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REVIEWED RESUB4 BLD2022-0381+Storm_Drainage_Report+6.9.2023_2.08.34_PM+3600524
STORMWATER SITE PLAN REPORT RIMMER RESIDENCE 919 Cedar Street, Edmonds, WA 98020 May 2023 PREPARED FOR: Nathan Rimmer 919 Cedar Street Edmonds, WA 98020 NathanR@pistolcreek.com PREPARED BY: Latitude 48 Engineers 600 1St Avenue Seattle, WA 98104 Phone: 206.556.1615 Contact: Brady Berriman RESUB Jun 09 2023 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT BLD2022-0381 73 3 'GIST N►iS1ONAI ��� latitude-48.com Stormwater Site Plan Report for Rimmer Residence Project Project No. 2021-33 May 2023 TABLE OF CONTENTS 1.0 PROJECT OVERVIEW..........................................................................................................................................1 2.0 MINIMUM REQUIREMENTS.............................................................................................................................2 MR#1: PREPARE STORMATER SITE PLANS........................................................................................2 MR#2: CONSTRUCT STORMWATER POLLUTION PREVENTION PLAN(SWPPP)...........................2 MR#3: SOURCE CONTROL OF POLLUTION.........................................................................................2 MR#4: PRESERVATION OF NATURAL DRAINAGE SYSTEMS AND OUTFALLS...............................2 MR#5: ON -SITE MANAGE STORMWATER MANAGEMENT.................................................................2 3.0 SITE AND BASIN ASSESSMENT........................................................................................................................4 3.1 OFF -SITE ANALYSIS.........................................................................................................................4 3.2 SOILS/INFILTRATION RATES..........................................................................................................4 3.3 CRITICAL AREAS AND FLOOD PLAIN............................................................................................4 3.4 ASSESSMENT SUMMARY...............................................................................................................4 4.0 PERMANAENT STORMWATER CONTROL......................................................................................................5 4.1 LOW IMPACT DEVELOPMENT AND FLOW CONTROL................................................................5 5.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN............................................................6 6.0 SPECIAL REPORTS AND STUDIES....................................................................................................................6 7.0 OTHER PERMITS.................................................................................................................................................6 8.0 FIGURES...............................................................................................................................................................7 FIGURE 1: VICINITY MAP..........................................................................................................................7 FIGURE 2: EXISTING CONDITIONS.........................................................................................................7 FIGURE 3: PROPOSED CONDITIONS......................................................................................................7 FIGURE 4: SITE ASSESSMENT AND SUMMARY....................................................................................7 FIGURE 5: CITY OF EDMONDS EROSION HAZARD AREAS................................................................7 APPENDICES................................................................................................................................................................8 APPENDIXA: GEOTECHNICAL REPORT ................................................................................................8 APPENDIX B: MGS FLOOD ENGINEERING CALCULATIONS...............................................................8 APPENDIX C: COVENANTS, DEDICATIONS, EASEMENTS..................................................................8 APPENDIX D: CONSTRUCTION SWPPP.................................................................................................8 1.0 PROJECT OVERVIEW General Description The following Surface Water Report provides the technical information and design analysis summarizing the drainage requirements for the Rimmer Residence Project. The stormwater design for this project is based on the requirements set forth in the Washington State Department of Ecology Stormwater Management Manual for Western Washington and the 2017 Edmonds Stormwater Addendum. The 6,139 square foot property is located at 919 Cedar Street, Edmonds WA 98020 (Parcel # 00371900100700). The site is in the NW'/a of the NE'/a of Section 25, Township 27N, Range 3E, Willamette Meridian. Refer to Figure 1 for the site Vicinity Map. The Rimmer Residence project site is currently a vacant lot with some associated driveways and site features left over from the adjacent property to the east. The proposed development will include constructing a new single- family residential building, driveway, and other associated site features to support the new home. Existing Conditions The project site located on Cedar Street in Edmonds, Washington. It is bound by Cedar Street to the south, and existing single family residential properties to the west, north and east. The existing project site is currently vacant and has some existing site features that encroach on the property from the adjacent residence to the east. This includes sidewalks, landscaping, driveways and a few utilities. The property is relatively flat but slopes from east to west ranging from 0%-10% across till grass. Soils onsite are generally fine to medium sand with local interbeds of silt and clay. These deposits are typically permeable and become denser with depth. Please refer to Figure 2 Existing Conditions located at the end of this report. Proposed Conditions The proposed development will include constructing a centrally located new single-family residential building, driveway, and other associated site features to support the new home. All site stormwater will be routed to an infiltration trench located in the backyard of the proposed residence. Because there is no adjacent storm main located in Cedar Street, this project will be required to infiltrate 100% of stormwater onsite. Further information on the project site areas, calculations and description can be found in Section B of this report. Please refer to Figure 3 Proposed Conditions located at the end of this report. Page II latitude-48.com 2.0 MINIMUM REQUIREMENTS According to the City of Edmonds Stormwater Addendum, this project site is considered a "Category 1" because new and replaced hard surfaces are within 2,000 square feet and 5,000 square feet. Therefore, Minimum Requirements #1 through #5 of the Edmonds Drainage Addendum apply. See Figure 3.1 on the next page for this flow chart. A description of each minimum requirement is shown below: MR#1: Prepare Stormater Site Plans A stormwater site plan is included in Sheet C-100 — Civil Site Plan. Refer to separate plans. MR#2: Construct Stormwater Pollution Prevention Plan (SWPPP) A Stormwater Pollution Prevention Plan (SWPPP) has been prepared for this project and a copy of this document can be found in Appendix D of this report. MR#3: Source Control of Pollution Stormwater will be prevented from coming in contact with pollutants through a series of BMPs listed within the SWPPP. MR#4: Preservation of Natural Drainage Systems and Outfalls Stormwater for this project will maintain it's current drainage system and outfalls. All site stormwater will be routed to an infiltration trench located at the back of the property and will infiltrate 100% of all stormwater onsite. All other stormwater or any failure of this infiltration system will match all existing stormwater patterns. This project does not propose to alter any sub -basin delineation or natural drainage patterns. MR#5: On -Site Manage Stormwater Management The proposed project will demonstrate compliance with the LID Performance Standard and meet stormwater discharges that match developed discharge durations to pre -developed durations for the range of pre -developed discharge rates from 8% of the 2-year peak flow to 50% of the 2-year peak flow (in addition to 100% infiltration of the 100-year storm event). See Section 5.0 for further discussion on MR#5 on this project. Page12 WWBW�W latitude-48.com EDMONDS STORMWATER ADDENDUM JUNE 2017 Does the project result in 2,000 square feet, or greater, of new plus replaced hard surface area'? OR Does the land disturbing activity total 7,000 square feet or greater? Yes No Minimum Rcquircmcnts No. 1 through 5 apply Minimum Requirement No. 2 applies Next Question Does the project add 5,000 square feet or more of new plus replaced hard surfaces? OR Convert 0.75 acres or more of vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? No Yes Is this a road related project'? All Minimum Requirements apply to the new and replaced Yes hard surfaces and converted 4 vegetation areas. All Minimum Requirements apply to the new hard surfaces and converted vegetation areas. No Yes Does the project add 5,000 square feet or No more of new hard surfaces? Yes Do new hard surfaces add 50% or more to the existing hard surfaces within the project limits? No Figure 3.1. Flow Chart for Determining Requirements for Development. I No additional I requirements. latitude-48.com 3.0 SITE AND BASIN ASSESSMENT The Rimmer Residence project site is currently vacant, and the proposed development will include the development of a new single-family home and associated site features. There are no current drainage concerns on the property and soils are conducive for infiltration. Further discussion is provided below. 3.1 Off -site Analysis All surface runoff disperses across the site following the property's natural topography. There is no public storm conveyance system within 65 feet of the property and therefore, the project is required to infiltrate 100% of all stormwater onsite. Upstream Conditions Due to the topographic nature of the site, there is limited run-on to the project site. There will be some trivial runoff from the adjacent site to the east, but it's not expected to create any substantial drainage concerns for this project. Downstream Conditions The project proposes to infiltrate 100% of all stormwater generated onsite; therefore, there is no downstream to evaluate as part of this project. In the case the stormwater infiltration trench fails, stormwater would be routed to the west into the adjacent property and ultimately connect into the storm main located in 9th Avenue South. This public storm main continues to run north in 9th Avenue S for approximately 0.4 miles until discharging into Shell Creek. Shell Creek runs northwest for approximately 0.8 miles before ultimately discharging into the Puget Sound. This project does not propose to alter any sub -basin delineation or natural drainage patterns. 3.2 Soils/Infiltration Rates According to the results of a Small -Scale Pilot Infiltration Test (PIT) performed by the geotechnical engineer on October 21, 2021, this project site has a measured infiltrate rate of 3.6 inches/hour. After proper correction factors, a design infiltration rate should be used of 0.972 inches/hour. Refer to the Geotechnical Report in Appendix A for additional information. 3.3 Critical Areas and Flood Plain According to the City of Edmonds GIS Maps, a portion of the project site is listed as "Erosion Hazard 15%-40%"; however, we do not anticipate this as an issue as part of this development. See Figure 5 at the end of this report. 3.4 Assessment Summary Construction activity will only disturb the necessary area to construct the new residential building, install utilities, and construct a new driveway. All improvements are limited to only what is required for functional needs of the site. Disturbance to existing vegetation on the property will be limited. Refer to Figure 3 for the Proposed Conditions. latitude-48.com 4.0 PERMANAENT STORMWATER CONTROL 4.1 Low Impact Development and Flow Control According to the 2019 Department of Ecology (DOE) Stormwater Management Manual for Western Washington, "Projects triggering only Minimum Requirements # 1 through #5 shall either. • Use On -site Stormwater Management BMPs from List #1 for all surfaces within each type of surface in List # 1; or • Demonstrate compliance with the LID Performance Standard. Projects selecting this option cannot use Rain Gardens. They may choose to use Bioretention BMPs as described in Chapter V-7 - Infiltration and Bioretention Treatment Facilities to achieve the LID Performance Standard." The proposed project will demonstrate compliance with the LID Performance Standard and meet stormwater discharges that match developed discharge durations to pre -developed durations for the range of pre -developed discharge rates from 8% of the 2-year peak flow to 50% of the 2-year peak flow. There is no public drainage system within the immediate Right -of -Way available for this project site. Therefore, an infiltration investigation was conducted by the geotechnical engineer and determined that infiltration is feasible. Through geotechnical investigation, this project site has a measured long-term design infiltration rate of 0.972 inches/hour. The proposed project site will disturb approximately 6,139 square feet and consist of 2,805 square feet of new and replaced hard surfaces. The project will implement All disturbed soils on -site will be amended to post construction quality and depth per the City of Edmonds standards. Below is a table of the existing and proposed areas: Land Cover Existing Proposed Pervious 5,408 SF 3,334 SF Impervious 731 SF 2,805 SF Total 6,139 SF 6,139 SF PGIS 608 SF 405 SF Natural drainage patterns on site will be maintained. In accordance with Section V-5.3 Best Management Practices for On -Site Stormwater Management, this project proposes two infiltration BMPs to fully manage stormwater infiltration on -site: an infiltration trench and pervious concrete. Infiltration Trench The infiltration trench was sized using MGS Flood using the 0.97 inch/hour design infiltration rate determined by the geotechnical engineer. The infiltration trench was sized to be a total of 324 SF including 36-inches of storage depth (40% voids) in accordance with BMP T5.10A: Downspout Full Infiltration. The infiltration trench is 12.0'W x 271. All new impervious surfaces shown on the Site Development Plan, will discharge to this infiltration trench facility. See Appendix C for the MGS Flood Report. The infiltration trench calculations are located in Appendix B which reflects compliance with the LID performance standard requirements. 5.0 Wl\lS I KUC. I IUIV 51 UKIVIVVA I LK NULLU I IUIV NKLVLIN I IUIV NLAIN A Stormwater Pollution Prevention Plan (SWPPP) has been prepared for this project and a copy of this document can be found in Appendix D of this report. 6.0 SPECIAL REPORTS AND STUDIES A copy of the Geotechnical Report is included in Appendix B of this report. 7.0 OTHER PERMITS No additional permits are anticipated at this time. latitude-48.com 8.0 FIGURES FIGURE 1: VICINITY MAP FIGURE 2: EXISTING CONDITIONS FIGURE 3: PROPOSED CONDITIONS FIGURE 4: SITE ASSESSMENT AND SUMMARY FIGURE 5: CITY OF EDMONDS EROSION HAZARD AREAS latitude-48.com 8.com FIGURE 2 - EXISTING CONDITIONS LEGEND AREA (sf) ❑ IMPERVIOUS 731 ❑ PERVIOUS 5,408 TOTAL o, 0 20 40 Feet SCALE 1"=20' S88°39'37"E ❑ PROPOSED RESIDENCE WITH 4.7' EA o FOUND 1/2" LS# 7892 sa CEDAR STREET If -� o FIGURE 3 - PROPOSED CONDITIONS LEGEND AREA s ❑ IMPERVIOUS - BUILDING 2,172 ❑ IMPERVIOUS - CONCRETE 501 ❑ IMPERVIOUS - SITE WALL 132 ❑ PERVIOUS - GRASS 3,334 TOTAL 6,139 0 20 40 Feet SCALE 1"=20' f - City of Edmonds Downstream Conveyance ° 13 Public storm system appears to be conveyed north in 9th Avenue 0 CD co and discharges into Shell � � co ON ° N Creek. j Shell Creek appears to ultimately Legend discharge into the Puget Sound LC'1 �� 401 Storm Catch Basins o Edmonds CrIN Q1 O` O� n z O a o Private ■ Infiltration WALNUT ST Storm Manholes Project proposes p Edmonds O Private .o 100% stormwater 00 926 infiltration onsite 914 9 N co 9 Infiltration . Detention Facilities _ /o o\ a 0 o N CD Culvert — � _ _ � <all other values> ONNA • Yes _ 0 N O PD12,-rn 961 1 o Facility Feature p7 C PD1 _ Ln Creeks 1012 �Q Storm Line — <all other values> - PROJECT SITE o 1 MONo, NTL E COUNTY; No, LYNI MOUNTLAKE TERRACE; No, POF POF ■ SHORELINE; No, STATE; No, WO, rf r� 601 ^ 12 � oo � O 00 — Yes, EDMONDS; Yes, PRIVATE; 1 Facility Lines O` — Storm Ditch T Ad O O F� Contour Lines Q) 921 If the stormwater infiltration trench oI 9 , N CD 0 10 — 50; 100 o were to fail, site stormwater would ,- discharge west and ultimately be Notes collected in public storm main 1: 1,516 O located in 9th Avenue S (matching 0 126.30 252.6 Feet existing site conditions). map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, WGS_1984_Web-Mercator _Auxiliary -Sphere current, or otherwise reliable. © City of Edmonds THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION City of Edmonds Map Title Lynnwood 926 o NWMIeL+ 1 tr,e�e Legend 900 914 M Ln = Creeks ` � 0 • ❑ Seismic Hazard Areas Earth Subsidence and Landslide / ! Minimum Buffer Adjacent to Haz ■ Wetlands Wetlands Boundary MWetland Boundaries Not Completel Wetland Known Extents F®odplains A \.% V • ® AE rn� v ® VE X PROJECT CFDARLandslide Hazard Area 40% SITE❑ Q severe Erosion Hazard 15%-40% Erosion Hazard Areas 15%-40% 601 934 0TO 1: 758 O Notes 0 63.15 126.3 Feet 94.0 This ma is a user generated static output from an Internet mapping site and is for �,�28 p� B p pp B WGS_1984_Web-Mercator _Auxiliary -Sphere reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. © City of Edmonds THIS MAP IS NOT TO BE USED FOR DESIGN OR CONSTRUCTION W APPENDICES APPENDIX A: GEOTECHNICAL REPORT APPENDIX B: MGS FLOOD ENGINEERING CALCULATIONS APPENDIX C: COVENANTS, DEDICATIONS, EASEMENTS APPENDIX D: CONSTRUCTION SWPPP latitude-48.com APPENDIX A: GEOTECHNICAL REPORT latitude-48.com COBALT G E O S C I E N C E S October 22, 2021 Nathan Rimmer nsrimmer(a_gmail.com RE: Geotechnical Evaluation Proposed Residence 919 Cedar Street Edmonds, Washington Cobalt Geosciences, LLC P.O. Box 82243 Kenmore, Washington 98028 In accordance with your authorization, Cobalt Geosciences, LLC has prepared this letter to discuss the results of our geotechnical evaluation at the referenced site. The purpose of our evaluation was to provide recommendations for foundation design, grading, and earthwork. Site Description The site is located at 919 Cedar Street in Edmonds, Washington. The site consists of one rectangular shaped parcel (No. 00371900100700) with a total area of 0.14 acres. The property is mostly undeveloped and vegetated with grasses, bushes and variable diameter trees. The site is nearly level to slightly sloping downward to the northwest and west at magnitudes of less than 15 percent and relief of about 8 feet. There is a portion of concrete driveway for the property to the east in the southeast corner of the site. There are local rockery walls near the east property line. The site is bordered to the north, east, and west by residential properties and to the south by Cedar Street. The proposed development includes a new residence in the central portion of the site. Stormwater will include infiltration or other systems depending on feasibility. Site grading may include cuts and fills of 10 feet or less for a new daylight basement and foundation loads are expected to be light. We should be provided with the final plans to verify that our recommendations remain valid and do not require updating. Area Geology The Geologic Map of Edmonds East and West Quadrangles, indicates that the site is underlain by Vashon Advance Outwash. Vashon Advance Outwash includes fine to medium sand with local interbeds of silt and clay. These deposits are typically permeable and become denser with depth. Soil & Groundwater Conditions As part of our evaluation, we excavated one test pit and two hand borings within the property, where accessible. The explorations encountered approximately 12 inches of grass and topsoil underlain by approximately 3 to 3.5 feet of loose to medium dense, silty -fine to medium grained sand trace gravel (Weathered Advance Outwash and possible fill). These materials were underlain by www.cobaltgeo.com (2o6) 331-1097 October 22, 2021 Page 2 of 11 Geotechnical Evaluation medium dense to dense, fine to medium grained sand trace silt trace gravel (Advance Outwash), which continued to the termination depths of the explorations. There were local cemented pieces of outwash or till at variable depths below the site, including a thin layer in TP-1 at 2.5 to 3.25 feet below grade. Groundwater was not encountered in the explorations. Groundwater may develop on silty interbeds or on the unit that underlies the outwash (Transitional Beds). We did not observe these deposits in the explorations and anticipate that groundwater will be at least 10 feet below site elevations during the wet season, and likely deeper. Water table elevations often fluctuate over time. The groundwater level will depend on a variety of factors that may include seasonal precipitation, irrigation, land use, climatic conditions and soil permeability. Water levels at the time of the field investigation may be different from those encountered during the construction phase of the project. Erosion Hazard The Natural Resources Conservation Services (NRCS) maps for Snohomish County indicate that the site is underlain by Alderwood-Urban land complex (8 to 15 percent slopes) and Everett very gravelly sandy loam (o to 8 percent slopes). These soils would have a slight to moderate erosion potential in a disturbed state depending on the slope magnitude. It is our opinion that soil erosion potential at this project site can be reduced through landscaping and surface water runoff control. Typically, erosion of exposed soils will be most noticeable during periods of rainfall and may be controlled by the use of normal temporary erosion control measures, such as silt fences, hay bales, mulching, control ditches and diversion trenches. The typical wet weather season, with regard to site grading, is from October 31st to April ist. Erosion control measures should be in place before the onset of wet weather. Seismic Hazard The overall subsurface profile corresponds to a Site Class D as defined by Table 1613.5.2 of the International Building Code (IBC). A Site Class D applies to an overall profile consisting of stiff/medium dense soils within the upper too feet. We referenced the U.S. Geological Survey (USGS) Earthquake Hazards Program Website to obtain values for Ss, Sl, FQ, and F,,. The USGS website includes the most updated published data on seismic conditions. The following tables provide seismic parameters from the USGS web site with referenced parameters from ASCE 7-10 and 7-16. Seismic Design Parameters (ASCE 7-10) Site Spectral Spectral Site Design Spectral Design Class Acceleration Acceleration Coefficients Response Parameters PGA at 0.2 sec. (g) at 1.o sec. (g) Fa Fv SDs SDl D 1.269 0.497 1.0 1.503 o.846 0.498 0.514 www.cobaltgeo.com (2o6) 331-1097 October 22, 2021 Page 3 of 11 Geotechnical Evaluation Seismic Design Parameters (ASCE 7-16) Site Spectral Spectral Site Design Spectral Design Class Acceleration Acceleration Coefficients Response Parameters PGA at 0.2 sec. (g) at 1.o sec. (g) Fa F, SDs SD1 D 1.284 0.452 1.0 Null 0.856 Null 0.546 Additional seismic considerations include liquefaction potential and amplification of ground motions by soft/loose soil deposits. The liquefaction potential is highest for loose sand with a high groundwater table. The site has a low likelihood of liquefaction. For items listed as "Null" see Section 11.4.8 of the ASCE. Conclusions and Recommendations General The site is underlain by weathered and unweathered outwash which becomes denser with depth. The proposed residential structure may be supported on a shallow foundation system bearing on medium dense or firmer native soils or on structural fill placed on the native soils. Local overexcavation or recompaction of loose weathered native soils may be necessary depending on the proposed elevations and locations of the new footings. The basement will require excavations of 10 to 12 feet approximately 5 feet from the east property line. We recommend utilizing an interior basement footing with either block shoring, excavation easements onto the east parcel, and/or installation of a pile wall as shoring in this area. Infiltration is generally feasible in the coarser outwash deposits at depth. Based on the elevation of the proposed basement, drywells or trenches will need to be located north and west of the residence so systems can be set at an elevation lower than the finish floors. We should be provided with the civil plans to verify suitability. Local overexcavation of any pieces or layers of silty -sand or cemented soils will need to be removed. We can provide additional recommendations once a civil plan has been prepared. Site Preparation Trees, shrubs and other vegetation should be removed prior to stripping of surficial organic -rich soil and fill. Based on observations from the site investigation program, it is anticipated that the stripping depth will be 6 to 18 inches. Deeper excavations will be necessary below large trees and in any areas underlain by undocumented fill. The native soils consist of silty -sand with gravel and poorly graded sand with silt. Most of the native soils may be used as structural fill provided they achieve compaction requirements and are within 3 percent of the optimum moisture. Some of these soils may only be suitable for use as fill during the summer months, as they will be above the optimum moisture levels in their current state. These soils are variably moisture sensitive and may degrade during periods of wet weather and under equipment traffic. www.cobaltgeo.com (206) 331-1097 October 22, 2021 Page 4 of ii Geotechnical Evaluation Imported structural fill should consist of a sand and gravel mixture with a maximum grain size of 3 inches and less than 5 percent fines (material passing the U.S. Standard No. 200 Sieve). Structural fill should be placed in maximum lift thicknesses of 12 inches and should be compacted to a minimum of 95 percent of the modified proctor maximum dry density, as determined by the ASTM D 1557 test method. Temporary Excavations Based on our understanding of the project, we anticipate that the grading could include local cuts on the order of approximately 12 feet or less for foundation and most of the utility placement. Temporary excavations should be sloped no steeper than 1.511:1V (Horizontal:Vertical) in loose native soils and fill, 1H:1V in medium dense native soils and 3/411:1V in dense to very dense native soils. If an excavation is subject to heavy vibration or surcharge loads, we recommend that the excavations be sloped no steeper than 2H:1V, where room permits. Temporary cuts should be in accordance with the Washington Administrative Code (WAC) Part N, Excavation, Trenching, and Shoring. Temporary slopes should be visually inspected daily by a qualified person during construction activities and the inspections should be documented in daily reports. The contractor is responsible for maintaining the stability of the temporary cut slopes and reducing slope erosion during construction. Temporary cut slopes should be covered with visqueen to help reduce erosion during wet weather, and the slopes should be closely monitored until the permanent retaining systems or slope configurations are complete. Materials should not be stored or equipment operated within io feet of the top of any temporary cut slope. Soil conditions may not be completely known from the geotechnical investigation. In the case of temporary cuts, the existing soil conditions may not be completely revealed until the excavation work exposes the soil. Typically, as excavation work progresses the maximum inclination of temporary slopes will need to be re-evaluated by the geotechnical engineer so that supplemental recommendations can be made. Soil and groundwater conditions can be highly variable. Scheduling for soil work will need to be adjustable, to deal with unanticipated conditions, so that the project can proceed and required deadlines can be met. If any variations or undesirable conditions are encountered during construction, we should be notified so that supplemental recommendations can be made. If room constraints or groundwater conditions do not permit temporary slopes to be cut to the maximum angles allowed by the WAC, temporary shoring systems may be required. The contractor should be responsible for developing temporary shoring systems, if needed. We recommend that Cobalt Geosciences and the project structural engineer review temporary shoring designs prior to installation, to verify the suitability of the proposed systems. Temporary Shoring Temporary shoring utilizing soldier piles may be necessary depending on the planned excavation depths and proximity to adjacent properties and structures. A soldier pile wall with pressure treated timber (wood) or concrete lagging would be suitable to support the proposed excavations along the north and south margins of the property. www.cobaltgeo.com (206) 331-1097 October 22, 2021 Page 5 of ii Geotechnical Evaluation Soldier piles typically consist of steel W or H-beams inserted into oversized drilled shafts, which are backfilled with structural concrete, lean mix {Controlled Density Fill (CDF)}, or a combination of lean mix to the base of the excavation and structural concrete below the excavation to anchor the soldier piles. Due to the potential for local caving during drilling operations for the soldier pile holes due to soft soil conditions and shallow groundwater, consideration should be given to using slurry or drilling fluid to reduce the risk of caving of the pile holes during installation. If water is present within the pile hole at the time of soldier pile concrete placement, the concrete should be placed starting at the bottom of the hole with a tremie pipe and the column of concrete should be raised slowly to displace the water. We recommend that soldier piles have a maximum spacing of eight feet on center. To account for arching effects, lateral loading on the lagging can be reduced by 50 percent. Unlagged excavation heights should not exceed three feet. No portion of the excavation should remain unsupported overnight. Lagging sections may be up to 6 feet in height depending on stability. Cantilever soldier pile walls for this site may be designed based on an active lateral earth pressure Of 35 pcf for level backslope conditions, provided the wall is unrestrained (not fixed; permitted to move at least 0.2 percent of the wall height). The pressure will act on the soldier pile width below the base of the excavation as well. All applicable surcharge pressures should be included. A lateral uniform seismic pressure of 7H is recommended for seismic conditions (active). Building surcharge loads should be incorporated into the design, where present. Note: these are preliminary recommendations that may need modification once plans have been developed. In front of the soldier piles, resistive pressure can be estimated using an allowable passive earth pressure of 300 pcf acting over 2 times the soldier pile diameter, neglecting the upper 2 feet below the base of the excavation. A factor of safety of 1.5 has been incorporated into the passive pressure value. A lateral pressure reduction of 50 percent may be used for design of the lagging for a pile spacing of three diameters. Lagging should be backfilled with 5/8 inch clean angular rock to minimize void spaces. If there is adequate space and an excavation easement, it may be possible to utilize an Ultra block wall for shoring. We anticipate that a single -depth block wall set at basement grade with a 6 degree batter would be suitable. This wall could be 3 or 4 blocks tall (7.5 to io feet) and located near the east property line. Fill between blocks and the cut should consist of 5/8 inch clean rock and the cuts should not be made until blocks are on site. Each section of wall should be completed the same day they are cut. Foundation Design The proposed structure may be supported on a shallow spread footing foundation system bearing on undisturbed dense or firmer native soils or on properly compacted structural fill placed on the suitable native soils. Any undocumented fill and/or loose native soils should be removed and replaced with structural fill below foundation elements. Structural fill below footings should consist of clean angular rock 5/8 to 4 inches in size. We should verify soil conditions during foundation excavation work. For shallow foundation support, we recommend widths of at least 16 and 24 inches, respectively, for continuous wall and isolated column footings supporting the proposed structure. Provided that the footings are supported as recommended above, a net allowable bearing pressure of 2,500 pounds per square foot (psf) may be used for design. www.cobaltgeo.com (206) 331-1097 October 22, 2021 Page 6 of ii Geotechnical Evaluation A 1/3 increase in the above value may be used for short duration loads, such as those imposed by wind and seismic events. Structural fill placed on bearing, native subgrade should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. Footing excavations should be inspected to verify that the foundations will bear on suitable material. Exterior footings should have a minimum depth of 18 inches below pad subgrade (soil grade) or adjacent exterior grade, whichever is lower. Interior footings should have a minimum depth of 12 inches below pad subgrade (soil grade) or adjacent exterior grade, whichever is lower. If constructed as recommended, the total foundation settlement is not expected to exceed 1 inch. Differential settlement, along a 25-foot exterior wall footing, or between adjoining column footings, should be less than 1/2 inch. This translates to an angular distortion of 0.002. Most settlement is expected to occur during construction, as the loads are applied. However, additional post -construction settlement may occur if the foundation soils are flooded or saturated. All footing excavations should be observed by a qualified geotechnical consultant. Resistance to lateral footing displacement can be determined using an allowable friction factor of 0.40 acting between the base of foundations and the supporting subgrades. Lateral resistance for footings can also be developed using an allowable equivalent fluid passive pressure of 225 pounds per cubic foot (pcf) acting against the appropriate vertical footing faces (neglect the upper 12 inches below grade in exterior areas). The frictional and passive resistance of the soil may be combined without reduction in determining the total lateral resistance. Care should be taken to prevent wetting or drying of the bearing materials during construction. Any extremely wet or dry materials, or any loose or disturbed materials at the bottom of the footing excavations, should be removed prior to placing concrete. The potential for wetting or drying of the bearing materials can be reduced by pouring concrete as soon as possible after completing the footing excavation and evaluating the bearing surface by the geotechnical engineer or his representative. Concrete Retaining Walls The following table, titled Wall Design Criteria, presents the recommended soil related design parameters for retaining walls with a level backslope. Contact Cobalt if an alternate retaining wall system is used. This has been included for new cast in place walls, if any are proposed. Wall Design Criteria "At -rest" Conditions (Lateral Earth Pressure — EFD+) 55 pcf (Equivalent Fluid Density) "Active" Conditions (Lateral Earth Pressure — EFD+) 35 pcf (Equivalent Fluid Density) Seismic Increase for "At -rest" Conditions (Lateral Earth Pressure) 21H* (Uniform Distribution) 1 in 2,500 year event Seismic Increase for "At -rest" Conditions (Lateral Earth Pressure) 14H* (Uniform Distribution)1 in 500 year event Seismic Increase for "Active" Conditions (Lateral Earth Pressure) 7H* (Uniform Distribution) Passive Earth Pressure on Low Side of Wall Neglect upper 2 feet, then 275 pcf EFD+ www.cobaltgeo.com (206) 331-1097 October 22, 2021 Page 7 of 11 Geotechnical Evaluation (Allowable, includes F.S. = 1.5) Soil -Footing Coefficient of Sliding Friction (Allowable; includes F.S. = 1.5) 0.40 'H is the height of the wall; Increase based on one in 500 year seismic event (io percent probability of being exceeded in 50 years), 'EFD — Equivalent Fluid Density The stated lateral earth pressures do not include the effects of hydrostatic pressure generated by water accumulation behind the retaining walls. Uniform horizontal lateral active and at -rest pressures on the retaining walls from vertical surcharges behind the wall may be calculated using active and at -rest lateral earth pressure coefficients of 0.3 and 0.5, respectively. A soil unit weight Of 125 pcf may be used to calculate vertical earth surcharges. To reduce the potential for the buildup of water pressure against the walls, continuous footing drains (with cleanouts) should be provided at the bases of the walls. The footing drains should consist of a minimum 4-inch diameter perforated pipe, sloped to drain, with perforations placed down and enveloped by a minimum 6 inches of pea gravel in all directions. The backfill adjacent to and extending a lateral distance behind the walls at least 2 feet should consist of free -draining granular material. All free draining backfill should contain less than 3 percent fines (passing the U.S. Standard No. 200 Sieve) based upon the fraction passing the U.S. Standard No. 4 Sieve with at least 30 percent of the material being retained on the U.S. Standard No. 4 Sieve. The primary purpose of the free -draining material is the reduction of hydrostatic pressure. Some potential for the moisture to contact the back face of the wall may exist, even with treatment, which may require that more extensive waterproofing be specified for walls, which require interior moisture sensitive finishes. We recommend that the backfill be compacted to at least 90 percent of the maximum dry density based on ASTM Test Method D1557. In place density tests should be performed to verify adequate compaction. Soil compactors place transient surcharges on the backfill. Consequently, only light hand operated equipment is recommended within 3 feet of walls so that excessive stress is not imposed on the walls. Stormwater Management Feasibility The site is underlain by minor fill and at depth by weathered and unweathered outwash. There were local silty -sand pieces within the outwash, indicating that local overexcavation of finer or denser materials may be required in infiltration systems, if utilized. We performed a small scale pilot infiltration test (PIT) in TP-1. The test was performed in general accordance with the Washington State Department of Ecology stormwater manual. The area was excavated to a testing depth of approximately 4.5 feet below the ground surface. The design infiltration rate was determined by applying correction factors to the measured infiltration rate as prescribed in Volume III, Section 3.3.6 of the DOE. The measured rate must be reduced through appropriate correction factors for site variability (CFv), uncertainty of test method (CFT), and degree of influent control (CFM) to prevent siltation and bio-buildup. It should be noted that construction traffic or other disturbance to the target infiltration area could compact the soil, which may decrease the effective infiltration rates. The correction factors and resulting design infiltration rate are also shown in the table below. www.cobaltgeo.com (2o6) 331-1097 October 22, 2021 Page 8 of ii Geotechnical Evaluation Test Test Measured Correction Factors Design Number Depth (ft) Infiltration Infiltration Rate (in/hr) Rate CFv CFT CFM (in/hr) TP-1 4.5 3.6 o.6 0.5 0.9 0.972 Infiltration appears to be feasible in the underlying outwash with less than 7 percent fines. We recommend removal of any dense soils or silty -sand layers/pieces during system placement. We should be on site during construction to verify the soil conditions. We can provide additional recommendations upon request and once civil plans have been prepared. We should be provided with final plans for review to determine if the intent of our recommendations has been incorporated or if additional modifications are needed. Slab -on -Grade We recommend that the upper 12 inches of the native soils within slab areas be re -compacted to at least 95 percent of the modified proctor (ASTM D1557 Test Method). Often, a vapor barrier is considered below concrete slab areas. However, the usage of a vapor barrier could result in curling of the concrete slab at joints. Floor covers sensitive to moisture typically requires the usage of a vapor barrier. A materials or structural engineer should be consulted regarding the detailing of the vapor barrier below concrete slabs. Exterior slabs typically do not utilize vapor barriers. The American Concrete Institutes ACI 36oR-o6 Design of Slabs on Grade and ACI 302.1R-04 Guide for Concrete Floor and Slab Construction are recommended references for vapor barrier selection and floor slab detailing. Slabs on grade may be designed using a coefficient of subgrade reaction of 210 pounds per cubic inch (pci) assuming the slab -on -grade base course is underlain by structural fill placed and compacted as outlined in Section 8.1. A 4- to 6-inch-thick capillary break layer should be placed over the prepared subgrade. This material should consist of pea gravel or 5/8 inch clean angular rock. A perimeter drainage system is recommended unless interior slab areas are elevated a minimum Of 12 inches above adjacent exterior grades. If installed, a perimeter drainage system should consist of a 4-inch diameter perforated drain pipe surrounded by a minimum 6 inches of drain rock wrapped in a non -woven geosynthetic filter fabric to reduce migration of soil particles into the drainage system. The perimeter drainage system should discharge by gravity flow to a suitable stormwater system. Exterior grades surrounding buildings should be sloped at a minimum of one percent to facilitate surface water flow away from the building and preferably with a relatively impermeable surface cover immediately adjacent to the building. www.cobaltgeo.com (2o6) 331-1097 October aa, 2021 Page 9 of ii Geotechnical Evaluation Erosion and Sediment Control Erosion and sediment control (ESQ is used to reduce the transportation of eroded sediment to wetlands, streams, lakes, drainage systems, and adjacent properties. Erosion and sediment control measures should be implemented, and these measures should be in general accordance with local regulations. At a minimum, the following basic recommendations should be incorporated into the design of the erosion and sediment control features for the site: • Schedule the soil, foundation, utility, and other work requiring excavation or the disturbance of the site soils, to take place during the dry season (generally May through September). However, provided precautions are taken using Best Management Practices (BMP's), grading activities can be completed during the wet season (generally October through April). • All site work should be completed and stabilized as quickly as possible. • Additional perimeter erosion and sediment control features may be required to reduce the possibility of sediment entering the surface water. This may include additional silt fences, silt fences with a higher Apparent Opening Size (AOS), construction of a berm, or other filtration systems. • Any runoff generated by dewatering discharge should be treated through construction of a sediment trap if there is sufficient space. If space is limited other filtration methods will need to be incorporated. Utilities Utility trenches should be excavated according to accepted engineering practices following OSHA (Occupational Safety and Health Administration) standards, by a contractor experienced in such work. The contractor is responsible for the safety of open trenches. Traffic and vibration adjacent to trench walls should be reduced; cyclic wetting and drying of excavation side slopes should be avoided. Depending upon the location and depth of some utility trenches, groundwater flow into open excavations could be experienced, especially during or shortly following periods of precipitation. In general, sandy soils were encountered at shallow depths in the explorations at this site. These soils have low cohesion and density and will have a tendency to cave or slough in excavations. Shoring or sloping back trench sidewalls is required within these soils in excavations greater than 4 feet deep. All utility trench backfill should consist of imported structural fill or suitable on site soils. Utility trench backfill placed in or adjacent to buildings and exterior slabs should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. The upper 5 feet of utility trench backfill placed in pavement areas should be compacted to at least 95 percent of the maximum dry density based on ASTM Test Method D1557. Below 5 feet, utility trench backfill in pavement areas should be compacted to at least 90 percent of the maximum dry density based on ASTM Test Method D1557. Pipe bedding should be in accordance with the pipe manufacturer's recommendations. The contractor is responsible for removing all water -sensitive soils from the trenches regardless of the backfill location and compaction requirements. Depending on the depth and location of the proposed utilities, we anticipate the need to re -compact existing fill soils below the utility structures and pipes. The contractor should use appropriate equipment and methods to avoid damage to the utilities and/or structures during fill placement and compaction procedures. www.cobaltgeo.com (2o6) 331-1097 October aa, 2021 Page io of ii Geotechnical Evaluation CONSTRUCTION FIELD REVIEWS Cobalt Geosciences should be retained to provide part time field review during construction in order to verify that the soil conditions encountered are consistent with our design assumptions and that the intent of our recommendations is being met. This will require field and engineering review to: ■ Monitor and test structural fill placement and soil compaction ■ Observe bearing capacity at foundation locations ■ Observe slab -on -grade preparation ■ Verify infiltration system placement ■ Monitor foundation drainage placement ■ Observe excavation stability Geotechnical design services should also be anticipated during the subsequent final design phase to support the structural design and address specific issues arising during this phase. Field and engineering review services will also be required during the construction phase in order to provide a Final Letter for the project. CLOSURE This report was prepared for the exclusive use of Nathan Rimmer and his appointed consultants. Any use of this report or the material contained herein by third parties, or for other than the intended purpose, should first be approved in writing by Cobalt Geosciences, LLC. The recommendations contained in this report are based on assumed continuity of soils with those of our test holes and assumed structural loads. Cobalt Geosciences should be provided with final architectural and civil drawings when they become available in order that we may review our design recommendations and advise of any revisions, if necessary. Use of this report is subject to the Statement of General Conditions provided in Appendix A. It is the responsibility of Nathan Rimmer who is identified as "the Client" within the Statement of General Conditions, and its agents to review the conditions and to notify Cobalt Geosciences should any of these not be satisfied. Sincerely, Cobalt Geosciences, LLC HONr,y Wgsy��'48�� CA. 54896 �ONAI. 10/22/2021 Phil Haberman, PE, LG, LEG Principal www.cobaltgeo.com (2o6) 331-1097 October aa, 2021 Page n of n Geotechnical Evaluation Statement of General Conditions USE OF THIS REPORT: This report has been prepared for the sole benefit of the Client or its agent and may not be used by any third party without the express written consent of Cobalt Geosciences and the Client. Any use which a third parry makes of this report is the responsibility of such third parry. BASIS OF THE REPORT: The information, opinions, and/or recommendations made in this report are in accordance with Cobalt Geosciences present understanding of the site specific project as described by the Client. The applicability of these is restricted to the site conditions encountered at the time of the investigation or study. If the proposed site specific project differs or is modified from what is described in this report or if the site conditions are altered, this report is no longer valid unless Cobalt Geosciences is requested by the Client to review and revise the report to reflect the differing or modified project specifics and/or the altered site conditions. STANDARD OF CARE: Preparation of this report, and all associated work, was carried out in accordance with the normally accepted standard of care in the state of execution for the specific professional service provided to the Client. No other warranty is made. INTERPRETATION OF SITE CONDITIONS: Soil, rock, or other material descriptions, and statements regarding their condition, made in this report are based on site conditions encountered by Cobalt Geosciences at the time of the work and at the specific testing and/or sampling locations. Classifications and statements of condition have been made in accordance with normally accepted practices which are judgmental in nature; no specific description should be considered exact, but rather reflective of the anticipated material behavior. Extrapolation of in situ conditions can only be made to some limited extent beyond the sampling or test points. The extent depends on variability of the soil, rock and groundwater conditions as influenced by geological processes, construction activity, and site use. VARYING OR UNEXPECTED CONDITIONS: Should any site or subsurface conditions be encountered that are different from those described in this report or encountered at the test locations, Cobalt Geosciences must be notified immediately to assess if the varying or unexpected conditions are substantial and if reassessments of the report conclusions or recommendations are required. Cobalt Geosciences will not be responsible to any parry for damages incurred as a result of failing to notify Cobalt Geosciences that differing site or sub -surface conditions are present upon becoming aware of such conditions. PLANNING, DESIGN, OR CONSTRUCTION: Development or design plans and specifications should be reviewed by Cobalt Geosciences, sufficiently ahead of initiating the next project stage (property acquisition, tender, construction, etc), to confirm that this report completely addresses the elaborated project specifics and that the contents of this report have been properly interpreted. Specialty quality assurance services (field observations and testing) during construction are a necessary part of the evaluation of sub -subsurface conditions and site preparation works. Site work relating to the recommendations included in this report should only be carried out in the presence of a qualified geotechnical engineer; Cobalt Geosciences cannot be responsible for site work carried out without being present. www.cobaltgeo.com (2o6) 331-1097 :ONC 1 FND 1" IRON PIPE J IN TOP OF CONC. RETAINING WALL SO.04, EO.18 , f r� G fn RET.i WALL- i N8g09'31"E 1 N CjkFRRY % W/Wh HER ;_ MiO EX. GARAGE CF FE �n " y / C1 TWI HB-i I N X 30C 4 z w 2-6' t /� r 1\4 SSC0 o 2 w DOGWOOD 1 w O O C O 4r •r • 1, 1 AEX, Ln BLDG L b' �j I g 304 9 ; •a 301.33 7-2 .�r • i /X 304 6 ,9 4"PL Q A V. e r SA ITARY S M'� b'' • EAST EDfaE d FND REBAR & CA f BAR ' LS#4561 I M£DCF, 4"PLbmp a i <,' ` GR 'EI. 32"CED ` ( v v� FND RED �A LSf78 32'CFy RODADENDRUM .f> _ / -- /' $" C�SANITARY �EDA�(Il 1 ►JT�, SEWER LINE f ! N9O•00�0 "E �47B.04 1 1 TP-1 Approximate N HB-i Test Pit & Hand Boring Location Not to Scale Cobalt Geosciences, LLC Proposed Residence SITE PLAN P.O. Box 82243 � COBALT 919 Cedar Street 9$O28 Kenmore, WA � Edmonds, Washington FIGURE � www obalt eo.com g cobaltgeoC&gmail.com Unified Soil Classification System (USCS) MAJOR DIVISIONS SYMBOL TYPICAL DESCRIPTION Clean Gravels Gw Well -graded gravels, gravels, gravel -sand mixtures, little or no fines Gravels (more than 50% (less than 5% fines) GP Poorly graded gravels, gravel -sand mixtures, little or no fines COARSE GRAINED SOILS of coarse fraction retained on No. 4 sieve) Gravels with Fines (more than 12% fines) GM Silty gravels, gravel -sand -silt mixtures GC Clayey gravels, gravel -sand -clay mixtures (more than 50% retained on Clean Sands :•: sw Well -graded sands, gravelly sands, little or no fines No. 200 sieve) Sands (50% or more of coarse fraction (less than 5% fines) sP Poorly graded sand, gravelly sands, little or no fines passes the No. 4 sieve) Sands with Fines sM Silty sands, sand -silt mixtures (more than 12% fines) sc Clayey sands, sand -clay mixtures ML Inorganic silts of low to medium plasticity, sandy silts, gravelly silts, FINE GRAINED (50% or more Silts and Clays (liquid limit less than 50) Inorganic cL or clayey silts with slight plasticity Inorganic clays of low to medium plasticity, gravelly clays, sandy clays silty clays, lean clays Organic rganic oL Organic silts and organic silty clays of low plasticity passes the MH Inorganic silts, micaceous or diatomaceous fine sands or silty soils, No. 200 sieve) Silts and Clays (liquid limit 50 or more) Inorganic elastic silt CH Inorganic clays of medium to high plasticity, sandy fat clay, or gravelly fat clay Organic OHOrganic clays of medium to high plasticity, organic silts HIGHLY ORGANIC SOILS Primarily organic matter, dark in color, and organic odor PT Peat, humus, swamp soils with high organic content (ASTM D4427) Classification of Soil Constituents MAJOR constituents compose more than 50 percent, by weight, of the soil. Major constituents are capitalized (i.e., SAND). Minor constituents compose 12 to 50 percent of the soil and precede the major constituents (i.e., silty SAND). Minor constituents preceded by "slightly" compose 5 to 12 percent of the soil (i.e., slightly silty SAND). Trace constituents compose o to 5 percent of the soil (i.e., slightly silty SAND, trace gravel). Relative Density (Coarse Grained Soils) Consistency (Fine Grained Soils) N, SPT, Relative N, SPT, Relative Blows/FT Density Blows/FT Consistency 0-4 Very loose Under 2 Very soft 4 -10 Loose 2-4 Soft 10 - 30 Medium dense 4-8 Medium stiff 30 - 50 Dense 8 -15 Stiff Over 50 Very dense 15 - 30 Very stiff Over 3o Hard Grain Size Definitions Description Sieve Number and/or Size Fines <#200 (o.o8 mm) Sand -Fine #200 to #40 (o.o8 to 0.4 mm) -Medium #40 to #10 (0.4 to 2 mm) -Coarse #10 to #4 (2 to 5 mm) Gravel -Fine #4 to 3/4 inch (5 to 19 mm) -Coarse 3/4 to 3 inches (19 to 76 mm) Cobbles 3 to 12 inches (75 to 305 mm) Boulders >12 inches (305 mm) 1 Moisture Content Definitions 1 Dry Absence of moisture, dusty, dry to the touch Moist Damp but no visible water Wet Visible free water, from below water table Cobalt Geosciences, LLC P.O. Box 82243 Kenmore, WA 98028 Soil Classification Chart Figure Ci (2o6) 331-1097 _ www.cobaltgeo.com cobaltgeo(&gmail.com Test Pit TP-1 Date: October 21, 2021 Depth: 12' Groundwater: None Contractor: Jim Elevation: Logged By: PH Checked By: SC N JO o Q N Moisture Content (%) Plastic I / Liquid U E 3 Limit Limit } � t N Material Description DCP Equivalent N-Value Q a)? o O 0 10 20 30 40 50 Topsoil/Vegetation ---- ---- c • -- SM TvTedi7r dense, —sift Tine To medium ralnecTTana wlfFi— raveT Y- 9 g - dark yellowish brown to grayish brown, dry to moist. 2 •. (Fill) ------ 3 -- SP/ --------------------------------------------- Loose to medium dense, silty -fine to medium grained sand trace gray I, SM reddish brown to yellowish brown, moist. 4 :r ;: (Weathered Advance Outwash) 5 Ar- ',';=; �': SP Medium dense to dense, fine to medium grained sand trace silt trace gravel, grayish brown, moist. (Advance Outwash) 6 1+ 1 Local pieces of cemented outwash or silty -sand 8 9 :+ 10 End of Test Pit 12' Cobalt Geosciences, LLC Proposed Residence P.O. Box 82243 COBALT 919 Cedar Street Test Pit Kenmore, WA 98028 (2o6) 331-1097 =-G E 0 S C I E IN C E S Edmonds, Washington Logs www.cobaltgeo.com cobaltgeo(digmail.com Hand Boring HB-1 Date: October 22, 2021 Depth: 8' Groundwater: None Contractor: Elevation: Logged By: PH Checked By: SC N 0) o -0 Moisture Content (%) Plastic I Liquid U L N Limit Limit F � N Material Description ? o DCP Equivalent N-Value o O 0 10 20 30 40 50 = Topsoil/Grass ; ------ ---- SM SP -------------------------------------------- Loose to medium dense, silty -fine to medium grained sand trace gravel, %-: reddish brown to yellowish brown, moist. 2 :? (Weathered Advance Outwash) 3 .; r :1 SP --------------------------------------- Medium dense to dense, fine to medium grained sand trace silt trace 5 : �:: ;:; : ;r gravel, grayish brown, moist. (Advance Outwash) 6 Local pieces of cemented outwash or silty -sand 7 ti End of Hand Boring 8' 9 10 Hand Boring HB-2 Date: October 22, 2021 Depth: 6' Groundwater: None Contractor: Elevation: Logged By: PH Checked By: SC 0 0) J o -0 Moisture Content (%) Plastic Liquid IL U E 15 3 Limit Limit N Material Description ? o DCP Equivalent N-Value o C 0 10 20 30 40 50 1 2 3 4 5 7 8 9 10 --- -- --- --------------------------------------------- SM/ Loose to medium dense, silty -fine to medium grained sand trace gravE I SP reddish brown to yellowish brown, dry to moist. (Weathered Advance Outwash) --- SP Medium dense to dense, fine to medium grained sand trace silt trace gravel, grayish brown, moist. (Advance Outwash) i 7 : e Local pieces of cemented outwash or silty -sand i End of Hand Boring 6' Proposed Residence 919 Cedar Street Edmonds Washington Test Pit & Hand Boring Logs Cobalt Geosciences, LLC P.O. Box 82243 Kenmore, WA 98028 (2o6) 331-1097 www.cobaltgeo.com cobaltgeo(digmail.com Slab on Grade Basement or Shallow Foundation Wall 12" Free Draining Backfill and/or Drainage Mat Attached to Wall Backfill Soils Compacted per Geotechnical Report 4" Diameter Perforated Pipe -- --�H H Native Soils Benched as Required Filter Fabric Over Rock (Mirafi 14oN) 3//4" Washed Rock or Clean Angular Rock Not to Scale Cobalt Geosciences, LLC PO Box 1792 Typical Foundation Drain Detail Attachment North Bend, WA 98045 • _ (2o6) 331-1097 GEOSCIENCES www.cobaltgeo.com Philpcobaltgeo.com APPENDIX B: MGS FLOOD REPORT CALCULATIONS latitude-48.com MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.55 Program License Number: 201910009 Project Simulation Performed on: 06/21/2022 9:55 AM Report Generation Date: 06/21/2022 9:55 AM Input File Name Project Name: Analysis Title: Comments: 2022.06.21 - Rimmer Infiltration.fld Rimmer Residence Infiltration Calculation 06.21.2022 - CPS Updated PRECIPITATION INPUT Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 14 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) 0.141 0.141 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 0.141 0.141 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 ---------- Subbasin Till Forest ------------------------- Subbasin Total Subbasin 1--------- ------- Area (Acres) 0.141 0.141 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 ---------- Subbasin Till Pasture Impervious ------------------------- Subbasin Total Subbasin 1--------- ------- Area (Acres) 0.077 0.064 0.141 ************************* LIN K DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 Link Name: Infiltration Trench Link Type: Infiltration Trench Downstream Link: None Trench Type Trench Length (ft) Trench Width (ft) Trench Depth (ft) Trench Bottom Elev (ft) Trench Rockfill Porosity (%) Constant Infiltration Option Used Infiltration Rate (in/hr): 0.97 Trench on Embankment Sideslope 27.00 12.00 3.00 300.00 INFILTRATION 40.00 TRENCH GEOMETRY **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 1 Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 1 Number of Links: 1 ***********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 21.534 Total: 21.534 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) Subbasin: Subbasin 1 12.465 Link: Infiltration Trench 33.763 Total: 46.228 Total Predevelopment Recharge is Less than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 0.136 ac-ft/year, Post Developed: 0.293 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 0 ----------------------SCENARIO: POSTDEVELOPED Number of Links: 1 ********** Link: Infiltration Trench ********** Infiltration/Filtration Statistics -------------------- Inflow Volume (ac-ft): 33.76 Inflow Volume Including PPT-Evap (ac-ft): 33.76 Total Runoff Infiltrated (ac-ft): 33.76, 100.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 0.00 Secondary Outflow To Downstream System (ac-ft): 0.00 Volume Lost to ET (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered+ET)/Total Volume: 100.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Subbasin: Subbasin 1 Scenario Postdeveloped Compliance Link: Infiltration Trench *** 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 2.308E-03 2-Year 0.000 5-Year 3.935E-03 5-Year 0.000 10-Year 5.397E-03 10-Year 0.000 25-Year 7.219E-03 25-Year 0.000 50-Year 9.676E-03 50-Year 0.000 100-Year 1.059E-02 100-Year 0.000 200-Year 1.591 E-02 200-Year 0.000 500-Year 2.308E-02 500-Year 0.000 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): 0.0% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): 0.0% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 0.0% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS After recording return to: City Clerk City of Edmonds 121 Fifth Avenue North Edmonds, WA 98020 Document Title(s) Declaration of Covenant - Private Stormwater Facility Reference Number(s) of Related Documents 11.11M1) OPA1191.01I Grantor(s) (Last, First and Middle Initial) Nathan Rimmer Grantee(s) (Last, First and Middle Initial) City of Edmonds Legal Description (abbreviated form; i.e., lot, plat or section,. township, range, quarter/quarter) Exact Legal Description TBD. NW 1/4 of the NE 1/4 Sec. 25 TWP 27 N., TNG 3E., W.M. Assessor's Property Tax Parcel/Account Number at the Time of Recording: Parcel No. 00371900100700 The Auditor/Recorder will rely on the information provided on this form. The staff will not read the document to verify the accuracy or completeness of the indexing information provided herein. DECLARATION OF COVENANT Private Stormwater Facility WHEREAS, the undersigned Declarant(s) have installed a stormwater facility under Edmonds Community Development Code Chapter 18.30 known as a "low impact development best management practices (LID BMP)" in lieu of other required more conventional stormwater systems, as selected below: ❑ Drywell ❑ Permeable Pavement ❑ Gravelless Chamber ❑ Rain Garden / Bioretention Cell ❑ Other ❑ Infiltration Trench WHEREAS, the City of Edmonds has allowed installation of the LID BMP, subject to the execution and recording of this Declaration of Covenant; NOW, THEREFORE, THE UNDERSIGNED DECLARANT(S), being the owners of the real property ("the Property") located at the following address: 919 Cedar Street, Edmonds, WA 98020 in the City of Edmonds, Washington, and legally described on Exhibit A attached hereto and incorporated herein by this reference as if set forth in full, hereby covenants and agrees, on behalf of himself/herself/themselves/itself and his/her/their/its successors and assigns, as follows: 1. Declarant(s) warrant that he/she/they are the owners of the property described on Exhibit A and have the authority to impose this covenant on the property and bind all future owners, successors, and assigns of the Declarant(s). The Declarant(s), future owners, successors, and assigns of the Declarant(s) shall be referred to collectively as "Owners." 2. The Owners of the property described on Exhibit A agree that the property contains a stormwater management facility called a "LID BMP," which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious or non-native pervious surfaces on the property. "Low impact development" means development conducted in a way that seeks to minimize or completely prevent alterations to the natural hydrology of the site. Low impact development includes site planning and design to reduce alterations of natural soil and vegetation cover, minimize impervious surfaces, and specific practices that help to replicate natural hydrology such as permeable pavements, green roofs, soil amendments, bioretention systems, and dispersion of runoff. 3. The Owners of the property described on Exhibit A shall maintain the size, placement, and design of the LID BMP as depicted on the approved site plan, Exhibit B, and design details shall be maintained and may not be changed without written approval either from the Engineering Division of the City of Edmonds or through a future development permit from the City of Edmonds. Chemical fertilizers and pesticides shall not be used where LID BMP is located. . All costs of maintenance and repair shall be the sole responsibility of the Owners. 4. The Owners of the property described on Exhibit A shall inspect LID BMPs annually for physical defects. After major storm events, the system shall also be checked to ensure that the overflow system is working properly. The Owners also shall maintain all LID BMP so it functions as designed on a year-round basis. 5. The City of Edmonds is hereby granted by the Owners the right, but not the obligation, to enter upon the property described on Exhibit A at all reasonable times for the purpose of inspecting the private stormwater LID BMP facility. If, as the result of any such inspection the City of Edmonds determines that the LID BMP is in disrepair, requires maintenance or repair, or is otherwise not functioning as provided in the BMP site plan, the City Engineer or his designee shall have the right, but not the obligation, to order the Owners of the property described on Exhibit A to maintain or repair the same. 6. If the City of Edmonds determines that the LID BMP requires maintenance or repair pursuant to Section 5, the City of Edmonds shall provide notice to the Owners of the deadline within which such maintenance or repair must be completed. Said notice may further advise that, should the violator fail to perform required maintenance or make repairs within the established deadline, the work may be done by the city or a contractor designated by the City Engineer and the expense thereof shall be charged to the Owners. The City's officers, agents, employees, and contractors shall have the right, which is hereby granted by the Owners, to enter upon the property described on Exhibit A in order to perform such work. The Owners shall bear the cost of all work performed. 7. The Owners shall indemnify, defend and hold harmless the City of Edmonds, its officers, officials, employees and agents from any and all claims, demands, suits, penalties, losses, damages, judgments, attorneys' fees and/or costs of any kind whatsoever, arising out of or in any way resulting from the approval of the LID BMP, the installation and presence of the LID BMP, and the acts or omissions of the Owners, their officers, employees, contractors, and agents relating to the construction, operation and maintenance of the LID BMPs on the property, except for the City's intentional and willful tortious acts, and waive and release the City of Edmonds from any and all claims for damages and injunctive relief which the Owners may themselves have now or in the future, by reason of the construction, maintenance and operation of said LID BMPs. 8. This covenant shall run with the land and be binding upon the Declarant(s), as the owner of the property described on Exhibit A, and on Declarant's successors and assigns as to such property. Dated: DECLARANT(S): (Signature) Nathan Rimmer (Print Name) (Signature) (Print Name) State of Washington ) ss. County of Snohomish ) APPROVED: CITY OF EDMONDS (Signature) (Print Name) (Title) On this day personally appeared before me f Declarant(s) } to me known to be the individual, or individuals described in and who executed the within and foregoing instrument, and acknowledged that he/she/they signed the same as his/her/their free and voluntary act and deed, for the uses and purposes therein mentioned. SUBSCRIBED AND SWORN before me this day of , 201_. (Signature) (Name legibly printed or stamped) Notary Public in and for the State of Washington. Residing at: My commission expires Exhibit A Legal Description Section 25 Township 27 Range 03 Quarter NE - ALBERT B LORDS GRANDVIEW ADD TO ED BLK 001 D-00 - LOTS 7 & 8 TGW TH PTN LOT 9 OF SD BLK LY W LN WH PLW & 60FT E OF W LN OF SD LOT 7 TGW TH PTN OF ADJPROP LY S OF TH CERT LN OF OCCUPATION AGREED UPON PER AGREE DATED 12/16/87 REC AFN 8712189124 & SHOWN AS PROP BLA SURV FILED VOL 24 PG 181 & LY BTW NLY EXT OF LATERAL BOUNDARIES DESC ABV - PER CITYOF ED LLA NO LL-98-131 REC AFN 201001130424 Exhibit B EXHIBIT B: SITE PLAN 27'x12'x3' PROPERTY INFILTRATION LINE S88°39'37"E THE PROPERTY > o LINE 0 / o C o PROPOSED Z / ZIDENCE I PROPERTY / LINE PROPOSED DRIVEWAY o ' er El El m -- of o'/ G� #40"CEtlAR \ *36"CED R// / \ SS SS s W W$1 i� INE / o o� CEDTIEET G- G �G G G i-O \ OP / l / WM OP / l op op-_ 0 20 40 " Feet SCALE: 1"=20' PERMIT NUMBER: BLD2022-0381 APPROVED BY: DATE: Construction Stormwater General Permit (CSWGP) Stormwater Pollution Prevention Plan (SWPPP) for Rimmer Residence Prepared for: City of Edmonds / Department of Ecology Northwest Regional Office Permittee / Owner Developer Operator / Contractor Nathan Rimmer - TBD Project Site Location: 9611 SE 72nd Street, Mercer Island WA 98040, Parcel No. 3575304875 General Contractor Name Organization Contact Phone Number TBD TBD TBD Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Brady Berriman, PE Latitude 48, P.S. 206-556-1615 SWPPP Preparation Date January 10, 2022 Project Construction Dates Activity / Phase Start Date End Date General Construction TBD TBD 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 COz 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 Project Information (1.0) Project/Site Name: Rimmer Residence Street/Location: 919 Cedar Street, Edmonds, Parcel No. 00371900100700 City: Mercer Island State: WA Zip code: 98020 Subdivision: N/A Receiving waterbody: Puget Sound Existing Conditions (1.1) Total acreage (including support activities such as off -site equipment staging yards, material storage areas, borrow areas). Total acreage: 0.14 Acres (6,139 SF) Disturbed acreage: 0.14 Acres (6,139 SF) Existing structures: N/A Landscape topography: The site slopes down towards the west at slopes of about 0% to 10%. Drainage patterns: The site slopes mildly from east or west towards and stormwater sheet flows to adjacent properties eventually making its way towards 9' Avenue South, ultimately discharging into the Puget Sound. There are no detention, water quality or LID facilities currently on the project site to be maintained, protected or replaced. Groundwater is not anticipated to be encountered during site excavation. Existing Vegetation: The site includes two trees, one of which will be removed as part of the development. Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): Erosion Hazard area (slopes of 15%-40%). List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: Puget Sound (North -central) is listed by Washington State Department of Ecology as a Category 5 water body for PCBs and other contaminants, and Category 1 water body for Bacteria — Fecal coliform, Phosphorus, and Bacteria — Escherichai coli. See Appendix F. Table 1 — Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration None Proposed Construction Activities (1.2) Description of site development: General Site Development for Single Family Residence Description of construction activities: The proposed project consists of site development associated with the single-family building permit. Construction activities will include clearing, excavation, shoring installation of utilities, and construction to support the single-family residence. Description of site drainage including flow from and onto adjacent properties: Under developed conditions, stormwater from proposed site improvements will be collected and fully infiltrated into the native soil. Description of final stabilization: Final stabilization will include site landscaping and paving. Contaminated Site Information: No contaminated soils have been identified on the site. Proposed activities regarding contaminated soils or groundwater: No contaminated soils or groundwater are anticipated to be encountered by this development. Monitoring: According to the geotechnical report, no groundwater was found during site investigations and the project does not anticipate encountering groundwater during site excavation. Construction runoff will be captured before being infiltrated into the native subgrade. Construction Stormwater Best Management Practices (BMPs) (2.0) The 12 Elements (2.1) Element 1: Preserve Vegetation / Mark Clearing Limits (2.1.1) The construction limits will be delineated by a high visibility orange fence or silt fence with orange fabric. The fence will provide clear and physical limits for construction. List and describe BMPs: BMP C103: High Visibility Plastic or Metal Fence BMP C233: Silt Fence (Double silt fence will be installed upstream of onsite wetlands) Installation Schedules: Prior to clearing Inspection and Maintenance plan: ■ Weekly inspection, maintain as needed to allow proper functioning of structures. ■ Any damage shall be repaired immediately. If concentrated flows are evident uphill of the fence, they must be 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. Responsible Staff: Contractor Element 2: Establish Construction Access (2.1.2) A single construction entrance will be used to access the site for construction traffic. Construction access to the site will be directly off Cedar Street. List and describe BMPs: BMP C105: Stabilized Construction Entrance BMP C107: Construction Road/Parking Stabilization Installation Schedules: Initial construction stage, prior to grading Inspection and Maintenance plan: ■ Inspect stabilized areas regularly, especially after large storm events. ■ 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 and/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. ■ 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. Responsible Staff: Contractor Element 3: Control Flow Rates (2.1.3) Construction stormwater will be detained onsite before infiltrating into the native subgrade. 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: BMP C209: Outlet Protection BMP C233: Silt Fence Installation Schedules: Prior to grading Inspection and Maintenance plan: ■ Repair and replace rock as necessary. ■ Remove sediment when 30 percent of structure capacity is filled. Inspect and repair as needed. ■ Add rock as needed to maintain the intended function. ■ Clean energy dissipater if sediment builds up. Responsible Staff: Contractor Element 4: Install Sediment Controls (2.1.4) Silt fence has been specified at locations on the work boundaries where runoff has the potential to leave the project site. List and describe BMPs: BMP C220: Storm Drain Inlet Protection BMP C233: Silt Fence BMP C235: Sediment Trap (If required) Inspection and Maintenance plan: Any damage shall be repaired immediately. If concentrated flows are evident uphill of the fence, they must be 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 Responsible Staff: Contractor Element 5: Stabilize Soils (2.1.5) Disturbed soils will be stabilized with appropriate measures. The exact BMP will depend upon the final configuration of that portion of the site and the phase of construction. Areas that will ultimately become landscape will be seeded and mulched once they reach their final grade and configuration. The area of clearing will be limited where possible to minimize the amount of exposed soil surfaces, and the potential of erosion and sedimentation impacts on surface water. Temporary and permanent cover measures will be provided to protect disturbed areas. Mulching will be used to provide immediate temporary protection from erosion and to enhance plant growth. Plastic covering will be used to cover soil stockpiles and trench excavations, and to protect steep slopes behind wall construction, stockpiles or to encourage grass growth in newly seeded areas. The contractor should consider using a more durable geomembrane material in lieu of plastic for covering soil stockpiles. A more durable material will perform better and can be re -used several times over the life of the project. Dust control will be implemented as needed. All of these features will be maintained throughout the construction effort. From October 1 through March 31, no soils shall remain exposed and unworked for more than 2 days. From April 1 to September 30, no soils shall remain exposed and unworked for more than 7 days. This stabilization requirement applies to all soils on site, whether or not at final grade. 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: TBD End date: TBD Will you construct during the wet season? Yes No List and describe BMPs: BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C122: Nets and Blankets BMP C123: Plastic Covering BMP C130: Surface Roughening BMP C140: Dust Control Installation Schedules: During site grading Inspection and Maintenance plan: Temporary and Permanent Seeding Any seeded areas that fail to establish at least 80 percent cover (100 percent cover for areas that receive sheet or concentrated flows) shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding, mulching, or nets/blankets, shall be used. If winter weather prevents adequate grass growth, this time limit may be relaxed at the discretion of the local authority when sensitive areas would otherwise be protected. After adequate cover is achieved, any areas that experience erosion shall be reseeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area reseeded and protected by mulch. Seeded areas shall be supplied with adequate moisture, but not watered to the extent that it causes runoff. Mulching ■ The thickness of the cover must be maintained. ■ Any areas that experience erosion shall be re -mulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the problem shall be fixed and the eroded area re -mulched. Nets and Blankets ■ Good contact with the ground must be maintained, and erosion must 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. Plastic Covering ■ 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. Surface Roughening ■ Areas that are graded in this manner should be seeded as quickly as possible. ■ Regular inspections should be made of the area. If rills appear, they should be re- graded and re -seeded immediately. Dust Control ■ Re -spray area with water as necessary to keep dust to a minimum. Responsible Staff: Contractor Element 6: Protect Slopes (2.1.6) Nets and blankets, seeding, and surface roughening may be used to stabilize embankments. Will steep slopes be present at the site during construction? Yes No List and describe BMPs: BMP C120: Temporary and Permanent Seeding BMP C121: Mulching BMP C122: Nets and Blankets BMP C130: Surface Roughening Installation Schedules: During grading Inspection and Maintenance plan: See Element 5 Responsible Staff: Contractor Element 7: Protect Drain Inlets (2.1.7) Existing drainage structures may collect surface runoff within the project area if constructed prior to other improvements. Sediment should not be allowed to enter any of these structures. Filter fabric or socks will be placed on or in the inlets. List and describe BMPs: BMP C220: Storm Drain Inlet Protection Installation Schedules: Prior to grading Inspection and Maintenance plan: ■ Inlets will be inspected weekly at a minimum and daily during storm events. ■ Inlet protection devices will be cleaned (or removed and replaced), when sediment has filled the device by one third (1/3) or as specified by the manufacturer. ■ 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. Responsible Staff: Contractor Element 8: Stabilize Channels and Outlets (2.1.8) 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. List and describe BMPs: BMP C202: Channel and Lining BMP C207: Check Dams BMP C209: Outlet Protection Installation Schedules: Prior to and during grading Inspection and Maintenance plan: ■ Repair and replace rock as necessary. ■ Remove sediment when 30 percent of structure capacity is filled. Responsible Staff: Contractor Element 9: Control Pollutants (2.1.9) The following pollutants are anticipated to be present on -site: Table 2 — Pollutants Pollutant (and source, if applicable) Concrete Fuel Paints and supplies Residential building, insulation, and roofing materials All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well -organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. Chemical storage: Any chemicals stored in the construction areas will conform to the appropriate source control BMPs listed in Volume IV of the Ecology stormwater manual. In Western WA, all chemicals shall have cover, containment, and protection provided on site, per BMP C153 for Material Delivery, Storage and Containment in SWMMWW 2005 Application of agricultural chemicals, including fertilizers and pesticides, shall be conducted in a manner and at application rates that will not result in loss of chemical to stormwater runoff. Manufacturers' recommendations for application procedures and rates shall be followed. Excavation and tunneling spoils dewatering waste: • Dewatering BMPs and BMPs specific to the excavation and tunneling (including handling of contaminated soils) are discussed under Element 10. Demolition: • Dust released from demolished sidewalks, buildings, or structures will be controlled using Dust Control measures (BMP C140). • Storm drain inlets vulnerable to stormwater discharge carrying dust, soil, or debris will be protected using Storm Drain Inlet Protection (BMP C220 as described above for Element 7). • Process water and slurry resulting from sawcutting and surfacing operations will be prevented from entering the waters of the State by implementing Sawcutting and Surfacing Pollution Prevention measures (BMP C152). Concrete and grout: • Process water and slurry resulting from concrete work will be prevented from entering the waters of the State by implementing Concrete Handling measures (BMP C151). Concrete wash out areas shall not be allowed on bare dirt or allowed to drain to bare dirt or the storm system. Sanitary wastewater: • Portable sanitation facilities will be firmly secured, regularly maintained, and emptied when necessary. • Wheel wash or tire bath wastewater shall be discharged to a separate onsite treatment system or to the sanitary sewer as part of Wheel Wash implementation (BMP C106). Solid Waste: • Solid waste will be stored in secure, clearly marked containers. Other: • Other BMPs will be administered as necessary to address any additional pollutant sources on site. The facility does not require a Spill Prevention, Control, and Countermeasure (SPCC) Plan under the Federal regulations of the Clean Water Act (CWA). Installation Schedules: Prior to and during building construction Inspection and Maintenance plan: ■ Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. ■ Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. ■ Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. ■ Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. ■ Contain wash water and leftover product in a lined container when no formed areas are available. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. Responsible Staff: Contractor 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 Table 3 — pH -Modifying Sources None Bulk cement Cement kiln dust Fly ash x Other cementitious materials x New concrete washing or curing waters x Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults x Concrete pumping and mixer washout waters Recycled concrete Other (i.e. calcium lignosulfate) [please describe] List and describe BMPs: BMP C252: High pH Neutralization Using COz Installation Schedules: As needed Inspection and Maintenance plan: ■ Weekly Responsible Staff: Contractor 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. Element 10: Control Dewatering (2.1.10) Dewatering may be required as part of the utility trenching and/or excavation. Dewatering BMPs will include infiltration. Only clean, non -turbid dewatering water (such as well -point groundwater) will be discharged to systems tributary to, or directly into, surface waters of the State, provided the dewatering flow does not cause erosion or flooding of receiving waters. Table 4 — Dewatering BMPs x 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: BMP C205: Subsurface Drains Installation Schedules: During construction Inspection and Maintenance plan: ■ The outlet shall be kept clean and free of debris ■ Surface inlest will be kept open and free of sediment and other debris ■ The area will be protected to protect from traffic of heavy vehicles Responsible Staff: Contractor Element 11: Maintain BMPs (2.1.11) 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 11 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. Element 12: Manage the Project (2.1.12) The project will be managed based on the following principles: • Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. 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. • 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 x Design the project to fit the existing topography, soils, and drainage patterns x Emphasize erosion control rather than sediment control x Minimize the extent and duration of the area exposed x Keep runoff velocities low x Retain sediment on -site x Thoroughly monitor site and maintain all ESC measures x 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 Element 13: Protect Low Impact Development (LID) BMPs (2.1.13) The project is proposing to install an infiltration trench. The area that the project will be installing a infiltration trench will be marked and protected to protect the native soil from traffic from heavy vehicles. Selected graded slopes will be restored to native meadow by roughening the surface to increase surface storage, amending the soil, and planting native vegetative species. Pollution Prevention Team (3.0) Table 7 — Team Information Title Names Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer TBD TBD Emergency Ecology Contact Northwest Regional Office 425-640-7000 Emergency Permittee/ Owner Contact TBD TBD Non -Emergency Owner Contact TBD TBD City of Edmonds Business hours contact 425-771-0220 City of Edmonds After hours contact 425-771-0220 Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office 425-640-7000 Monitoring and Sampling Requirements (4.0) 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: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data 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. Complete the following paragraph for sites that discharge to impaired waterbodies for fine sediment, turbidity, phosphorus, or pH: Site Inspection (4.1) 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. Stormwater Quality Sampling (4.2) Turbidity Sampling (4.2.1) 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) x 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: 1. 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. https://www.ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue • Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (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 (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 • Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 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: • Turbidity is 25 NTU (or lower). • Transparency is 33 cm (or greater). • 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 • The discharge stops or is eliminated. pH Sampling (4.2.2) pH monitoring is required for "Significant concrete work" (i.e. greater than 1000 cubic yards poured concrete or recycled concrete over the life of the project).The use of 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 su 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 (CO2) 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. Method for sampling pH: Table 8 — pH Sampling Method x pH meter pH test kit Wide range pH indicator paper Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies (5.0) 303(d) Listed Waterbodies (5.1) Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): Puget Sound (North -central) is listed by Washington State Department of Ecology as a Category 5 water body for PCBs and other contaminants, and Category 1 water body for Bacteria — Fecal coliform, Phosphorus, and Bacteria — Escherichai coli. See Appendix F Reporting and Record Keeping (6.0) Record Keeping (6.1) Site Log Book (6.1.1) A site log book will be maintained for all on -site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs Records Retention (6.1.2) 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: • CSWGP • Permit Coverage Letter • SWPPP • 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. Updating the SWPPP (6.1.3) The SWPPP will be modified if: • Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. • 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. Reporting (6.2) Discharge Monitoring Reports (6.2.1) Cumulative soil disturbance is less than (1) acre. Notification of Noncompliance (6.2.2) 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. • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 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 COz sparging is planned for adjustment of high pH water. Appendices A. Site Map B. BMP Details C. Correspondence D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303(d) List Information G. Engineering Calculations A. Site Map 8.com B. BMP Details NOT TO SCALE cu roadsi Notes: 1. Driveway shall meet the requirements of the permitting agency. 2. It is recommended that the entrance be crowned so that runoff drains off the pad. 1 DEPARTMENT OF ECOLOGY State of Washington 12" minimum thickness A lb'min. Provide full width of ingress/egress area Figure II-4.1.1 Stabilized Construction Entrance Revised June 2015 Please see http://www.ecy.wa.govlcopyright.html for copyright notice including permissions, limitation of liability, and disclaimer. Straw bale 10 mil plastic lining Staples Native material (2 per bale) (optional) Wood or metal stakes (2 per bale) Section B-B 3m Minimum Stake (typ) B� Varies if Straw bale (typ- ) ftdkk DEPARTMENT OF ECOLOGY State of Washington raM Binding wire Plywood 1200mmx610mm painted white Lag screws (12.5 mm) , CONCRETE WASHOUT" 915 mm o Wood post (89 mm x 89 mm x 2.4 m) Black letters 150 mm height fu u 915 mm -F Concrete Washout Sign Detail (or equivalent) �BI an 50 mm 200 mm nip 3.05 mm dia. steel wire Staple Detail 10 mil plastic lining Notes: 1. 2 Type "Above Grade" with Straw Bales BMP C151 Figure II-4.1.7b Concrete Washout Area Actual layout determined in the field. The concrete washout sign shall be installed within 10 m of the temporary concrete washout facility. NOT TO SCALE Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. Plan i vvv-a�ai,ncu 2x12 rough Plan wood frame ftdkk DEPARTMENT OF ECOLOGY State of Washington Lath and flagging on 3 sides Sandbag 3erm 10 mil plastic lining 0 1m lining Section A -A Type "Below Grade" Sandbag Berm Notes: 1. Actual layout determined in the field. 2. A concrete washout sign shall be installed within 10 m of the temporary concrete washout facility. Wood frame B securely fastened around entire perimeter with two stakes 10 mil plastic lining Stake (typ.) Section B-B iil plastic lining Type "Above Grade" with Wood Planks BMP C151 Figure II-4.1.7a Concrete Washout Area NOT TO SCALE Revised June 2015 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. IINIS� DEPARTMENT OF ECOLOGY State of Washington BMP C151 NOT TO SCALE Figure II-4.1.8 Prefabricated Concrete Washout Container w/Ramp Revised June 2015 Please see http://www.ecy.wa.govlcopyright.html for copyright notice including permissions, limitation of liability, and disclaimer. Joints in filter fabric shall be spliced at posts. Use staples, wire rings or equivalent to attach fabric to posts 2"x2" by 14 Ga. wire or equivalent, if standard strength fabric used ='\X' Minimum I I 6' max I I 4"x4" trench I u Post spacing may be increased to 8' if wire backing is used 2"x2" wood posts, steel fence posts, or equivalent ftdkk DEPARTMENT OF ECOLOGY State of Washington 2"x2" by 14 Ga. wire or equivalent, if standard strength fabric used Backfill trench with native soil or %4' - 1.5" washed gravel Filter fabric Minimum 4"x4" trench 2"x2" wood posts, steel fence posts, or equivalent 2' min 12" min BMP 233 Figure II-4.2.12 Silt Fence NOT TO SCALE Revised October 2014 Please see http://www.ecy.wa.gov/copyright.html for copyright notice including permissions, limitation of liability, and disclaimer. C. Correspondence N/A D. Site Inspection Form Construction Stormwater Site Inspection Form Project Name Permit # Inspection Date 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 ❑ Other ❑ B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Concrete pours Offsite improvements C. Questions: Time Clearing/Demo/Grading Infrastructure/storm/roads Vertical Utilities Construction/buildings Site temporary stabilized Final stabilization 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 & S5) 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. 5 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 ❑ All disturbed soils ❑ All concrete wash out area ❑ All material storage areas All discharge locations ❑ All equipment storage areas ❑ All construction entrances/exits ❑ 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: "I 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 E. Construction Stormwater General Permit (CSWGP) Issuance Date: Effective Date: Expiration Date November 18, 2020 January 1, 2021 December 31, 2025 CONSTRUCTION STORMWATER GENERAL PERMIT National Pollutant Discharge Elimination System (NPDES) and State Waste Discharge General Permit for Stormwater Discharges Associated with Construction Activity State of Washington Department of Ecology Olympia, Washington 98504 In compliance with the provisions of Chapter 90.48 Revised Code of Washington (State of Washington Water Pollution Control Act) and Title 33 United States Code, Section 1251 et seq. The Federal Water Pollution Control Act (The Clean Water Act) Until this permit expires, is modified, or revoked, Permittees that have properly obtained coverage under this general permit are authorized to discharge in accordance with the special and general conditions that follow. Vincent McGowan, P.E. Water Quality Program Manager Washington State Department of Ecology TABLE OF CONTENTS LISTOF TABLES..................................................................................................................................ii SUMMARY OF PERMIT REPORT SUBMITTALS......................................................................................1 SPECIAL CONDITIONS.........................................................................................................................3 S1. Permit Coverage.............................................................................................................................. 3 S2. Application Requirements............................................................................................................... 7 S3. Compliance with Standards.............................................................................................................9 S4. Monitoring Requirements, Benchmarks, and Reporting Triggers ................................................. 10 S5. Reporting and Recordkeeping Requirements................................................................................ 17 S6. Permit Fees.................................................................................................................................... 20 S7. Solid and Liquid Waste Disposal....................................................................................................20 S8. Discharges to 303(D) or TMDL Waterbodies................................................................................. 20 S9. Stormwater Pollution Prevention Plan.......................................................................................... 23 S10. Notice Of Termination................................................................................................................... 32 GENERAL CONDITIONS.....................................................................................................................34 G1. Discharge Violations....................................................................................................................... 34 G2. Signatory Requirements................................................................................................................ 34 G3. Right of Inspection and Entry......................................................................................................... 35 G4. General Permit Modification and Revocation............................................................................... 35 G5. Revocation of Coverage Under tPermit......................................................................................... 35 G6. Reporting a Cause for Modification............................................................................................... 36 G7. Compliance with Other Laws and Statutes.................................................................................... 36 G8. Duty to Reapply.............................................................................................................................. 36 G9. Removed Substance....................................................................................................................... 36 G10. Duty to Provide Information.......................................................................................................... 36 G11. Other Requirements of 40 CFR...................................................................................................... 37 G12. Additional Monitoring....................................................................................................................37 G13. Penalties for Violating Permit Conditions...................................................................................... 37 G14. Upset..............................................................................................................................................37 G15. Property Rights.............................................................................................................................. 37 G16. Duty to Comply.............................................................................................................................. 37 G17. Toxic Pollutants..............................................................................................................................38 G18. Penalties for Tampering................................................................................................................. 38 G19. Reporting Planned Changes........................................................................................................... 38 G20. Reporting Other Information......................................................................................................... 38 G21. Reporting Anticipated Non-Compliance........................................................................................ 38 Construction Stormwater General Permit Page i G22. Requests to Be Excluded From Coverage Under the Permit......................................................... 39 G23. Appeals...........................................................................................................................................39 G24. Severability.....................................................................................................................................39 G25. Bypass Prohibited.......................................................................................................................... 39 APPENDIX A — DEFINITIONS..............................................................................................................42 APPENDIX B —ACRONYMS ................................................................................................................50 LIST OF TABLES Table 1 Summary of Required Submittals................................................................................................1 Table 2 Summary of Required On -site Documentation...........................................................................2 Table 3 Summary of Primary Monitoring Requirements.......................................................................12 Table 4 Monitoring and Reporting Requirements.................................................................................14 Table 5 Turbidity, Fine Sediment & Phosphorus Sampling and Limits for 303(d)-Listed Waters................................................................................................................22 Table 6 pH Sampling and Limits for 303(d)-Listed Waters.....................................................................22 Construction Stormwater General Permit Page ii SUMMARY OF PERMIT REPORT SUBMITTALS 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 S5.13 Discharge Monitoring Report Monthly* Within 15 days following the end of each month S5.F and Noncompliance Notification - As necessary Within 24 hours S8 Telephone Notification S5.F Noncompliance Notification - Written As necessary Within 5 Days of Report non-compliance S9.D Request for Chemical Treatment Form As necessary Written approval from Ecology is required prior to using chemical treatment (with the exception of dry ice, CO2 or food grade vinegar 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 S2.A Notice of Permit Transfer As necessary G19 Notice of Planned Changes As necessary G21 Reporting Anticipated Non-compliance As necessary 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 S5.6 of this General Permit for more specific information regarding DMRs. Construction Stormwater General Permit Page 1 Table 2 Summary of Required On -site Documentation Document Title Permit Conditions Permit Coverage Letter See Conditions S2, S5 Construction Stormwater General Permit (CSWGP) See Conditions S2, S5 Site Log Book See Conditions S4, S5 Stormwater Pollution Prevention Plan (SWPPP) See Conditions S5, S9 Site Map See Conditions S5, S9 Construction Stormwater General Permit Page 2 SPECIAL CONDITIONS S1. 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 S1.E.3 and 4. 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 related to construction -support activity as 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. This category 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): Determines to be a significant contributor of pollutants to waters of the State of Washington. Reasonably expects to cause a violation of any water quality standard. Operators of the following activities are not required to seek coverage under this CSWGP (unless specifically required under Special Condition S1.B.1.b, above): a. Construction activities that discharge all stormwater and non-stormwater to groundwater, 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 S1.F). c. Routine maintenance that is performed to maintain the original line and grade, hydraulic capacity, or original purpose of a facility. 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 Construction Stormwater General Permit Page 3 State" may exist on a construction site as well as off site; for example, a creek running through a site.) 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. 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. f. Uncontaminated groundwater or spring water. g. Uncontaminated excavation dewatering water (in accordance with S9.D.10). h. Uncontaminated discharges from foundation or footing drains. Uncontaminated or potable water used to control dust. Permittees must minimize the amount of dust control water used. 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. 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 groundwater, are prohibited: Construction Stormwater General Permit Page 4 1. 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.D.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. Stormwater from any federal operator. 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. Construction Stormwater General Permit Page 5 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. F. 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 five (5) acres and the site is not a portion of a common plan of development or sale that will disturb five (5) acres or greater. Calculation of Erosivity "R" Factor and Regional Timeframe: The project's calculated rainfall erosivity factor ("R" Factor) must be less than five (5) during the period of construction activity, (See the CSWGP homepage http://www.ecy.wa.gov/programs/wq/stormwater/construction/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: For sites west of the Cascades Crest: June 15 — September 15. 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 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: http://www.ecy.wa.gov/programs/wq/stormwater/construction/resourcesguida nce.html. 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 S1.B.1.b or for any size construction activity that could Construction Stormwater General Permit Page 6 reasonably expect to cause a violation of any water quality standard as defined in Special Condition S1.6.1.b.ii. This waiver does not apply to construction activities which include non-stormwater discharges listed in Special Condition S1.C.3. 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 S1.F.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. S2. APPLICATION REQUIREMENTS A. Permit Application Forms Notice of Intent Form 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://ecy.wa.gov/programs/wq/stormwater/construction/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 c. The operator must submit the NOI at least 60 days before discharging stormwater from construction activities and must submit it prior to the date of the first public notice (See Special Condition S2.6, 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, coverage under the general permit will automatically commence on the 31" 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). See S8.13 for Limits on Coverage for New Discharges to TMDL or 303(d)-Listed Waters. 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, the applicant must provide notice of the Construction Stormwater General Permit Page 7 selection of an equivalent BMP to Ecology at least 60 days before intended use of the equivalent BMP. e. 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: List or table of all known contaminants with laboratory test results showing concentration and depth, Map with sample locations, iii. Related portions of the Stormwater Pollution Prevention Plan (SWPPP) that address the management of contaminated and potentially contaminated construction stormwater and dewatering water, iv. Dewatering plan and/or dewatering contingency plan. 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 complete Transfer of Coverage Form to Ecology, signed by the current and new discharger and containing a specific date for transfer of permit responsibility, coverage and liability (including any Administrative Orders associated with the permit); and Ecology does not notify the current discharger and new discharger of 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 indicate the remaining permitted acreage after the transfer. Transfers do not require public notice. Modification of Coverage Form Permittees must notify Ecology regarding any changes to the information provided on the NOI by submitting an Update/Modification of Permit Coverage form in accordance with General Conditions G6 and G19. Examples of such changes include, but are not limited to: Changes to the Permittee's mailing address, Changes to the on -site contact person information, and iii. Changes to the area/acreage affected by construction activity. Construction Stormwater General Permit Page 8 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 be run after the NOI has been submitted and must contain: A statement that "The applicant is seeking coverage under the Washington State Department of Ecology's Construction Storm water NPDES and State Waste Discharge General Permit." The name, address, and location of the construction site. 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 total number of acres to be disturbed over the lifetime of the project. 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 and the receiving water(s) the system discharges to. 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 11 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. S3. COMPLIANCE WITH STANDARDS A. Discharges must not cause or contribute to a violation of surface water quality standards (Chapter 173-201A WAC), groundwater quality standards (Chapter 173-200 WAC), sediment management standards (Chapter 173-204 WAC), and human health -based criteria in the Federal water quality criteria applicable to Washington. (40 CFR Part 131.45) Discharges that are not in compliance with these standards are prohibited. 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: Construction Stormwater General Permit Page 9 Comply with all permit conditions, including; planning, sampling, monitoring, reporting, and recordkeeping conditions. Implement stormwater BMPs contained in stormwater management manuals published or approved by Ecology, or BMPs that are demonstrably equivalent to BMPs contained in stormwater management 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 1 Municipal Stormwater Permit are approved by Ecology.) D. Where construction sites also discharge to groundwater, the groundwater discharges must also meet the terms and conditions of this CSWGP. Permittees who discharge to groundwater through an injection well must also comply with any applicable requirements of the Underground Injection Control (UIC) regulations, Chapter 173-218 WAC. 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 Construction sites one (1) acre or larger that discharge stormwater to surface waters of the State must have site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL). Sites less than one (1) acre may have a person without CESCL certification conduct inspections. (See Special Conditions S4.13.3 and 13.4, below, for detailed requirements of the Permittee's CESCL.) Site inspections must include all areas disturbed by construction activities, all BMPs, and all stormwater discharge points under the Permittee's operational control. 1. 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: 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. The SWPPP must identify the CESCL or inspector, who must be present on site or on -call at all times. The CESCL (sites one (1) acre or more) 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.) 2. The CESCL or inspector must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. BMP effectiveness must be evaluated to Construction Stormwater General Permit Page 10 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, 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. The CESCL or inspector 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 (1) day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one (1) inspection is required that week.) Inspection frequency may be reduced to once every calendar month for inactive sites that are temporarily stabilized. 4. 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. c. The general conditions during inspection. d. The approximate amount of precipitation since the last inspection. e. The approximate amount of precipitation within the last 24 hours. A summary or list of all implemented BMPs, including observations of all erosion/sediment control structures or practices. g. A description of: i. BMPs inspected (including location). ii. BMPs that need maintenance and why. iii. BMPs that failed to operate as designed or intended, and iv. Where additional or different BMPs are needed, and why. h. A description of stormwater discharged from the site. The Permittee must note the presence of suspended sediment, turbidity, discoloration, and oil sheen, as applicable. Construction Stormwater General Permit Page 11 Any water quality monitoring performed during inspection. General comments and notes, including a brief description of any BMP repairs, maintenance, or installations made following the inspection. An implementation schedule for 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. A summary report of the inspection. m. 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 Weekly Weekly CESCL Size of Soil Weekly Site / Sam lin w p g Sampling w/ Weekly pH Required for Disturbance' Inspections Turbidity Meter Transparency Sampling2 Inspections? Tube Sites that disturb less than 1 acre, but are Required Not Required Not Required Not Required No 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 Required4 Required Yes acres or more 1 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 1 acre or more, and involves significant concrete work (1,000 cubic yards of concrete or recycled concrete placed or poured over the life of a project) or the use of 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.a or b. 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.4.a. Construction Stormwater General Permit Page 12 C. Turbidity/Transparency Sampling Requirements Sampling Methods a. If construction activity involves the disturbance of five (5) acres or more, the Permittee must conduct turbidity sampling per Special Condition S4.C.4.a, below. b. If construction activity involves one (1) acre or more but fewer than five (5) acres of soil disturbance, the Permittee must conduct either transparency sampling or turbidity sampling per Special Condition S4.C.4.a or b, below. 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). f. 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. Sampling Locations 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) in the SWPPP and on the 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. 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. Construction Stormwater General Permit Page 13 4. Sampling and Analysis Methods 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 1% 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 Frequency Benchmark Value Turbidity NTU SM2130 Weekly, if 25 NTUs discharging Manufacturer Weekly, if Transparency Cm instructions, or discharging 33 cm Ecology guidance Turbidity/Transparency Benchmark Values and Reporting Triggers The benchmark value for turbidity is 25 NTUs. 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 and follow S5.F — Noncompliance Notification for reporting requirements applicable to discharges which exceed the numeric effluent limit for turbidity. a. Turbidity 26 — 249 NTUs, or Transparency 32 — 7 cm: If the discharge turbidity is 26 to 249 NTUs; or if discharge transparency is 32 to 7 cm, the Permittee must: Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs, and no later than 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. 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. Document BMP 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 Construction Stormwater General Permit Page 14 management process described below. For discharges which are subject to a numeric effluent limit for turbidity, see SS.F — Noncompliance Notification. Within 24 hours, 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), in accordance with Special Condition SS.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 These numbers and a link to the ERTS reporting page are also listed at the following website: http://www.ecy.wa.gov/programs/wq/stormwater/construction/index.html. 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. iii. Sample discharges daily until: a) Turbidity is 25 NTUs (or lower); or b) Transparency is 33 cm (or greater); or c) The Permittee has demonstrated compliance with the water quality standard 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 *Note: background turbidity in the receiving water must be measured immediately upstream (upgradient) or outside of the area of influence of the discharge. d) The discharge stops or is eliminated. iv. Review the SWPPP for compliance with Special Condition S9 and make appropriate revisions within seven (7) days of the date the discharge exceeded the benchmark. Construction Stormwater General Permit Page 15 Document BMP implementation and maintenance in the site log book. Compliance with these requirements does not relieve the Permittee from responsibility to maintain continuous compliance with permit benchmarks. 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 placed or poured concrete or recycled concrete used over the life of a project) or the use of 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. 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. During the applicable pH monitoring period defined below, the Permittee must obtain a representative sample of stormwater and conduct pH analysis at least once per week. a. For sites with significant concrete work, the Permittee must begin the pH sampling period when the concrete is first placed or poured and exposed to precipitation, and continue weekly throughout and after the concrete placement, pour and curing period, until stormwater pH is in the range of 6.5 to 8.5 (su). b. For sites with recycled concrete where monitoring is required, 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 with the stormwater pH in the range of 6.5 to 8.5 (su). c. 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. 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. 4. The benchmark value for pH is 8.5 standard units. Anytime sampling indicates that pH is 8.5 or greater, the Permittee must either: a. Prevent the high pH water (8.5 or above) from entering storm sewer systems or surface waters of the state; 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, dry ice or food grade vinegar. The Permittee must obtain written approval from Ecology before using any form of chemical treatment other than COz sparging, dry ice or food grade vinegar. Construction Stormwater General Permit Page 16 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 notify Ecology within 24 hours of analysis either by calling the applicable Ecology Region's Environmental Report Tracking System (ERTS) number by phone or by submitting an electronic ERTS report (through Ecology's Water Quality Permitting Portal (WQWebPortal) — Permit Submittals when the form is available). See the CSWGP website for links to ERTS and the WQWebPortal. (http://www.ecy.wa.gov/programs/wq/stormwater/ construction/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 G12 (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. 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, WA 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 must 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 the first full month following the effective date of permit coverage up until Ecology has approved termination of the coverage). For more information, contact Ecology staff using information provided at the following website: www.ecy.wa.gov/programs/wq/permits/paris/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 five (5) 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 Construction Stormwater General Permit Page 17 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: 1. 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 samples or monitors any pollutant more frequently than required by this permit using test procedures specified by Special Condition S4 of this permit, the sampling results for 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 or fuels or other materials, catastrophic pond or slope failure, and discharges that violate water quality standards), or exceed numeric effluent limitations (see S8 — Discharges to 303(d) or TMDL Waterbodies), the Permittee must, upon becoming aware of the circumstance: 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 go to https://ecology.wa.gov/About-us/Get-involved/Report-an-environmental-issue to find contact information for the regional offices.) 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 (See S5.F.3, below, for details on submitting results in a report). 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. Construction Stormwater General Permit Page 18 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(I)(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 e. Erosivity Waiver (if applicable) The Permittee must address written requests for plans and records listed above (Special Condition S5.G.1) as follows: 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: Provide a copy of the plans and records to the requester within 14 days of a receipt of the written request; or 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 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. Construction Stormwater General Permit Page 19 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 S10 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 173-216-110. 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 Water Bodies Permittees who discharge to segments of water bodies 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 S&C and S&D. 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, 2021, 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 Construction sites that discharge to a TMDL or 303(d)-listed waterbody are not eligible for coverage under this permit unless the operator: Construction Stormwater General Permit Page 20 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 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 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 only after Ecology makes an affirmative determination that the discharge will not cause or contribute to the existing impairment or exceed the TMDL. 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. 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. Discharges that exceed the numeric effluent limit for turbidity constitute a violation of this permit. 4. Permittees whose discharges exceed the numeric effluent limit must sample discharges daily until the violation is corrected and comply with the non-compliance notification requirements in Special Condition SS.F. Construction Stormwater General Permit Page 21 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 point • Fine Sediment discharging where stormwater is • Phosphorus 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). Table 6 pH Sampling and Limits for 303(d)-Listed Waters Parameter identified in 303(d) Parameter Analytical Sampling Numeric Effluent listing Sampled/Units Method Frequency Limit High pH pH /Standard pH meter Weekly, if In the range of Units discharging 6.5 - 8.5 su 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. 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 must sample discharges daily until the violation is corrected and comply with the non-compliance notification requirements in Special Condition SS.F. E. Sampling and Limits for Sites Discharging to Waters Covered by a TMDL or another Pollution Control Plan Construction Stormwater General Permit Page 22 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/programs/wq/tmdl/TMDLsbyWria/TMDLbyWria.html 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. The Permittee must sample discharges weekly, unless otherwise specified by the TMDL, to evaluate compliance with the specific waste load allocations or requirements. 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. iii. 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, 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. S9. STORMWATER POLLUTION PREVENTION PLAN 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: 1. To identify best management practices (BMPs) which prevent erosion and sedimentation, and to reduce, eliminate or prevent stormwater contamination and water pollution from construction activity. 2. To prevent violations of surface water quality, groundwater quality, or sediment management standards. 3. To control peak volumetric flow rates and velocities of stormwater discharges. Construction Stormwater General Permit Page 23 B. General Requirements 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. c. The 13 elements of a SWPPP in Special Condition S9.D.1-13, including BMPs used to address each element. 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. Engineering calculations for ponds, treatment systems, and any other designed structures. When a treatment system requires engineering calculations, these calculations must be included in the SWPPP. Engineering calculations do not need to be included in the SWPPP for treatment systems that do not require such calculations. 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 Construction Stormwater General Permit Page 24 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 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 4. Documentation in the SWPPP that the BMPs selected provide an equivalent level of pollution prevention, compared to the applicable stormwater management manuals, including: 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. 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. e. Conduct street washing only after sediment removal in accordance with Special Condition S9.D.2.d. f. Control street wash wastewater by pumping back on site or otherwise preventing it from discharging into systems tributary to waters of the State. Construction Stormwater General Permit Page 25 Control Flow Rates Protect properties and waterways downstream of construction sites from erosion and the associated discharge of turbid waters due to increases in the 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 infiltration or detention BMPs as one of the first steps in grading. Assure that detention BMPs 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 sedimentation 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: 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. 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 Construction Stormwater General Permit Page 26 control fabrics and matting, soil application of polyacrylamide (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. c. 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. e. 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. i. 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). b. The Permittee must divert off -site stormwater (run-on) or groundwater 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. Construction Stormwater General Permit Page 27 West of the Cascade Mountains Crest: Temporary pipe slope drains must handle the peak 10-minute flow rate from a Type 1A, 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. e. Place check dams at regular intervals within constructed channels that are cut down a slope. 7. Protect Drain Inlets 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: West of the Cascade Mountains Crest: Channels must handle the peak 10- minute flow rate from a Type 1A, 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 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." 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. Construction Stormwater General Permit Page 28 Control Pollutants Design, install, implement and maintain effective pollution prevention measures to minimize the discharge of pollutants. The Permittee must: 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. Minimize storage of hazardous materials on -site. Safety Data Sheets (SDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. 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 of 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 pumping and mixer washout waters. (Also refer to the definition for "concrete wastewater" in Appendix A — Definitions.) 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 truck drums onto the ground, or into storm drains, open ditches, streets, or streams. Washout of small concrete handling equipment may be disposed of in a formed area awaiting concrete where it will not contaminate surface or groundwater. Do not dump excess concrete on site, except in designated concrete washout areas. Concrete spillage or concrete discharge directly to groundwater or surface waters of the State is Construction Stormwater General Permit Page 29 prohibited. At no time shall concrete be washed off into the footprint of an area where an infiltration BMP will be installed. Obtain written approval from Ecology before using any chemical treatment, with the exception of CO2, dry ice or food grade vinegar, 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 Permittees must discharge foundation, vault, and trench dewatering water, which have characteristics similar to stormwater runoff at the site, in conjunction with BMPs to reduce sedimentation before discharge to a sediment trap or sediment pond. b. Permittees may discharge clean, non -turbid dewatering water, such as well -point groundwater, 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: Infiltration 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. 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 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. Construction Stormwater General Permit Page 30 12. Manage the Project a. Phase development projects to the maximum degree practicable and take into account seasonal work limitations. b. 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. 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 on -site LID Stormwater Management is to reduce the disruption of the natural site hydrology through infiltration. LID BMPs are permanent facilities. a. Permittees must protect all LID BMPs (including, but not limited to, 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 BMPs 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 LID BMPs by protecting against compaction by construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. c. Permittees must control erosion and avoid introducing sediment from surrounding land uses onto permeable pavements. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment -laden runoff onto permeable pavements or base materials. 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 BMPs 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. The direction of north, property lines, and existing structures and roads. Cut and fill slopes indicating the top and bottom of slope catch lines Construction Stormwater General Permit Page 31 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. S10. NOTICE OF TERMINATION Partial terminations of permit coverage are not authorized. A. The site is eligible for termination of coverage when it has met any of the following conditions: 1. 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 S10.A.1 have been sold and/or transferred (per Special Condition S2.A), 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, WA 98504-7696 Construction Stormwater General Permit Page 32 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 31st calendar day following the date Ecology receives a complete NOT form, unless Ecology notifies the Permittee that termination request is denied because the Permittee has not met the eligibility requirements in Special Condition S10.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. Construction Stormwater General Permit Page 33 GENERAL CONDITIONS G1. 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: 1. 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. 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: 1 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 knowledge and belief, true, accurate, and complete. 1 am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Construction Stormwater General Permit Page 34 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. G4. GENERAL PERMIT MODIFICATION AND REVOCATION 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 43.2113 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. 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. Construction Stormwater General Permit Page 35 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. G8. DUTY TO REAPPLY 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, WA 98504-7696 G9. REMOVED SUBSTANCE 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. G10. DUTY TO PROVIDE INFORMATION 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)]. Construction Stormwater General Permit Page 36 G11. OTHER REQUIREMENTS OF 40 CFR All other requirements of 40 CFR 122.41 and 122.42 are incorporated in this permit by reference. G12. ADDITIONAL MONITORING Ecology may establish specific monitoring requirements in addition to those contained in this permit by administrative order or permit modification. G13. 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. 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. G14. 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 SS.F, 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. G15. PROPERTY RIGHTS This permit does not convey any property rights of any sort, or any exclusive privilege. G16. 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. Construction Stormwater General Permit Page 37 G17. 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. G18. 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. G19. 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: 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. G20. 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. G21. 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 unavoidable interruption of Construction Stormwater General Permit Page 38 operation and degradation of effluent quality, must be scheduled during non -critical water quality periods and carried out in a manner approved by Ecology. G22. 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. G23. 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 43.21E 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 43.21B 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 nonapplicability 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. G24. SEVERABILITY 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. G25. BYPASS PROHIBITED 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 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. 1. Bypass of stormwater is consistent with the design criteria and part of an approved management practice in the applicable stormwater management manual. Bypass for essential maintenance without the potential to cause violation of permit limits or conditions. Construction Stormwater General Permit Page 39 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. 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.F 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. 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. Steps taken or planned to reduce, eliminate, and prevent reoccurrence of the bypass. 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 Construction Stormwater General Permit Page 40 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. Construction Stormwater General Permit Page 41 APPENDIXA - DEFINITIONS 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, 2021, or before the date the operator's complete permit application is received by Ecology, whichever is later. TMDLs completed after a 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. 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 Stormwater General Permit Page 42 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 groundwater. Construction Activity means land disturbing operations including clearing, grading or excavation which disturbs the surface of the land (including off -site disturbance acreage related to construction -support activity). 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. Construction Support Activity means off -site acreage that will be disturbed as a direct result of the construction project and will discharge stormwater. For example, off -site equipment staging yards, material storage areas, borrow areas, and parking areas. 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 soil means soil which contains contaminants, pollutants, or hazardous substances that do not occur naturally or occur at levels greater than natural background. Contaminated groundwater means groundwater 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. 2. The pollutant removal performance expected from the BMPs selected. Construction Stormwater General Permit Page 43 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. 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 groundwater 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 groundwater 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 groundwater 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 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 completion of all soil disturbing activities at the site and the establishment of permanent vegetative cover, or equivalent permanent stabilization measures (such as pavement, riprap, gabions, or geotextiles) which will prevent erosion. See the applicable Stormwater Management Manual for more information on vegetative cover expectations and equivalent permanent stabilization measures. Construction Stormwater General Permit Page 44 Groundwater 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 sub -stance as defined in RCW 70.105.010(14) 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, 42U.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 S10 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 • 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. Construction Stormwater General Permit Page 45 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 the 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 non-stormwater 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 groundwater drainage, redirecting stream natural flows, or for conveyance of irrigation water/return flows that coincidentally convey stormwater are considered the receiving water. 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. Construction Stormwater General Permit Page 46 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 groundwater quality or sediment management standards. Significant Concrete Work means greater than 1000 cubic yards placed or poured concrete or recycled 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 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. Construction Stormwater General Permit Page 47 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. Transfer of Coverage (TOC) means a request for transfer of coverage under this general permit as specified by Special Condition S2.A 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. 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. 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 Construction Stormwater General Permit Page 48 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 S9.13.9. Construction Stormwater General Permit Page 49 APPENDIX B - ACRONYMS 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 CPD Common Plan of Development 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 FIR 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 Construction Stormwater General Permit Page 50 F. 303(d) List Information o Assessed Waters/Sedimento Water y Category 5 - 303d y Category 4C y Category 4B y Category 4A Category 2 y Category 1 Sediment ® Category 5 - 303d ® Category 4C ® Category 4B ® Category 4A Category 2 ® Category 1 E 0 O PugeI Or Mal 2*: Z Q L EV Q f8 a e, O. N Daley St : C ma Cen»r Edmonds Pbyfibw Main St �C,%41 o Dayton St Attple St YOaPafk Alder St Walnu St Ednw ida m She1, N t�tfl 0tl H Y� •V� dnnod: �4 < 3 da� P. i A Ce �'ut• St x � 21, � roal r 3 220th a > L Q _ m = Q Listing ID: 42488 Main Listing Information Listing ID: 42488 Current Category: 5 11�— Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Water view Category History) Parameter: Bacteria W01 Project: None Designated Use: None Assessment Unit Assessment Unit ID: 4712213A9 County: Snohomish WRIA: 8 - Cedar-Sammamish Basis Statement Location ID [303D ITEDWARDSPI — In 2008, 2 out of 12 (16.7%) samples exceeded the percent criterion (43 coV100 mL). The geometric mean oT19.1 col/100 mL exceeded the geometric mean criterion (14 coV100 mL). Location ID [303D ITEDWARDSP] — In 2007, 1 out of 12 (8.3%) samples exceeded the percent criterion (43 col/100 mL). The geometric mean of-7.2 col/100ml- did not exceed the geometric mean criterion (14 col/100 mL). Location ID [303D_ITEDWARDSP] -- In 2006, 3 out of 12 (25%) samples exceeded the percent criterion (43 coV100 mL). The geometric mean of 6.9 col/100ml- did not exceed the geometric mean criterion (14 col/100 mL). _ Location ID [303D_ITEDWARDSP] — In 2005, 3 out of 12 (25%) samples exceeded the percent criterion (43 col/100 mL). The geometriRemarks This listing contains both enterococcus and fecal coliform bacteria data. Impairment was determined by exceedance of both fecal coliform criteria in 2008 and 2007. Marina Beach is an off leash dog park. A swimming advisory sign was posted in 2007. Combined Listing: Listing IDs 45098, 46736, 46735. 46734, 46031 were rolled into this listing Data . Study Id Location Id EPABEACH SNO031A EPABEACH SNO031B EPABEACH SNO031C EPABEACH SNO031 D EPABEACH SNO031E EPABEACH SNO031F KCmar-1 303D ITEDWARDSP 0 Map Link Listing ID: 36159 Main Listing Information Listing ID: 36159 Current Category: 4C 6E—) Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Habitat View Category History) Parameter: Fish And Shellfish Habitat WOI Project: None Designated Use: None Assessment Unit Assessment Unit ID: 4712213A9 County: Snohomish WRIA: 8 - Cedar-Sammamish Basis Statement Thom. et al 1998 show that eelgrass beds at the Edmonds Ferry Dock are impaired due to inorganic nitrogen loading resulting in human - caused eutrophication No Remarks Entered Data . No Source Records 0 Map Link Listing ID: 42476 Main Listing Information Listing ID: 42476 Current Category: 2 C-�— Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Water view Category Hist0 Parameter: Ammonia -IN WOI Project: None Designated Use: None Assessment Unit Assessment Unit ID: 4712213A9 County: Snohomish WRIA: 8 - Cedar-Sammamish Basis Statement King County data (submitted by Kimberle Stark on 4115104) station ITEDWARDSPT (Edwards Point) shows 1 sample exceeded the criterion on 10/28/02 No Remarks Entered Data Sources No Source Records 0 Map Link Listing ID: 64427 . Listing ID: 64427 Current Category: 1 Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Tissue View Category History Parameter: Mercury WQI Project: None Designated Use: None Assessment Unit Assessment Unit ID: 4712213A9 County: King WRIA: 8 - Cedar-Sammamish Basis Statement Location ID [303D ITEDWARDSP) - In 2006, a composite sample of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Mercury. Location ID [303D ITEDWARDSP) - In 2007, composite samples of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Mercury. Location ID [303D ITEDWARDSP] - In 2008, composite samples of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Mercury. No Remarks Entered Data . Study Id Location Id KCmar-1 303D ITEDWARDSP 0 Map Link Listing ID: 64428 Listing ID: 64428 Current Category: 1 F— Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Tissue View Category History J Parameter: Nickel WQI Project: None Designated Use: None Assessment Unit Assessment Unit ID: 4712213A9 County: King WRIA: 8 - Cedar-Sammamish Basis Statement J Location ID [303D ITEDWARDSP) - In 2006, a composite sample of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Nickel. Location ID [303D ITEDWARDSP) - In 2007, composite samples of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Nickel. Location ID [303D ITEDWARDSP) - In 2008, composite samples of Butter clam (Saxidomus giganteus) soft -part tissue did not exceed the National Toxics Rule criterion for Nickel. No Remarks Entered Data . Stud Id Location Id Kr-1Cma303D ITEDWARDSP Map Link 0 Map Link Listing ID: 65384 AIRUIIIAWAIM. . Listing ID: 65384 Current Category: 1 Waterbody Name: PUGET SOUND (NORTH -CENTRAL) Medium: Water view Category HistO Parameter: Temperature WOI Project: None Designated Use: None Assessment Unit Assessment Unit ID:-3712213A9 County: King WRIA: 8 - Cedar-Sammamish Basis Statement Location ID [303D_ITEDWARDSP] -- In 2006, 1 out of 6 (17%) samples showed an excursion beyond the criterion of 13 degrees Celsius. Location ID [303D_ITEDWARDSP] -- In 2005, 3 out of 12 (25%) samples showed an excursion beyond the criterion of 13 degrees Celsius. Location ID [303D_ITEDWARDSP] -- In 2004, 4 out of 12 (33%) samples showed an excursion beyond the criterion of 13 degrees Celsius. Remarks This listing was reviewed by Department of Ecology Environmental Assessment Program staff, who concluded that the excursions in this water body are a natural condition and that human influences in this area are not sufficient to cause the observed temperature increases Data Sources Stud Id Location Id KCmar-1 303D ITEDWARDSP Map Link 0 Map Link G. Engineering Calculations N/A