCO304 SO 0.06% STA. T - LLL... 106+ . 1, 263.32' R- 10 " � 76 IF e" m ®ncm�,;< SDCQ 5 I 6 NOTES 1. MANIFOLD PIPES AND CONNECTED STRUCTURES SHOULD BE INSPECTED EVERY MONTH DURING THE FIRST YEAR OF OPERATION AND EVERY 6 MONTHS THEREAFTER FOR SEDIMENT BUILDUP. 2. IF ANY SEDIMENT IS FOUND DURING INSPECTION, IT SHOULD IMMEDIATELY BE REMOVED, 3. DURING MANIFOLD MAINTENANCE JETTING OPERATIONS, THE OUTLETS TO THE UIC WELLS SHALL BE PLUGGED TO PREVENT SEDIMENT FROM ENTERING AND FOULING THE UIC WELLS. LEGEND UIC WELL __.__ nenn11cn1 n ®1oc to SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST MATCHLINE: SEE SHEET C-403 t0 SECTION 36, TOWNSHIP 27 NORTH, RANGE 3 EAST FINISHED GRADE it UIC OVSERVATIGN PIPE TO REMAN. CUT 6" ABOVE 8" UIC VERTICAL TRANSMISSION PIPE. INSTALL WATER -TIGHT REMOVABLE PLUG CUT 8' STEEL UIC VETICAL PIPE FLRAT 48" SDMH PER PLANTRANSMISSION INLET PIPE CUT UIC STEEL SURFACE CASING PIPE 6' 6" RIPRAP PAD 3 BELOW INVERT ELEVATION OF INLET 6" UIC FILTER SAND PIPE 6" UIC 4X8 FILTER SAND 4" UIC GRAVEL FILL SPACE BETWEEN SDMH AND UIC STEEL URFACE CASING WTH NON -SHRINK CEMENT GROUT IC GRAVEL PRECAST OR CAST -IN -PLACE CONCRETE BASE W/ 40"0 OPENING FOR STEEL CASING MAINTAIN ABLE SAND LAYERS UIC WELL PHASE 2 C-400 - 406 1_1 END CAP STEEL END CAP UIC WELL PHASE 1 C-400 - 406 1--/ NOTES: 1. UIC WELLS SHOULD BE INSPECTED EVERY MONTH Nowilwo ME 1 VAR 0I'm- INS to 5