The URL can be used to link to this page

APPROVED STM RESUB 1 BLD2021-1653+Storm_Drainage_Report+4.28.2022_4.29.49_PM+2835207RESUB C � ENGINEERING 250 411 Ave S Ste 200 Edmonds, WA 98020 Phone: (425)778-8500 Fax: (425) 778-5536 civil & structural engineering & planning BLD2021-1653 Apr 29 2022 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT DRAINAGE REPORT Apollo Apartments 23601 Highway 99 Edmonds, WA 98026 0412812022 CG Project No.: 20261.20 COMPLIES WITH APPLICABLE CITY STORMWATER CODE 05/24/2022 Table of Contents Section I — Project Overview Section II — Off -Site Analysis Section III — Permanent Stormwater Control Plan Section IV —Construction Stormwater Pollution Prevention Plan (CSWPPP) Section V — Special Reports and/or Studies Section VI — Other Permits Section VII — Bond Quantities, Declaration of Covenant, & Operation and Maintenance Manual 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 1 Section I — Project Overview Section I Summary Overview Project Applicant/Engineer Existing Condition Developed Condition Minimum Requirements nvarviaiei This drainage report has been written for a new 5-story apartment building project with two parking levels underneath on a four -parcel site (1.76 ac) located at 23601 Highway 99 in Edmonds (Tax Parcel Numbers: 0045-1900-100201, 0045-1900-100202, 0045-1900-100203, 0045-1900-100204). The building will have a roof area of approximately 40,847 sf (0.94 ac). The development also consists of road and side walk improvements and utility trenching in the right-of-ways (ROW) of Highway 99 and 236th St SW. The site is currently developed with two office buildings and associated parking lots, walkways and landscaping. The project will meet minimum requirements 1 through 9 of the 2014 Department of Ecology Stormwater Management Manual for Western Washington (herein referred to as the SWMMWW) and comply with those requirements as modified in the Edmonds Community Development Code Chapter 18.30 (herein referred to as ECDC 18.30) and the December 2016 Addendum to ECDC 18.30 (herein referred to as the Edmonds Stormwater Addendum). Proiect Applicant/Engineer Jared Underbrink, PE CG Engineering 250 4th Ave S, Suite 200 Edmonds, WA 98020 425.778.8500 jaredu@cgengineering.com Existing Condition The site is currently developed with office buildings, parking and landscaping. All existing impervious areas on -site are expected to be demolished for the proposed construction. The site sits at the SE corner of the intersection of Highway 99 and 236th St SW in Edmonds. The site is bordered by Highway 99 to the west, 236th St SW to the north, an apartment complex to the east and townhomes and a business lot to the south. Storm, water and sewer utilities are located in Highway 99 and 236th St SW. The project proposes to access water from Highway 99 and storm and sewer from 236th St SW. Site topography descends from west to east with an average slope of approximately 12%. The site does not appear to take on any significant upstream flows as it is located at the top of a hill. The site is in the Lake Ballinger Watershed. CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 2 Site soils generally consist of asphalt pavement or sod over undocumented fill and undisturbed native soils consisting of weathered glacial till over unweathered glacial till. Groundwater and perched groundwater seepage was not observed in the geotechnical borings at the time of drilling. However, there was evidence that light, perched groundwater seepage was developing near the base of the weathered glacial till and fill layers during periods of extended precipitation. Infiltration was determined by the geotechnical engineer to be infeasible due to hydraulically -restrictive glacial till deposits, limited space outside of the large building footprint, and infiltrating into loose fill soils could cause settling. See Section V for the full geotechnical report. The existing land coverage on -site was considered as follows: Roof: 9,908 sf (0.23 ac) Pavement: 40,087 sf (0.92 ac) Lawn/Landscaping: 26,821 sf (0.62 ad Total: 76,816 sf (1.76 ac) Developed Condition The project consists of the construction of an approximately 40,847 sf building and sub -level parking that will take up most of the site. There will also be street and sidewalk improvements in the ROW. The total of new plus replaced hard surfaces (including ROW) is 71,915 sf (1.65 ac). Disturbance will affect the entire site. The site will utilize a rectangular detention vault that will be 208' long, 22.5' wide and 10.5' deep (inside dimensions). The detention vault will have a flow control structure and be located under the lowest parking level. Most runoff on -site will drain to the detention vault through roof drains and discharge through a flow control structure out to an existing catch basin in 236th St SW. There will be new sidewalk in the ROW parallel to the property lines on Highway 99 and 236t" St SW. Other work in the ROW consists of utility trenching and asphalt overlay/pavement restoration. The project's proposed hard surface areas (including ROW) are as follows: Roof: 40,847 sf (0.94 ac) Driveway, flat: 6,735 sf (0.16 ac) Driveway, mod: 1,050 sf (0.02 ac) Underground Parking (outside bldg ft print): 12,362 sf (0.28 ac) Sidewalk/on-site walkways, flat: 8,769 sf (0.20 ac) Sidewalk, mod: 2,152 sf (0.05 ac) Total: 71,915 sf (1.65 ac) CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 3 The new and replaced pollution -generating impervious areas are as follows: Uncovered Driveway: 7,785 sf (0.18 ac) Total: 7,785 sf (0.18 ac) The pervious areas modeled in WWHM are as follows: C, lawn, flat: 1,401 sf (0.03 ac) C, lawn, mod: 3,500 sf (0.08 ac) Total: 4,901 sf (0.11 ac) The impervious areas above were used to model the project in WWHM. The total lot area (1.76 ac) was used as the basin area for modeling. The remaining area (0.11 ac) was split between moderately -sloped grass and flat grass with the moderately -sloped grass being the actual amount on the plan and the flat grass being what was left over. See surfaces exhibit in Figure 1-4 later in this section and see Section III for WWHM report and more. a z 34TH 5 z ov �, Total project area: 1.76 ac Total hard surfaces: 1.64 ac PGHS/PGIS: 0.18 ac W. NMI �• ■ a 3,zb■� �S 99 d z353] $ x3 x w3. :.363r � ■ TH S7.SW z� erg � � �,�■ _� � II Figure 1-1: Vicinity map (from Edmonds GIS) 4M 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section I, Page 4 •, n r� 4 r� J � Y • 1 �•i r# .1 •M �i y a Figure 1-2: Aerial image (from Edmonds GIS) C 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 5 16-1 2 w 16-690 -392 16 393 _ FET 6 14 1 b-34 t b 3 23 16-bb :Ora'=R T;, Pn 1 fr15 P616-20 6-194 16-76 6-243 0 6 45 -242 0 � 6-195 ;9 .. 23635 titnt 16-7 6-240 Figure 1-3: Map with storm pipe material (from Edmonds GIS) 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section I, Page 6 J I I I qu GO � 1~ 71 13 ID .. �� UNDERGROUND PARKING DRIVEWAY, FLAT DPIVEWAY, "01) S IPEWALK. FLAT jII`-FVVAi K. h1061) LAWN, MOO LAWN, FLAT: AREA LEF'rovERAFTER INCLUDING HARE) SURFACISARD LA'hN, MOD !N PASI?4ARE A Figure 1-4: Developed conditions exhibit C 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 7 Minimum Requirements Stormwater requirements were determined per the Edmonds Stormwater Addendum, ECDC 18.30, and the SWMMWW. This report is based on the steps recommended in Chapter 7 of the Edmonds Stormwater Addendum and Section 3.1.7 of the SWMMWW. The project is classified as a Category 2 because it will result in more than 5,000 sf of new plus replaced hard surfaces. Following the flow chart in Figure 1-5, Minimum Requirements #1-9 will apply to all new and replaced hard surfaces. Minimum Requirement #1: Preparation of Stormwater Site Plans: The stormwater site plan consists of this report and the civil drawings, and is prepared in accordance with Chapter 3 of Volume 1 of the SWMMWW and the requirements in the Edmonds Stormwater Addendum. Minimum Requirement #2: Construction Stormwater Pollution Prevention Plan (SWPPP): The SWPPP shall include a narrative and drawings. Since this project consists of more than one acre of land disturbance, the Department of Ecology's SWPPP template was used. See Section IV and the civil drawings for more. Minimum Requirement #3: Source Control of Pollution: All known, available and reasonable source control BMPs must be required for all projects approved by the City. Mandatory Operational Source Control BMPs must be implemented by forming a pollution prevention team, good housekeeping practices, preventive maintenance, spill prevention and cleanup, employee training, inspections, and record keeping. See Section IV for a source control discussion and Section VII for source control guide sheets from the SWMMWW. Minimum Requirement #4: Preservation of Natural Drainage Systems and Outfalls: Natural drainage patterns shall be maintained, and discharges from the project site shall occur at the natural location, to the maximum extent practicable. The manner by which runoff is discharged from the project site must not cause a significant adverse impact to downstream receiving waters and down -gradient properties. All projects shall submit an off -site qualitative analysis. A qualitative analysis of the upstream and downstream system entering the site is presented in Section 11. Minimum Requirement #5: On -Site Stormwater Management: This project is classified as a Category 2 project per the Edmonds Stormwater Addendum. To meet the On -site Stormwater Management requirement, on -site stormwater BMPs must be evaluated for feasibility and implemented if applicable. This is discussed in Section III. Minimum Requirement #6: Runoff Treatment: This requirement applies to the new plus replaced hard surfaces and the converted vegetated areas that will generate pollutants and be conveyed to the public storm system through stormwater runoff. The proposed roof is consistently called out to be coated with an inert, non -leachable enamel coating on civil, structural and architectural plans and, therefore, will not be a pollution -generating surface. The courtyard area consists of grass and concrete and is not expected to be a pollution -generating surface. Runoff treatment is required for the proposed driveway access 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section I, Page 8 because it consists of more than 5,000 sf of new pollution -generating hard surfaces that are exposed to rainfall. Since the site is in the Lake Ballinger watershed, phosphorous treatment and enhanced treatment are required. See Section III and the civil plans for more. Minimum Requirement #7: Flow Control: Projects must provide flow control to reduce the impacts of stormwater runoff from hard surfaces and land cover conversions. Flow control is required for projects in which the total of effective impervious surfaces is 10,000 sf or more in a threshold discharge area, convert % acres or more of vegetation to lawn or landscape or projects that cause a 0.15 cfs or more increase in the 100-year flow frequency. This project proposes more than 10,000 sf of effective impervious surfaces and flow control is required. A detention vault has been designed for this project to meet the flow control standard. See Section III and the civil plans for more. Minimum Requirement #8: Wetlands Protection: Not applicable. There is a wetland identified by Edmonds GIS in Lake Ballinger. However, the increase in impervious surface from existing to proposed conditions is relatively small in a 2+ square mile watershed and is anticipated to have little or no effect on the wetland identified in Lake Ballinger. Minimum Requirement #9: Operation and Maintenance: An operation and maintenance manual that is consistent with the provisions in Volume I and Volume V of the SWMMWW is required for proposed Stormwater Treatment and Flow Control BMPs/facilities. The party (or parties) responsible for maintenance and operation shall be identified in the operation and maintenance manual. For private facilities approved by the City, a copy of the operation and maintenance manual shall be retained on -site or within reasonable access to the site, and shall be transferred with the property to the owner. For public facilities, a copy of the operation and maintenance manual shall be retained in the appropriate department. A log of maintenance activity that indicates what actions were taken shall be kept and be available for inspection. C 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section I, Page 9 D x.sthe project result in 2,000 square feet, or greater, of new plus replaced hard surfacc area? OR Laws the land disturbing activity total 7,000 square feet or greater? me Minimum RcquircmcnLs No. I through 5 apply Minntunn Requirement No. 2 applies Ne= Question Does the proj out add 5,000 square feet or more ofnciv plus replaced hard surfaces'.' OR Convert 0.75 acres or more of vegetation to lawn or landscaped areas? OR Convert 2.5 acros or more of native vegetation to pastu rr? es Is this a road rclatud project? All Minimum Requiremcnts yes apply to the new and replaced hard surfaces and converted vegetation areas_ All Minimum Requirements apply to the new hard surfaces and converted vegetation areas. Yes Does the project acid 5,000 square feet or more of new hard surfaces? Yes Do new hard surfaces add 50%or more to the existing hard surfaces within the project limits? No No I No additional rcquircments. Figure 1-5: Flow chart for determining requirements for development (Figure 3.1 in the Edmonds Stormwater Addendum) CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section II, Page 1 Section II — Off -Site Analysis Section II Summary Task 1— Define and map the study area Task 2 — Review all available information of the study area Task 3 — Field inspect the area Task 4 - Describe the drainage system, and its existing and predicted problems Task 1— Define and map the study area An initial qualitative analysis shall document potential off -site impacts of stormwater discharges for each upstream drainage system entering a site, and each downstream drainage system leaving a site according to Section 6.2 of the Edmonds Stormwater Addendum. The downstream analysis shall extend from the project site to the receiving water, up to one -quarter mile or to the point at which runoff will enter the City's MS4, whichever is less. Runoff from the site is proposed to enter the City's MS4 through an existing catch basin in 2361h St SW. The downstream flowpath can be seen below in Figure II-1 from the City GIS map. The site is located in the Lake Ballinger Watershed. o II ii PROPOSED DISCHARGE ! ""S LOCATION FOR SITE 41 RUNOFF IN EXISTING CB xx (CITY MS4) P�16-13 � 8 E IN P�12 P 1 �,xx L,I x •8 INGER OU cPD1611=PD16'1 i` v� G xxm 0 0 • � 5T A� o-ED1617 =� o a • f I' o PD16-19 w p Figure II-1: Vicinity map showing stormwater flow path to outfall (from Edmonds GIS) Task 2 — Review all available information on the study area Existing stormwater improvements were determined from the survey and the City GIS map. Runoff from the site is proposed to discharge into CB 16-323 (from Edmonds GIS) where it will then be conveyed east through a series of 8" to 30" diameter pipes all the way to 76th Ave W. Conveyance turns north for about 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section II, Page 2 270' and turns east where it discharges into Lake Ballinger through about 760 lineal feet of pipes. The entire flow path consists of approximately 2,500 lineal feet of concrete pipes and structures. Task 3 — Field inspect the study area A site visit was done on the afternoon of August 18, 2020. The weather was clear and it had not rained that day. From evaluating surrounding conditions, the site does not appear to take on significant upstream runoff since most runoff upstream in the ROW appears to be sloped to sheet flow runoff to the gutter and into catch basins. The site contains existing stormwater infrastructure consisting of catch basins and conveyance pipes that will be removed for the proposed development. Existing catch basins on -site and in the ROW appeared to be free of problems. See Figures II-2 through II-9 for photos from the field inspection. The photos only show images of the site walk to the site's proposed point of discharge. However, the field inspection was conducted all the way to Lake Ballinger. There were no drainage problems to be noted and no predicted problems with the stormwater route from the site. Task 4 — Describe the drainage system, and its existing and predicted problems A Type II catch basin with a riser pipe was observed on the field inspection and was not picked up by the surveyor and it is assumed that the site utilizes this as a flow control structure (see Figure II-7). This project proposes to route all site runoff to a detention vault and flow control structure beneath the building and discharge to the public storm system in 236t" St SW. To be conservative, the detention vault was designed to include the new and replaced hard surface areas in the ROW even though this area will not be contributing runoff to the vault. There were no problems observed with the existing system on the field inspection and there are no problems anticipated with the proposed development (see Section III and civil plans for more details). 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section II, Page 3 Figure II-2: SW corner of site, facing NE EXISTI POLEd A Figure II-3: SW corner of site, facing north C CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section II, Page 4 Figure II-4: West edge of site, facing NE Figure II-5: Near NW corner of site, facing NE C CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section II, Page 5 s Figure II-6: From 236" St SW, facing SW Figure II-7: North edge of site, facing east CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section II, Page 6 Figure II-8: North edge of site, facing NE Figure II-9: NE corner of site, facing east C CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 1 Section III — Permanent Stormwater Control Plan Section III Summary Narrative On -site Stormwater Management Feasibility Review Runoff Treatment Flow Control WWHM2012 Report Nn rrn ti uo This project is classified as a Category 2 per the Edmonds Stormwater Addendum because it results in more than 5,000 sf of new plus replaced hard surfaces. Therefore, the project must address Minimum Requirements #1-9. This section addresses On -site Stormwater Management, Runoff Treatment and Flow Control. On -site Stormwater Management Feasibility Review (MR5) The project must implement on -site stormwater management BMPs to the maximum extent feasible per Minimum Requirement #5. The following BMPs were evaluated per ECDC 18.30.060.D.5.e. for all new plus replaced hard surfaces and land disturbed: Lawn and landscaped areas: 1. Post -construction soil quality and depth in accordance with BMP T5.13 in Chapter 5 of Volume V of the SWMMWW will be used for all disturbed pervious areas. Roofs: 1. Full Dispersion in accordance with BMP T5.30 is infeasible because a 65 to 10 ratio of forested or native vegetation area to impervious area cannot be achieved. Downspout Full Infiltration Systems in accordance with BMP T5.10A are infeasible because based on soil explorations, undocumented fill soils were found. Infiltrating into loose fill soils could cause them to settle. The geotechnical engineer does not recommend infiltration be used on this site. See Section V for full geotechnical report. 2. Bioretention in accordance with Chapter 7 are infeasible because the site cannot be reasonably designed to locate bioretention facilities on slopes less than 8% and lack of separation to hardpan. The courtyard area may be feasible as a bioretention/vegetated roof area, but the feasibility of plumbing conveyance to these areas on its path to underground detention system still needs to be determined. There are only approximately 3,800 sf of these planters so modeling credits toward the detention and amount of on -site stormwater management would be minimal. This will be further detailed in engineering review. 3. Downspout Dispersion Systems in accordance with BMP T5.1013 are infeasible because there is not enough usable area for trenches or splashblocks. 4. A Perforated Stub -Out Connection in accordance with BMP T5.10C is infeasible because the only location available to place a level perforated stub -out connection is under impervious surfaces. 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section III, Page 2 5. Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum are feasible and a detention vault will be used to manage runoff for the roof. The detention vault will be designed for flow control and does not have to be installed to meet Minimum Requirement #5. Other Hard Surfaces: 1. Full Dispersion in accordance with BMP T5.30 is infeasible because a 65 to 10 ratio of forested or native vegetation area to impervious area cannot be achieved. 2. Permeable pavement in accordance with BMP T5.15 in Chapter 5 of Volume V of the SWMMWW is infeasible because of the proposed multi -level parking garages. 3. Bioretention in accordance with Chapter 7 are infeasible because the site cannot be reasonably designed to locate bioretention facilities on slopes less than 8% and lack of separation to hardpan. The courtyard area may be feasible as a bioretention/vegetated roof area, but the feasibility of plumbing conveyance to these areas on its path to underground detention system still needs to be determined. There are only approximately 3,800 sf of these planters so modeling credits toward the detention and amount of on -site stormwater management would be minimal. This will be further detailed in engineering review. 4. Sheet Flow Dispersion in accordance with BMP T5.12, or Concentrated Flow Dispersion in accordance with BMP T5.11 in Chapter 5 of Volume V of the SWMMWW is infeasible because the vegetated flow path cannot be achieved. 5. Detention vaults or pipes in accordance with the Edmonds Stormwater Addendum are feasible and a detention vault will be used to manage runoff for the other hard surfaces of the site. The detention vault will be designed for flow control and does not have to be installed to meet Minimum Requirement #5. A detention vault has been designed to meet the Flow Control duration standard. This is discussed later in this section. Runoff Treatment (MR6) A stormwater treatment facility must be provided because the project will add more than 5,000 sf of pollution -generating hard surface (PGHS) in the form of the proposed driveway access off of 236" St SW. The required treatment was determined using Figure III-1 on the following page and Chapter 2 of Volume V of the SWMMWW. Phosphorous treatment is required because site runoff drains to Lake Ballinger (ECDC 18.30.060.D.6.b.i). Enhanced treatment is required because site runoff discharges to a conveyance system that is tributary to a fresh water that has existing aquatic life. Therefore, a treatment facility must be selected that will provide both phosphorous control and enhanced treatment. Modular Wetlands System Linear (Bio Clean Environmental Services) was selected from DOE's TAPE program's list of emerging stormwater technologies. MWS Linear was selected because it offers both phosphorous and enhanced treatment. The MWS Linear facility chosen was a Vault Type 4-4 since this can handle the proposed water quality flows from the driveway surface. The location detail of the treatment facility can be seen on the civil plans. See civil plans and WWHM report for more. 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section III, Page 3 Table III-1: Water qualitv flows for drivewav (from WWHM) Surface Surface Area (ac) 15-Min Online WQ Flow (cfs) 15-Min Offline WQ Flow (cfs) Driveway (flat) 0.18 0.027 0.0153 Flow Control (MR7) WWHM 2012 was used to model the project site and design the detention vault. The existing basin was modeled as C, Forest, Mod because the site's soils appear to be till based on the USDA's Soil Resource Report and the existing topography appears to be between 5% and 15% based on the survey. The proposed basin was modeled based on the proposed areas from the architectural site plan and includes the proposed frontage improvements as a conservative measure. The proposed basin was connected to a detention vault and iterations of the model were run to get a passing and optimized detention vault matching or subceeding the flow control duration standard (see WWHM report later in this section). The vault was sized with a discharge orifice of 0.46" diameter, which is smaller than the minimum diameter of 0.5". It was the only way to get a passing detention system when considering the low target flows. Per conversations with the City stormwater reviewer, this is allowable if a debris cage/strainer is provided in order to protect against clogging. C 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 4 hnnly'PTctreatmrnf • Ptvseuling Fiasili ■ Any Basic Treatments B.M P ■ Erncrging Tech_ Aanly Infiltration • Infiltration Basin • lnfiltration Trench + Bioretention Step I. Identify Pollutants of Concern and Perform Off -site Analysis to Determine Rwxivine Waters Step 2: Dclerrninc if 'ram an Oil Control Facility iS RegUired - Step 3: Dcterminc if Infiltration for Pollutant Removal is Practicable Apply Oil Control Facillt-V AP! Separator ■ C P Separator • Lincar Sand Filter • Emerging Tech. a Phusphurus Conlrol is Required we Step S: Descrrnine if Enhanced Treatment is fiicquircd No Step 6- Apple a Basic Treatment Facility 49 Biofrltration Swales • Filter Strip Basic Welpond * Wetvault • Treatment W ctlands • Combined Detention/Welpool Sand Filtors • Biorctention + Media Filter Drain • Emerging ,rech, es Apply Phosphorus Control Facility Large Sand Filtcr Large Wetpond* !Media Filter Ywo Facility Treatment Train Emerging Tech.* Appiy an Enhanced Trealment Facility Ib Large Sand Filler Treatment Wetland 1111Compost-amended Vegetated Filtcr Sine • Two Facility Trenimcm Train � Biorctention + Media Filter Drain + Emer6nng Tcch. `When Phoaphdrouc Comrol and Enhanced treatment are required, the Large Wetarnd and certain types of emergng ta[hnologles will I W meet Coth types of treatment regwm remes_ A different or an additlard l Ireatmer: '..',ihLmVm p Will he required Lo meet Enhanced VeaeM. Figure III-1: Treatment Facility Selection Flow Chart (Figure 2.1.1, SWMMWW) GM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 5 WWHM2012 PROJECT REPORT 15-MINUTE TIME STEPS Project Name: Apollo Apts Detention Vault 01.05.21 Site Name: Apollo Apartments Site Address: 23601 Highway 99 City Edmonds Report Date: 1/5/2021 MGS Regoin Puget East 36 Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 03 Version Date: 2019/09/13 Version : 4.2.17 Low Flow Threshold for POC 1 : 50 Percent of the 2 Year High Flow Threshold for POC 1: 50 year PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use C, Forest, Mod Pervious Total Impervious Land Use Impervious Total Basin Total Element Flows To: Surface MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use C, Lawn, Flat C, Lawn, Mod acre 1.76 1.76 acre 0 1.76 Interflow Groundwater acre .03 actual moderately sloping lawn .08 area remaining in basin after including ROW sidewalks CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 6 Pervious Total 0.11 Impervious Land Use acre ROOF TOPS FLAT 0.94 actual roof area on plan DRIVEWAYS FLAT 0.16 actual flat driveway area on plan DRIVEWAYS MOD 0.02 actual moderate sloping driveway area on plan SIDEWALKS FLAT 0.2 actual new/repl flat sidewalk area on plan (includes ROW) SIDEWALKS MOD 0.05 actual moderate sloping sidewalk area on plan (includes ROW) PARKING FLAT 0.28 underground parking area not covered by building roof Impervious Total 1.65 total new/repl on -site & ROW areas Basin Total 1.76 actual lot area Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 Name Vault 1 Width 22.5 ft. Length 208 ft. Depth: 10.5 ft. Discharge Structure Riser Height: 10 ft. Riser Diameter: 18 in. Notch Type: Rectangular Notch Width: 0.010 ft. (1/8") Notch Height: 1.700 ft. Orifice 1 Diameter: 0.46 in. Elevation: 0.5 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.107 0.000 0.000 0.000 0.1167 0.107 0.012 0.000 0.000 0.2333 0.107 0.025 0.000 0.000 0.3500 0.107 0.037 0.000 0.000 0.4667 0.107 0.050 0.000 0.000 0.5833 0.107 0.062 0.001 0.000 0.7000 0.107 0.075 0.002 0.000 0.8167 0.107 0.087 0.003 0.000 0.9333 0.107 0.100 0.003 0.000 1.0500 0.107 0.112 0.004 0.000 1.1667 0.107 0.125 0.004 0.000 1.2833 0.107 0.137 0.005 0.000 1.4000 0.107 0.150 0.005 0.000 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 7 1.5167 0.107 0.162 0.005 0.000 1.6333 0.107 0.175 0.006 0.000 1.7500 0.107 0.188 0.006 0.000 1.8667 0.107 0.200 0.006 0.000 1.9833 0.107 0.213 0.007 0.000 2.1000 0.107 0.225 0.007 0.000 2.2167 0.107 0.238 0.007 0.000 2.3333 0.107 0.250 0.007 0.000 2.4500 0.107 0.263 0.008 0.000 2.5667 0.107 0.275 0.008 0.000 2.6833 0.107 0.288 0.008 0.000 2.8000 0.107 0.300 0.008 0.000 2.9167 0.107 0.313 0.008 0.000 3.0333 0.107 0.325 0.009 0.000 3.1500 0.107 0.338 0.009 0.000 3.2667 0.107 0.351 0.009 0.000 3.3833 0.107 0.363 0.009 0.000 3.5000 0.107 0.376 0.009 0.000 3.6167 0.107 0.388 0.010 0.000 3.7333 0.107 0.401 0.010 0.000 3.8500 0.107 0.413 0.010 0.000 3.9667 0.107 0.426 0.010 0.000 4.0833 0.107 0.438 0.010 0.000 4.2000 0.107 0.451 0.011 0.000 4.3167 0.107 0.463 0.011 0.000 4.4333 0.107 0.476 0.011 0.000 4.5500 0.107 0.488 0.011 0.000 4.6667 0.107 0.501 0.011 0.000 4.7833 0.107 0.513 0.011 0.000 4.9000 0.107 0.526 0.012 0.000 5.0167 0.107 0.539 0.012 0.000 5.1333 0.107 0.551 0.012 0.000 5.2500 0.107 0.564 0.012 0.000 5.3667 0.107 0.576 0.012 0.000 5.4833 0.107 0.589 0.012 0.000 5.6000 0.107 0.601 0.013 0.000 5.7167 0.107 0.614 0.013 0.000 5.8333 0.107 0.626 0.013 0.000 5.9500 0.107 0.639 0.013 0.000 6.0667 0.107 0.651 0.013 0.000 6.1833 0.107 0.664 0.013 0.000 6.3000 0.107 0.676 0.013 0.000 6.4167 0.107 0.689 0.014 0.000 6.5333 0.107 0.701 0.014 0.000 6.6500 0.107 0.714 0.014 0.000 6.7667 0.107 0.727 0.014 0.000 6.8833 0.107 0.739 0.014 0.000 7.0000 0.107 0.752 0.014 0.000 7.1167 0.107 0.764 0.014 0.000 7.2333 0.107 0.777 0.014 0.000 7.3500 0.107 0.789 0.015 0.000 7.4667 0.107 0.802 0.015 0.000 7.5833 0.107 0.814 0.015 0.000 7.7000 0.107 0.827 0.015 0.000 7.8167 0.107 0.839 0.015 0.000 7.9333 0.107 0.852 0.015 0.000 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 8 8.0500 0.107 0.864 0.015 0.000 8.1667 0.107 0.877 0.015 0.000 8.2833 0.107 0.889 0.016 0.000 8.4000 0.107 0.902 0.017 0.000 8.5167 0.107 0.915 0.019 0.000 8.6333 0.107 0.927 0.022 0.000 8.7500 0.107 0.940 0.025 0.000 8.8667 0.107 0.952 0.029 0.000 8.9833 0.107 0.965 0.033 0.000 9.1000 0.107 0.977 0.036 0.000 9.2167 0.107 0.990 0.040 0.000 9.3333 0.107 1.002 0.045 0.000 9.4500 0.107 1.015 0.050 0.000 9.5667 0.107 1.027 0.055 0.000 9.6833 0.107 1.040 0.060 0.000 9.8000 0.107 1.052 0.082 0.000 9.9167 0.107 1.065 0.089 0.000 10.033 0.107 1.078 0.192 0.000 10.150 0.107 1.090 1.014 0.000 10.267 0.107 1.103 2.219 0.000 10.383 0.107 1.115 3.544 0.000 10.500 0.107 1.128 4.735 0.000 10.617 0.107 1.140 5.596 0.000 10.733 0.000 0.000 6.110 0.000 ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.76 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:0.11 Total Impervious Area:1.65 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.030024 5 year 0.04985 10 year 0.061102 25 year 0.072834 50 year 0.079927 100 year 0.085822 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.013404 5 year 0.021216 10 year 0.028512 25 year 0.040858 50 year 0.052865 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 9 100 year 0.067817 Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. Year Predeveloped Mitigated 1902 0.041 0.012 1903 0.014 0.010 1904 0.036 0.012 1905 0.016 0.014 1906 0.006 0.009 1907 0.047 0.012 1908 0.029 0.011 1909 0.031 0.013 1910 0.055 0.012 1911 0.026 0.012 1912 0.113 0.015 1913 0.044 0.015 1914 0.010 0.010 1915 0.014 0.014 1916 0.024 0.013 1917 0.011 0.011 1918 0.029 0.018 1919 0.021 0.012 1920 0.027 0.012 1921 0.027 0.014 1922 0.031 0.012 1923 0.027 0.014 1924 0.014 0.011 1925 0.013 0.011 1926 0.025 0.012 1927 0.033 0.012 1928 0.021 0.013 1929 0.052 0.015 1930 0.027 0.013 1931 0.027 0.014 1932 0.020 0.013 1933 0.023 0.014 1934 0.071 0.157 1935 0.023 0.015 1936 0.038 0.014 1937 0.035 0.012 1938 0.031 0.014 1939 0.001 0.010 1940 0.025 0.014 1941 0.026 0.011 1942 0.038 0.041 1943 0.012 0.012 1944 0.039 0.015 1945 0.027 0.015 1946 0.026 0.012 1947 0.018 0.010 1948 0.060 0.012 1949 0.051 0.015 1950 0.026 0.012 1951 0.032 0.014 C CM ENGINEERING POC #1 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 10 1952 0.103 0.015 1953 0.083 0.032 1954 0.023 0.013 1955 0.019 0.011 1956 0.013 0.011 1957 0.034 0.015 1958 0.083 0.087 1959 0.050 0.060 1960 0.017 0.011 1961 0.050 0.039 1962 0.025 0.014 1963 0.011 0.010 1964 0.023 0.010 1965 0.060 0.084 1966 0.010 0.011 1967 0.024 0.010 1968 0.030 0.014 1969 0.021 0.013 1970 0.038 0.012 1971 0.063 0.016 1972 0.041 0.014 1973 0.048 0.015 1974 0.032 0.012 1975 0.075 0.037 1976 0.030 0.013 1977 0.018 0.012 1978 0.057 0.052 1979 0.015 0.011 1980 0.028 0.013 1981 0.029 0.013 1982 0.019 0.012 1983 0.047 0.014 1984 0.012 0.011 1985 0.028 0.011 1986 0.022 0.013 1987 0.048 0.017 1988 0.035 0.015 1989 0.028 0.011 1990 0.035 0.012 1991 0.027 0.014 1992 0.041 0.031 1993 0.034 0.014 1994 0.060 0.013 1995 0.014 0.011 1996 0.070 0.079 1997 0.031 0.013 1998 0.029 0.013 1999 0.000 0.008 2000 0.021 0.014 2001 0.015 0.011 2002 0.057 0.013 2003 0.031 0.013 2004 0.036 0.014 2005 0.052 0.014 2006 0.020 0.013 2007 0.022 0.013 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 11 2008 0.030 0.013 2009 0.018 0.011 2010 0.015 0.014 2011 0.018 0.013 2012 0.026 0.011 2013 0.022 0.011 2014 0.014 0.010 2015 0.066 0.011 2016 0.008 0.011 2017 0.052 0.015 2018 0.094 0.077 2019 0.100 0.075 2020 0.034 0.012 2021 0.039 0.016 2022 0.013 0.011 2023 0.032 0.015 2024 0.127 0.013 2025 0.025 0.013 2026 0.046 0.015 2027 0.019 0.011 2028 0.009 0.010 2029 0.032 0.015 2030 0.068 0.015 2031 0.017 0.011 2032 0.013 0.009 2033 0.015 0.011 2034 0.017 0.011 2035 0.072 0.038 2036 0.039 0.014 2037 0.006 0.010 2038 0.044 0.015 2039 0.002 0.008 2040 0.013 0.012 2041 0.020 0.011 2042 0.078 0.030 2043 0.033 0.016 2044 0.045 0.015 2045 0.028 0.015 2046 0.033 0.052 2047 0.021 0.014 2048 0.029 0.012 2049 0.028 0.013 2050 0.017 0.012 2051 0.029 0.013 2052 0.017 0.014 2053 0.029 0.045 2054 0.056 0.015 2055 0.011 0.010 2056 0.011 0.011 2057 0.019 0.014 2058 0.023 0.015 Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 12 1 0.1267 0.1568 2 0.1131 0.0866 3 0.1031 0.0843 4 0.1003 0.0788 5 0.0941 0.0766 6 0.0834 0.0748 7 0.0828 0.0598 8 0.0782 0.0519 9 0.0749 0.0517 10 0.0722 0.0449 11 0.0711 0.0406 12 0.0700 0.0393 13 0.0681 0.0384 14 0.0660 0.0370 15 0.0631 0.0316 16 0.0605 0.0311 17 0.0600 0.0295 18 0.0598 0.0182 19 0.0572 0.0165 20 0.0571 0.0159 21 0.0557 0.0158 22 0.0547 0.0158 23 0.0524 0.0154 24 0.0520 0.0154 25 0.0518 0.0153 26 0.0509 0.0153 27 0.0496 0.0152 28 0.0495 0.0152 29 0.0485 0.0152 30 0.0478 0.0151 31 0.0474 0.0151 32 0.0468 0.0150 33 0.0458 0.0149 34 0.0453 0.0148 35 0.0441 0.0148 36 0.0438 0.0148 37 0.0413 0.0148 38 0.0410 0.0147 39 0.0409 0.0147 40 0.0395 0.0146 41 0.0394 0.0146 42 0.0389 0.0145 43 0.0384 0.0145 44 0.0384 0.0145 45 0.0379 0.0145 46 0.0363 0.0144 47 0.0360 0.0143 48 0.0354 0.0142 49 0.0352 0.0142 50 0.0348 0.0141 51 0.0343 0.0141 52 0.0341 0.0140 53 0.0338 0.0139 54 0.0328 0.0139 55 0.0328 0.0139 56 0.0326 0.0139 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 13 57 0.0323 0.0138 58 0.0320 0.0138 59 0.0319 0.0138 60 0.0316 0.0137 61 0.0315 0.0137 62 0.0315 0.0137 63 0.0313 0.0136 64 0.0311 0.0136 65 0.0308 0.0136 66 0.0305 0.0135 67 0.0300 0.0135 68 0.0298 0.0135 69 0.0293 0.0133 70 0.0291 0.0133 71 0.0290 0.0133 72 0.0289 0.0133 73 0.0288 0.0133 74 0.0286 0.0132 75 0.0285 0.0132 76 0.0284 0.0132 77 0.0279 0.0131 78 0.0277 0.0131 79 0.0276 0.0130 80 0.0276 0.0129 81 0.0274 0.0128 82 0.0273 0.0128 83 0.0273 0.0128 84 0.0273 0.0128 85 0.0272 0.0128 86 0.0270 0.0127 87 0.0268 0.0126 88 0.0263 0.0126 89 0.0261 0.0125 90 0.0261 0.0125 91 0.0259 0.0125 92 0.0257 0.0125 93 0.0254 0.0125 94 0.0251 0.0124 95 0.0247 0.0124 96 0.0247 0.0124 97 0.0240 0.0123 98 0.0235 0.0123 99 0.0234 0.0122 100 0.0232 0.0122 101 0.0231 0.0122 102 0.0228 0.0121 103 0.0228 0.0121 104 0.0224 0.0121 105 0.0222 0.0121 106 0.0222 0.0120 107 0.0214 0.0120 108 0.0213 0.0119 109 0.0210 0.0119 110 0.0209 0.0118 111 0.0206 0.0118 112 0.0204 0.0116 CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 14 113 0.0201 0.0116 114 0.0199 0.0116 115 0.0194 0.0115 116 0.0193 0.0115 117 0.0192 0.0114 118 0.0187 0.0113 119 0.0185 0.0113 120 0.0183 0.0113 121 0.0179 0.0112 122 0.0176 0.0112 123 0.0174 0.0112 124 0.0173 0.0111 125 0.0172 0.0111 126 0.0170 0.0111 127 0.0170 0.0111 128 0.0159 0.0111 129 0.0152 0.0109 130 0.0151 0.0109 131 0.0149 0.0109 132 0.0145 0.0109 133 0.0144 0.0109 134 0.0143 0.0108 135 0.0142 0.0108 136 0.0140 0.0108 137 0.0136 0.0107 138 0.0133 0.0107 139 0.0133 0.0106 140 0.0131 0.0106 141 0.0130 0.0106 142 0.0127 0.0106 143 0.0122 0.0104 144 0.0122 0.0104 145 0.0114 0.0103 146 0.0113 0.0102 147 0.0112 0.0100 148 0.0112 0.0099 149 0.0105 0.0097 150 0.0102 0.0097 151 0.0094 0.0096 152 0.0080 0.0095 153 0.0062 0.0095 154 0.0061 0.0095 155 0.0024 0.0089 156 0.0015 0.0084 157 0.0004 0.0081 Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0150 12743 10060 78 Pass 0.0157 11583 5166 44 Pass 0.0163 10528 3103 29 Pass CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 15 0.0170 9610 2773 28 Pass 0.0176 8785 2530 28 Pass 0.0183 8066 2342 29 Pass 0.0189 7435 2187 29 Pass 0.0196 6845 2069 30 Pass 0.0203 6299 1978 31 Pass 0.0209 5812 1870 32 Pass 0.0216 5332 1768 33 Pass 0.0222 4901 1656 33 Pass 0.0229 4509 1559 34 Pass 0.0235 4171 1490 35 Pass 0.0242 3845 1401 36 Pass 0.0248 3547 1319 37 Pass 0.0255 3273 1236 37 Pass 0.0262 3029 1170 38 Pass 0.0268 2805 1105 39 Pass 0.0275 2614 1038 39 Pass 0.0281 2443 969 39 Pass 0.0288 2290 910 39 Pass 0.0294 2118 859 40 Pass 0.0301 1985 809 40 Pass 0.0307 1868 771 41 Pass 0.0314 1762 729 41 Pass 0.0321 1652 684 41 Pass 0.0327 1562 645 41 Pass 0.0334 1478 611 41 Pass 0.0340 1393 582 41 Pass 0.0347 1324 552 41 Pass 0.0353 1243 526 42 Pass 0.0360 1172 489 41 Pass 0.0367 1119 464 41 Pass 0.0373 1053 445 42 Pass 0.0380 1000 420 42 Pass 0.0386 953 397 41 Pass 0.0393 901 374 41 Pass 0.0399 868 352 40 Pass 0.0406 833 329 39 Pass 0.0412 799 319 39 Pass 0.0419 774 304 39 Pass 0.0426 740 287 38 Pass 0.0432 717 275 38 Pass 0.0439 688 257 37 Pass 0.0445 658 239 36 Pass 0.0452 630 224 35 Pass 0.0458 598 213 35 Pass 0.0465 564 203 35 Pass 0.0471 538 193 35 Pass 0.0478 511 186 36 Pass 0.0485 487 176 36 Pass 0.0491 465 162 34 Pass 0.0498 447 155 34 Pass 0.0504 434 140 32 Pass 0.0511 412 134 32 Pass 0.0517 399 125 31 Pass 0.0524 375 117 31 Pass 0.0530 360 ill 30 Pass CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 16 0.0537 343 107 31 Pass 0.0544 326 103 31 Pass 0.0550 309 98 31 Pass 0.0557 292 94 32 Pass 0.0563 279 90 32 Pass 0.0570 264 85 32 Pass 0.0576 254 81 31 Pass 0.0583 237 76 32 Pass 0.0589 225 75 33 Pass 0.0596 214 71 33 Pass 0.0603 203 66 32 Pass 0.0609 185 64 34 Pass 0.0616 176 60 34 Pass 0.0622 166 58 34 Pass 0.0629 156 52 33 Pass 0.0635 139 49 35 Pass 0.0642 128 47 36 Pass 0.0648 120 43 35 Pass 0.0655 112 41 36 Pass 0.0662 99 41 41 Pass 0.0668 93 39 41 Pass 0.0675 84 39 46 Pass 0.0681 79 39 49 Pass 0.0688 78 37 47 Pass 0.0694 73 35 47 Pass 0.0701 66 35 53 Pass 0.0707 61 31 50 Pass 0.0714 53 29 54 Pass 0.0721 47 27 57 Pass 0.0727 43 27 62 Pass 0.0734 39 27 69 Pass 0.0740 36 26 72 Pass 0.0747 34 25 73 Pass 0.0753 31 23 74 Pass 0.0760 29 20 68 Pass 0.0766 27 18 66 Pass 0.0773 27 18 66 Pass 0.0780 25 18 72 Pass 0.0786 21 16 76 Pass 0.0793 21 14 66 Pass 0.0799 19 14 73 Pass Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0.0141 acre-feet On-line facility target flow: 0.0196 cfs. Adjusted for 15 min: 0.0222 cfs. Off-line facility target flow: 0.0111 cfs. Adjusted for 15 min: 0.0126 cfs. Perind and Impind Changes No changes have been made. This program and accompanying documentation are provided 'as -is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section III, Page 17 either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section IV, Page 1 Section IV — Construction Stormwater Pollution Prevention Plan (CSWPPP) Section IV Summary: Narrative Source Controls CESCL Erosion control details are provided consistent with the 2014 SWMMWW and City of Edmonds standards. Erosion control plan sheets are provided in full size as a part of the civil drawing set. Ecology's full Construction SWPPP and a Construction Stormwater General Permit are required because land disturbance will be more than one acre. See attached for Ecology's SWPPP. Source Controls This project should incorporate required BMPs from Volume IV of the SWMMWW: Mandatory Operational Source Control BMPs; S402 — BMPs for Commercial Animal Handling Areas; S407 — BMPs for Dust Control at Disturbed Land Areas and Unpaved Roadways and Parking Lots; S411 — BMPs for Landscaping and Lawn/Vegetation Management; S417 — BMPs for Maintenance of Stormwater Drainage and Treatment Systems; and S430— BMPs for Urban Streets. The Operation & Maintenance Manual found in Section VII contains guide sheets for the aforementioned BMPs. CESCL Anderson Construction Group Builds, Inc. 1900 Airport Way S., Suite 102 Seattle, WA 98134 206.329.2878 Contact: D. Chad Quilici 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com C � ENGINEERING civil & structural engineering & planning STORMWATER POLLUTION PREVENTION PLAN Apollo Apartments 23601 Highway 99 Edmonds, WA 98026 0412212022 250 4th Ave S Ste 200 Edmonds, WA 98020 CG Project No.: 20261.20 Phone: (425) 778-8500 Fax: (425) 778-5536 Construction Stormwater General Permit Stormwater Pollution Prevention Plan (SWPPP) for Apollo Apartments Prepared for: The Washington State Department of Ecology Northwest Regional Office Permittee / Owner Developer Operator / Contractor Black Fish Capital Black Fish Capital TBD 23601 Highway 99, Edmonds, WA 98026 Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Bennett Lanners CG Engineering 425.778.8500 SWPPP Preparation Date April 22, 2022 Project Construction Dates Activity / Phase Start Date End Date Construction September 2022 March 2024 Table of Contents 1 Project Information.............................................................................................................. 4 1.1 Existing Conditions...................................................................................................... 4 1.2 Proposed Construction Activities.................................................................................. 5 2 Construction Stormwater Best Management Practices(BMPs)........................................... 6 2.1 The 13 Elements.......................................................................................................... 6 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 6 2.1.2 Element 2: Establish Construction Access............................................................ 7 2.1.3 Element 3: Control Flow Rates............................................................................. 8 2.1.4 Element 4: Install Sediment Controls.................................................................... 9 2.1.5 Element 5: Stabilize Soils....................................................................................10 2.1.6 Element 6: Protect Slopes....................................................................................11 2.1.7 Element 7: Protect Drain Inlets............................................................................12 2.1.8 Element 8: Stabilize Channels and Outlets..........................................................13 2.1.9 Element 9: Control Pollutants...............................................................................14 2.1.10 Element 10: Control Dewatering..........................................................................16 2.1.11 Element 11: Maintain BMPs.................................................................................17 2.1.12 Element 12: Manage the Project..........................................................................18 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs.................................20 3 Pollution Prevention Team.................................................................................................21 4 Monitoring and Sampling Requirements............................................................................22 4.1 Site Inspection............................................................................................................22 4.2 Stormwater Quality Sampling......................................................................................22 4.2.1 Turbidity Sampling...............................................................................................22 4.2.2 pH Sampling........................................................................................................24 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................25 5.1 303(d) Listed Waterbodies..........................................................................................25 5.2 TMDL Waterbodies.....................................................................................................25 6 Reporting and Record Keeping..........................................................................................26 6.1 Record Keeping..........................................................................................................26 6.1.1 Site Log Book......................................................................................................26 6.1.2 Records Retention...............................................................................................26 6.1.3 Updating the SWPPP...........................................................................................26 6.2 Reporting....................................................................................................................27 6.2.1 Discharge Monitoring Reports..............................................................................27 6.2.2 Notification of Noncompliance..............................................................................27 Page 1 1 List of Tables Table 1 — Summary of Site Pollutant Constituents..................................................................... 4 Table2 — Pollutants..................................................................................................................14 Table 3 — pH -Modifying Sources...............................................................................................14 Table4 — Dewatering BMPs......................................................................................................16 Table5 — Management.............................................................................................................18 Table 6 — BMP Implementation Schedule.................................................................................19 Table7 — Team Information......................................................................................................21 Table 8 — Turbidity Sampling Method........................................................................................22 Table 9 — pH Sampling Method.................................................................................................24 List of Appendices Appendix/Glossary A. Site Map B. BMP Detail C. Correspondence D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303(d) List Waterbodies / TMDL Waterbodies Information G. Contaminated Site Information H. Engineering Calculations Page 12 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 Page 13 Project Information Project/Site Name: Apollo Apartments Street/Location: 23601 Highway 99 City: Edmonds State: WA Zip code: 98026 Subdivision: N/A Receiving waterbody: Lake Ballinger 1.1 Existing Conditions Total acreage (including support activities such as off -site equipment staging yards, material storage areas, borrow areas). Total acreage: 1.76 ac Disturbed acreage: 1.76 ac Existing structures: 0.23 ac Landscape 0.62 ac Drainage patterns: Site topography decends from west to east at an average slope of about 12% and does not take on significant upstream flows. Stormwater currently flows into an existing storm drain system on site. Existing Bushes, shrubs, grass, trees Vegetation: Critical Areas (wetlands, streams, high Edmonds GIS indicates Erosion Hazard erosion risk, steep or difficult to stabilize Areas on -site slopes): List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: Ballinger Lake has four known Category 5 impairments: 2,3,7,8-TCDD (Dioxin), Dieldrin, Polychlorinated Biphenyls (PCBs), and Bacteria.There is currently an approved TMDL project for Ballinger Lake for total phosphorus. See Section 5.1 for full list of impairments. Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. No known or suspected contaminants are associated with the site. Table 1 — Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration Page 14 1.2 Proposed Construction Activities Description of site development (example: subdivision): Multi -family residential. The project will add two 6 story modular buildings over two levels of concrete parking. Description of construction activities (example: site preparation, demolition, excavation): Clearing and grubbing of existing forested and brushed areas; excavating, filling, and grading; utility installation, parking lot surfacing, building construction and frontage improvements. Description of site drainage including flow from and onto adjacent properties. Must be consistent with Site Map in Appendix A: All runoff on site will be routed to a detention vault and discharge through a flow control structure out to an existing catch basin in 2361h St SW. Description of final stabilization (example: extent of revegetation, paving, landscaping): The building, parking lot, driveway, and walkways will cover about 1.52 ac of the site (not including ROW improvements), and the remaining areas will be landscaping. Contaminated Site Information: Proposed activities regarding contaminated soils or groundwater (example: on -site treatment system, authorized sanitary sewer discharge): N/A Page I5 2 Construction Stormwater Best Management Practices (BMPs) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e., hand-written notes and deletions). Update the SWPPP when the CESCL has noted a deficiency in BMPs or deviation from original design. 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land -disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated in the field. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. A protective barrier shall be placed aound the protected trees prior to land preparation or construction activities, and shall remain in place until all construction activity is terminated. No equipment, chemicals, soil deposits or construction materials shall be placed within the protective barriers. Any landscaping activities subsequent to the removal of the barriers shall be accomplished with light machinery or hand labor. High Visibility Fence will be placed around the entire site running along the property lines. List and describe BMPs: • BMP C101: Preserving Natural Vegetation • BMP C102: Buffer Zones • BMP C103: High Visibility Plastic or Metal Fence • BMP C233: Silt Fence Installation Schedules: Install BMPs prior to clearing and grading. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Page 16 2.1.2 Element 2: Establish Construction Access Limit vehicle access to one route, if possible. Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads.Street sweeping, street cleaning, or wheel wash/tire baths may be necessary if the stabilized construction access is not effective. If sediment is tracked off site, clean the affected roadway thoroughly at the end of each day, or more necessary as needed. All wheel wash wastewater shall be controlled on -site and CANNOT be discharged into waters of the State. Stabilized construction entrances will be added along the north edge of the site at the locations of the proposed entrances to the complex. This will help to prevent sediment tracking into the right of way. List and describe BMPs: • BMP C105: Stabilized Construction Entrance/Exit • BMP C107: Construction Road/Parking Area Stabilization Installation Schedules: Install BMPs prior to clearing and grading. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Page 17 2.1.3 Element 3: Control Flow Rates The project site has a slope from west to east for most of the site (--12%). Stormwater will be directed to a temporary sediment trap with an emergency overflow spillway at the southwest sorner corner of the site, and flow rates will be controlled per the BMPs listed below. The construction of the temporary sediment trap must be done as one of the first steps in grading. Infitration facilities will be constructed for permanent stormwater control. Stormwater should not be directed to these facilities until the site has been stabilized. Protect Low Impact Development BMPs from compaction and sedimentation per Element 13. Flow rates around the rest of the site will be controlled by the silt fence that will be placed around the entire site. 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 C207: Check Dams • BMP C209: Outlet Protection • BMP C240: Sediment Trap Installation Schedules: Install BMPs prior to grading. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Page 18 2.1.4 Element 4: Install Sediment Controls Stormwater must be filtered prior to being discharged to an infiltration system or leaving the construction site. Sediment control BMPs will be installed as one of the first steps of grading. These BMPs must be functional before other land -disturbing activities, especially grading and filling, take place. A silt fence will be installed around the perimeter of the developed site areas. A temporary sediment trap will be installed in the southwest quadrant of the site where some sediment will be able to settle out prior to discharge to the public storm system. If sediment controls are ineffective and turbid water is observed discharging from the site, additional energy dissipation BMPs and sediment control BMPs should be installed such as wattles. It may also be necessary to stabilize soils per Element 5 that are not being worked on. List and describe BMPs: • BMP C233: Silt Fence • BMP C235: Wattles • BMP C241: Temporary Sediment Trap Installation Schedules: Install BMPs prior to clearing and grading. Inspection and Maintenance plan: Repair sediment controls as needed. Remove sediment from pond as needed. Responsible Staff: CESCL. Page 19 2.1.5 Element 5: Stabilize Soils Stabilize exposed and unworked soils by the BMPs listed below to prevent erosion. Protect stockpiles with plastic covering or other approved sediment trapping measures. Stabilize exposed soils with Temporary and Permanent Seeding, Mulching, Sodding, Topsoiling/Compost, or Surface Roughening. Minimize soil compaction by applying gravel base early on areas to be paved. The ESC Supervisor shall be familiar with BMPs for soil stabilization and dust control and implement these BMPs where needed on the proposed site. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 — September 30 7 days During the Wet Season October 1 —April 30 2 days Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: September 2022 End date: March 2024 Will you construct during the wet season? ❑ Yes ❑ No List and describe BMPs: • BMP C120: Temporary and Permanent Seeding • BMP C121: Mulching • BMP C123: Plastic Covering • BMP C124: Sodding • BMP C125: Topsoiling/Composting • BMP C130: Surface Roughening • BMP C131: Gradient Terraces • BMP C140: Dust Control Installation Schedules: As needed as soil is exposed. Inspection and Maintenance plan: End of the shift before a holiday or weekend and prior to forecasted rain events. Responsible Staff: CESCL. Page 1 10 2.1.6 Element 6: Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner that minimizes erosion. The interceptor swale and check dams will be located along the west side of the site as needed. Will steep slopes be present at the site during construction? ® Yes ❑ No (temporary excavations may create brief temporary slopes during wall construction) List and describe BMPs: • BMP C120: Temporary and Permanent Seeding • BMP C121: Mulching • BMP C123: Plastic Covering • BMP C124: Sodding • BMP C130: Surface Roughening • BMP C200: Interceptor Dike and Swale • BMP C201: Grass -Lined Channels • BMP C207: Check Dams Installation Schedules: Install BMPs prior to grading and as needed to minimize erosion. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Page 1 11 2.1.7 Element 7: Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment -laden runoff on and near the project site. Inlet protection should be provided as shown on the C2.1 Plan. 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. List and describe BMPs: • BMP C220: Storm Drain Inlet Protection Installation Schedules: Before land disturbance for existing catch basins and as new catch basins are made operable. Inspection and Maintenance plan: Inlets will be inspected weekly at a minimum and daily during storm events. Responsible Staff: CESCL. Page 112 2.1.8 Element 8: Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The project site is located west of the Cascade Mountain Crest. As such, all temporary on -site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. 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 Lining • BMP C207: Check Dams • BMP C209: Outlet Protection Installation Schedules: Install BMPs prior to grading. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Page 113 2.1.9 Element 9: Control Pollutants The following pollutants are anticipated to be present on -site: Table 2 — Pollutants Pollutant (List pollutants and source, if applicable) Concrete Concrete process water Concrete slurry Asphalt materials Utility Materials List and describe BMPs: • BMP C151: Concrete Handling • BMP C152: Sawcutting and Surfacing Pollution Prevention • BMP C153: Material Delivery, Storage and Containment Installation Schedules: As needed as pollutant source materials are used on -site. Inspection and Maintenance plan: As needed. Responsible Staff: CESCL. Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on -site? ❑ Yes ❑ No Will wheel wash or tire bath system BMPs be used during construction? ❑ Yes ❑ No Will pH -modifying sources be present on -site? ® Yes ❑ No Table 3 — pH -Modifying Sources ❑ None ® Bulk cement ® Cement kiln dust ® Fly ash ® Other cementitious materials ❑ New concrete washing or curing waters ❑ Waste streams generated from concrete grinding and sawing ® Exposed aggregate processes ❑ Dewatering concrete vaults ❑ Concrete pumping and mixer washout waters Page 1 14 ❑ Recycled concrete ❑ Recycled concrete stockpiles ❑ Other (i.e., calcium lignosulfate) [please describe: ] Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on -site, except in designated concrete washout areas with appropriate BMPs installed. Will uncontaminated water from water -only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? ❑ Yes ® No Page 115 2.1.10 Element 10: Control Dewatering Dewatering is not anticipated to be associated with this construction project. Most excavations are intended to occur in the dry seasons above the groundwater table. If necessary, only clean, non -turbid dewatering water (such as well -point groundwater) may 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 ❑ 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: N/A. Installation Schedules: N/A. Inspection and Maintenance plan: N/A. Responsible Staff: CESCL. Page 116 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume 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. Page 117 2.1.12 Element 12: Manage the Project 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 ® Design the project to fit the existing topography, soils, and drainage patterns ® Emphasize erosion control rather than sediment control ® Minimize the extent and duration of the area exposed ® Keep runoff velocities low ® Retain sediment on -site ® Thoroughly monitor site and maintain all ESC measures ® Schedule major earthwork during the dry season ❑ Other (please describe) Page 1 18 Table 6 — BMP Implementation Schedule In general it is expected that most early grading will occur in the dry season of 2019 and be picked up again in dry season of 2020. Phase of Construction Project Stormwater BMPs Date Wet/Dry Season Pre -construction Preserving Natural Vegetation (BMP C101) 09/01/2022 Dry Pre -construction High Visibility Fence (BMP C103) 09/01/2022 Dry Pre -construction Silt Fence (BMP C233) 09/01/2022 Dry Pre -construction Storm Drain Inlet Protection BMP C220 09/01/2022 Dry Land disturbance Interceptor Dike and Swale (BMP C200) 09/02/2022 Dry Land disturbance Check Dams BMP C207 09/02/2022 Dr Land disturbance Stabilized Construction Entrance/Exit (BMP C105) 09/02/2022 Dry Land disturbance Sediment Trap BMP C240 09/02/2022 Dr Land disturbance Temporary and Permanent Seeding BMP C120 As needed Dry/Wet Land disturbance Mulching (BMP C121) As needed Dry/Wet Land disturbance Nets and Blankets (BMP C122) As needed Dry/Wet Land disturbance Plastic Covering (BMP C123) As needed Dry/Wet Land disturbance Sodding (BMP C124) As needed Dry/Wet Land disturbance Topsoiling/Composting (BMP C125) As needed Dry/Wet Land disturbance Surface Roughening (BMP C130) As needed Dry/Wet Land disturbance Dust Control (BMP C140) As needed Dry/Wet Land disturbance Channel Lining BMP C202 As needed Dry/Wet Land disturbance Outlet protection BMP C209) As needed Dry/Wet Construction Wattles (BMP C235) As needed Dry/Wet Construction Concrete handling (BMP C151) As needed Dry/Wet Construction Sawcutting and Surfacing Pollution Prevention (BMP C152) As needed Dry/Wet Construction Material Delivery, Storage and Containment (BMP C153) As needed Dry/Wet Page 1 19 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs There are no LID BMPs proposed on this project. Page 120 Pollution Prevention Team Table 7 — Team Information Title Names Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer CG Engineering 425.778.8500 Emergency Ecology Contact Jess Eakens 360.407.6442 Emergency Permittee/ Owner Contact Johnny Vong 206.403.8043 Non -Emergency Owner Contact Johnny Vong 206.403.8043 Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office 425.649.7000 Page 121 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on -site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data File a blank form under Appendix D. The site log book must be maintained on -site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. Numeric effluent limits may be required for certain discharges to 303(d) listed waterbodies. See CSWGP Special Condition S8 and Section 5 of this template. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) are indicated on the Site Map (see Appendix A) and in accordance with the applicable requirements of the CSWGP. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 8 — Turbidity Sampling Method ❑ Turbidity Meter/Turbid imeter (required for disturbances 5 acres or greater in size) ® Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge's turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: Page 122 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. • Central Region (Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, Yakima): (509) 575-2490 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/CRO nerts online.html • Eastern Region (Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, Whitman): (509) 329-3400 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/ERO nerts online.html • Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecy.wa.gov/programs/spills/forms/nerts online/NWRO nerts online.html • Southwest Region (Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, Wahkiakum,): (360) 407-6300 or httD://www.ecv.wa.aov/Droarams/spills/forms/nerts online/SWRO nerts online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: • 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. Page 123 4.2.2 pH Sampling pH monitoring is required for "Significant concrete work" (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement -treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (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 9 — pH Sampling Method ® pH meter ❑ pH test kit ❑ Wide range pH indicator paper Page 124 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies 5.1 303(d) Listed Waterbodies Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? ❑ Yes ❑ No List the impairment(s): • Category 5: 2,3,7,8-TCDD (Dioxin), Dieldrin, PCBs, and Bacteria • Category 4A: Total Phospohorous • Category 2: 2,3,7,8-TCDD TEQ • Category 1: 4,4'-DDD, 4,4'-DDE, 4,4'-DDT, Aldrin, Alpha-BHC, Beta-BHC, Endrin, Endrin Aldehyde, Hexachlorocyclohexane (Lindane), Heptachlor, Heptachlor Epoxide, Hexachlorobenzene, Mercury, Total Chlordane, Toxaphene, Chlordane, and Endosulfan 5.2 TMDL Waterbodies Waste Load Allocation for CSWGP discharges: N/A List and describe BMPs: N/A Discharges to TMDL receiving waterbodies will meet in -stream water quality criteria at the point of discharge. Page 125 6 Reporting and Record Keeping 6.1 Record Keeping 6.1.1 Site Log Book A site log book will be maintained for all on -site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs 6.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.0 of the CSWGP. Permit documentation to be retained on -site: • 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. 6.1.3 Updating the SWPPP 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. Page 126 6.2 Reporting 6.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting "No Discharge". The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology's WQWebDMR System. 6.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. • Central Region at (509) 575-2490 for Benton, Chelan, Douglas, Kittitas, Klickitat, Okanogan, or Yakima County • Eastern Region at (509) 329-3400 for Adams, Asotin, Columbia, Ferry, Franklin, Garfield, Grant, Lincoln, Pend Oreille, Spokane, Stevens, Walla Walla, or Whitman County • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County • Southwest Region at (360) 407-6300 for Clallam, Clark, Cowlitz, Grays Harbor, Jefferson, Lewis, Mason, Pacific, Pierce, Skamania, Thurston, or Wahkiakum Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results Page 127 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. Page 128 ADDendix/Glossary A. Site Map w Figure A-1. Site map. Page 129 B. BMP Detail BMP details are shown on the approved TESC plan. Additional/alternative BMPs are listed below and available for download from the Ecology Construction Stormwater website: http://www.ecV.wa.gov/programs/wq/stormwater/construction/index.htmI Element #1 - Mark Clearing Limits • BMP C101: Preserving Natural Vegetation • BMP C102: Buffer Zones • BMP C103: High Visibility Plastic or Metal Fence • BMP C233: Silt Fence Element #2 - Establish Construction Access • BMP C105: Stabilized Construction Entrance/Exit • BMP C107: Construction Road/Parking Area Stabilization Element #3 - Control Flow Rates • BMP C207: Check Dams • BMP C209: Outlet Protection • BMP C241: Temporary Sediment Trap Element #4 - Install Sediment Controls • BMP C233: Silt Fence • BMP C235: Wattles • BMP C241: Temporary Sediment Trap Element #5 - Stabilize Soils • BMP C120: Temporary and Permanent Seeding • BMP C121: Mulching • BMP C123: Plastic Covering • BMP C124: Sodding • BMP C125: Topsoiling/Composting • BMP C130: Surface Roughening • BMP C131: Gradient Terraces • BMP C140: Dust Control Element #6 - Protect Slopes • BMP C120: Temporary and Permanent Seeding • BMP C121: Mulching • BMP C123: Plastic Covering • BMP C124: Sodding • BMP C130: Surface Roughening • BMP C200: Interceptor Dike and Swale • BMP C201: Grass -Lined Channels • BMP C207: Check Dams Element #7 - Protect Drain Inlets • BMP C220: Storm Drain Inlet Protection Element #8 - Stabilize Channels and Outlets • BMP C202: Channel Lining • BMP C207: Check Dams Page 130 • BMP C209: Outlet Protection Element #9 — Control Pollutants • BMP C151: Concrete Handling • BMP C152: Sawcutting and Surfacing Pollution Prevention • BMP C153: Material Delivery, Storage and Containment • See Volume IV — Source Control BMPs Element #10 - Control Dewatering NA Element #11: Maintain BMPs • BMP C150: Materials On Hand • BMP C160: Certified Erosion and Sediment Control Lead Element #12: Manage the Project • BMP C150: Materials On Hand • BMP C160: Certified Erosion and Sediment Control Lead • BMP C162: Scheduling Element #13: Protect LID BMPs NA Page 131 C. Correspondence Page 132 D. Site Inspection Form Permit # Inspection Time Project Date Name 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 Clearing/Demo/Grading Infrastructure/storm/roads erosion/sediment controls Concrete pours Vertical Utilities Construction/buildings Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected? Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, Yes No or oil sheen 3. Was a water quality sample taken during inspection? (refer to permit Yes No conditions S4 & S5) 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or Yes No less?* 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 Page 133 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 D. Check the observed status of all items. Provide "Action Required "details and dates. Element # Inspection BMPs BMP BMP Action Inspected needs failed required maintena (describe yes no n/a nce in 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 Control Flow installed to control stormwater Rates volumes and velocity during construction and do they protect Page 134 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 Soils been stabilized with effective BMP to prevent erosion and sediment deposition? Are stockpiles stabilized from erosion, protected with sediment trapping 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 Slopes disturbed areas with interceptor dikes, 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? Page 135 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? Wheel wash wastewater is handled and disposed of properly. 10 Concrete washout in designated Control areas. No washout or excess concrete Dewatering on the 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 BMP erosion and sediment control BMPs 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? Page 136 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 All disturbed All concrete wash out All material storage BMPs soils n area areas All discharge All equipment storage All construction locations n areas n entrances/exits 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 137 E. Construction Stormwater General Permit (CSWGP) Page 138 F. 303(d) List Waterbodies / TMDL Waterbodies Information Page 139 G. Contaminated Site Information Page 140 H. Engineering Calculations WWHM2012 PROJECT REPORT Project Name: Edmonds Modular Sediment Trap Site Name: Apollo Apartments Site Address: 23601 Hwy 99 City Edmonds Report Date: 8/4/2020 MGS Regoin Puget East Data Start 1901/10/1 Data End : 2058/09/30 DOT Data Number: 03 Version Date: 2018/10/10 Version : 4.2.16 Low Flow Threshold for POC 1 : 50 Percent of the 2 Year High Flow Threshold for POC 1: 50 year PREDEVELOPED LAND USE Name : Basin 1 Bypass: No Groundwater: No Pervious Land Use C, Forest, Mod Pervious Total Impervious Land Use Impervious Total Basin Total acre 1.76 1.76 acre 0 1.76 Element Flows To: Surface Interflow MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Page 141 Groundwater C, Lawn, Flat .13 C, Lawn, Mod .11 Pervious Total 0.24 Impervious Land Use acre ROOF TOPS FLAT 0.98 DRIVEWAYS FLAT 0.46 SIDEWALKS FLAT 0.06 SIDEWALKS MOD 0.02 Impervious Total 1.52 Basin Total 1.76 Element Flows To: Surface Interflow Groundwater ANALYSIS RESULTS Stream Protection Duration Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.76 Total Impervious Area:O Mitigated Landuse Totals for POC #1 Total Pervious Area:0.24 Total Impervious Area:1.52 Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.030024 5 year 0.04985 10 year 0.061102 25 year 0.072834 50 year 0.079927 100 year 0.085822 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.387241 5 year 0.514292 10 year 0.605876 25 year 0.730395 50 year 0.829747 100 year 0.934922 Page 142 Sediment Trap Design Calculations for: Edmonds Modular Building SA=F S(WV s ) Water surface area FS= 2 Factor of Safety Q2= 0.397 cfs 2-yr developed peak from WWHM Q10= 0.606 cfs 10-yr developed peak from WWHM Vs= 0.00096 ftf s Settling Velocity Side Slopes= 3 H:1V Depth= 3.5 ft Minimum 2-year Trap Geometry SA= B06 sf Min. Pond Dimensions= 28 by 28 ft Incl. 1 ft Freeboard= 34 by 34 ft (Assumed square trap) 10-year Trap Geometry SA= 1263 sf Min. Pond Dimensions 36 by 36 ft (Assumed square trap) Incl. I ft Freeboard= 42 by 42 ft Sediment Trap Calculations BY TAF [mt- 81412020 CNGINs E 1G 2- and 10-year Storms Chkd Date 250 4th Ave. South Ie N.T.S. sheet no. Suite 200 job mo. Edmonds, WA 98020 I Edmonds Modular Building 20261.20 Page 143 Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section V, Page 1 Section V — Special Reports and/or Studies Section V Summ Narrative The following reports are included in this section: 1. Geotechnical Engineering Report by ZipperGeo, dated April 22, 2022. 2. Soil Resource Report from USDA's Web Soil Survey, dated July 23, 2020. 4M 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com GEOTECHNICAL ENGINEERING REPORT REVISION 2 APOLLO APARTMENTS 23601 Highway 99 EDMONDS, WASHINGTON Project No. 2361.01 April 22, 2022 Prepared for: Blackfish Capital, LLC - Ri '9-1 Prepared by: ZipperGeo Geoprofessional Consultants 19019 36th Ave West, Suite E I Lynnwood, WA 98036 1 Phone: 425.582.9928 1 zippergeo.com Zipp Geo Geoprofessional Consultants Project Number 2361.01 April 22, 2022 Blackfish Capital LLC 2442 Market Street NW, #562 Seattle, WA 98107 Attention: Mr. Johnny Vong Subject: Geotechnical Engineering Report Apollo Apartments Project 23601 Highway 99 Edmonds, Washington Dear Mr. Vong, In accordance with your request and written authorization, Zipper Geo Associates, LLC (ZGA) has completed the subsurface exploration and geotechnical engineering evaluation for the proposed Apollo Apartments project at 23601 Highway 99 in Edmonds, Washington. We previously issued reports for this project dated 12/15/20 and 2/24/22 (Rev 1). This report presents Revision 2 to our December 15, 2020 report. The purpose of this revision was to address City of Edmonds review comments. Specifically, this report updates seismic design parameters to 2018 IBC. Our services were completed in general accordance with our Proposal for Geotechnical Engineering Services (Proposal No. P19322_Rev3) dated June 29, 2020. Written authorization to proceed was provided by Black -fish Capital, LLC on July 2, 2020. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us. Sincerely, Zipper Geo Associates LLC Robert A. Ross, P.E. Principal /2022 19019 3611 Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 TABLE OF CONTENTS INTRODUCTION.............................................................................................................................................1 SITEDESCRIPTION.........................................................................................................................................1 PROJECT UNDERSTANDING..........................................................................................................................1 SUBSURFACE CONDITIONS...........................................................................................................................2 PublishedGeologic Mapping.................................................................................................................... 2 SoilConditions.......................................................................................................................................... 2 GroundwaterConditions..........................................................................................................................4 Geotechnical Laboratory Testing..............................................................................................................4 CONCLUSIONS AND RECOMMENDATIONS...................................................................................................4 General Considerations.............................................................................................................................4 Geologically Hazardous Areas...................................................................................................................5 SeismicConsiderations.............................................................................................................................7 SitePreparation........................................................................................................................................9 Structural Fill Materials and Placement..................................................................................................10 Utility Trenching and Backfilling.............................................................................................................13 Temporary and Permanent Slopes.........................................................................................................14 TemporaryShoring.................................................................................................................................15 ShallowFoundations...............................................................................................................................17 GradeBeams...........................................................................................................................................18 Permanent Backfilled Retaining Walls....................................................................................................19 Slab -on -Grade Floors..............................................................................................................................20 Drainage Considerations.........................................................................................................................21 Pavements............................................................................................................................................... 21 AsphaltPavements.............................................................................................................................21 ConcretePavements...........................................................................................................................22 Infiltration Considerations......................................................................................................................23 CLOSURE.....................................................................................................................................................23 FIGURES Figure 1 — Site and Exploration Plan Figure 2 — Lateral Earth Pressures for Surcharge Loads APPENDICES Appendix A — Subsurface Exploration Procedures and Logs Appendix B — Laboratory Testing Procedures and Results GEOTECHNICAL ENGINEERING REPORT - REVISION 2 APOLLO APARTMENTS 23601 HIGHWAY 99 EDMONDS, WASHINGTON Project No. 2361.01 April 22, 2022 INTRODUCTION This report documents the surface and subsurface conditions encountered at the site and our geotechnical engineering recommendations for the proposed Apollo Apartments project located at 23601 Highway 99 in Edmonds, Washington. The project description, site conditions, and our geotechnical conclusions and design recommendations are presented in the text of this report. Supporting data including detailed exploration logs, field exploration procedures, results of laboratory testing, and other supporting information are presented as appendices. Our geotechnical engineering scope of services for the project included a site reconnaissance, subsurface evaluation, laboratory testing, geotechnical analysis, and preparation of this report. The subsurface evaluation completed for this study included 13 exploratory borings (B-1 through B-13) completed across the site. The explorations extended to depths of about 17'/2 to 40 feet below existing grades. SITE DESCRIPTION The project site is situated at the southeast corner of Highway 99 and 236th Street SW in Edmonds, Washington. An existing one-story office building with a daylight basement is located in the northwest corner of the project site and a three-story office building is situated in the central portion of the site. The remainder of the site is covered with grass and asphalt pavement. The site slopes down from west to east and varies in elevation from about 448 feet in the southwest corner to 414 feet along the east side of the site, for a total relief of about 34 feet across the site. Site topography and existing site conditions are presented on the enclosed Site and Exploration Plan, Figure 1. The site is bordered to the west by Highway 99 and commercial developments beyond, to the east by an apartment development, to the south by undeveloped land and a restaurant beyond, and to the north by 236th Street SW and a mobile home park beyond. PROJECT UNDERSTANDING It is our understanding that the existing buildings will be demolished, and the project site will be redeveloped with a new apartment building. We understand that the new building will include two levels of below -grade parking that daylight to the east and five levels of residential space above. The parking levels will be accessed from 236th Street SW. Drawings provided to us indicate the P1 parking level finished floor elevation is about 422 feet. Assuming that excavations for foundation elements may extend about 2 to 3 feet below finished floor, we anticipate that maximum temporary construction excavation depths may approach 20 to 21 feet along the Page 1 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 topographically high western side of the site with decreasing excavation depths to the east. The excavations will be completed as open cuts in the central portion of the site and shored cuts along the west side of the site. We anticipate that the building will be supported on conventional shallow spread foundations and the P1 parking level will utilize concrete pavement. SUBSURFACE CONDITIONS Published Geologic Mapping According to the U.S. Geological Survey Geologic map of the Edmonds East and part of the Edmonds West quadrangles, Washington (Miscellaneous Field Studies Map MF-1541 by Minard, J.P., 1983), the site is mapped as being mantled by Quaternary Vashon till deposits (Qvt). The Vashon till is described as a compact, non -sorted mixture of clay, silt, sand, pebbles, cobbles, and boulders. Vashon till is often referred to as "hardpan" in its unweathered state due to its very dense nature caused by compaction resulting from the weight of an overriding glacial mass thousands of years ago, which was hundreds of meters thick in some areas. The Vashon till has been glacially over -consolidated and therefore typically has good foundation, floor slab, and pavement support characteristics in its undisturbed condition. However, the till usually has a very low permeability. Soil Conditions The subsurface evaluation completed for this project included thirteen borings (B-1 to B-13) located across the site. The borings extended to depths of about 3 to 40 feet below existing grade. Boring B-8 was terminated at a depth of about 3 feet when a 1-inch diameter PVC pipe was encountered. Approximate exploration locations are shown on Figure 1 enclosed with this report. Soils were visually classified in general accordance with the Unified Soil Classification System. Detailed, descriptive logs of the subsurface explorations and the procedures utilized in the subsurface exploration program are presented in Appendix A. Stratification boundaries on the boring logs represent the approximate depth of changes in soil types, although the transition between materials may have been gradual. The soil types observed in our borings were relatively consistent but may vary at other locations. The nature and extent of variations may not become evident until construction. If variations become apparent during construction, it may be necessary to reevaluate the recommendations of this report. In general, the explorations encountered asphalt pavement or sod over undocumented fill and undistubed native soils consisting of weathered glacial till over unweathered glacial till. The following table presented a summary stratigraphy of the soils encountered in the explorations followed by a summary description of each soil unit. Page 2 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Summary of Subsurface Conditions Boring Approx. Ground Surface Elevation(ft) Asphalt Pavement Thickness (in) Approximate Thickness of Soil Unit (ft) Total Approx. Depth Explored (ft) Topsoil Fill Weathered Glacial Till Unweathered Glacial Till B-1 438 2'/2 N/E 3'/4 3/4 > 13'/z 17'/z B-2 419 2 N/E 7 2 >9 18 B-3 419 2'/2 N/E 7 2 >12 21 B-4 417 N/E N/E 4% 2'/2 >13'/2 20'/z B-5 437 N/E '/z 2 '/z >19 22 B-6 446 '/z N/E 4'/2 2 >29 35'/2 B-7 440 6'/2 N/E 2% 1 >36 40 B-8 429 3 N/E 3 - - 3 B-9 420 2 N/E 4'/2 1 >15 20'/z B-10 421 1'/2 N/E 5'/2 '/2 >9'/z 15'/z B-11 422 N/E N/E 2'/2 2 >12 16'/2 B-12 424 N/E '/2 N/E 2% >153/4 19 B-13 431 5 N/E 3 1 >27 31 1. Ground surface elevations were interpolated from topographic contour lines presented on Figure 1. 2. N/E = Not Encountered Existing Asphalt Pavement Section: Nine of the borings were completed through asphalt pavement. The asphalt varied in thickness from approximately'/2 to 6'/2 inches thick and was underlain by little to no crushed gravel base course. Topsoil: Organic -rich topsoil was only observed in borings B-5 and B-12 and was estimated to be approximately 6 inches thick. Existing Fill: Undocumented fill soils were encountered in all of the borings except boring B-12. The fill varied in thickness from approximately 2 to 7 feet in thickness. The fill was generally covered with asphalt or sod and topsoil. It generally consisted of very loose to medium dense sand with varying proportions of silt and gravel. Weathered Glacial Till: Soils interpreted as weathered glacial till were encountered in all of the borings and generally consisted of medium dense sand with variable silt and gravel content. Unweathered Glacial Till: Soils interpreted as unweathered glacial till were encountered below the weathered glacial till in all of the borings and extended to the maximum depths explored. In general, the unweathered glacial till consisted of dense to very dense sand with variable silt and gravel content. Page 3 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Cobbles and boulders were encountered in some of the borings and are not uncommon within weathered and unweathered glacial till deposits due to the depositional environment of these soils. Cobbles and boulders should be expected during construction. Groundwater Conditions Groundwater and perched groundwater seepage was not observed in the borings at the time of drilling. However, several soil samples collected within the existing fill soils and weathered glacial till layer had above -average moisture contents. Borings left open during the day of drilling collapsed at the approximate depths that were coincident with the elevated moisture contents indicating that light perched groundwater seepage was present in these zones. Given the dense to very dense nature and low permeability of the underlying unweathered glacial till soils encountered, perched groundwater conditions appear to be developed or are developing near the base of the weathered glacial till and fill layers or in sandy seams within the unweathered glacial till during periods of extended precipitation. The periodic development of near -surface perched groundwater conditions is supported by iron oxide staining and soil mottling observed in the weathered glacial till deposits. Groundwater conditions should be expected to fluctuate due to variations in the amount of rainfall, runoff, and other factors not evident at the time the exploration was performed. Therefore, groundwater levels during construction or at other times in the life of the structure may vary from those indicated on the logs. Geotechnical Laboratory Testing Laboratory testing was completed on select soil samples obtained from the explorations. Moisture content testing of soil samples obtained within the fill and weathered glacial till ranged from 9.5 to 22.9 percent while the moisture contents within the unweathered glacial till ranged from 5.6 to 15.9 percent. Gradation testing of 17 representative soil samples indicates that the fines content (the clay and silt fraction) of the soils vary from approximately 7.4 to 36.8 percent. CONCLUSIONS AND RECOMMENDATIONS General Considerations Based on our subsurface exploration program and geotechnical evaluation, we conclude that the proposed project is feasible from a geotechnical standpoint, contingent on proper design and construction practices and implementation of the recommendations presented in this report. Based on our analyses, conventional spread footings and slab -on -grade concrete floors and pavement can be used for the new building. Geotechnical engineering recommendations for temporary cuts, temporary shoring, foundations, floor slabs, and other earthwork related phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and 8), engineering analyses, and our current understanding of the proposed project. ASTM and Washington State Department of Page 4 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Transportation (WSDOT) specifications cited herein refer to the current manual published by the American Society for Testing & Materials and the 2020 edition of the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction (M41-10). Geologically Hazardous Areas The City of Edmonds has established regulations that apply to development of property containing geologically hazardous areas. Chapter 23.80 of the City of Edmonds Community Development Code (ECDC) regulates development activities in Geologically Hazard Areas (GHAs). The reader is referred to the Code for definitions of individual GHAs. The City of Edmonds GIS Portal indicates that portions of the project site are mapped as Landslide and Erosion Hazard Areas. Geologically hazardous areas include erosion hazard, landslide hazard, and seismic hazard areas that are defined as follows: Erosion Hazard Areas: Erosion hazard areas are at least those areas identified by the U.S. Department of Agriculture's Natural Resources Conservation Service as having a "moderate to severe," "severe," or "very severe" rill and inter -rill erosion hazard. Erosion hazard areas are also those areas impacted by shoreland and/or stream bank erosion. Within the city of Edmonds erosion hazard areas include: 1. Those areas of the city of Edmonds containing soils that may experience severe to very severe erosion hazard. This group of soils includes, but is not limited to, the following when they occur on slopes of 15 percent or greater: a. Alderwood soils (15 to 25 percent slopes); b. Alderwood/Everett series (25 to 70 percent slopes); C. Everett series (15 to 25 percent slopes); 2. Coastal and stream erosion areas which are subject to the impacts from lateral erosion related to moving water such as stream channel migration and shoreline retreat; 3. Any area with slopes of 15 percent or greater and impermeable soils interbedded with granular soils and springs or ground water seepage; and 4. Areas with significant visible evidence of ground water seepage, and which also include existing landslide deposits regardless of slope. Landslide Hazard Areas: Landslide hazard areas are areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include areas susceptible because of any combination of soil, slope (gradient), slope aspect, structure, hydrology, or other factors. Within the city of Edmonds potential landslide hazard areas include: Page 5 ZipperGeo Geoprofessional Consultants Apollo Apartments Project No. 2361.01 April 22, 2022 1. Areas of ancient or historic failures in Edmonds which include all areas within the earth subsidence and landslide hazard area as identified in the 1979 report of Robert Lowe Associates and amended by the 1985 report of GeoEngineers, Inc., and further discussed in the 2007 report by Landau Associates; 2. Coastal areas mapped as class u (unstable), uos (unstable old slides), and urs (unstable recent slides) in the Department of Ecology Washington coastal atlas; 3. Areas designated as quaternary slumps, earthflows, mudflows, or landslides on maps published by the United States Geological Survey or Washington State Department of Natural Resources; 4. Any slope of 40 percent or steeper that exceeds a vertical height of 10 feet over a 25-foot horizontal run. Except for rockeries that have been engineered and approved by the engineer as having been built according to the engineered design, all other modified slopes (including slopes where there are breaks in slopes) meeting overall average steepness and height criteria should be considered potential landslide hazard areas); 5. Any slope with all three of the following characteristics: Slopes steeper than 15 percent; Hillsides intersecting geologic contacts with a relatively permeable sediment overlying a relatively impermeable sediment; and Springs or ground water seepage; 6. Any area potentially unstable as a result of rapid stream incision or stream bank erosion; 7. Any area located on an alluvial fan, presently subject to, or potentially subject to, inundation by debris flow or deposition of stream -transported sediments; and 8. Any slopes that have been modified by past development activity that still meet the slope criteria. Seismic Hazard Areas. Seismic hazard areas are areas subject to severe risk of damage as a result of earthquake -induced ground shaking, slope failure, settlement, soil liquefaction, lateral spreading, or surface faulting. These areas are designated as having a "high" and "moderate to high" risk of liquefaction as mapped on the Liquefaction Susceptibility Map of Snohomish County by the Washington State Department of Natural Resources or areas located within landslide hazard areas. [Ord. 4026 § 1 (Att. A), 2016; Ord. 3527 § 2, 2004]. As part of our services, we evaluated the presence of regulated geologically hazardous areas (GHAs) at the site. Page 6 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 The NRCS Web Soil Survey maps the site soils as Alderwood-Urban land complex, 2 to 8 percent slopes. The Alderwood gravelly sandy loam is rated as having a moderate erosion potential on bare soil where long flow paths can develop, such as roads and trails and slight erosion potential where 50 to 75 percent of surface soils are disturbed. Although the site is mapped by the NRCS as having slopes of 2 to 8 percent, and the average slope across the site is less than 15 percent, the topographic map of the site indicates that portions of the project site meet the ECDC definition of an Erosion Hazard Area because the slopes exceed 15 percent. Many of these areas will be eliminated as a result of the proposed development. Provided that the recommendations presented in this report, as well as the required erosion mitigation measures are implemented, it is our opinion that the proposed project will not increase the threat of the geological hazards to adjacent or abutting properties beyond pre -development conditions, will not adversely impact other critical areas, and the development can be safely accommodated on the site. The City of Edmonds GIS Portal indicates that portions of the site are mapped as a Landslide Hazard Area. The site is not mapped as a landslide hazard in the reports referenced above, nor is it mapped as unstable in the Department of Ecology Coastal Atlas as being unstable. The site does not appear to meet any on the other criteria presented by the City of Edmonds. Therefore, it is our opinion the site does not meet the definition of a Landslide Hazard Area. Based on the very dense soil conditions encountered in our borings and the lack of groundwater, it is our opinion, pending the development of a grading plan for the project, the site could be developed as proposed. Based on the soil and groundwater conditions encountered at the site, it is our opinion that the potential for liquefaction at the site is very low. The site is also mapped as having very low liquefaction susceptibility on the Liquefaction Susceptibility Map of Snohomish County'. Based on the subsurface conditions encountered, the site does not meet the criteria for a Seismic Hazard Area. Seismic Considerations The development was evaluated relative to seismic hazards resulting from ground shaking associated with the Risk -Targeted Maximum Considered Earthquake (MCER) Ground Motion Response Acceleration and the Maximum Considered Earthquake Geometric Mean (MCEG) Peak Ground Acceleration in accordance with the 2018 International Building Code (IBC). The results of our seismic hazard analyses and recommended seismic design parameters are presented in the following sections. Ground Surface Rupture: According to the U.S. Geological Survey Quaternary Fault and Fold Database of the United States, the closest mapped fault to the project site is the southern Whidbey Island fault zone. One limb of the fault is approximately 2,575 feet northeast of the project site and another is approximately 1,350 feet southwest of the site. The most recent deformation of the southern Whidbey Island fault zone is less than 15,000 years and is in the slip rate category of 1 Washington Division of Geology and Earth Resources, Open File Report 2004-20, Palmer, S.P., Magsino, S.L., Bilderback, E.L., Poelstra, J.L., Folger, P.S., and Niggeman, R.A., 2004 Page 7 ZipperGeo Apollo Apartments Project No. 2361.01 Geoprofessional Consultants April 22, 2022 between 0.2 and 1 mm/year. Based on the information described above, we estimate that the risk associated with fault surface rupture at the site is low. Landsliding: Based on the relatively gently sloping topography of the site and surrounding vicinity, as well as the subsurface conditions encountered at the site, the risk of earthquake -induced landsliding is low. Soil Liquefaction and Lateral Spread: Liquefaction is a phenomenon wherein saturated cohesionless soils build up excess pore water pressures during earthquake loading. Liquefaction typically occurs in loose soils but may occur in denser soils if the ground shaking is sufficiently strong. The explorations primarily encountered glacially consolidated glacial till. Based on the dense to very dense nature of these soils and the lack of a groundwater table, it is our opinion that the potential for liquefaction at the site is low. Lateral spreading is a phenomenon in which soil deposits which underlie a site can experience significant lateral displacements associated with the reduction in soil strength caused by soil liquefaction. This phenomenon tends to occur most commonly at sites where the soil deposits can flow toward a "free -face", such as a water body. Due to the lack of liquefiable soils at the site and the lack of a nearby "free -face" condition, it is our opinion that the risk of lateral spreading at the site is low. IBC Seismic Design Parameters: The City of Edmonds has adopted the 2018 edition of the International Building Code. The values presented in the following table are derived from the 2018 International Building Code and ASCE 7-16. 2015 IBC/ASCE 7-10 Seismic Design Parameters Parameter Value 2015 International Building Code Site Classification (IBC) Site Latitude/Longitude Mean Magnitude Earthquake Site Class C 47.7846 /-122.3418 7.01 Site Modified Ground Acceleration, PGAM 0.651g Spectral Short -Period Acceleration, Ss 1.277g (Site Class B) Spectral 1-Second Acceleration, S1 0.448g (Site Class B) Site Coefficient for a Short Period, Fa 1.0 Site Coefficient for a 1-Second Period, Fv 1.307 Spectral Acceleration for a 0.2-Second Period, SMs 1.533g (Site Class C) Spectral Acceleration for a 1-Second Period, SM1 0.672g (Site Class C) Design Short -Period Spectral Acceleration, SIDS 1.022g (Site Class C) Design 1-Second Spectral Acceleration, SD1 0.448g (Site Class C) Page 8 ZipperGeo Geoprofessional Consultants Site Preparation Apollo Apartments Project No. 2361.01 April 22, 2022 Existing Structure Removal: Prior to demolition of the existing buildings, it may be necessary to complete asbestos and lead -based paint surveys. We recommend the surveys be completed by an AHERA-certified inspection company. ZGA can provide these services, if requested. All existing foundation elements should be completely demolished and removed from the proposed building area. Existing Utility Removal: We recommend that all underground utilities within the building pad be completely removed. Utility pipes outside the building envelope could be abandoned in place, provided they are fully grouted with controlled density fill (CDF) and the trench backfill is density tested to verify that it meets the compaction levels presented in the project specifications. Localized excavations made for removal of utilities or existing unsuitable trench backfill should be backfilled with structural fill as outlined in the following section of this report. Erosion Control Measures: Stripped surfaces and soil stockpiles are typically a source of runoff sediments. We recommend that silt fences, berms, straw waddles, and/or swales be installed around the downslope side of stripped areas and stockpiles in order to capture runoff water and sediment. If earthwork occurs during wet weather, we recommend that soil stockpiles be protected with anchored plastic sheeting. Temporary Drainage: Stripping, excavation, grading, and subgrade preparation should be performed in a manner and sequence that will provide drainage at all times and provide proper control of erosion. The site soils that will be exposed during construction have a moderate to high fines (silt and clay) content (up to about 37 percent) and are therefore highly susceptible to disturbance and erosion when wet. The site should be graded to prevent water from ponding in construction areas and/or flowing into and/or over excavations. Exposed grades should be crowned, sloped, and smooth -drum rolled at the end of each day to facilitate drainage if inclement weather is forecasted. Accumulated water must be removed from subgrades and work areas immediately and prior to performing further work in the area. Equipment access may be limited and the amount of soil rendered unfit for use as structural fill may be greatly increased if drainage efforts are not accomplished in a timely manner. Successful drainage of saturated zones due to accumulations of surface water would be relatively slow due to the fines content of the surficial soils. Instead, aeration or removal and replacement would be more expeditious. Runoff from the existing paved areas around the site should not be allowed to flow into excavation areas. We recommend that asphalt berms or sandbags be used to divert runoff around the excavation areas to a suitable discharge location. Clearing and Stripping: We anticipate that clearing and stripping of organic -rich soils will be limited to the grass -covered area on the south side of the site and areas of landscaping. We anticipate that stripping depths will average about 6 to 8 inches. Areas of deeper organics should be expected around the root balls of the plants. Subgrade Preparation: Once site preparation is complete, all areas that do not require over - excavation and are at design subgrade elevation or areas that will receive new structural fill should Page 9 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 be compacted to a firm and unyielding condition. Depending on the time of year that earthwork takes place, some moisture conditioning of site soils may be required to achieve a moisture content appropriate for compaction. This is generally within ±2 percent of the soil's optimum moisture content. We recommend that earthwork be completed during drier periods of the year, if feasible, when soil moisture content can be controlled by aeration and drying. If earthwork or construction activities take place during extended periods of wet weather, or if the in -situ moisture conditions are elevated above the optimum moisture content, the soils could become unstable or not be compactable. In the event the exposed subgrade becomes unstable, yielding, or unable to be compacted due to high moisture conditions, we recommend that the materials be removed to a sufficient depth in order to develop stable subgrade soils that can be compacted to the minimum recommended levels. The severity of construction problems will be dependent, in part, on the precautions that are taken by the contractor to protect the subgrade soils. Once compacted, subgrades should be evaluated by a geotechnical engineer through visual observation, density testing, and proof rolling if the building excavation is accessible with heavy rubber -tired construction equipment to assess the subgrade adequacy and to detect soft and/or yielding soils. In the event that compaction fails to meet the specified criteria, the upper 12 inches of subgrade should be scarified and moisture conditioned as necessary to obtain at least 95 percent of the maximum laboratory density (per ASTM D1557). To protect stable subgrades, either inside or outside the building excavation, we recommend using crushed rock or crushed recycled concrete. The thickness of the protective layer should be determined at the time of construction and be based on the moisture condition of the soil and the amount of anticipated construction traffic. Freezing Conditions: If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to thaw and then be compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen material could be stripped from the subgrade to expose unfrozen soil prior to placing subsequent lifts of fill or foundation components. The frozen soil should not be reused as structural fill until it is allowed to thaw and adjusted to the proper moisture content, which may not be possible during winter months. Structural Fill Materials and Placement All fill placed within the building area, as well as beneath paved surfaces, sidewalks, and other settlement -sensitive structures, should be placed as structural fill. The structural fill should be placed after removal of any existing disturbed soils and after the surface has been prepared and compacted as recommended above. Subgrades should be evaluated by testing for the minimum compaction standard, and/or by proof -rolling in the presence of the geotechnical engineer, prior to filling. Laboratory Testing: Representative samples of on -site and imported soils to be used as structural fill should be submitted for laboratory testing at least 4 days in advance of its intended use in order to complete the necessary Proctor tests. Page 10 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Re -Use of Site Soils as Structural Fill: The suitability of excavated site soils for compacted structural fill will depend on the gradation and moisture content of the soil when it is placed. As the amount of fines (that portion passing the U.S. No. 200 sieve) increases, the soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines cannot be consistently compacted to a dense, non -yielding condition when the water content is greater than optimum. Optimum moisture content is that moisture which results in the greatest compacted dry density with a specified compactive effort. It is our opinion that the weathered and unweathered glacial till soils encountered at the site are suitable for reuse as general structural fill from a compositional standpoint provided it can be placed and compacted in accordance with the recommendations presented in this report. Our subsurface exploration was completed during the dry season and much of the soil encountered during our evaluation appeared to be slightly above its estimated optimum moisture content. We anticipate that some of these soils may be above their optimum moisture content during construction and require drying to achieve adequate compaction. The reuse of site soils as structural fill during wet weather will be much more difficult. We recommend that site soils used as structural fill have less than 4 percent organics by weight and have no woody debris greater than '/z inch in diameter. We recommend that all organic -rich soil derived from earthwork activities be utilized in landscape areas or wasted from the site. Some of the fill soils encountered across the site may also be suitable for reuse as structural fill, although we expect the composition and quality of the fill to vary across the site. This material should be considered as common borrow that is susceptible to disturbance when wet. Imported Structural Fill: During wet weather, under wet site conditions, or if the soils cannot be properly dried, the use of on -site soils for structural fill may not be acceptable, requiring suitable materials to be imported. Imported fill should consist of well -graded sand or sand and gravel. Under wet conditions, the fines content should be limited to less than 5 percent (based by weight on the minus No. 4 sieve fraction using the wet sieve analysis). Typically, soils containing less than 5 percent fines can be compacted under a wider variety of weather conditions. During extended periods of dry weather, we recommend imported fill meet the requirements of Common Borrow, Options 1 or 2, as specified in Section 9-03.14(3) of the WSDOT Standard Specifications. During wet weather, higher -quality structural fill might be required, as Common Borrow may contain sufficient fines to be moisture sensitive. In this case, we recommend that imported structural fill meet the requirements of Gravel Borrow as specified in Section 9-03.14(1) of the WSDOT Standard Specifications. Retaining Wall Backfill: With the exception of permanent foundation walls constructed directly in front of soldier pile retaining walls, any site retaining walls should include a drainage fill zone extending at least 18 inches back from the back face of wall for the entire wall height. The drainage fill should meet the requirements of Gravel Backfill for Walls as specified in Section 9-03.12(2) of the WSDOT Standard Specifications. Page 11 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Pavement Subgrades: Any structural fill used within the upper 2 feet below pavement sections should have a minimum California Bearing Ratio (CBR) of 15 when compacted to a minimum of 95 percent of the modified Proctor maximum dry density. A CBR value of 15 is representative of the existing soils encountered when compacted as recommended in this report. Moisture Content: The suitability of soil for use as structural fill will depend on the time of year, the moisture content of the soil, and the fines content (that portion passing the U.S. No. 200 sieve) of the soil. As the amount of fines increases, the soil becomes increasingly sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (such as most of the on -site soils) cannot be consistently compacted to the appropriate levels when the moisture content is more than approximately 2 percent above or below the optimum moisture content (per ASTM D1557). Optimum moisture content is that moisture content which results in the greatest compacted dry density with a specified compactive effort. Fill Placement: Structural fill should be placed in horizontal lifts not exceeding 10 inches in loose thickness. Each lift of fill should be compacted using compaction equipment suitable for the soil type and lift thickness. Each lift of fill should be compacted to the minimum levels recommended below based on the maximum laboratory dry density as determined by the ASTM D1557 Modified Proctor Compaction Test. Moisture content of fill at the time of placement should be within plus or minus 2 percent of optimum moisture content for compaction as determined by the ASTM D1557 test method. The actual lift thickness will be a function of the type, size, and weight of the compaction equipment. Compaction Criteria: Our recommendations for soil compaction are summarized in the following table. Structural fill for roadways and utility trenches in municipal rights -of -way should be placed and compacted in accordance with City of Seattle codes and standards. We recommend that a geotechnical engineer be present during grading so that an adequate number of density tests may be conducted as structural fill placement occurs. In this way, the adequacy of the earthwork may be evaluated as it proceeds. RECOMMENDED SOIL COMPACTION LEVELS Location Minimum Percent Compaction* All fill below building floor slabs and foundations 95 Upper 2 feet of fill below pavements 95 Pavement fill below two feet 92 Retaining wall backfill less than 2 feet from wall 90 - 92 Retaining wall backfill more than 2 feet from wall 95 Upper two feet of utility trench backfill 95 Utility trenches below two feet 92 Landscape Areas 90 * ASTM D 1557 Modified Proctor Maximum Dry Density Page 12 ZipperGeo Geoprofessional Consultants Utility Trenching and Backfilling Apollo Apartments Project No. 2361.01 April 22, 2022 We recommend that utility trenching conform to all applicable federal, state, and local regulations, such as OSHA and WISHA, for open excavations. Trench excavation safety guidelines are presented in WAC Chapter 296-155 and WISHA RCW Chapter 49.17. Dewatering: Perched groundwater was not observed in our borings at the time of drilling. However, zones of wet soils were encountered that would likely have seeped over a longer period of time that that at the time of drilling. Soil mottling and iron oxide staining suggest the development of periodic perched groundwater within the weathered glacial till deposits. Some excavations for utilities and underground structures may encounter zones of perched groundwater that may develop above the dense unweathered glacial till or in sandy seams within the unweathered fill. The amount of perched groundwater seepage that may be encountered in site excavations will likely be a function of the time of year, the size of the excavation, the excavation depth, and how long the excavation remains open. The type and extent of dewatering measures needed, if any, will be a function of the groundwater conditions at the time of construction. Temporary systems could include pumped sumps, wellpoints or pumped wells. If seepage is encountered, flattening excavation sidewalls may be necessary to reduce the risk of caving. Otherwise, some caving of utility trench sidewalls should be anticipated where groundwater seepage is encountered. If dewatering becomes necessary, the appropriate type of dewatering system and means of disposing the water should be determined by the contractor based on the conditions encountered. Utility Subgrade Preparation: We recommend that all utility subgrades be firm and unyielding and free of all soils that are loose, disturbed, or pumping. Such soils should be removed and replaced, if necessary. All structural fill used to replace over -excavated soils should be compacted as recommended in the Structural Fill section of this report. If soft utility foundation soils are encountered, we recommend that they be over -excavated and replaced with crushed rock. Structures such as manholes and catch basins which extend into soft soils should be underlain by at least 4 inches of crushed gravel fill compacted to a firm and unyielding condition. Bedding: We recommend that bedding material be placed above and below all utilities in general accordance with the City of Edmonds Standard Plans and Specifications. If water is encountered in the excavations, it should be removed prior to fill placement. We recommend that a minimum of 4 inches of bedding material be placed above and below all utilities or in general accordance with the utility manufacturer's recommendations and local ordinances. We recommend that pipe bedding consist of Gravel Backfill for Pipe Zone Bedding as specified in Section 9-03.12(3) of the WSDOT Standard Specifications. All trenches should be wide enough to allow for compaction around the haunches of the pipe, or material such as pea gravel should be used below the spring line of the pipes to eliminate the need for mechanical compaction in this portion of the trenches. If water is encountered in the excavations, it should be removed prior to fill placement. Trench Backfill: Materials, placement and compaction of utility trench backfill should be in accordance with the recommendations presented in the Structural Fill section of this report. In Page 13 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 our opinion, the initial lift thickness should not exceed one foot unless recommended by the manufacturer to protect utilities from damage by compacting equipment. Light, hand operated compaction equipment may be utilized directly above utilities if damage resulting from heavier compaction equipment is of concern. Some on -site soils may be suitable for use as trench backfill from a compositional standpoint, provided the moisture content allows for compaction to the minimum recommended levels. If borrow material is required, it should be selected based on the weather at the time of use. The use of gravel borrow, as described in the Structural Fill section of this report, would be suitable for trench backfill under most weather conditions. Temporary and Permanent Slopes We anticipate that temporary open cuts may be utilized in conjunction with shoring during the construction of foundation elements for the proposed structure. Temporary excavation slope stability is a function of many factors, including: • The presence and abundance of groundwater; • The type and density of the various soil strata; • The depth of cut; • Surcharge loadings adjacent to the excavation; and • The length of time the excavation remains open. As the cut is deepened, or as the length of time an excavation is open increases, the likelihood of sidewall sloughing or failure increases; therefore, maintenance of safe slopes and worker safety should remain the responsibility of the contractor, who is present at the site, able to observe changes in the soil conditions, and monitor the performance of the excavation. It is exceedingly difficult under the variable circumstances to pre -establish a safe and "maintenance -free" temporary cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe temporary slope configurations since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. Unsupported vertical slopes or cuts deeper than 4 feet are not recommended if worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. Temporary slope angles should conform to applicable Federal, State, and Local regulations based on the subsurface conditions observed at the time of construction. Based on the conditions observed in the borings, the fill and weathered glacial till soils encountered in the upper 7 feet of the explorations appear to be representative of Type B soils, as described in Chapter 296-155, Part N, Excavation Trenching and Shoring, of the Washington Administrative Code (WAC). According to the Code, excavations less than 20 feet deep in Type B soils may be cut at a maximum temporary slope angle of 45 degrees (1 H:1 V). The underlying unweathered glacial till soils encountered in the explorations appear to be representative of Type A soils, as described in Chapter 296-155, Part N, Excavation Trenching and Shoring, of the Page 14 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Washington Administrative Code (WAC). According to the Code, excavations less than 20 feet deep in Type A soils may be cut at a maximum temporary slope angle of 53 degrees (3/41-1:1V). Therefore, for preliminary planning purposes we recommend maximum temporary slope angles of 45 degrees (11-1:1V) and 53 degrees (3/41-1:1V) for weathered glacial till and fill spoils and unweathered glacial till, respectively. According to Chapter 296-155 of the WAC, the contractor should make a determination of excavation side slopes based on classification of soils and site conditions encountered at the time of excavation. Temporary cuts may need to be constructed at flatter angles based upon the soil moisture and groundwater conditions (including perched groundwater) at the time of construction and the location of soil stockpiles construction equipment, or other surcharge loads. Adjustments to the slope angles should be determined by the contractor at that time. We recommend that all permanent cut or fill slopes constructed in native soils be designed at a 2H:1 V (Horizontal:Vertical) inclination or flatter. All permanent cut and fill slopes should be adequately protected from erosion both temporarily and permanently. Temporary Shoring We understand that temporary shoring will be used to support the cut required to construct the lower parking level. Temporary shoring consisting of soil nail will be utilized to support the western side of the excavation. This section presents our recommendations for temporary shoring. Soil Nail Shoring Design Parameters: Based on soil conditions encountered in borings B-1 and B-7, we expect soil conditions encountered in soil nail excavations will generally consist of about 5 feet of loose sand fill/weathered glacial till underlain by medium dense to very dense glacial till soils. The following presents our recommended soil design parameters that should be utilized for soil nail shoring design and analysis. • Fill/Weathered Till: y = 125 pcf, cp = 30°, c = 0 psf, Qd = NA • Glacial Till: y = 135 pcf, cp = 40°, c = 200 psf, Qd = 3.4 k/ft • where: o y = moist unit weight in pounds per cubic foot, o cp = effective friction angle in degrees, o c = effective cohesion in pounds per square foot, and o Qd = allowable nail pullout resistance in kips per foot. ■ Note Qd assumes a minimum 6 inch diameter drill hole. The above -recommended values for friction angle and cohesion are based on typical values for Glacial Till deposits published in the Washington State Department of Transportation's Geotechnical Design Manual. The actual pullout strength values will depend on the materials and installation methods and should be confirmed by testing. Installation methods should be the responsibility of the contractor. Soil Nail Construction: We recommend that soil nail grout be pumped into the soil nail holes by tremie methods in order to force grout up from the bottom of the hole and to provide a continuously Page 15 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 grouted soil nail. We recommend that a minimum of two sacrificial, 200 percent verification tests be performed in order to evaluate the ultimate pullout resistance and the load deformation performance of the soil nail. Verification testing should be accomplished prior to installation of production nails. The location of the verification tests should be selected by the contractor and approved by Zipper Geo. The drilling method, hole diameter, and depth of soil nail should be identical to the production soil nails. Additionally, 5 percent of production soil nails should be proof tested to 150 percent of design load to confirm the design capacity and appropriate construction methods. Temporary Shoring Deformation Monitoring: Any time an excavation is made below the level of existing buildings, utilities, or other structures, there is risk of damage even if a well -designed shoring system has been planned. Therefore, we recommend that the shoring system and surrounding areas be monitored for deformation. Deformation monitoring should be completed through optical survey of points established as follows: • At the top of wall on 20 feet centers, and • between Wall Sta. 1+89 to 2+82 along the back of the Hwy. 99 sidewalk at 25 foot centers. Optical survey should have an accuracy of ± 0.01feet and should be completed by a licensed surveyor. Survey of the monitoring points should be performed a minimum of twice per week, with at least one of the readings completed during shoring installation and excavation. Survey frequency can be decreased after the shoring system has been installed and excavation is complete if the data indicates little or no additional movement. Surveying must continue until the permanent structure (including floor slabs as braces) is complete up to final and street grades. The survey frequency will be determined by Zipper Geo after review and approval by the City of Edmonds. Monitoring results should be provided weekly to Zipper Geo. Zipper Geo will review the survey data and provide an evaluation of wall performance along with graphical representation of wall movement versus time and survey data to the City of Edmonds on at least a weekly basis. Zipper Geo and the City of Edmonds should be immediately notified if any unusual or significantly increase movement occurs. If 0.5 inches or more movement occurs between two consecutive readings or if total movements reach 0.5 inches, Zipper Geo and the City of Edmonds should be notified immediately. At that level of movement, the contractor should determine the cause of displacement and develop remedial measures sufficient to limit total wall movements to 1 inch. All earthwork and construction activities must be directed towards immediate implementation of remedial measures necessary to limit total wall movements to 1 inch. Page 16 ZipperGeo Geoprofessional Consultants Shallow Foundations Apollo Apartments Project No. 2361.01 April 22, 2022 Conventional shallow spread and continuous footings are suitable for support of the proposed structure, provided the bearing soils are prepared in accordance with the recommendations presented herein. Based on the subsurface conditions encountered, we anticipate that the western portion of the garage structure, and some of the western residential wing, will be supported on dense to very dense unweathered glacial till. However, the eastern portion of the garage structure is situated over an area where loose to medium dense undocumented fill has been placed. When undocumented fill is present, there is risk of supporting footings, floor slabs, and pavements on or above the existing fill. The fill does not appear to be consistently or adequately compacted based on the blowcount data and may contain compressible or unsuitable materials that can cause excessive settlements. Therefore, we do not recommend supporting foundations on existing fill soils. Remedial improvement such as over -excavation and placing it back with more compactive effort is recommended. Other areas of loose soil may be revealed during earthwork and may need similar remedial measures. Even with the typical construction testing services, there is an inherent risk for the owner that compressible fill or unsuitable material within or buried by the fill will not be discovered. This risk of unforeseen conditions cannot be completely eliminated without removing the existing fill and replacing it with compacted structural fill. Bearing Subgrade: We recommend that building foundations be supported on a properly prepared native subgrade or on structural fill placed above suitable native soils. Foundations should not be supported on existing undocumented fill. We recommend that undocumented fill soils be over - excavated to a depth where the underlying medium dense to very dense glacial deposits are encountered and be replaced with compacted structural fill or controlled density fill (CDF) that has a minimum 28-day compressive strength of 150 psi. The foundation subgrade should be observed by a representative of ZGA prior to placement of any structural fill, formwork or reinforcing steel. The excavation to remove existing fill should extend laterally away from each side of the footing 8 inches for each foot the excavation extends vertically below the foundation if compacted structural fill is used. Alternatively, if CDF is used, the excavation should extend laterally away from each side of the footing a distance of 6 inches, regardless of the depth of over - excavation. The depth to suitable bearing soils is presented in the following table. Estimated Depth to Suitable Bearing Soils Boring No. Depth to 3,000 psf Bearing Soils (ft) Depth to 6,000 psf Bearing Soils (ft) B-1 4 5 B-2 61/2 7 B-3 7 9 B-4 4'/2 61/2 B-5 21/2 3 B-6 41/2 6'/2 B-7 4 41/2 B-8 B-9 41/2 5 Page 17 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 B-10 6 61/2 B-11 2'/2 4 t/2 B-12 1 t/2 4 B-13 31/2 8 Boring terminated at shallow depth due to utility Allowable Bearing Pressure: Continuous and isolated column footings bearing on subgrades prepared as recommended above may be designed for a maximum allowable, net, bearing pressure of 3,000 psf if supported on medium dense native weathered glacial till soils or compacted structural fill, and 6,000 psf if supported on dense to very dense native glacial soils or CDF placed on dense to very dense native glacial soils. A one-third increase of the bearing pressure may be used for short -tern dynamic loads such as wind and seismic forces. The above - recommended allowable bearing pressures include a 3.0 factor of safety. Shallow Foundation Depth and Width: For frost protection, the bottom of all exterior footings should bear at least 18 inches below the lowest adjacent outside grade, whereas the bottoms of interior footings should bear at least 12 inches below the surrounding slab surface level. We recommend that all continuous wall and isolated column footings be at least 12 and 24 inches wide, respectively. Lateral Resistance: We recommend using an ultimate base friction and passive earth values of 0.55 for footings supported on undisturbed native soils, CDF, and structural fill compacted to a minimum of 95 percent of the modified Proctor maximum dry density. We recommend using an ultimate passive resistance of 650 and 475 pcf equivalent fluid pressure, respectively, for footings cast directly against dense to very dense native soils and footings with compacted structural fill placed around them. An appropriate safety factor (or load/resistance factors) should be included for calculating resistance to lateral loads. For allowable stress design, we recommend a minimum 1.5 safety factor. We recommend that passive resistance be neglected in the upper 18 inches of embedment. Estimated Settlement: Assuming the foundation subgrade soils are prepared in accordance with recommendations presented herein, we estimate that total and differential settlements will be less than one inch and t/2 inch, respectively, over a distance of 40 feet. Grade Beams Because the west residential wing diverges off of the below -grade parking structure, the wing will transition off the garage structure and on to wall backfill and then on to native glacial till soils. The transition fill should be expected to settle a small amount even when compacted to 92 to 95 percent of its modified Proctor maximum dry density. Over time, we estimate that the backfill could settle one inch or more. In order to not rely on the backfill soils for foundation support, we understand that grade beams will be used to span over the wall backfill. Based on an assumed temporary cut on the order of 1 H:1 V, it appears that the grade beams would need to span about 25 feet perpendicular to the parking garage wall. Where grade beams are not perpendicular to the garage wall, the grade beams will be longer. We recommend using a subgrade modulus of Page 18 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 100 pci and 500 pci for structural fill compacted to a minimum of 95 percent of the modified Proctor maximum dry density and undisturbed dense to very dense glacial till, respectively. Permanent Backfilled Retaining Walls We expect the project to include backfilled cast -in -place concrete retaining walls. For recommended bearing capacities and lateral resistance parameters, refer to the Shallow Foundations section above. Additional recommendations for these structures are provided below. Lateral Earth Pressures: The lateral soil pressures acting on backfilled retaining walls will depend on the nature and density of the soil behind the wall, and the ability of the wall to yield in response to the earth loads. Yielding walls (i.e. walls that are free to translate or rotate) that are able to displace laterally at least 0.001 H, where H is the height of the wall, may be designed for active earth pressures. Non -yielding walls (i.e. walls that are not free to translate or rotate) should be designed for at -rest earth pressures. Non -yielding walls include walls that are braced to another wall or structure, and wall corners. The recommended lateral earth pressures are based on the assumption that no buildup of hydrostatic pressure behind the wall develop. If groundwater is allowed to saturate the backfill soils, hydrostatic pressures will act against the wall. Assuming that walls are backfilled and drained as described in the following paragraphs, we recommend that yielding and non -yielding walls supporting horizontal backfill be designed using the following equivalent fluid densities. Recommended Lateral Earth Pressures Fill Compaction Level Active Earth Pressure At -Rest Earth Pressure Min. 95% 40 60 Design of permanent retaining walls should consider additional earth pressure resulting from the design seismic event. For the seismic case, walls should be designed for an additional uniform, total seismic earth pressure distribution of 11 H. The above -recommended lateral earth pressures do not include the effects of sloping backfill surfaces, surcharges such as traffic loads, other surface loading, or hydrostatic pressures. For traffic surcharges located within a 1 H:1 V envelope extending up from finished grade at the face of the wall, we recommend an equivalent soil surcharge of 2 feet (250 psf) be added. Other surcharges from construction equipment and construction materials should be assessed using the surcharge diagrams presented on Figure 2 of this report. All backfilled walls should include a drainage aggregate zone extending a minimum of two feet from the back of wall for the full height of the wall and wide enough at the base of the wall to allow seepage to flow to the footing drain. We recommend that the drainage aggregate consist of material meeting the requirements of WSDOT 9-03.12(2), Gravel Backfill for Walls. A minimum 4-inch diameter, perforated PVC drainpipe should be provided at the base of backfilled walls to collect and direct subsurface water to an appropriate discharge point. We recommend that the drainpipe be enveloped in free -draining aggregate meeting WSDOT 9-03.12(4), Gravel Backfill Page 19 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 for Drains. We recommend wrapping the footing drain aggregate with a non -woven geotextile, such as Mirafi 140N, or equivalent. If wall backfill outside the drainage zone has more than 10 percent fines, we recommend that a non -woven filter fabric such as Mirafi 160N or equivalent be placed between the drainage aggregate and structural backfill to limit the amount of fines migration into the drainage aggregate. Slab -on -Grade Floors We anticipate the parking level P1 may include conventional concrete slab -on -grade floors for non -vehicle areas such as mechanical and/or storage rooms as well as concrete pavements intended to support passenger vehicle traffic. Recommendations for building slab -on -grade concrete floors and parking garage concrete pavements are presented below. Subgrade Conditions and Preparation: The native glacial till soils appear to be suitable for support of the slabs provided they can be compacted to the minimum recommended levels. Where unsuitable soil is present, such as loose soils or undocumented fill, we recommend that the material be over -excavated and replaced with common borrow or select borrow, depending on the prevailing weather conditions. Subgrades should be prepared in accordance with the recommendations presented in the Subgrade Preparation section of this report. Floor Slab Base: To provide a capillary break and uniform slab bearing surface, we recommend the on -grade slabs in non -parking areas be underlain by a 4-inch thick layer of compacted clean crushed rock. We recommend that the drainage aggregate conform to the graduation requirements for Crushed Surfacing Base Course with an adjusted maximum percent passing the U.S. No. 200 sieve of 3 percent or a free -draining sand and gravel with less than 3 percent passing the No. 200 sieve. Vapor Retarder: From a geotechnical standpoint, a vapor barrier is not considered to be necessary for the proposed building. Where potential slab moisture is a concern or where moisture sensitive floor coverings are planned, we recommend that a 10- to 15-mil moisture barrier be installed beneath all interior slabs. We recommend using a puncture -resistant product such as Stego Wrap or an approved equivalent that is classified as a Class A vapor retarder in accordance with ASTM E1745. Puncturing the vapor barrier should be avoided; construction traffic should not be allowed to drive over any vapor barrier material. The slab designer should and contractor should refer to ACI 302 for procedures and cautions regarding the use and placement of a vapor retarder. We recommend that installation of the vapor barrier be completed in accordance with the manufacturers recommendations. Subgrade Modulus: For design of on -grade concrete slabs supported on dense to very dense native soils, we recommend a vertical modulus of subgrade reaction of 300 pounds per cubic inch (pci) be used. Where structural fill will support the concrete slabs, we recommend using a modulus of 200 pci. Parking Garage Concrete Pavement: To provide a uniform slab bearing surface, capillary break, and even working surface, we recommend the on -grade slabs be underlain by a 6-inch thick layer of compacted crushed rock meeting the requirements of Crushed Surfacing Base Course as Page 20 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 specified in Section 9-03.9(3) of the WSDOT Standard Specifications with the modification that a maximum of 5 percent of the material passes the U.S. No 200 sieve. Alternatively, we recommend using Type 22, 1/4-inch Crushed Gravel, per City of Seattle Standard Specification 9-03.14, Mineral Aggregate Chart. Parking level concrete pavement design recommendations are based on an assumed modulus of rupture of 600 psi and a minimum compressive strength of 4,000 psi for the concrete. We recommend that concrete pavements be lightly reinforced to control cracking and have relatively closely spaced control joints on the order of 10 to 12 feet. We recommend that minimum reinforcement consist of 6x6-W2.OxW2.0 welded wire fabric, or equivalent. Drainage Considerations Surface Drainage: Final site grades should be sloped to carry surface water away from buildings and other drainage -sensitive areas. Additionally, site grades should be designed such that concentrated runoff on softscape surfaces is avoided. Subsurface Perimeter Drainage: We recommend a permanent subsurface drainage system be installed around the perimeter of the structure. A minimum 4-inch diameter, perforated PVC drainpipe should be provided at the base of backfilled walls to collect and direct subsurface water to an appropriate discharge point. We recommend that the drainpipe be enveloped in free - draining aggregate meeting WSDOT 9-03.12(4), Gravel Backfill for Drains. We recommend wrapping the footing drain aggregate with a non -woven geotextile, such as Mirafi 140N, or equivalent. We recommend that a minimum of 2 feet of free -draining aggregate be placed against stem walls and that it consist of material meeting the requirements of WSDOT 9-03.12(2), Gravel Backfill for Walls. Pavements Asphalt Pavements Pavement Life and Maintenance: It should be realized that asphaltic pavements are not maintenance -free. The following pavement sections represent our minimum recommendations for an average level of performance during a 20-year design life; therefore, an average level of maintenance will likely be required. A 20-year pavement life typically assumes that an overlay will be placed after about 12 years. Thicker asphalt, base, and subbase courses would offer better ling -term performance, but would cost more initially. Conversely, thinner courses would be more susceptible to "alligator" cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. Soil Design Values: The existing subgrade soils are anticipated to consist of a varying mixture of silt, sand and gravel. Based on the typical values provided by similar material, we have estimated a California Bearing Ratio (CBR) value of 15 percent for this project. Page 21 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 Traffic Design Values: No traffic loading was provided for this project. We have assumed relatively low traffic volumes for light- and heavy-duty pavements. If traffic routes are expected across the site that could increase the estimated traffic loading, ZGA should be notified so that we can re -analyze the pavement sections. Recommended Pavement Sections: For light -duty pavements (parking lot areas), we recommend 21/2 inches of asphalt concrete over 4 inches of crushed rock base course. For heavy-duty pavements (main access roads, truck delivery routes, etc.), we recommend 3 inches of asphalt concrete over 6 inches of crushed rock base course. Materials and Construction: We recommend the following regarding asphalt pavement materials and pavement construction. • Subgrade Preparation: In areas that are at grade, the upper 12 inches of pavement subgrade should be compacted to a minimum of 95 percent of the modified Proctor maximum dry density. Subsequently, the subgrades should be proof -rolled with a loaded dump truck or other suitable heavy equipment to determine that the subgrade is firm and unyielding. Areas that are soft or yielding should be repaired as necessary to meet the compaction and proof -rolling recommendations presented herein. • Asphalt Concrete: We recommend that the asphalt concrete conform to Section 9-02.1(4) for PG 58-22 or PG 64-22 Performance Graded Asphalt Binder as presented in the 2020 WSDOT Standard Specifications. We also recommend that the gradation of the asphalt aggregate conform to the aggregate gradation control points for 1/2-inch mixes as presented in Section 9-03.8(6), HMA Proportions of Materials. • Base Course: We recommend that the crushed aggregate base course conform to Section 9-03.9(3), Crushed Surfacing Base Course, of the WSDOT Standard Specifications. • Asphalt and Base Compaction: All base material should be compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D1557 or to a firm and unyielding condition based upon proof rolling. We recommend that asphalt be compacted to a minimum of 92 percent and a maximum of 97 percent of the theoretical maximum density. Concrete Pavements The following concrete pavement recommendations are intended for exterior concrete slabs subject to traffic loading. Please refer to the Parking Garage Concrete Pavement section on page 18 for on -grade parking garage recommendations. Concrete Properties and Thickness: Concrete pavement design recommendations are based on an assumed modulus of rupture of 600 psi and a minimum compressive strength of 4,000 psi for the concrete. For light duty pavements, we recommend 5 inches of concrete over 4 inches of Page 22 Zi pperGeo Apollo Apartments Project No. 2361.01 GeoprofessionalConsultants April 22, 2022 crushed aggregate base. For heavy duty pavements, we recommend 6 inches of concrete over 4 inches of crushed aggregate base. Concrete Pavement Joints and Reinforcing: We recommend that concrete pavements be reinforced and have relatively closely spaced control joints on the order of 10 to 12 feet. We recommend that minimum reinforcement consist of 6x6-W2.OxW2.0 welded wire fabric or equivalent. We also recommend that loading dock and trash enclosure pavements be reinforced with #4 bars at 15 inches each direction. Infiltration Considerations Our explorations encountered undocumented fill soils of varying relative compaction over hydraulically restrictive glacial till deposits that can lead to seasonal perched groundwater development. Additionally, there is limited space for placement of an infiltration system outside of the building footprint while maintaining minimum separations distances form the building and surrounding properties. Infiltrating into loose fill soils could cause them to settle. Based on the conditions encountered, it is our opinion that the site is not suitable for infiltration. CLOSURE The analysis and recommendations presented in this report are based, in part, on the explorations completed for this study. The number, location, and depth of the explorations were completed within the constraints of budget and site access so as to yield the information to formulate our recommendations. Project plans were in the preliminary stage at the time this report was prepared. We therefore recommend we be provided an opportunity to review the final plans and specifications when they become available in order to assess that the recommendations and design considerations presented in this report have been properly interpreted and implemented into the project design. The performance of earthwork, structural fill, shoring, foundations, and pavements depend greatly on proper site preparation and construction procedures. We recommend that Zipper Geo Associates, LLC be retained to provide geotechnical engineering services during the earthwork - related construction phases of the project. If variations in subsurface conditions are observed at that time, a qualified geotechnical engineer could provide additional geotechnical recommendations to the contractor and design team in a timely manner as the project construction progresses. This report has been prepared for the exclusive use of Blackfish Capital LLC, and their agents, for specific application to this project and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Zipper Geo Associates, LLC reviews the changes and either verifies or modifies the conclusions of this report in writing. Page 23 ----------- fL-------- ------- FOUND REBAR AND CAP / STAMPED iVEBB 162J0" 0.1'(W) OF CORNER / CB RIM=43701 / IE 12 DI(NE)=433.65 IE 12" DI(SW)=433.65 / SO / CB RIM=43717 / IE 4 PVC E=436.02 IE 6" PVC(SW)=4JS92 Q % 4�4 / % 44 / 35' ELECTRICAL j EASEMENT PER AFN 7903280295 / YKEYSTOi i I I LQ / CB RIM=442.16 '\ IE 12DI(NE)=439.16 CB RIM=439.03 =436\88 < \�b B-7 ( n CONCRETE / ''CONCRETE CURB .--- ------__-F-L----- L�/1L1U 1LlL/1/ !1 - _ --- -----,-� ------- - `SO Q' T FOUND REBAR CAP UNREADABLE AT CO 11 a -� •" / 0_ SSCO RIM= 429.16' 'I 236TH ST. S. � a ANCNDR FAlzr / AFN 84052f0087 - N 86'J651" W 181.43, / I I , IE 12' CMP(W)=4*42 IE 12" CUP(E)=413.16 IE 12" CMP(S)=413.16 / LI I {� I "� B-13 � i �iB-9 1:7 1 s� /h PARCEL A I INGwEss, EcaEss IY BOUNDARY LINE AFNAND PARKING r /T \ Q I AFN 7812060189 i, ADJUSTMENT B-1 / AFN 9810.125004 I I SDMH RIM=418.35 / 1 I IE 12 CUP N=415.50 / / 1 00451900100201 I I IE 12' CMP(S)=415.50 IX. / 11.31 SF s I I B-2 r COMMERICbll �a / 0.26 AC _ I I Y BUILDING / / 12360 BOL.I c� I i 00451900100204 Ia p XYYCIIii/ / I. I EA SEWER & ORM EASEMENTS A��IT 1588234 AND AFN 15882J8 ' / 20' INGRESS, EGRESS AND PARKING 189EASEMENT `r!' I CB RIM=418.20 AFN 7812060'Tb B-$ INGRESS, EGRESS IE 12 CMP N =415.7 yI AND PARKING IE 12' CMP(S)=415.70 ��- ��/�� i�� it AFN 7812 189 IE 6�CMP(W)=415.66 ✓ SDMH RIM=429.65 G IE 6 CMP E=426.70 /) I (• ✓ IE 4- PVC(N)=426.95 I a CB RIM=424.69 IE 6" CMP(W)=426.55 IE 6 CMPE=412.54'� B-1 0 I I j IE 6- CMP(W)=426.64 I IE 6" PVC(W)=412.81 W Iz IE 6" PVC(N)=427.18 I I IE 6' CMP(SW)-422.88 \ m t U j PARCEL B j l I I i I BOUNDARY LINE I I 3 I ADJUSTMENT AFN 9810125004 I I e j 00451900100203 ELECTRICAL I� 34,881 SF I EASEMENT ASPHALT AFN 7905180203 I I I 0.80 AC I CB RIM=4I8.59 rrh 1 E 12' ;i B-3 • I SUNSET BUILDING IE 6' CMP('_.., .. _._J m c 123607 ARCEL C OF'EDMONDS S-23-88 880921.0451 i 1 N 88'J7'03' W JJT07' I { ; FOUND NO B-11 �-----------I------i---�-+ /SSMH RIM= 417.45' S INV 8" P✓C(N)=410. 05' \ I� 1IY INV. 8' P✓C(s)=412.J5' 11I\ / INV. 8" P✓C(SW)=412.J5' CAPPEDI II II I 10' SANRARI��SEWER-�-:I� UT/LDY1 6o`ENT AFN 20020 60z42 I 1 T / 15' STtASEORMIYTTER GRAVEL AFN 20020 60241 i III i, \ / I I \ 15' STORM WATER ESMT. 10' S HOARY S ' B-12 AFN 200201160141 � & URLITY FASEM III m ---.1-- -� - I -- AFN 2002I01160 B-4 , I� -, --hr--- -/--1---------1------ I`r, CHAIN,LINK FENCE _ INV. 8' PVC(E)=406.71 LEGEND INV. 8" PVC(W)=406.96' IN,8' PVC(S)=406.76' / i� B-1 APPROXIMATE LOCATION AND ID OF FOGUNE-- BORING COMPLETED 11/21/2020 TO 2' BRASS DISK WITH PAVEMENT. g ,g 11 /22/2020. 1 AUGUST 2018. '_ _ _ _ _ i N 88'3651' W 1 475.34' _ _ _ a -/'SD ®B-8 APPROXIMATE LOCATION AND ID OF SD-4/ BORING COMPLETED 12/5/2020 TO �a cONCNETE Gu 12/6/2020. FOUND RERAR AND CAP CO RIM=407.48 STAMPED 'WEBS 16230 IE 12 CUP W =4 0. i'(E) OF CORNER IE IE 12" CMP(E)=4 IK I 24' EASEMENT PER PUT OF \ I WILLOWBROOK DIV. NO. 2 \ LOT 8 I I I 03 V +� i PLAT OF WILLOWBROOK DIV. NO. 2 VOL. 34, PG. 59 `I I LOT 7 I I I I I I I _1_______________________________________ I I I I I I I ^I I \VI I LOT 6 I I I -----I-------------------- I I I 40 0 20 40 % SCALE IN FEET 1 LOT 5 I REFERENCE: TOPOGRAPHIC SURVEY PREPARED BY PACIFIC COAST SURVEYS, INC. DATED 08.16.2018. I7/I I A IT 1 /lA rl x=mD (FOR m > 0.4) 1.77q m2n2 D 6h D 2 ' (m2+ n2)3 _7 D (FOR m < 0.4) 6 h 0.28q n 2 6h - D 2 (0.16 + n2)3 BASE OF EXCAVATION q, lb per ft2 x=mD %/x /\ // z=nD LINE LOAD D PRESSURE 6h BASE OF EXCAVATION q, lb per ft2 6'h =(yh cost (1.1*O) �q 6h O 6h PLAN VIEW OF WALL STRIP LOADING PARALLEL TO EXCAVATION (yh = 27q ((3-sin (3cos 2a) 1 IAIC I llAr% (FOR m > 0.4) 1.28q m 2 n 6h - D ' (m2+ n2)2 (FOR m < 0.4) 6h _ q 0.2n D (0.16 + n2)2 UNIFORM LOAD DISTRIBUTION 6h = (Ka or Ko) q q = Vertical pressure in psf Ka (Active) = Tan 2(45 - 0/2) Ko (At Rest) = 1 - Sin 0 O = 38' 6h BASE OF EXCAVATION APPENDIX A FIELD EXPLORATION PROCEDURES AND LOGS Page 1 FIELD EXPLORATION PROCEDURES Our field exploration included thirteen borings completed between November 21 and December 6, 2020. The approximate exploration locations are presented on the enclosed Site and Exploration Plan, Figure 1. The exploration locations were determined by measuring distances from existing site features shown on the Boundary and Topographic Survey. Ground surface elevations for the exploratory boring locations were interpolated from topographic lines presented on the Topographic and Boundary Survey. As such, the exploration locations and elevations should be considered accurate only to the degree implied by the measurement methods. The following sections describe our procedures associated with the explorations. Descriptive logs of the explorations are enclosed in this appendix. Soil Boring Procedures Borings were advanced using hollow -stem auger drilling methods by Environmental Drilling and Holocene Drilling working under subcontract to our firm. The borings were advanced using a Mobile B-57 truck -mounted drill rig and a D70 track -mounted drill rig. A geotechnical engineer or engineering geologist from our firm continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture -tight containers and transported to our laboratory for further visual classification and testing. Throughout the drilling operation, soil samples were obtained at 2.5- to 5-foot intervals by means of the Standard Penetration Test (ASTM: D-1586). This testing and sampling procedure consists of driving a standard 2-inch outside diameter steel split spoon sampler 18 inches into the soil with a 140-pound hammer free falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "blow count" (N value). If a total of 50 blows are struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in each boring, based primarily upon our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If groundwater was encountered in a borehole, the approximate groundwater depth, and date of observation, is depicted on the log. The boring logs presented in this appendix are based upon the drilling action, observation of the samples secured, laboratory test results, and field logs. The various types of soils are indicated as well as the depth where the soils or characteristics of the soils changed. It should be noted that these changes may have been gradual, and if the changes occurred between sample intervals, they were inferred. Page 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 438 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto 6-1 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E 8 U) E J _ Z 0- o Q 0 A m a � 2 (D co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 2 1/2 inches of asphalt over IIII ',II IIIIIIIII IIII ..- Loose, moist to wet, orange and dark brown, silty IIII III IIIIIIIII Illlii 7-I-I-rrt-rrt -r-r-r-r-rTTTT rr-rrr r r - SAND/sandy SILT, some gravel, trace charcoal. (Fill) -------------------------------------------- S-1 181, III �OTTT IIIIIII TTTTTTT-- 9 GSA Loose, wet, orange, silty SAND, with gravel. (Weathered Glacial Till) J J J 1 IIIIIIIII 1 L.L 111111 IIIIIIIII LL LLL L L IIIIIII, ,� ----------------------------------------- T Medium dense, moist, gray with moderate orange mottling, 9 Y 9 9, silty SAND, some gravel. (Weathered Glacial Till) s-z I 18^ 11 Q +-�-i-F+ I I +{+++++ IIIIIIIII +++I-+-+ +- IIII 30 IIIIIIII IIIIIII -t-17 t f-t-r-r-r 11IIIlI IIIIIIIII rtrt7 rtT7 *trt IIIIIIIII IIII t t.t r r (IIIIIII Very dense, moist, gray, silty SAND, some gravel. (Unweathered Glacial Till) Very dense, moist, gray, silty SAND, some gravel. (Unweathered Glacial Till) S-3 T 18„ 11 T S-4 18 1 IIIIIII 0-I--7-r-7 I------------------------ IIIIIIIII -77-T-T-TTTTT 1 1 IIIIIII TTTTTTT ` 74 71 II1111�11 lilll1i11 (IIIIIII -t(IIIIIII -I111 + f-F -(IIIIIII IIIIIIIII -+-t t t t t.t..t t IIIIIIIII I1i111'... t t+ t - .'.. ,... IIII '. Very dense, damp, gray, SAND, with silt, some gravel T S-5 11 181, -(IIIIIII IIIIIIIII IIIIIII: 89 '...(IIIIIII ''...11IIIlI -1-t r-r-r7-r-r-r IIIIIIIII IIIIIIIII -r-r-r rTTT IIIIl11 IIIIIII -I-1-G-4-4-4-1 -1---a--1---1--1--1--1- -4--4--1--1--1- 1- - _.. IIIIIIIII IIII Large rock at -17 1/2 feet. IIIIIIIII IIIIIII -++-4-4 IIIIIIIII IIIIIIIII +++++++++ IIIIIIIII IIII�.... ++++ - IIII ... Auger refusal at approximately 17 1/2 feet. IIIIIIIII IIIIIIIII -trt-r-r-fiTTT-r IIII trrrr r t No groundwater seepage observed ATD. IIIIIII 1 IIIIIIIII IIIIIIIII �'44 '..IIIIIII TTTTTTTTT III�IIII� TTTTTTTTr IIIIIIIII IIIIIIIII IIIIIIIII llllllll -.,... -I-4-F-F-44 IIIIIIIII IIIIIIIII 44+44-I-+- -+4- Li. L...L.. IIII II IIII II 4-4-4-4-4-1- I-...i-•.I-. ..11lllll 'Illlllll IIIIIIIII IIIIIIIII I1111-t-t-t-r IIIIIIIII IIIIIIIII fit� t t t..ttt IIIIIIIII IIII tttt r Illlii ' IIIIIIIII IIIIIIIII (IIIIIII T1TT7T77 77777TTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_� LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Aprox. 420 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-2 Date Drilled: 11/22/2020 Drill Rig: Mobile Drill B57 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) a U) E J _ m co o 0) Standard Penetration Test E The stratification lines represent the approximate boundaries Z 0- o a Q Hammer Weight and Drop: U � between soil types. The transition may be gradual. Refer to Q 0 � report text and appendices for additional information. A 2 m (D 0 20 40 60 2 inches of asphalt over Drilling action suggests cobbles/gravel in upper 3 feet. Moist, brown, gravelly SAND, some silt in cuttings. 1 III III 1 1 IIIIIIIII Illlii 11 1-1-144 (IIIIIII -r-r-r4,111 rr IIIIIIIII r11 14 r r - IIIIIII Dense, moist, brown, ravel) SAND, some silt. Gravel in gravelly 3_1 I q" 1 - 31 -f-ITT��-f7 77 T TTjTTTT _ TTTTTTT _ shoe. (Fill) �? 1 1 1 1 1 1 Medium dense, wet, dark brown, silt SAND, some ravel, Y 9 abundant decayed organics, trace charcoal. (Fill) 1I S-2 10" �JJL��1 IIIIIIIII -(IIIIIII 111111111 IIIIIIIII IIIIIIIII 1LLLLLLL IIIIIII (IIIIIII 12 �++++++++ +++++ ++- illllllll -IIIIIII IIIIIIIII (III Wet, dark gray -brown, silty SAND, some gravel. Large rock at i-17trt�rtrtrt IIIIIIIII rtrtt t t t ttt (III t r r r r -7 feet impeded auger. (Blowcount likely overstated, pounding m-rock.1QALaaove /]_---------------------------- S-3 I 3" I I I I I I I I I TT I f I I I I I I I I I 77TTTTTTT I I I I I I I TTT-TTI-Tr iF 50/6" (Medium dense Glacial Till) Very dense, damp, gray, SAND with gravel and silt. Orange- brown oxidation mottling in top 4 inches of sample interval, S-4 14" IIIIIIIII IIIIIIIII I I I I I I I I I IIIIIIIII IIIIIIIII I I I I I I I I I IIIIIIIII IIIIIII I I I I I I 1 I 76 GSA QI '..1111111 IIIIIII - IIIIIII gray below. (Weathered Glacial Till over Unweathered) IIIIIIIII _f_tt+tt.t.tt IIIIIIIII tt.t (III '. Very dense, damp, gray, SAND with silt and gravel. T s-5 I 10" '.IIIIIIII IIIIIIIII Illllli 50/6" GSA '..IIIIIII '..IIIIIII _ IIIIIIIII IIIIIIIII IIIIIII IIIIIII 1 1 17 11 i T 1 T TTT_ T_ 1 1; 1 1 7_ 1 1 1 1 1 1 01 i 1 (Unweathered Glacial Till) 4 IIIIIIIII - IIIIIIIII G - (III Very dense, damp, gray, silty SAND with gravel.+++-4-44 IIIIIIIII IIIIIIIII +++++++++ (III ++++- (Unweathered Glacial Till) S-6 I 4" 1 1 1 1 1 -I-I-lrtrtrtrt -Yrtt t t t-rt-r I I 1 1 rT r r t-r 50/6" Auger refusal at approximately 18 feet. No groundwater observed ATD. IIIIIII -1-177-1-t--T 1 IIIIIIIII IIIIIIIII lliiili 777- 7TTTT II1�1II1� TTTTTTTrr 1II1�1III IIIIIIIII llllllll IIIIIIIII IIIIIIIII (III '. Illlii ..11lllll IIIIIIIII (IIIIIII 'Illlllll IIIIIIIII IIIIIIIII fittttt.+tt IIIIIIIII (III ttrrr Illlii '. 1111-71 74444T44 TTTTTTT :- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits B_2 Geoprofessional Consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 419 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-3 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) a U) E J _ m co o 0) Standard Penetration Test E The stratification lines represent the approximate boundaries Z 0- o Q U � between types. The transition be Refer to a Hammer Weight and Drop: soil may gradual. Q 0 � report text and appendices for additional information. A 2 m (D 0 20 40 60 Approximately 2.5 inches of asphalt over Damp, light brown, silty SAND with gravel. (Fill) III ill IIIIIIIII Illlii 7-I�-i-i-rrt rt-r-r-r-rY7TT IIIIIIIII r-r-rrr r r- IIIIIII- Loose, moist, light brown mottled with gray, moderate Oran e- 9 Y, 9 9„9 S 1 I ..IIIIIIII � �7 7777 TTTTT TTTTTTT g brown oxidation staining, silt SAND, with Fill g, Y gravel. ( ) I I 1 1 1 1 -------------------------------------------- 11JL��1 ''I11��1� 1 .i i L L i.L L - L LLLLL s Medium dense, wet, brown sandy GRAVEL, with silt, some IIIIIIIII IIIIIII-.'. wood fibers. (Fill) T ----------------------------------------- --- Medium dense, damp, reddish brown, fine SAND, some silt S-2 10„ 11 -I-4-4-F-I-4 -H-++++++ +4-11 -11 _.. 20 1 1 1 1 1 1 1 1 1 -IIIII 1 1 1 1 1 1 1 II 1 1 1 III 1, and gravel. (Fill) . i-l7Itrt11rtrtrtIIIIII IIIIIIIII 1TIt tIt t t t l- IIIIIIIII r IIIIIII. ` `------------------------------------------ S-3 15" I-iIIIIIIII �TT_7Tk77 IIIIIIIII 77TT-T TTTTTTTTTT IIIIIII _ 31 GSA Dense, wet, light brown with moderate orange -brown oxidation 1 1 1 1 1 1� 1 1 l I 1 1 I 1 1 l l i l l l l staining,silt SAND with ravel. Weathered Glacial Till Y g ( ) Dense, damp, gray, gravelly SAND with silt. (Unweathered Glacial Till) S-4 12^ IIIIIIIII I I I I I I I I I IIIIIIIII I I I I I I I I I L L L L L _ IIIIIII I I 1 1 1 1 1 47 GSA ( '....IIIIIII IIIIIIIII 4, Ili '..IIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII III1 "...'... IIII '. Very dense, damp, gray, silty SAND with gravel. T s-5 I 12^ '.IIIIIIII IIIIIIIII Illllli 50/6" '..IIIIIII '..IIIIIII 71 IIIIIIIII IIIIIIIII -1 IIIIIII- IIIIIII.7 T i i 1T71 17 I T T TT_ T_TT- T T (Unweathered Glacial Till) IIIIIIIII IIIIIIIII 11I1�...... IIIIIIIII ++ -44 IIIIIIIII IIIIIIIII 4+4++++++ IIIIIIIII IIII +++ - IIII '...- IIIIIIIII -I��rtrtrtrtrt IIIIIIIII IIIIIIIII rtrtrt7rtrt7rtr IIIIIIIII trrrrr.. IrT_ (IIIIIIIII -IIIIIIII 1-177-1-7-T7 -1�111111 IIIIIIIII TTTTTTTTT III�II�I� Illlllll TTTTTTT '- I�II�II- Very dense, damp, gray, silty SAND with gravel. T (Unweathered Glacial Till) S-6 I 12 50/6" l l l l l Boring completed at approximately 21 feet. IIIIIIII IIIIIIIII Illlii No groundwater observed ATD. + ++-+-++++++ +++i- - r IIIIIIIII IIIIIII Boring left open after completion from 09:10 to 16:00. Boring caved in at approximately 12 feet. No groundwater observed .IIIIIII 11-t�_t t t IIIIIIIII fitt t t t tt t IIIIIIIII t t t r r Illlii in upper 12 feet of boring at end of day. T 7TTTTTTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample 0 Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis _ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits B_3 Geoprofessional Consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 422 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-4 Date Drilled: 12/6/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E a U) E J _ Z 0- o Q 0 A m a � 2 (D co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 1 to 2 inches of crushed gravel over IIII ',II IIIIIIIII IIII ..- -IIII1111 IIIIIIIII Illlii 7-I-17Y�rt-I-Y -IIIIIIII rtrtYYTY7TT IIIIIIIII rTTYT r r - :_... IIIIIIII gravelly (Fill) Medium dense, moist, brown, ravel) SAND with silt. Fill S_1 I1a 1 1 1 1 1 1 26 GSA ��TT ITTT1TT T 1 1 1 1 1 1 1 --'-"'-----"'---'-"'---'-"'---'-"'---'- Medium dense, wet, gray with brown mottling, ravel) SAND, g Y g� gravelly some silt. (Weathered Glacial Till) T S_2 I 12„ 11 -IIIIIIII 1.11111.1L IIIIIIIII 1LLLLLLL IIIIIII 30 111111111 1 1 1 1 I I-I-I-FQ+ 1 I 1 1,41 I 1 -{++ +++ 1 1 +++-++ - IIIIIIII (IIIIIIIII IIIIIIIII IIII _i7tt trtrt IIIIIIIII rtrtYtttttt IIII .. rt.trr,, , Verydense, moist, gray, SAND with silt and ravel. 9 Y 9 (Unweathered Glacial Till) Very dense, moist, gray, SAND, with gravel and silt. (Unweathered Glacial Till) s3 1 1s^�1 I T S-4 18 I 1 1 1 1 1 1 1 1 1 1 1 1 74 GSA ��-r�-r� IQ[ IIII II I I I I I I I I TTTTTTT III [[III I I I I I I III , III III TTTTTTT IIIIIII III III III III III I II III II _ + llllllill lillllill Illlllll IIIIIIII IIIIIIIII Ililll'... Very dense, moist, gray, SAND, with gravel and silt. (Unweathered Glacial Till) T s-5 1a 11 -IIIIIIII IIIIIIIII Illllli 72 '...illiiili ''...11iiili -tt rY-r7-r-r-r IIIIIIIII IIIIIIIII -r-r-r rTTT IIIIIIII IIIIIII IIIIIIIII IIII IIIIIIIII IIIIIII IIIIIIIII llil�...... IIIIIIIII -I��rtrtrtrtY IIIIIIIII rtrtYYYrt7tt IIII trrrrr Very dense, moist, gray, SAND, with gravel and silt. IIIIIIII IIIIIIIII IIIIIIIII -177-1-7-T7 TTTTTTTTT TTTTTi-T '- (Unweathered Glacial Till) s-6 16^ 50/6^ Boring completed at approximately 20 1/2 feet.- IIIIIIIII IIIIIIIII IIII No groundwater observed ATD. lliiili IIIIIIIII IIIIIIII 11 �� iilliiill 4444;t.tt1 iiil t4"; T11TYT�7 Y7777TTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample 0 Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_4 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 437 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-5 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E a U) E J _ Z 0- o Q 0 A m a � 2 (D co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 2 to 4 inches of sod over '..II '.. IIIIIIIII IIII ..- Light brown with gray mottling, silty SAND with gravel. III IIIIIII Illlii (Weathered Glacial Till) -------------------------------------------- Very dense, wet, gray, silty SAND, some gravel. Unweathered Glacial Till () Very dense, moist, gray with trace orange -brown oxidation S-1 6" 1n 12" S-2 I ^ 10 Q O ......... IIIIII TTTTTT 1 I a 11.11111.1 L ''...illllll IIIIIII TTT r1-1- r - 1 1 1 1 1 1 1LILLLL s IIIIIII- IIIIIIII 82 50/4" GSA bl l l l staining, silty, sandy GRAVEL. (Unweathered Glacial Till) 1 ++� I111111111 ++++ ..illll +++ -+-1— IIII IIIIIIIII -i-I17��rtrtrt ..11lllll IIIIIIIII rtt1-tttt�-t IIIIIIIII IIII ttrrr , , IIIIIIII Very dense, moist, gray, SAND with silt and gravel. (Unweathered Glacial Till) Very dense, moist, gray with trace orange -brown oxidation T s-s 11 is T S-4 I 12° IIIIIII Ol -1 77 II I„II I�lillilll I I I I I I I I I IIIIIIIII -77-T�TTTTT III IIIII II,IIIII,II IIIIIIIII I I I I I I I I I IIIIIII TTT T rT- IIIIIII IIIIILL-s.. IIIIIII'. I I I I I I I I ss 50/6" GSA staining, silty SAND with gravel. (Unweathered Glacial Till) -I + 111111111 + ++ + IIIIIIIII + IIIIIII -IIIIIIII --I11-" _f _ft IIIIIIIII IIIIIIIII 11-tttt.t.t+ IIIIIIIII Illl�i IIII '. Very dense, moist, gray with trace orange -brown oxidation S-5 I 12^ IIIIIIII IIIIIIIII III111� 50/6" 7TT1rt11 IIIIIII IIIIIII "TTTTTTT IIIIIIIII IIIIIIIII -r-r-r 14 IIIIIII IIIIIII staining, silty SAND with gravel. (Unweathered Glacial Till) IIIIIIIII IIIIIIIII ilil IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIII IIII -i��rtrtrtrtrt IIIIIIIII rtrtrt7rtrt7rtr IIIIIIIII III trrrrr.. Illllllli IIIIIIII IIIIIIIII IIIIIIIII -177-1-7- -T '..IIIIIII TTTTTTTTT III�IIII� TTT rl- 7 '- IIIIIII Very dense, damp, gray, silty SAND with gravel. s-s 2 5^ so/s° (Unweathered Glacial Till) IIIIIIIII IIIIIIIII IIII.............. S-7 I 6" IIIIIIIII IIIIIIIII IIII 50/6" '...... Boring completed at approximately 22 1/2 feet due to auger '..IIIIIII -1-11 _t_t_t IIIIIIIII 11 t t t t t" II 44; refusal. i No groundwater observed ATD. (IIIIIIIII IIIIIIIII IIII IIII 7TT7TTTTT TTTTrT-T- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample 0 Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_5 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 447 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-6 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E a U) E J _ Z 0- o Q 0 A m a � 2 (D co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 ,1/2-inch of asphalt. `------------------------------------------;..��-F...-i.-^-}-i--...tr trt-i-� f Loose, wet, gray, SAND. (Fill) Loose, wet, -reddish brown, silty SAND. (Fill)- - - - - - - - - - - - - - ---- -- ---- --- -- S-1 I 14" IIIII ill 1111 11 1 1 1 I 1 1 IIIIIIIII 1 1 I 1 Illlii 7 11 144 IIIIIIIII IIIIIIIII rt4411 I'll r IIIIIIIII IIIIIIIII - r-r-rrr r r--------------------------------------------- IIIIIII- IIIIIII T�T�7 II I1 1 77777TTTT 1I1111�11 TTTTTTT - 111111 Loose, wet, gray mottled with brown, silty SAND with gravel. 1 -I 171111 1 11 IIIIIIIII LI i, I , t IIIIIIIII i L L L >_ LL s 1111111, (Weathered Glacial Till) Dense, moist to wet, gray with trace g y race orange -brown oxidationS-2 staining, SAND with silt and gravel. (Weathered Glacial Till) 16" 37 GSA �+ �+ ++++++ +++++ +r- 1111111111 IIIIIIIII IIII IIIIIIIII -17yrt11rtrtrt IIIIIII IIIIIIIII rtrtrttttttt IIIIIIIII IIII ttrrr,,, IIIIIII Very dense, moist, gray with trace orange -brown oxidation staining, silty SAND with gravel. (Unweathered Glacial Till) Very dense, moist to wet, gray with trace orange -brown oxidation staining, silty SAND with gravel. (Unweathered s-3 12" S-4 181, I III11 -� �-�,-�� I I I I I I I I I IIIIIIIII I I I I I I I I I IIIIIIIII 47 �TT7TTT I I I I I I I I I t.T-iT1 1111 i.iTTiTi I I I I I I I I I IIIIIII TTT rTTr ` I I I I I I I 1111111 TTTTiii� 1 1 1 1 1 1 1 5oi6�� 53 GSA _I'�+Q� ++++ + + + Glacial Till) -IIIIIIII -+t1-t t t.t.t t IIIIIIIII t t.t t - , IIII '. Very dense, moist, gray, sandy SILT, some gravel over silty T S-5 I 12^ -IIIIIIII IIIIIIIII Illllli 50/6" '..IIIIIIII '..IIIIIII -TT -t-r r-TT7T-r-r IIIIIIIII IIIIIIIII 7T7 rrrr IIIIIII- IIIIIII- T 77777T_T_ T_TT-TT. 11 SAND with gravel. (Unweathered Glacial Till) IIIIIIII IIIIIIIII IIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIII IIII '...- IIIIIIIII ��rtrtrtrtrt IIIIIIIII IIIIIIIII rtrtrt7rtrt-rrtr IIIIIIIII IIII trrrt- 1111111111 IIIIIIII IIIIIIIII IIIIIIIII - -177-1-7-f7 '..IIIIIII TTTTTTTTT III�IIII� TTTTTT IIII�II- Very dense, moist, gray, silty SAND with gravel. T S-6 I 13" 50/6" QY (Unweathered Glacial Till)- IIIIIIIII IIIIIIIII iii1...... llllllll IIIIIIIII Illlii ..11lllll ''111��1� IIIIIIIII IIIIIIII 1-r11�� IIIIIIIII IIIIIIIII fittttt.+tt IIIIIIIII IIII tt-rrr Illlii '. (Driller added 3 to 5 gallons of water to assist in clearing��T�� IIIIIIIII IIIIIIIII IIIIIII 7T77TTTTT TTTTrTr - cuttings.) SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample 0 Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_6 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 447 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-6 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E a U) E J _ Z 0- o Q 0 A m a � 2 (D 0 co o U —° m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 20 40 60 Very dense, moist, gray, silty SAND with gravel. s-7 51, sois (Unweathered Glacial Till) III III IIIIIIIII IIIIIII' (Drilling action suggests the presence of cobbles between ( 9 99 P r r 1 1 1-1-1 r l I I i I- l l 1 1 1 -1-T-1-1 -T.-1.-1 -1 1 1 1 1 1 7777777 -, approximately 26 and 28 feet) I LLLLLLLLLJLLJLJ (IIIIIIII I I I I I I I I I I I I I I I I IIIIIIIII I I I I I I L-JLJL1 IIIIIII' IIIII 1+11— (IIIIIII III 1—.I i I--I._I_I IIIIIIIII IIIIIII' Very ry densedamp, gray, silty SAND with gravel. , S-8 = a^ .IIIIIIII IIIIIIIII IIIIIII' sofa 1 1 1 1 1 1 1 1 Glacial Till) IIIIIIIII �rt4-1 IIIIIIIII rt4(Unweathered IIi1111' i .i iiliiiiiiiii1111 LLLLLLLLJLLJL� i .i 1- i_I-l_i__l_i_i i i i. i i i 7777777 i i 7 7 7 7 T_, LJLJLaJ Very dense, damp, gray, sandy GRAVEL with silt. Unweathered Glacial Till ) s-s s^ 2 sois° MINN'IIIIIII IIIIIIIII Auger refusal at approximately 36 feet. 'IIIIIII I I I I I I I I I1 1 1 1 1 IIIIIIIII IIIIIII No groundwater observed ATD. IIIIIIIII I I I-t-i I -i-17 7 rt 7 7 7 IIIIIIIII rtrt rt 7-t 7 t IIi1111' ��777 77-1 il� iili 7777777 iii1111 Illllllll IIIIIIII I Ilia 111 i IIIIIIII .IIIIIIII I I 111111111 I I I I— IIIIIII' 4—F—+444 IIIIIIII IIIIIIIII IIIIIII' r.r IIIIIIIII IIIIIII r l I—t—I—I I— llllllll —I.—I—I � y rt.�.� 7 IIIIIIIII IIIIII' rt rtrt7777 IIIIIII' llllllll llllllll —17-177-177 IIIIII' 7F7Fl-7-7 IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII 7777777 IIIIIII' L.L.IIIII IIIIIII' IIIIIIIII IIIIIIIII �.�1—I IIIIIIIII I—Iti I--l—I.-1-4�-44-� IIIIIIIII IIIIIIIII IIIIIIIII IIIIIII' IIIIIII' 44.4444+1 IIIIIII' llllllll IIIIIII' IIIIIIII IIIIIIIII IIIIIII' IIIIIIII �rr1l-t-i-I 1--i-1-177rt.�.77 IIIIIIIII IIIIIII' rtrtrtrtrtrtrt _.... 7-T7-T77-T SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. =Consolidation Test � measurement. ZipperGeo BORING B_6 Att. = Atterberg Limits Geoprofesslonal consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Page 2 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 440 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-7 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ E SOIL DESCRIPTION a U) E J _ Z 0- o Q 0 A m a � 2 (D PENETRATION RESISTANCE (blows/foot) co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 Approximately 6 1/2 inches of asphalt over 2 inches of crushed gravel base course over I I I I I I I I I I I I I I I I I I I Loose, moist to wet, orange -brown, SAND with silt, some IIII III IIIIIIIII Illlii 11 1-1-144 -rT-r-r-r-rTTr 1114 r r - gray_el,tracecharcoal_�Fil�_________________________ Loose, moist to wet, orange -brown, SAND with silt, some g s-� T �s I i7f�f� `' 77 T T TT TT TTTTI TT g g ravel. � i ------------------------------------------- Verydense, moist, tan -gray, SAND with silt and ravel. g Y, g (Unweathered Glacial Till) 1 T S-z I 181 11+� JLL_JJI IIIIIIIII IIIIIIIII I-LLILLl.L1 IIIIIIIII IIIIIIIII 1LLLLLLL IIIIIIII IIIIIII-�'.. ss GSA + +{++++++ +++ + +- IIIIIIIIII IIIIIIIII IIII IIIIIIIII -+ , trtrt-r-r IIIII IIIIIIIII rtrtrt t t t ttt IIIIIIIII IIII t t.- r T- IIIIIII Very dense, moist, yellow -tan, SAND with silt, some gravel. (Unweathered Glacial Till) Very dense, moist, gray with light -orange mottling, silty SAND with gravel. (Unweathered Glacial Till) s-s 12° S-4 181, IIII 1 1017-7-777-77TT IIIIIIIII �.-._._. I I I I I I I I I IIIIIIIII TTTTT IIIIIIIII _._._._._._._._._. I I I I I I I I I IIIIIII TTT-Tl-1-T ` IIIIIIII TTI _s I I I I I I I I Sois" ss GSA IIIIIIIII Q +++++++ IIIIIIIII + - IIIIIIII IIIIIIIII 1 11 �t IIIIIIII IIIIIIIII -+t1-ttt.t.tt IIIIIIIII Ililll'... IIII Very dense, moist, gray, SAND, with silt some gravel. S-5 I s IIIIIIII IIIIIIIII IIIIIII 50i6° ..'...IIIIIIII IIIIIIIII IIIIIIII 1119111 1 (Unweathered Glacial Till) a IIIIIIII IIIIIIIII IIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII lilt +++ - IIII IIIIIIIII -I��rtrtrtrtrt IIIIIIIII IIIIIIIII rtrtrt7rtrt7rtr IIIIIIIII IIII trrrrr. IIIIIIII IIIIIIII 7-177-17 f7 -IIIIIIII IIIIIIIII 77777TTTT III�IIII� IIIIIIII TT77T77 'L IIIIIIII Very dense, damp, gray, SAND with silt, some gravel. s-s 2 s^ 10i5" (Unweathered Glacial Till) IIIIIIIII IIIIIIIII Ilil............. IIIIIIIII IIIIIIIII IIII IIIIIIII ....IIIIIIII IIIIIIIII IIIIIIII IIIIIIIII IIIIIIIII fittttt.ttt IIIIIIIII IIII tfirrr IIII�� IIIIIIIII IIIIIIIII IIIIIIII _... T11T�T�7 777TTTTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_7 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 440 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-7 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ E SOIL DESCRIPTION a U) E J _ Z 0- o Q 0 A m a � 2 (D 0 PENETRATION RESISTANCE (blows/foot) co o U —° m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 20 40 60 Very dense, damp to moist, gray, SAND with silt and gravel. S-7 6" 50/6" (Unweathered Glacial Till) 1 III IIIIIIIII IIIIIII' .ill Hi iii F.F F 1 I I i L- �� -T -17 - 7777777 LLLLLLLL IIIIIIIII ��J��JJJ IIIIIIIII 1JJJJ11 IIIIIII' IIIIIIIII 1+11- 1-.i i I--I._I_I illlllll IIIIIIIII IIIIIIIII IIIIIII' IIIIIII' Very dense, moist, gray, silty SAND, some gravel. S-8 I 6" .illlllll IIIIIIIII IIIIIII' 50/5" (Unweathered Glacial Till) r1 1 1-i-1 1 111ii11 r-1-l-1yrt11 7�� IIIIIIIII rtrt4-1-4 IIIIIII' liiiiii ii1111'' _ _ I—r1-7-7F I11iii1 I II _iii i__.. Illi Illi 7777777 i iiiiTT_ , IIIII ii1111' IIIIII' Very dense, damp to moist, gray, SAND with silt, some gravel. S-9 I 6" I I 50/6" (Unweathered Glacial Till) IIIIIII IIIIII III .rFI I—t-1_1 I--L_I-177rt iiii _�.rtY4711 T777 L.L LI I_f_L_I I_ 111111111 _L_L_IJ J JJ.L � i�i ii�i� 11.11111 _ , IIIIIII' S-10 0" illllll� llllll' L50/0-- Boring completed at approximately 40 feet. illllll ii IIIIII' No groundwater observed ATD. lllllll �4444 - iiliiiil r.rr1 1-i-i-1 � iiliiiil 111i ��rt , , 111i ii1111 7rtrt777rt ii1111 iiliiiil 111i 17-1- _. 111i Illi ii1111 -777777 _ ii1111 111111' FT77 -r-7 IIIIIIIII iiliiiili —I—I.-1 -4 4 -� IIIIIIIII iii1111 4 4.4 4 4 4+ 1 IIIIIII' illlllll IIIIIIIII IIIIIII' illlllll IIIIIIIII IIIIIII' illlllll �rF11-t-i-11--i-i-177rt.�.77 IIIIIIIII IIIIIII' rtrtrtrtrtrtrt _.... 777-T77-T SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis _ on date of Date: December 2020 Project No.: 2361.01 Consol. =Consolidation Test � measurement. ZipperGeo BORING B_7 Att. = Atterberg Limits Geoprofesslonal consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Page 2 of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 429 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto 6-8 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) a U) E J _ m co o 0) Standard Penetration Test E The stratification lines represent the approximate boundaries Z 0- o a Q Hammer Weight and Drop: U � between soil types. The transition may be gradual. Refer to Q 0 � report text and appendices for additional information. A 2 m (D 0 20 40 60 Approximately 3 inches of asphalt over moist to wet, brown, silty SAND. (Fill) IIII ',II IIIIIIIII IIII .. Boring encountered a 1-inch diameter PVC pipe with a red - coated copper wire protruding at approximately 2 feet below grade. Wire did not appear to be live. Water drained from the damaged PVC to fill the boring. Bailed water from hole to observe the damaged utility. No bedding observed around PVC, which entered boring from the northwest. Boring advancement halted after encountering utility. SAMPLELEGEND I2-inch O.D. split spoon sample 3-inch I.D. Shelby tube sample TESTING KEY GSA = Grain Size Analysis 20OW = 200 Wash Analysis Consol. = Consolidation Test Att. = Atterberq Limits GROUNDWATER LEGEND O % Fines (<0.075 mm) Clean Sand O % Water (Moisture) Content ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments n Blank Casing 23601 Highway 99 Groundwater level at time of drilling (ATD) or Edmonds, WA _ on date of Date: December 2020 Project No.: 2361.01 measurement. ZipperGeo BORING B_8 Geoprofessional Consultants LOG`: 19019 36th Ave. W, Suite E Lynnwood, WA Page 1 of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 420 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto 6-9 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ E SOIL DESCRIPTION a U) E J _ Z 0- o Q 0 A m a � 2 (D PENETRATION RESISTANCE (blows/foot) co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 Approximately 2 inches of asphalt over IIII ',II IIIIIIIII IIII ..- '.III11111 '... IIIIIIIII Illlii . -17Y�rt-I-Y rtYYYYY7TY IIIIIIIII rTTYT r r - :_... IIIIIIII Loose, wet, dark brown, silty SAND, trace to some ravel, Y 9 wood shavingsin cuttings. Probable Fill -------------------------------------------- _ I a ..IIIIIIII �I1T��7 1=tlllll .''IIIIIIII 77-T-TTTTTT IIIIIIIII .L I L L L.L L TTTTIT-T 1111111 L L LL L L L s Very dense, wet, gray with slight orange mottling, SAND with IIIIIIIII 1111111-.. silt and gravel. (Slightly Weathered Glacial Till) S-2 15" I 1 1 1 1 -Ii -4�-F-+ 1 -44 +++++ +++++-+-I- 60 GSA (I IIIIIIII IIIIIIIII IIII IIIIIIII r-17yrt�rtrtrt 1111111 IIIIIIIII rttY t t t t�- t IIIIIIIII 11111'..'.. t t r r r,�' IIIIIIII Verydense, moist to wet, SAND with silt, trace to some gray, gravel. (Unweathered Glacial Till) Very dense, moist, gray, SAND with silt and gravel. (Unweathered Glacial Till) T S3 I 18" 11 T s a 18 l IIIII IIIIIIIII 1 1 1 1 1 1 1 60 56 GSA T77 11 1 1't'i 11 1 IIIIIIIII IIIIIIIII I I I I I I I I I 7TTT-TTTTT 1 1 1 1 1 1 1 1 1 II,,,IIIII,II 7IIIIIIII I I I I I I I I I TTTTI-TT 1 1 1 1 1 1 IIIIILL-s.. TTTTTF7 I I I I I I I I 111111111 IIIIIIIII IIII '... III '.. ill IIIIIIIII IIIIIIII IIII '... IIII Very dense, moist, gray, silty SAND with gravel Very dense, moist, gray, silty SAND with gravel T S-5 11 18" T S-g 11 18" II �rt�Y 01 (IIII -�T r r r Illllli i r r rrrrrr 60 60 GSA 0�J-4-4-1 IIII 111111111 -1---a--1---1--1--1--1- IIIIIIIII -4-4--1--1-_ IIII IIIIIIIII IIIIIIIII IIIIIIIII IIII�.... IIIIIIIII IIIIIIIII ��YYYYrtY IIIIIIIII IIIIIIIII YYYYYTTtY IIIIIIIII IIIIIIIII �tT�t�Yrrr..rr.. IIIIIIIII IIIIIIII IIIIIIIII IIIIIIIII -177-17 7 '..IIIIIII 77777TTTT III�IIII� TTTTTi-T '- IIII�II- -249- dense, moist. aray. silty SAND with aravel S-7 I 6" k 50/5^ —Ve[� Boring completed at approximately 20.5 feet.- IIIIIIIII IIIIIIIII IIII No groundwater observed ATD. ,_,...-1-f-i-i-I-+ 4444+++++ ++4F-4-4-1-I- :_... 1111111 111111111 IIIIIIII I1111111 I-iI'll -h-F 111111111 1111II111 444 t t t..11 "1 1111II111 1111 tfi 4 ; 1111�� 111111111 11111 T YTTYTTTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis _ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_9 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 421 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-10 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) E a U) E J _ Z 0- o Q 0 A m a � 2 (D co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 Approximately 1 1/4 inches of asphalt over IIII ',II IIIIIIIII IIII ..- -11111111 IIIIIIIII Illlii 7-I-17Y�rt-I-Y -(IIIIIII rtrtYYTY7TT IIIIIIIII rTTYT r r - :_... (IIIIIII Medium dense, moist to wet, tan -gray light brown, silt 9 Y and ht 9 Y SAND with gravel. (Possible Fill) s_t I ts• t3 ��T �� 1'1� 7T T T TTTTT 1 I I 1 1 1 1 1 I TTTTTTT - 1 1 1 1 1 1 ------------------------------------------ Pushed a rock with sampler, blowcount overstated, low p recovery. Very loose to loose, wet, orange -brown, SAND with 11 S-2 3" IIIIIIIII -(IIIIIII 11.LILLI.LL IIIIIIIII IIIIIIIII 1LLLLLLL IIIIIII (IIIIIII 28 IIIIIII + III I1111 +++� ++++ IIIIIII ++T + - 11111111 IIIIIIIII IIII \silt, some gravel. ----------------------------------------- ,.._I7yrt-f'-t'rtrt ..11lllll rtt-tttt.ttt IIIIIIIII tt...firr '.. (IIIIIII Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) S-3 T 4" 11 T s a l to �II�III Q -177 !Li Ilillilll 1 1 1 1 1 I 1 1 1 IIIIIIIII -7-7-TTTTTTT iL.LiLLL1L IIIIIIIII I I I I I I I I I IIIIIII TTTTTTT ` LLLLLLL (IIIIIII I I I I I I 1 1 60 55 GSA IIIIIIIII � IIIIIIIII IIII (IIIIIII -(IIIIIII IIIIIIIII IIIIIIIII 11i11'...'... IIII '. Very dense, moist, gray, SAND with silt and gravel s-5 16° -(IIIIIII IIIIIIIII IIIIIII: k 50/6" '..IIIIIIII '..IIIIIII IIIIIIIII IIIIIIIII (IIIIIII IIIIIII-L I II III Boring completed at approximately 15.5 feet. ,..IIIIIII G IIIIIIIII a a G = li IIIIIII IIIIIIIII IIII No groundwater observed ATD. 1 1 1 1 1 1 1 111111111 1 1 1 1 1 1 1 1 1 111111111 l i 1 1 +++ - 1111 111111111 �YYttrtrt 111111111 111111111 ttYYYtTt-r 111111111 1111 YTttt-r'` 11111111i --IIIIIII 17f-177-1-7-T7 -IIIIIII IIIIIIIII TTTTTTTTT 111�1111� IIIIIIIII TTTTTTTTT IIIIIIIII IIIIIIIII IIIIIIIII 111111111 ... -I-4-F-F-44 IIIIIIIII IIIIIIIII 44444-I--I-+-4- L...L.. IIII _I IIII 11 -4--4-4--I- 1- I-...F-4- '.1111111 111111111 111111111 'Illlllll -i-1-11tt-h-F IIIIIIIII IIIIIIIII ttt t t t..ttt IIIIIIIII IIII tfi-'tt r Illlii ' IIIIIIIII IIIIIIIII (IIIIIII TITTYT�7 YTTTTTTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_� o LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: EDI Bore Hole Dia.: 8-inch Top Elevation: Approx. 422 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-11 Date Drilled: 11/21/2020 Drill Rig: Mobile Drill B57 Logged by_: TAJ E SOIL DESCRIPTION a L E J _ Z 0- o Q 0 A - io a � 2 (D PENETRATION RESISTANCE (blows/foot) co r- o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 Approximately 4 inches of crushed gravel surfacing over IIII ',II -L...-i IIIIIIIII IIII ..- -IIIIIIII IIIIIIIII Illlii 7rI-17Y�rt-I-Y -IIIIIIII rtrtYYTY7-tT IIIIIIIII rtTTYT r r - :_... IIIIIIII Pushed a rock with sampler. Blowcounts overstated. Medium dense, moist to wet, brown, silty SAND with gravel. (Possible g_1 q^ 30TTTT ITT�T 77T TT TTTTTTT _ Fill or Weathered Glacial Till)�JJ��1 -------------------------------------------- Ve dense, moist, gray, silt SAND with ravel. ry 9 Y, Y g (Unweathered Glacial Till) 1 s-z 18" -IIIIIIII 111111111 IIIIIIIII 1LLLL L L s IIIIIIII 66 I I I I I I I I I I I I I I I I I I I I I I I IIIIIIII IIIIIIIII IIIIIIII IIIIIIIII r-i7yrt�rtrtrt ,..IIIIIIII IIIIIIIII rttYttt-ttt IIIIIIIII IIIIIIIII trrrrrr�r IIIIIIII Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) Very dense, moist, gray, SAND with silt and gravel. (Unweathered Glacial Till) s-3 T 181 11 T s_q 18 11 IIIIIII 07-1T-T-T III,II Ilillllll I I I I I I I I I IIIIIIIII -7TTTTTTTT II,IIIII,II IIIIIIIII I I I I I I I I I IIIIIII TTTTTTT ` IIIIIII_,,, TTTTTIIII I I I I I I I I I ss 67 ++ IIIIIIII ++ ++ -+ IIIIIIIII + + + - - IIIIIIII IIIIIIII IIIIIIII IIIIIIIII IIIIIIIII Ililll'... IIII Very dense, moist, gray, silty SAND with gravel S-5 T 181, IIIIIIII --IYT rt�7 .'...IIIIIIII IIIIIII IIIIIIIII 7rt7Y77T7T IIIIIIIII IIIIIIIII IIIIII�I� TT?-TTTrr7 IIIIIIII IIIIIIII 91 IIIIIIIII IIIIIIIII IIII Boring completed at approximately 16.5 feet. IIIIIIIII IIIIIIIII IIII it -++++- - No groundwater observed ATD. 9 IIIIIIIII ��rtrtrtrtY IIIIIIIII IIIIIIIII rtrtYYYrt7rtr IIIIIIIII IIII. trrrt-r IIIIIIIII IIIIIIII IIIIIIIII IIIIIIIII -177-1777 '..IIIIIII 777T7TTTT III�IIII� TT7TT77T-7 IIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII +I-I+I+I-I-III-+I IIII -.. IIII 4-4I-:_... ..'IIIIIIIIIIIIII II-+I I-4I-4I I-4 I -I'll IIIIIIIII 444 t t t.tItI IIIIIIIII I14 I1;1I-II- Illlii IIIIIIIII IIIIIIIII IIIIIIII TITTYT�7 YTTYTTTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B_11 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 424 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-1 2 Date Drilled: 12/5/2020 Drill Rig: Diedrich D70 Logged by_: JST SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) 8 U) E J _ m co o 0) Standard Penetration Test E The stratification lines represent the approximate boundaries Z 0- o a Q Hammer Weight and Drop: U � between soil types. The transition may be gradual. Refer to Q 0 � report text and appendices for additional information. A 2 m (D 0 20 40 60 2 inches of sod mixed with crushed gravel over approximately .4 inches of dark brown, sandy topsoil. ----------------------------------------- - + in r� iiiiii _ TTYl"i iiii� r-r-rrr r r - Wet, reddish brown, silty SAND, with gravel. (Fill) iiii i -------------------------------------------- S-1 18" i I iiiii TTTTTT iiiiii iiiii TrTTTTT - T 44 Dense, moist to wet, gray, silt SAND with ravel. Strong g Y, Y g g orange -brown oxidation staining at contact. (Unweathered �JJJ��_j1 _L_L 1L11 _LLLLLLL Glacial Till) T Verydense, moist, gray, silt SAND with ravel. 9 Y, Y g (Unweathered Glacial Till) s-z T 18" 1 + ++ ++++++ +++ + r- 78 iiiiiiii -i-Iyrt-trtrtrt rtrty- t t t tt t t t.r r r,, Verydense, moist, gray, silt SAND with ravel. 9 Y Y g T S3 I 15" T T f7 7TTT T TTTT TTrTTTT - Ti 46 (Unweathered Glacial Till) Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) 11 T s a 1a l iiLLiiii LiLLi iTi i iiiiiii 66 GSA Very dense, moist, gray, silty SAND with gravel. S-5 I 4^ 50/5" -t-r TTT7T-r-r -rT77rTT (Unweathered Glacial Till) a G (Drilling action suggests gravels/cobbles between++ -4 -4-4-4 +++++++++ ++ +i+- approximately 16.5 and 18 feet. -I��rtrtrtrtrt rtrtrt7rtrt7rtr i trrrrr.. Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) s-s I s" - - - sots" nTT�� r7 77T r T T TT-r r- r Auger refusal at approximately 19 feet. No groundwater observed ATD. iiiiiiiii iiiiilii '.,. -I-f-F-F-I-+ - iiiiiiiii iiiiiiii -+-i-- 44- —+++ ++4-4-4-1- -111 -t-t-t-t iiiiiiiii fitttttttt tfitt- T11T7T77 77777TTTT TTTTTTT:- SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample 0 Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits B_� 2 Geoprofessional Consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Page 1 of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 431 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-13 Date Drilled: 12/6/2020 Drill Rig: Diedrich D70 Logged by_: JST E SOIL DESCRIPTION a U) E J _ Z 0- o Q 0 A m a � 2 (D PENETRATION RESISTANCE (blows/foot) co o U m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 0 20 40 60 Approximately 5 inches of asphalt over IIII ',II IIIIIIIII IIII ..- Medium dense, moist, brown, gravelly SAND, with silt. (Fill) '.IIIIIIII '... IIIIIIIII Illlii . -17Yrt-I-Y rtYYYYY7TY rTTYT r r -------------------------------------------- Medium dense, moist, gray, gravelly SAND, some silt. (Weathered Glacial Till) Verydense, moist, gray, SAND with silt and ravel. g Y+ g (Unweathered Glacial Till) S-1 8" S_2 I 18. 11 IIIIIIIII -i-I 7777 `r'I1 J-JJ1J 11171111i11 IIIIIIIII IIIIIIIII 7T77TTT 77 1 IIIIIIIII IIIIIII _ 1-T TTTTT _ 1 LLL1LLL!_ (IIIIIII 20 59 GSA 1 I 1 1 1 1 Q --I�-i-I+ 1 1 1 1 1 1 +++�+++++ 1 1 1 1 1 +++++-+ �- IIIIIIII (II IIIIIIIII IIII IIIIII -1I7yrt11rtrtrt lllllll IIItIIIIII rttY t t t� t IIIIIIIII Ilt r ilr rl'..'.. t , (IIIIIII Verydense, moist, gray, SAND, with ravel and silt. 9 Y 9 (Unweathered Glacial Till) Very dense, moist, gray, silty SAND with gravel. (Unweathered Glacial Till) S_3 I 181, 1I T s a 1a l 50 55 GSA IIIIIIIII IIIIIIIII l l l l l l l l l 7TTT T TTTT II,,,IIIII,II IIIIIIIII I I I I I I I I I TTTT4 T - T1 IIIIIII. IIIIIII ( I I I I I I I IIIIIIIII IIIIIIIII IIIIIII'• IIIIIIIII -(IIIIIII IIIIIIIII IIIIIIIII llilll'... IIII '. Very dense, moist, gray, SAND, with gravel and silt. (Unweathered Glacial Till) S-5 16° -(IIIIIII IIIIIIIII IIIIIII: so/s° --IYYrt�7 '...I1111111 ''...I111111 7rt7Y77T7T IIIIIIIII IIIIIIIII TT?-Trrr. :_... (IIIIIII IIIIIII IIIII I II II i IIIIIIIII -1l.l 4--1--1--1- '',I1111111 IIIIIIIII IIII llllllll IIIIIIIII IIIIIIIII IIIIIIIII IIII IIII '...- IIIIIIIII -I��rtrtrtrtY IIIIIIIII IIIIIIIII rtrtYYYrt7rtr IIIIIIIII IIII trrrrr (IIIIIIIII -(IIIIIII 7-177-17 f7 -1111111� IIIIIIIII -777777T_ '..IIIII IIIIIIIII TT7-7-777 IIIIIII Very dense, moist, gray, gravelly, SAND, with silt. s-s I z^ 50/6" (Unweathered Glacial Till)- .'...1111111 ..'',..IIIIIII IIIIIIIII IIII....... IIIIIIIII Illlii lllllll 'Illlllll IIIIIIIII (IIIIIII -r11�� IIIIIIIII IIIIIIIII fitY t t t +t t IIIIIIIII IIII tfi r r r Illlii '. IIIIIIIII IIIIIIIII (IIIIIII 71777777 Y7777TTTT T:- TT7r77 SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. = Consolidation Test measurement. Zi pperGeo BORING Att. = Atterberq Limits Geoprofessional Consultants B-13 LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Pagel of 2 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Bore Hole Dia.: 8-inch Top Elevation: Approx. 431 Feet Drilling Method: Hollow Stem Auger Hammer Type: Auto B-13 Date Drilled: 12/6/2020 Drill Rig: Diedrich D70 Logged by_: JST E SOIL DESCRIPTION a U) E J _ Z 0- o Q 0 A m a � 2 (D 0 PENETRATION RESISTANCE (blows/foot) co o U —° m 0) � The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Q Hammer Weight and Drop: 20 40 60 Very dense, moist, gray, SAND with gravel and silt. (Unweathered Glacial Till) Over -driven with D&M sampler to obtain soil sample. 111 r.rrl_I_I_L_L- l ��.�.7� IIIF 77777T7_ . -------------------------------------------- LLLLL LL�JJJJ JJJJJ111 IIIIIIIII IIIIIIIII Illllll IIIIIIII 1+11- I-.i i I--I._I-1A��.�.�-1 illlllll IIIIIIII IIIIIIIII 44�� IIIIIIIII Very dense, moist, gray, SAND with gravel, some silt. T S-8 I 11" .illlllll IIIIIIIII IIIIIIIII 50/5' GSA t 11 I _I f--L—I—I�yrt.�.�7 IIIIIIIII IIIIIIII rt.rt.rt*rt+T Boring completed at approximately 31 feet. No groundwater observed ATD. ''IIIIIIII IIIIIIIII —17-177-177 IIIII - 7rl-7F 111ii11 i.I I_i_I I 1 II IIIIIIIII Illiiiil _I-_.. 111i 777771 1- 1ii111i' iiliiii i i i i i iT,. I I I I I I i iiliiii .rrl l—t-1_I I--L_I-177rt _ r-t 7i.TT. �i iiliiiiii ii111ii L.LLI I f_L_I I Illllllli illllll L_IJJJJ.J� ICI III II J1.11111.1.1. IIIIIIIII illlllll) illllll .illllll illllll IIIIIIIII li Ili IIIIIIII IIIIIIII .._j -F4 -1 4-i-+ IIIIIIII r.rrl I-i-I-I IIIIIIII Illi -yrt Illi IIIIIIII -rtttrtttt.t. IIIIIIII Illi 17-7- , Illlllll IIIIIIIII 11111111 -7 77777T 11111111 1 1 IIIIIIIII IIIIIIIII 1 7r�T IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII IIIIIIIII -4 -� -.4 IIIIIIIII 11111111 IIIIIIIII -4 4.4 4 4 4 - .- .- . IIIIIIIII illlllll IIIIIIIII IIIIIIIII illlllll IIIIIIIII -I--I--I- IIIIIIIII illlllll �rrl I-t-i-I I--i-i-177rt.�.77 IIIIIIIII IIIIIIIII rtrtrtrtrtrtrt.t.t. F 7�7?7-TTT TTTT ill) SAMPLE LEGEND GROUNDWATER LEGEND O % Fines (<0.075 mm) I2-inch O.D. split spoon sample Clean Sand O % Water (Moisture) Content 3-inch I.D. Shelby tube sample ® Bentonite Plastic Limit Liquid Limit Grout/Concrete Natural Water Content ® Screened Casing Apollo Apartments TESTING KEY n Blank Casing 23601 Highway 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 200W = 200 Wash Analysis_ on date of Date: December 2020 Project No.: 2361.01 Consol. =Consolidation Test � measurement. ZipperGeo BORING B_13 Att. = Atterberg Limits Geoprofesslonal consultants LOG: 19019 36th Ave. W, Suite E Lynnwood, WA Page 2 of 2 APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS Page 1 LABORATORY TESTING PROCEDURES A series of laboratory tests were performed during the course of this study to evaluate the index and geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed are given below. Visual Classification Samples recovered from the exploration locations were visually classified in the field during the exploration program. Representative portions of the samples were carefully packaged in moisture tight containers and transported to our laboratory where the field classifications were verified or modified as required. Visual classification was generally done in accordance with ASTM D2488. Visual soil classification includes evaluation of color, relative moisture content, soil type based upon grain size, and accessory soil types included in the sample. Soil classifications are presented on the exploration logs in Appendix A. Moisture Content Determinations Moisture content determinations were performed on representative samples obtained from the explorations in order to aid in identification and correlation of soil types. The determinations were made in general accordance with the test procedures described in ASTM D2216. Moisture contents are presented on the exploration logs in Appendix A. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM D6913. The results of the grain size determinations for the samples were used in classification of the soils, and are presented in this appendix. Page 1 GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 C9 W 70 m 60 W Z_ LL 50 Z W U W 40 W d 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Coarse Medium Fine Silt IGRAINED Clay BOULDERS COBBLES GRAVEL SAND FINE Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-1 S-1 2'/2 - 4 19.5 32.8 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-2 S-4 10 - 11'/z 6.2 20.0 SAND with gravel and silt PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-2 S-5 15 - 16 15.9 27.2 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-3 S-3 7'/2 - 9 13.6 31.9 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-3 S-4 10 - 11'/z 5.6 23.3 Gravelly SAND with silt PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-4 S-1 2'/2 - 4 11.7 23.3 Gravelly SAND with silt PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-4 S-3 7'/2 - 9 7.8 27.4 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-5 S 1A 3 - 3'h 9.1 36.8 Silty SAND, some gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-5 S-3 7'h - 9 8.0 28.1 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-6 S-2 5 - 6'/2 9.0 28.5 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-6 S-4 10-11'/2 9.9 34.6 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-7 S-2 5 - 6'/2 6.6 27.6 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B 7 S-4 10 - 11'/z 8.7 34.8 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-9 S-2 5 - 6'/2 9.2 27.3 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-9 S-4 10 - 11'/z 7.8 26.7 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-9 S-5 12'/2 - 14 8.0 30.5 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-10 S-4 10 - 11'/z 8.3 31.8 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-11 S-4 10 - 11'/z 6.7 29.1 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-12 S-4 10 - 11'/z 10.8 35.8 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-13 S-2 5 - 6'/2 7.3 28.1 SAND with silt and gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-13 S-4 10 - 11'/z 9.1 35.4 Silty SAND with gravel PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-13 S-7 25 - 25'/z 5.6 21.8 SAND with gravel and silt PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D6913 100 90 = 80 W ?� 70 m 60 W Z 50 Z W tU W 40 W a 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS Coarse Fine Medium Fine Silt Clay BOULDERS COBBLES GRAVEL ::E FINE GRAINED Comments: Exploration Sample Depth (feet) Moisture (%) Fines (%) Description B-13 S-8 30 - 31 4.8 7.4 SAND with gravel, some silt PROJECT NO: 2361.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATE OF TESTING: 12/9/2020 Apollo Apartments USDA United States Department of Agriculture N RCS Natural Resources Conservation Service A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Snohomish County Area, Washington Apollo Apartments July 23, 2020 3 Custom Soil Resource Report Soil Map O NV N 549240 5492M 5492M 549M 549280 549290 5493M 47° 47 6" N Ilk 76 7-2 P. r o J+ • .i4 , g � �— �+# • � t 'S O Soil,Map may n, 1'r hi1 47° 47 2" N 549240 549250 549260 549M 549MO 549290 549300 3 in a Map Scale: 1:678 if printed on A portrait (8.5" x 11") sheet. N Meters 0 10 20 40 60 Feet 0 30 W 120 180 Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone 1ON WGS84 2 549310 549320 549330 r.r 310 549320 3 N O NV N 47° 476" N 47° 472" N LAI MAP LEGEND Area of Interest (AOI) Area of Interest (AOI) Soils 0 Soil Map Unit Polygons rwr Soil Map Unit Lines Soil Map Unit Points Special Point Features Uo Blowout ® Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp + Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot d Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip oa Sodic Spot Custom Soil Resource Report MAP INFORMATION Spoil Area The soil surveys that comprise your AOI were mapped at 1:24,000. Stony Spot Very Stony Spot Warning: Soil Map may not be valid at this scale. Wet Spot Enlargement of maps beyond the scale of mapping can cause Other misunderstanding of the detail of mapping and accuracy of soil .- Special Line Features line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed Water Features scale. Streams and Canals Transportation Please rely on the bar scale on each map sheet for map 1 1 F Rails measurements. Interstate Highways Source of Map: Natural Resources Conservation Service r.x US Routes Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Major Roads Local Roads Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts Background distance and area. A projection that preserves area, such as the Aerial Photography Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Snohomish County Area, Washington Survey Area Data: Version 22, Jun 4, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Sep 2, 2018—Sep 25, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Custom Soil Resource Report Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 5 Alderwood-Urban land complex, 2 to 8 percent slopes Totals for Area of Interest 1.5 1.5 100.0% 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. Custom Soil Resource Report An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha -Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report Snohomish County Area, Washington 5—Alderwood-Urban land complex, 2 to 8 percent slopes Map Unit Setting National map unit symbol: 2hz9 Elevation: 50 to 800 feet Mean annual precipitation: 25 to 60 inches Mean annual air temperature: 48 to 52 degrees F Frost -free period: 180 to 220 days Farmland classification: Not prime farmland Map Unit Composition Alderwood and similar soils: 60 percent Urban land: 25 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Alderwood Setting Landform: Till plains Parent material: Basal till Typical profile H1 - 0 to 7 inches: gravelly ashy sandy loam H2 - 7 to 35 inches: very gravelly ashy sandy loam H3 - 35 to 60 inches: gravelly sandy loam Properties and qualities Slope: 2 to 8 percent Depth to restrictive feature: 20 to 40 inches to densic material Natural drainage class: Moderately well drained Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table: About 18 to 36 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Low (about 3.0 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 4s Hydrologic Soil Group: B Forage suitability group: Limited Depth Soils (G002XN302WA) Hydric soil rating: No Minor Components Terric medisaprists, undrained Percent of map unit: 5 percent Landform: Depressions Hydric soil rating: Yes Norma, undrained Percent of map unit: 5 percent Custom Soil Resource Report Landform: Depressions Hydric soil rating: Yes Mckenna Percent of map unit: 5 percent Landform: Depressions Hydric soil rating: Yes Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section VI, Page 1 Section VI — Other Permits Section VI Summary: Narrative Other than typical permits from the City of Edmonds, this project requires Ecology's Construction Stormwater General Permit. This will be applied for in a future submittal. 4M 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section VI I, Page 1 Section VII — Bond Quantities, Declaration of Covenant, & Operation and Maintenance Manual Section VII Summary: Narrative The Bond Quantity Worksheet is a standalone document that has been submitted separately from this document. A Declaration of Covenant is provided for the detention vault and catch basins. The Operation and Maintenance Manual is a standalone document that will be given to the owner following the construction of the project. The maintenance manual contained herein is for the Apollo Apartments project. The contractor will be responsible for the maintenance and operation of all stormwater structures and BMPs requiring maintenance during construction and, after construction, responsibility will pass to the building owner. The project contractor will be responsible for passing along the information in this maintenance manual to the owner. Upon request by the City, it shall be made available for their inspection. It is generally expected that few to none of these defects will be present upon the yearly inspection of each facility. 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com 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 City of Edmonds (permit number) Grantor(s) (Last, First and Middle Initial) Blackfish Capital LLC Grantee(s) (Last, First and Middle Initial) City of Edmonds Legal Description (abbreviated form; i.e., lot, plat or section,. township, range, quarter/quarter) NE 1/4, SE 1/4, SECTION 31, TOWNSHIP 27 NORTH, RANGE 4 EAST, W.M. Assessor's Property Tax Parcel/Account Number at the Time of Recording: Tax Parcel Numbers: 0045-1900-100201, 0045-1900-100202, 0045-1900-100203, 0045-1900-100204. 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: ❑ Permeable Pavement ❑ Rain Garden / Bioretention Cell ❑ Infiltration Trench ❑ Drywell ❑ Gravelless Chamber x❑ OtherDetention Vault, catch basins BioClean MWS (treatment) 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: 23601 Highway 99 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) (Print Name) (Signature) (Print Name) State of Washington M1 County of Snohomish APPROVED: CITY OF EDMONDS (Signature) (Print Name) (Title) On this day personally appeared before me { 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 PARCEL A: PARCEL A, CITY OF EDMONDS SHORT PLAT NO. 5-23-88, RECORDED SEPTEMBER 21, 1988 UNDER RECORDING NUMBER 8809210451, BEING A PORTION OF LOTS 2, 3 AND 4, BLOCK 1, FRUITLAND ACRES TO LAKE BALLINGER, ACCORDING TO THE PLAT RECORDED IN VOLUME 10 OF PLATS, PAGE 47, IN SNOHOMISH COUNTY, WASHINGTON. PARCEL B: PARCEL B, CITY OF EDMONDS SHORT PLAT NO. 5-23-88, RECORDED SEPTEMBER 21, 1988 UNDER RECORDING NUMBER 8809210451, BEING A PORTION OF LOTS 2,3 AND 4, BLOCK 1, FRUITLAND ACRES TO LAKE BALLINGER, ACCORDING TO THE PLAT RECORDED IN VOLUME 10 OF PLATS, PAGE 47, IN SNOHOMISH COUNTY, WASHINGTON. PARCEL C: THE SOUTH 100 FEET OF LOTS 2 AND 3, AND THAT PORTION OF THE SOUTH 100 FEET OF LOT 4, LYING EAST OF STATE HIGHWAY #1, ALL IN BLOCK 1, FRUITLAND ACRES TO LAKE BALLINGER, ACCORDING TO THE PLAT RECORDED IN VOLUME 10 OF PLATS, PAGE 47, IN SNOHOMISH COUNTY, WASHINGTON. SITUATE IN THE COUNTY OF SNOHOMISH, STATE OF WASHINGTON. Exhibit B 236rH ST S.W 0 Modular , I Wetlands System for runoff treatment I I Stormwater I' catch basin Stormwater I / detention vault I under sub -level /parking garage I I 0 Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section VII, Page 2 Apollo Apartments 23601 Highway 99 Edmonds, WA 98026 OPERATION AND MAINTENANCE MANUAL Date: April 2022 C CM ENGINEERING 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 April 28, 2022 Drainage Report Section VI I, Page 3 Operation and Maintenance Manual This Operation and Maintenance Manual has been created for Apollo Apartments, a 40,847 sf building project on a 1.76 acre lot. The proposed storm system primarily consists of a detention vault below a proposed parking lot. The detention vault will collect most on -site runoff from the building's roof drains and convey it to a Type II catch basin with a flow control structure before connecting to an existing catch basin in 236th St SW. Included in this Operation and Maintenance Manual is an 11" x 17" Grading and Drainage Plan sheet showing the location of the system. Please note that this map is generated during the design phase and may not reflect all changes made in permitting and construction. CG Engineering may be contacted for an updated copy of this map once the as -built drawings are completed for the site. The contractor will be responsible for the maintenance and operation of all stormwater structures and BMPs requiring maintenance during construction and, after construction, responsibility will pass to the owner. A map of the project area can be seen on the following page in Figure VII-1. Included in this manual are source control guide sheets and maintenance sheets taken from the 2012 Stormwater Management Manual for Western Washington (as amended in 2014) for the following facilities/activities: Catch Basins: Concrete structures with steel grates that collect stormwater runoff from the site and act as junctions for storm conveyance pipes. Control Structures: Control structures are catch basins or manholes with a restrictor device for controlling outflow from a facility to meet the desired performance. Detention Pipes/Tanks: Detention tanks are underground storage facilities typically constructed with large diameter corrugated pipe. Please note, the detention pipe and control structure are located underneath the roof overhang. For any maintenance activities, extreme caution should be exercised when performing maintenance in the vicinity of the roof overhang. Verify sufficient vehicle and equipment clearances. Vegetation Management: Landscaping can include grading, soil transfer, vegetation removal, pesticide and fertilizer applications, and watering. Stormwater contaminants include toxic organic compounds, heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and pesticides. Facilities shall be inspected for defects listed in the following facility sheets. Most maintenance tasks are generally reactionary to a defect being found, rather than a matter of constant upkeep. It is generally expected that few to none of these defects will be present upon the yearly inspection of each facility. The facility sheets list the potential conditions warranting maintenance and the expected result following any maintenance. Several engineer's notes for specific tasks are provided within the facility sheets. Unless otherwise noted on the facility sheets the maintenance tasks should be performed on an "as needed" basis: (a) when the described defect is visible to whomever performs the yearly inspection, or (b) should any defect become apparent between inspections. CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section VII, Page 4 7��T " y l 1 � r J- �r � 1 �.�.3� � 4f�1:• W ] Figure VII-1: Map of project area (from Edmonds GIS) C CM 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com GRADING AND DRAINAGE PLAN NOTES: 1. ALL DISTURBED AREAS TO BE COMPOST -AMENDED PER 2014 SWMMWW BMP / T5.13. / 62 / 2. TOP AND TOE REFER TO FINISHED GRADE AT THE TOP AND BOTTOM OF THE WALLS, RESPECTIVELY. 3. AM INIMUM OF T HORIZONTAL SEPARATION AND V VERTICAL SEPARATION IS ol{p ❑ / / REQUIRED BETWEEN DRY UTILITIES(POWER, GAS, PHONE, CAB LE, ETC) AND SEWER, WATER AND STORM, AND A MINIMUM OF S'HORIZONTAL \ __ SEPARATION AND VVERTICAL SEPARATION FROM ANY CITY -OWNED LINES. ID SSMH/RIM=436.74 ONp 4. A TYPE II CATCH BASIN IS REQUIRED WHENEVER RIM TO INVERT EXCEEDS 5'. \ NO N/D 11\\ 5. A MINIMUM OF T OF COVER IS REQUIRED FOR ALL PIPES LOCATED UNDER DRIVEABLE SURFACES AND I'OF COVER UNDER LANDSCAPE SURFACES. S/ 10 0 6. ROOF DRAINS SHALL BE ROUTED TO DETENTION VAULT BY PLUMBING CONSULTANT. INLETS BE LOCATIONS ACCESS _ MUST ROUTED TO WITH OPENINGS DIRECTLY ABOVE. / / / ,TMAXEXPOED 7. ROOF SHALL BE COATED WITH AN INERT, NON -LEACHABLE ENAMEL COATING._ HT RETAW4IING , / WALL � FONvo REBAR S. IN COVERED PARKING GARAGES, CATCH BASINS SHALL HAVE 01L/WATER SEPARATORS AND SHALL CONNECT TO SANITARY SEWER REFER TO / Si MPED'WE NE 1 /4, SE 1 /4, SECTION 31, TOWNSHIP 27 NORTH, RANGE 4 EAST, W.M. ORAINIGNE / WATERLINE/ 'A SSMH RIM- 411.96' I INV. 8" PVC(E)=406.71 INV. 8" PVC(W)=406.96' EXIST LINE II 6" WA IE (BASED ON POTHOLING): 410.9 NEW 12" STORM TOP OF PIPE: 409.4 T OHP-\\\ INV 8" PVC(S76' _ �\\ CONTINUED ON I/C3.1 /'J I SEWERLINE l *SCD RIM- 4 16" 1N1 J. W. -t- +I5M=4I5.91I1,� V // 0.5% I ;8L-F"121"?PVC 2 38LF"12"DIP@64%3 A@ 12 I 5T66'51 I "/,,4 PLUMBING PLAN. / \, 0�r'(W) OF pR Ri` I' - - -P o °' I " /-- n�. - ON -._'�: 6" PVC FOOTING DRAIN _ \ I _ I N 3631'I 181.13' - DISCHARGE LINE SHALL BE II 9. SEE C3.3 FOR CATCH BASIN DETAILS. / / \ / .' - TIGHTLINED TO 12" VAULT / CB M=4370A - 43 e \ e - 1 -DISCHARGE PIPE --- IE 2" DI(NE){4�.T.654z6.TOP:41'' 10. RETAINING WALLS AND DETENTION VAULT REQUIRE SEPARATE BUILDING 9t DI(SW7/=433'�5 e�.. f T 42 0 TOE: 42�. TOE :4 .0 ae e \ TOP: 416.15 / e =4376i j5 '• 1 ° I \ ,"';�^ v I TOE: 416.0 11. DRIVEWAY SLOPE SHALL NOT EXCEED 14%. 433.95 �/�7 TOP: 430. - / IE ' DI f L 432. \ I N 41 i�rI CONTINUEDI 3/C3.1 DI(SW)><433.95 492.7 TOE: 423.01 7.0' MAX / TOP: 418.3 7�-440 / So' I RETAINING p5/1TOE: 414.0 CONTINUED ON 2/C3.1 I I WALL 8 ` / °�/�, /I I //'/ / 1' t' 6.5'MAX EXPOSED " ENTRY. 1 �41' / I I HT RETAINING WALL 432 75 ENTRY (TRASH 8/99 / Imo, PERSTRUCTURAL r.yti 41I ROOM): 417.06 420.47am / CONTINUED ON 3/C3.1 v 5 9 I I TOP: 0.25 4 I d TOE: j4.o / I / STORM PROFILE C3. 22 LF-6" / I _-- ' / DIP @0.5% TOP: 4aaOs TOE: 4114.0 / / (C,R 11'I FROM DETENTION 2.0 I I 1 VAULT SEE 3/C3.1 N p I II II TOP: 421.01 TOC 442TOE: 411.0 ,6 302L-12" 11 CB RIM411,,, / < / , PVC @ 0.5% / I IE " DIME) 12= -943 MAIN ENTRY: 443.0-_----L------- / TOP:421.5 NEW 15.00' PRIVATE UTILITY II \ TOE: 415.5 1 TOP: 444.0 1 EASEMENT TO 00451900101-803 /: \ TOE: 0 0 I I , 0 / �� 8 0 1 FOOTING I h 443.II iCl �L11 PROPOSED APARTMENT BUILDING FFE: 443.0 � I YOP: 445.0 l II II� TOE: 443.0 z LOT 6 II � III TO 2 TOE:416.5 llo iNO M/D 7+$0 TOP: 44.0 \� TOE: 4433.0 / "i TOP422_5 -TOE: 418.0 TOP: 447.0 / a / TOE: 443.0 / 7,t00 PROPOSED APARTMENT BUILIDING I 1 FFE: 443.0 TOP: 447.5 r m l TOP 423.0$ \ / TOE: 443.0 z I 42 7 _-�\ Y I TOE: 418.OI \ TOP; 448.0 I BASEMENT WAL TOE: 443.0 - BELOW 2 3 a w �_/ 1 TIE WALL FTG DRAINS I ti I CAP STORM STUB I B RIM RAMP DOWN TO a z Z FOR FUTURE USE BY / TO BLDG FTG DRAINS CONTINUED z ADIACENTLOT 1 TOP: 423. IE 12° MATCH EXISTING .AqB 4�O . L 0 $ w $ f I N TOE: 421.1 IM=447 - 'p ON 2/C3.1 r u o MIN IE:411.68 T99P4 3.95 ()_ \ </ < / y ore 3� L TyE42.8 I RCP 445 15 7/ ENTRY: 437.6 ,y N 3 I TOP: 423.1i " RCP(N)-4442y I ^� z z 0 z 3 ENTRY: 422.75 TOE: 418.Q 0 49310 -� ) TRANSFORMER .I _ 3 ;�' / A-54449 PER SNO PUD u h, �NGRE55/EGRESS / . I ` ° ,-_ - a �- - -� - - _ L f � / / � / / -4' 55.60' I of \ I 440.6 440OY CONTINUED ON 1/C3.1 CONTINUED ON 3/C3.1 SEE 1/C3.1 FOR BUILDING ABOVE C cMl� ENGINEERING 250 4TH AVE. S., SUITE 200 EDMONDS, WASHINGTON 98020 PHONE (425) 778-8500 FAX (425) 778-5536 FOR REPORT USE ONLY NOT FOR CONSTRUCTI 09/25/22 Q Q ak k 3.7 m � m Q 3 3 F m 0 W W m m W azz�v�i�rr F F o F o C] O d a D a 2 1ST BASEMENT PLAN (2ND LEVEL SCALE: 1" = 40' 40 0 20 40 80 4" FTG DRAIN IE: 411.75 TIGHTLINE CONNECTION TO CONTINUED ON 2/C3.1 CONTINUED ON I/C3.1 CONTINUED ON I/C3.1 VAULT DISCHARGE PIPE. FTG DRAINS AROUND VAULT LAID FLAT p 208'x22.5'x10.5' BETENTION VAULT W/ FLOW CONTROL ASSEMBLY C3. C3. C3. POSSIBLE CONNECTION LOCATION FROM PLUMBING, TYP (SEE NOTE 6) 2.0' ACCESS MANHOLE WITH STEP AND LADDER TO VAULT eBOTTOM, TIP C3. CONTINUED ON 2/C3.1 78 LF - 6" PVC @ 0.5%(STORM LINE FROM MWS) GARAGE SLAB GRADING PER ARCH. DRAINAGE IN GARAGE PER PLUMBING. GARAGE MUST DRAIN TO SANITARY SEWER, TYP r2.0% 2 423.3 �� 423.7 2.0% 423.9 S 2NDBASEMENT PLAN LEVEL 40 0 20 40 80 UND REBAR cc P \ - - - - 3 - -�Ar / 42 / 1 30 GRADING QUANTITIES aC, LjNREADABLE AT ORNE \ \ \ 12" I 437/55 N 37bJ' 3J1.07' T I - 1 / TOP: 447.5 T 446.0 \ \ U / I -- l CNAIN, LINK. FENCE- --=_--L--------- \ - \ / I FOUNDJIN BAR NO 4AP I I , - - TOTAL EXCAVATION (CUT) - 21,760 CU VDS TOTAL / TOE: 443.0 TO : � I / --_- \ I I D.2"(N) uNE. I 15' UnuTY MA14TENCANCE l ��1 CHAIN UNK FENCE EMBANKMENT (FILL)- 15,010 CU YDS \�� \ I 1 I WOOD CE END D. 1'(S). I EASEMENT (NOT N RECORD) TPACT 99S I.0(S)OF SET CORNK FENCq START I TOTAL 36,770 CU VDS 0.1'(S) OF PROPERTY LINE t THE QUANTITIES SHOWN ABOVE ARE FOR THE PERMIT PROCESS i --- --� � ONLY. THESE VALUES ARE APPROXIMATE. DO NOT USE FOR LOT 7 BIDDING, PAYMENT, OR ESTIMATING PURPOSES. GRADING AND DRAINAGE PLAN SCALE: 1" = 20' 201 0 10 20 4l1 APPROVED FOR CONSTRUCTION CITY OF EDMONDS DATE: BY: CITY ENGINEERING DIVISION DESIGN: TAF DRAWN: ATD _I IF CK: JPU JOB NO: 20261.20 DATE: 09/21/2020 Z Q J 'W V N Q Z Z Q cD 0, O Z rn I..I..I a Q w Q = 2 0 Q = o Q Z m Z J O O O co :2 Q Q N W of Z w 0 Q y S LA E ET C3.1 ON Apollo Apartments - CG #20261.20 Drainage Report April 28, 2022 Section VII, Page 5 SAMPLE ACTIVITY LOG DATE FACILITY MAINTENANCE PERFORMED RESULTS / NOTES 250 4th Avenue South, Suite 200 Edmonds, WA 98020 ENGINEERING ph.425.778.8500 1 f.425.778.5536 www.cgengineering.com No. 3 — Closed Detention Systems (Tanks/Vaults) Maintenance Defect Conditions When Maintenance is Needed Results Expected Component When Maintenance is Performed Storage Area Plugged Air Vents One-half of the cross section of a vent is Vents open and blocked at any point or the vent is damaged. functioning. Debris and Sediment Accumulated sediment depth exceeds 10% All sediment and of the diameter of the storage area for 1/2 debris removed from length of storage vault or any point depth storage area. exceeds 15% of diameter. (Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2 length of tank.) Joints Between Any openings or voids allowing material to All joint between Tank/Pipe Section be transported into facility. tank/pipe sections (Will require engineering analysis to are sealed. determine structural stability). Tank Pipe Bent Out Any part of tank/pipe is bent out of shape Tank/pipe repaired or of Shape more than 10% of its design shape. (Review replaced to design. required by engineer to determine structural stability). Vault Structure Cracks wider than 1/2-inch and any Vault replaced or Includes Cracks in evidence of soil particles entering the repaired to design Wall, Bottom, structure through the cracks, or specifications and is Damage to Frame maintenance/inspection personnel structurally sound. and/or Top Slab determines that the vault is not structurally sound. Cracks wider than 1/2-inch at the joint of any No cracks more than inlet/outlet pipe or any evidence of soil 1/4-inch wide at the particles entering the vault through the walls. joint of the inlet/outlet pipe. Manhole Cover Not in Place Cover is missing or only partially in place. Manhole is closed. Any open manhole requires maintenance. Locking Mechanism Mechanism cannot be opened by one Mechanism opens Not Working maintenance person with proper tools. Bolts with proper tools. into frame have less than 1/2 inch of thread (may not apply to self-locking lids). Cover Difficult to One maintenance person cannot remove lid Cover can be Remove after applying normal lifting pressure. Intent removed and is to keep cover from sealing off access to reinstalled by one maintenance. maintenance person. Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, Ladder meets design misalignment, not securely attached to standards. Allows structure wall, rust, or cracks. maintenance person safe access. Catch Basins See "Catch Basins" See "Catch Basins" (No. 5). See "Catch Basins" (No. 5) (No. 5). Volume V — Runoff Treatment BMPs — December 2014 4-36 No. 4 - Control Structure/Flow Restrictor Maintenance Defect Condition When Maintenance is Needed Results Expected Component When Maintenance is Performed General Trash and Debris Material exceeds 25% of sump depth or 1 Control structure (Includes Sediment) foot below orifice plate. orifice is not blocked. All trash and debris removed. Structural Damage Structure is not securely attached to Structure securely manhole wall. attached to wall and outlet pipe. Structure is not in upright position (allow up Structure in correct to 10% from plumb). position. Connections to outlet pipe are not watertight Connections to outlet and show signs of rust. pipe are water tight; structure repaired or replaced and works as designed. Any holes --other than designed holes --in the Structure has no structure. holes other than designed holes. Cleanout Gate Damaged or Missing Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one Gate moves up and maintenance person. down easily and is watertight. Chain/rod leading to gate is missing or Chain is in place and damaged. works as designed. Gate is rusted over 50% of its surface area. Gate is repaired or replaced to meet design standards. Orifice Plate Damaged or Missing Control device is not working properly due to Plate is in place and missing, out of place, or bent orifice plate. works as designed. Obstructions Any trash, debris, sediment, or vegetation Plate is free of all blocking the plate. obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the Pipe is free of all potential of blocking) the overflow pipe. obstructions and works as designed. Manhole See "Closed See "Closed Detention Systems" (No. 3). See "Closed Detention Systems" Detention Systems" (No. 3). (No. 3). Catch Basin See "Catch Basins" See "Catch Basins" (No. 5). See "Catch Basins" (No. 5). (No. 5). Volume V — Runoff Treatment BMPs — December 2014 4-37 No. 5 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed General Trash & Trash or debris which is located immediately No Trash or debris located Debris in front of the catch basin opening or is immediately in front of blocking inletting capacity of the basin by catch basin or on grate more than 10%. opening. Trash or debris (in the basin) that exceeds 60 No trash or debris in the percent of the sump depth as measured from catch basin. the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. Trash or debris in any inlet or outlet pipe Inlet and outlet pipes free blocking more than 1/3 of its height. of trash or debris. Dead animals or vegetation that could No dead animals or generate odors that could cause complaints vegetation present within or dangerous gases (e.g., methane). the catch basin. Sediment Sediment (in the basin) that exceeds 60 No sediment in the catch percent of the sump depth as measured from basin the bottom of basin to invert of the lowest pipe into or out of the basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. Structure Top slab has holes larger than 2 square Top slab is free of holes Damage to inches or cracks wider than 1/4 inch and cracks. Frame and/or Top Slab (Intent is to make sure no material is running into basin). Frame not sitting flush on top slab, i.e., Frame is sitting flush on separation of more than 3/4 inch of the frame the riser rings or top slab from the top slab. Frame not securely and firmly attached. attached Fractures or Maintenance person judges that structure is Basin replaced or repaired Cracks in unsound. to design standards. Basin Walls/ Bottom Grout fillet has separated or cracked wider Pipe is regrouted and than 1/2 inch and longer than 1 foot at the secure at basin wall. joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. Settlement/ If failure of basin has created a safety, Basin replaced or repaired Misalignment function, or design problem. to design standards. Vegetation Vegetation growing across and blocking more No vegetation blocking than 10% of the basin opening. opening to basin. Vegetation growing in inlet/outlet pipe joints No vegetation or root that is more than six inches tall and less than growth present. six inches apart. Contamination See "Detention Ponds" (No. 1). No pollution present. and Pollution Volume V — Runoff Treatment BMPs — December 2014 4-38 No. 5 — Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Component Maintenance is performed Catch Basin Cover Not in Cover is missing or only partially in place. Catch basin cover is Cover Place Any open catch basin requires maintenance. closed Locking Mechanism cannot be opened by one Mechanism opens with Mechanism maintenance person with proper tools. Bolts proper tools. Not Working into frame have less than 1/2 inch of thread. Cover Difficult One maintenance person cannot remove lid Cover can be removed by to Remove after applying normal lifting pressure. one maintenance person. (Intent is keep cover from sealing off access to maintenance.) Ladder Ladder Rungs Ladder is unsafe due to missing rungs, not Ladder meets design Unsafe securely attached to basin wall, standards and allows misalignment, rust, cracks, or sharp edges. maintenance person safe access. Metal Grates Grate opening Grate with opening wider than 7/8 inch. Grate opening meets (If Applicable) Unsafe design standards. Trash and Trash and debris that is blocking more than Grate free of trash and Debris 20% of grate surface inletting capacity. debris. Damaged or Grate missing or broken member(s) of the Grate is in place and Missing. grate. meets design standards. ai ena e �Deeyct on do he ai na a is R ults xpe ed en C po nts N de aint an is P rfor ed Ge ral Vi t i lug ' g e Tra or /eo B rier ear e to d ign w t n 2 o of ing n th arri apa y. M I ama d/ ent t of ape ore an Khac ith be s m e Mis ' g /�Baare B s. ars a miing enti bar ' r Ba�inpl a ordi to ign. mis ng. ars a to e a rus ca ing % Ba err ace �ra�i�o/de rior ' n t ny rt of arrie . sign an ds Ou t x1p eb ' bar ' r m' �nno tac d to XBi r f Xyah �to' e pi Volume V — Runoff Treatment BMPs — December 2014 4-39 No. 18 — Catchbasin Inserts Maintenance Defect Conditions When Maintenance is Results Expected When Component Needed Maintenance is Performed General Sediment When sediment forms a cap over the No sediment cap on the insert Accumulation insert media of the insert and/or unit. media and its unit. Trash and Trash and debris accumulates on insert Trash and debris removed Debris unit creating a blockage/restriction. from insert unit. Runoff freely Accumulation flows into catch basin. Media Insert Not Effluent water from media insert has a Effluent water from media Removing Oil visible sheen. insert is free of oils and has no visible sheen. Media Insert Catch basin insert is saturated with water Remove and replace media Water Saturated and no longer has the capacity to insert absorb. Media Insert -Oil Media oil saturated due to petroleum spill Remove and replace media Saturated that drains into catch basin. insert. Media Insert Use Media has been used beyond the typical Remove and replace media at Beyond Normal average life of media insert product. regular intervals, depending on Product Life insert product. Volume V — Runoff Treatment BMPs — December 2014 4-51 Operators under the ISGP or Boatyard permits should take special care to review this chapter in its entirety to ensure that all of the applicable (mandatory) source control BMPs are included within their industrial or boatyard SWPPP (regardless of the listings in Appendix IV -A). 2.1 Applicable (Mandatory) Operational Source Control BMPs Sites & facilities Where required by local code or by an Ecology NPDES Stormwater that require the General Permit, implement the following operational source control BMPs implementation at: of source • Commercial properties control BMPs • Industrial properties • Multifamily properties • Boatyards • Sand and gravel mining operations • Assign one or more individuals to be responsible for stormwater Formation of pollution control. Hold regular meetings to review the overall a Pollution operation of the BMPs. Establish responsibilities for inspections, Prevention operation, maintenance, and for emergencies. Train all team members Team in the operation, maintenance, and inspections of BMPs, and reporting procedures. • Promptly contain and clean up solid and liquid pollutant leaks and Good spills including oils, solvents, fuels, and dust from manufacturing Housekeeping operations on any exposed soil, vegetation, or paved area. • Sweep all appropriate surfaces with vacuum sweepers quarterly or more frequently as needed for the collection and disposal of dust and debris that could contaminate stormwater. • Do not hose down pollutants from any area to the ground, storm drains, conveyance ditches, or receiving water unless necessary for dust control purposes to meet air quality regulations. Convey pollutants before discharge, to a treatment system approved by the local jurisdiction. • Clean oils, debris, sludge, etc. from all stormwater facilities regularly, including catch basins, settling/detention basins, oil/water separators, boomed areas, and conveyance systems to prevent the contamination of stormwater. Refer to Appendix IV-D R.3 for references to assist in handling potentially dangerous waste. • Promptly repair or replace all substantially cracked or otherwise damaged paved secondary containment, high -intensity parking, and any other drainage areas, subjected to pollutant material leaks or spills. Promptly repair or replace all leaking connections, pipes, hoses, valves, etc., which can contaminate stormwater. Volume IV - Source Control BMPs — December 2014 2-2 • Do not connect floor drains in potential pollutant source areas to storm drains, surface water, or to the ground. Additional good housekeeping BMPs: • Clean up pollutant liquid leaks and spills in impervious uncovered containment areas at the end of each working day. • Use solid absorbents, e.g., clay and peat absorbents and rags for cleanup of liquid spills/leaks, where practicable. • Promptly repair/replace/reseal damaged paved areas at industrial facilities • Recycle materials, such as oils, solvents, and wood waste, to the maximum extent practicable. • Prevent the discharge of unpermitted liquid or solid wastes, process Preventive wastewater, and sewage to ground or surface water, or to storm drains Maintenance that discharge to surface water, or to the ground. Conduct all oily parts cleaning, steam cleaning, or pressure washing of equipment or containers inside a building, or on an impervious contained area, such as a concrete pad. Direct contaminated stormwater from such an area to a sanitary sewer where allowed by local sewer authority, or to other approved treatment. Pressure wash impervious surfaces contaminated with oils, metals, sediment, etc. Collect the resulting washwater for proper disposal (usually involves plugging storm drains, or otherwise preventing discharge and pumping or vactoring up washwater, for discharge to sanitary sewer or for vactor truck transport to a waste water treatment plant for disposal). • Do not pave over contaminated soil unless it has been determined that ground water has not been and will not be contaminated by the soil. Call Ecology for assistance. • Construct impervious areas that are compatible with the materials handled. Portland cement concrete, asphalt, or equivalent material may be considered. • Use drip pans to collect leaks and spills from industrial/ commercial equipment such as cranes at ship/boat building and repair facilities, log stackers, industrial parts, trucks and other vehicles stored outside. • At industrial and commercial facilities, drain oil and fuel filters before disposal. Discard empty oil and fuel filters, oily rags, and other oily solid waste into appropriately closed and properly labeled containers, and in compliance with the Uniform Fire Code or International Building Code. • For the storage of liquids use containers, such as steel and plastic drums, that are rigid and durable, corrosion resistant to the weather Volume IV - Source Control BMPs December 2014 2-3 and fluid content, non -absorbent, water tight, rodent -proof, and equipped with a close fitting cover. For the temporary storage of solid wastes contaminated with liquids or other potential polluted materials use dumpsters, garbage cans, drums, and comparable containers, which are durable, corrosion resistant, non -absorbent, non -leaking, and equipped with either a solid cover or screen cover to prevent littering. If covered with a screen, the container must be stored under a roof or other form of adequate cover. • Where exposed to stormwater, use containers, piping, tubing, pumps, fittings, and valves that are appropriate for their intended use and for the contained liquid. Additional preventive maintenance BMPs: • Where feasible, store potential stormwater pollutant materials inside a building or under a cover and/or containment. • Minimize use of toxic cleaning solvents, such as chlorinated solvents, and other toxic chemicals. • Use environmentally safe raw materials, products, additives, etc. such as substitutes for zinc used in rubber production. • Recycle waste materials such as solvents, coolants, oils, degreasers, and batteries to the maximum extent feasible. Refer to Appendix IV-C for recommendations on recycling or disposal of vehicle waste liquids and other waste materials. • Empty drip pans immediately after a spill or leak is collected in an uncovered area. • Stencil warning signs at stormwater catch basins and drains, e.g., "Dump no waste — Drains to waterbody." Note: Evidence of stormwater contamination by oils and grease can include the presence of visible sheen, color, or turbidity in the runoff, or present or historical operational problems at the facility. Operators can use simple pH tests, for example with litmus or pH paper. These tests can screen for high or low pH levels (anything outside a 6.5-8.5 range) due to contamination in stormwater. Spill Prevention • Stop, contain, and clean up all spills immediately upon discovery. and Cleanup • If pollutant materials are stored on -site, have spill containment and cleanup kits readily accessible. • If the spill has reached or may reach a sanitary or a storm sewer, ground water, or surface water notify the local jurisdiction, Ecology, and the local sewer authority immediately. Notification must comply with and federal spill reporting requirements. (See also record keepiinn Volume IV - Source Control BMPs — December 2014 2-4 at the end of this section and S406 BMPs for Spills of Oil and Hazardous Substances) • Do not flush or otherwise direct absorbent materials or other spill cleanup materials to a storm drain. Collect the contaminated absorbent material as a solid and place in appropriate disposal containers. Recommended additional BMP: Place and maintain emergency spill containment and cleanup kit(s) at outside areas where there is a potential for fluid spills. These kits should be appropriate for the materials and the size of a potential spill. Locate spill kits within 25 feet of all fueling/fuel transfer areas, including on- board mobile fuel trucks. Facilities covered under Industrial Stormwater General Permit must provide secondary containment for all chemical liquids, fluids, and petroleum products stored on -site. Note: Ecology recommends that the kit(s) include salvage drums or containers, such as high density polyethylene, polypropylene or polyethylene sheet -lined steel; polyethylene or equivalent disposal bags; an emergency response guidebook; safety gloves/clothes/equipment; shovels or other soil removal equipment; and oil containment booms and absorbent pads; all stored in an impervious container. Train all employees that work in pollutant source areas in: Employee Training • Identifying pollutant sources • Understanding pollutant control measures • Responding to spills • Handling practices that are environmentally acceptable. Particularly those related to vehicle/equipment liquids such as fuels, and vehicle/equipment cleaning. Qualified personnel shall conduct visual inspections monthly. Make and Inspections maintain a record of each inspection on -site . Inspections shall: • Verify the accuracy of the pollutant source descriptions in the SWPPP. • Verify the performance of the stormwater operational and structural source controls and the treatment BMPs . • Reflect current conditions on the site. • Include written observations of the presence of floating materials, suspended solids, oil and grease, discoloration, turbidity and odor in the stormwater discharges; in outside vehicle maintenance/repair; and liquid handling, and storage areas. In areas where acid or alkaline materials are handled or stored use a simple litmus or pH paper to identify those types of stormwater contaminants where needed. Volume IV - Source Control BMPs — December 2014 2-5 Eliminate or obtain a permit for unpermitted non-stormwater discharges to storm drains or receiving waters, such as process wastewater and vehicle/equipment washwater. Retain the following reports for five years: Record keeping • Visual inspection reports which should include: • Time and date of the inspection • Locations inspected • Statement on status of compliance with the permit • Summary report of any remediation activities required • Name, title, and signature of person conducting the inspection • Reports on spills of oil or hazardous substances in greater than Reportable Quantities (Code of Federal Regulations Title 40 Parts 302.4 and 117). Report spills of the following: antifreeze, oil, gasoline, or diesel fuel, that cause: A violation of the State of Washington's Water Quality Standards. A film or sheen upon or discoloration of the waters of the State or adjoining shorelines. • A sludge or emulsion to be deposited beneath the surface of the water or upon adjoining shorelines. • To report a spill or to determine if a spill is a substance of a Reportable Quantity, call the Ecology regional office and ask for an oil spill operations or a dangerous waste specialist: Northwest Region (425)649-7000 Southwest Region (360)407-6300 Eastern Region (509)329-3400 Central Region (509) 575-2490 In addition, call the Washington Emergency Management Division at I- 800-258-5990 or 1-800-OILS-911 AND the National Response Center at 1-800-424-8802. Also, refer to Emergency Spill Response in Washington State, Publication # 97-1165-CP. The following is additional recommended record keeping: Maintain records of all related pollutant control and pollutant generating activities such as training, materials purchased, material use and disposal, maintenance performed, etc. Volume IV - Source Control BMPs — December 2014 2-6 S402 BMPs for Commercial Animal Handling Areas Description of Pollutant Sources: Animals at racetracks, kennels, fenced pens, veterinarians, and businesses that provide boarding services for horses, dogs, cats, etc., can generate pollutants from the following activities: manure deposits, animal washing, grazing, and any other animal handling activity that could contaminate stormwater. Pollutants can include coliform bacteria, nutrients, and total suspended solids. Individual Stormwater Permits covering commercial animal handling facilities include additional applicable source controls. Pollutant Control Approach: To prevent, to the maximum extent practicable, the discharge of contaminated stormwater from animal handling and keeping areas. Applicable Operational BMPs • Regularly sweep and clean animal keeping areas to collect and properly dispose of droppings, uneaten food, and other potential stormwater contaminants. • Do not hose down areas that contain potential stormwater contaminants where they drain to storm drains or to receiving waters. • Do not discharge any washwater to storm drains or to receiving waters without proper treatment. • If the operator keeps animals in unpaved and uncovered areas, the ground must have either vegetative cover or some other type of ground cover such as mulch. • Surround the area where animals are kept with a fence or other means to prevent animals from moving away from the controlled area where BMPs are used. S40.3 BMPs for Commercial Com ' s g j ; scrdo ''of •till ant our es: om erc' co po ng cil' 'es,.: Op tin out 'de th c er, qui lar ear s t dec p e w stes, d o er eds ck e ' n t se cil' 'es t se ate o at frarh le at i.e.. and tri a w r) t the rea st e en os ' le. ' hem' o at co act ny ctiv co os ' g as cl in as re iv' g a pr ess' g a as, ' be me ea ate of an inch e ncl e rie s, ch is ox en m d ( D , or is col' b cter' , a ' is , c or nd sp de oli . St ter co os ' g ili ' s i ud n f fr a as t a oci ed th tiv oc in nd ri , s a ro ct ra are , v icl a' en ce ar s, a ess ad . Volume IV - Source Control BMPs — December 2014 2-10 S40� BMPs. for.:Streetsi;Highways ;Appl ab ' BMPs: . •: SeYect ;p"113"" ant' ice tha cau th eas adv se 'vir 'm tal mp t. nls n de si m' m q tit' S. he pr tic e ro w de' rs c s c ciu ma es' in ac ate of iu ace te, si lar at als at us ess dv e nvn to in t t u a, a so iu hl de. or nd ans r d nd nti-' in at ials n a im rvi s co al en ad* ac rd ce th P for e o r s er Ou de S id w ater' is -P du s o Fi ' he ro cts i is olu e. • S ep/ ea p cu at de d ti-i ng ate ' ls�fid � from oad as on po ibl fte he ad rf e cl rs. ' ec d A iti al P I ens' r dw cl in in ly ri to p o pa cu es fro ro su cc ncl e 1' its n t is tal n t sp ific io for e/a 1-ic s. S407 BMPs for Dust Control at Disturbed Land Areas and Unpaved Roadways and Parking Lots Description of Pollutant Sources: Dust can cause air and water pollution problems particularly at demolition sites and in and areas where reduced rainfall exposes soil particles to transport by air. Pollutant Control Approach: Minimize dust generation and apply environmentally friendly and government approved dust suppressant chemicals, if necessary. Applicable Operational BMPs: • Sprinkle or wet down soil or dust with water as long as it does not result in a wastewater discharge. • Use only local and/or state government approved dust suppressant chemicals such as those listed in Ecology Publication #96-433, Techniques for Dust Prevention and Suppression. • Avoid excessive and repeated applications of dust suppressant chemicals. Time the application of dust suppressants to avoid or minimize their wash -off by rainfall or human activity such as irrigation. • Apply stormwater containment to prevent the conveyance of sediment into storm drains or receiving waters. Volume IV - Source Control BMPs — December 2014 2-15 Ecology prohibits the use of motor oil for dust control. Take care when using lignin derivatives and other high BOD chemicals in areas susceptible to contaminating surface water or ground water. Consult with Ecology and the local permitting authority on discharge permit requirements if the dust suppression process results in a wastewater discharge to the ground, ground water, storm drain, or surface water. Recommended Additional Operational BMPs for Roadways and Other Trafficked Areas: • Consider limiting use of off -road recreational vehicles on dust generating land. • Consider graveling or paving unpaved permanent roads and other trafficked areas at municipal, commercial, and industrial areas. • Consider paving or stabilizing shoulders of paved roads with gravel, vegetation, or local government approved chemicals. • Encourage use of alternate paved routes, if available. • Vacuum sweep fine dirt and skid control materials from paved roads soon after winter weather ends or when needed. • Consider using pre -washed traction sand to reduce dust emissions. Additional Recommended Operational BMPs for Dust Generating Areas: • Prepare a dust control plan. Helpful references include: Control of Open Fugitive Dust Sources (EPA-450/3-88-088), and Fugitive Dust Background Document and Technical Information Document for Best Available Control Measures (EPA-450/2-92-004). • Limit exposure of soil (dust source) as much as feasible. • Stabilize dust -generating soil by growing and maintaining vegetation, mulching, topsoiling, and/or applying stone, sand, or gravel. • Apply windbreaks in the soil such as trees, board fences, tarp curtains, bales of hay, etc. S408 BMPs for, Du Co ro at an actdrin.g Ar 'as es pt' o olltttanf4o ces• nd tri ma ial an ng tives c ge rat co ider bre o s o dus a 's t cal re ove usi ;exh st ste in cc nt d c cr pr uc an an in d ed ate s n a g era du . P icu e ter' s t t c ca e ai of io ncl e in st, w st, al, av , c e oc me , a bo' er as . Ai mi ion can ont in e s ter he ob' cti of is P ' to du th to wa r p ut s c se y ust ene do an on 1. Volume IV - Source Control BMPs — December 2014 2-16 p ' ab O at' al M • El' in u e to asadi ar s t tose er, oui ;. at , or rfa w er.: / onv u e to isc rg to an' ry we fa we,.&by;the to se er tho i y, to e pp e ea en • Ob in ro iat tat nd oca e is th e d' cha es. e m en d dit' nal pe do al P . At in erc' an du ial cil' 'es, nd t a ry of ast at dis ar co ec ' ns to o dra' s a to rf e w er fo1 ws• • on ct iel su y ui in , pa cu y der it ' gs nd o er i us al as to to rai Er b ' di a pa d sur ces of h e t e j .n t pu is s rm rai ). • ur' g n -st er nd' on 'ns t e s rm ai or n- s ter isc rge . Re rd e 1 ati s o 11 n-s rm ater is ar I ud 11 rm' ed sch ge • us 1, ep e a ap ea ar . S w th a he o I o atio of o ew s, s it se ers nd er ' ed d np i d ' ch es er. p os ay us 1. e re rds s ch pi ' g s e ics o f of n n s. e s er on do an ho the o e ap. on ' er in in e, e, o the ica al s t st et co ec 'ons etw en o c ve nc ys s (e , p ces a a sto w er). de rab , c duc 'TV sp do of e s rm rai an ec t I fo ge v' eot e. om re e o se d 1 ati s o co ect' ns ith e ' o do o e ap d r is e ap co n N e s pe co ecf ns at e i ons' ten it e eld ry • ent' a co ect' ns st er or su ace at an tak th cti s s cif d a ve a is e BMPs S411 BMPs for Landscaping and Lawn/ Vegetation Management Description of Pollutant Sources: Landscaping can include grading, soil transfer, vegetation removal, pesticide and fertilizer applications, and watering. Stormwater contaminants include toxic organic compounds, heavy metals, oils, total suspended solids, coliform bacteria, fertilizers, and pesticides. Lawn and vegetation management can include control of objectionable weeds, insects, mold, bacteria, and other pests with pesticides. Examples include weed control on golf course lawns, access roads, and utility corridors and during landscaping; sap stain and insect control on lumber and logs; rooftop moss removal; killing nuisance rodents; fungicide application to patio decks, and residential lawn/plant care. It is possible to Volume IV - Souree Control BMPs — Deeember 2014 2-21 release toxic pesticides such as pentachlorophenol, carbamates, and organometallics to the environment by leaching and dripping from treated parts, container leaks, product misuse, and outside storage of pesticide contaminated materials and equipment. Poor management of the vegetation and poor application of pesticides or fertilizers can cause appreciable stormwater contamination. Pollutant Control Approach: Control of fertilizer and pesticide applications, soil erosion, and site debris to prevent contamination of stormwater. Develop and implement an Integrated Pest Management Plan (IPM) and use pesticides only as a last resort. Carefully apply pesticides/ herbicides, in accordance with label instructions. Maintain appropriate vegetation, with proper fertilizer application where practicable, to control erosion and the discharge of stormwater pollutants. Where practicable grow plant species appropriate for the site, or adjust the soil properties of the subject site to grow desired plant species. Applicable Operational BMPs for Landscaping: • Install engineered soil/landscape systems to improve the infiltration and regulation of stormwater in landscaped areas. Do not dispose of collected vegetation into waterways or storm sewer systems. Recommended Additional Operational BMPs for Landscaping: • Conduct mulch -mowing whenever practicable • Dispose of grass clippings, leaves, sticks, or other collected vegetation, by composting, if feasible. • Use mulch or other erosion control measures on soils exposed for more than one week during the dry season or two days during the rainy season. • Store and maintain appropriate oil and chemical spill cleanup materials in readily accessible locations when using oil or other chemicals. Ensure that employees are familiar with proper spill cleanup procedures. • Till fertilizers into the soil rather than dumping or broadcasting onto the surface. Determine the proper fertilizer application rate for the types of soil and vegetation encountered. • Till a topsoil mix or composted organic material into the soil to create a well -mixed transition layer that encourages deeper root systems and drought -resistant plants. • Use manual and/or mechanical methods of vegetation removal rather than applying herbicides, where practical. Volume IV - Source Control BMPs December 2014 2-22 Applicable Operational BMPs for the Use of Pesticides: • Develop and implement an IPM (See section on IPM in ,4pplicable Operational BM for Vegetation Management) and use pesticides only as a last resort. • Implement a pesticide -use plan and include at a minimum: a list of selected pesticides and their specific uses; brands, formulations, application methods and quantities to be used; equipment use and maintenance procedures; safety, storage, and disposal methods; and monitoring, record keeping, and public notice procedures. All procedures shall conform to the requirements of Chapter 17.21 RCW and Chapter 16-228 WAC (Appendix IV-D R.7). • Choose the least toxic pesticide available that is capable of reducing the infestation to acceptable levels. The pesticide should readily degrade in the environment and/or have properties that strongly bind it to the soil. Conduct any pest control activity at the life stage when the pest is most vulnerable. For example, if it is necessary to use a Bacillus thurin _ ig ens application to control tent caterpillars, apply it to the material before the caterpillars cocoon or it will be ineffective. Any method used should be site -specific and not used wholesale over a wide area. • Apply the pesticide according to label directions. Do not apply pesticides in quantities that exceed manufacturer's instructions. • Mix the pesticides and clean the application equipment in an area where accidental spills will not enter surface or ground waters, and will not contaminate the soil. • Store pesticides in enclosed areas or in covered impervious containment. Do not discharge pesticide contaminated stormwater or spills/leaks of pesticides to storm sewers. Do not hose down the paved areas to a storm sewer or conveyance ditch. Store and maintain appropriate spill cleanup materials in a location known to all near the storage area. • Clean up any spilled pesticides. Keep pesticide contaminated waste materials in designated covered and contained areas. • The pesticide application equipment must be capable of immediate shutoff in the event of an emergency. • Spraying pesticides within 100 feet of open waters including wetlands, ponds, and rivers, streams, creeks, sloughs and any drainage ditch or channel that leads to open water may have additional regulatory requirements beyond just following the pesticide product label. Additional requirements may include: • Obtaining a discharge permit from Ecology. • Obtaining a permit from the local jurisdiction. • Using an aquatic labeled pesticide. Volume IV - Source Control BMPs — December 2014 2-23 Flag all sensitive areas including wells, creeks, and wetlands prior to spraying. • Post notices and delineate the spray area prior to the application, as required by the local jurisdiction or by Ecology. Conduct spray applications during weather conditions as specified in the label direction and applicable local and state regulations. Do not apply during rain or immediately before expected rain. Recommended Additional Operational BMPs for the use of pesticides: Consider alternatives to the use of pesticides such as covering or harvesting weeds, substitute vegetative growth, and manual weed control/moss removal. • Consider the use of soil amendments, such as compost, that are known to control some common diseases in plants, such as Pythium root rot, ashy stem blight, and parasitic nematodes. The following are three possible mechanisms for disease control by compost addition (USEPA Publication 530-F-9-044): 1. Successful competition for nutrients by antibiotic production; 2. Successful predation against pathogens by beneficial microorganism; and 3. Activation of disease -resistant genes in plants by composts. Installing an amended soil/landscape system can preserve both the plant system and the soil system more effectively. This type of approach provides a soil/landscape system with adequate depth, permeability, and organic matter to sustain itself and continue working as an effective stormwater infiltration system and a sustainable nutrient cycle. • Once a pesticide is applied, evaluate its effectiveness for possible improvement. Records should be kept showing the effectiveness of the pesticides considered. Develop an annual evaluation procedure including a review of the effectiveness of pesticide applications, impact on buffers and sensitive areas (including potable wells), public concerns, and recent toxicological information on pesticides used/proposed for use. If individual or public potable wells are located in the proximity of commercial pesticide applications, contact the regional Ecology hydrogeologist to determine if additional pesticide application control measures are necessary. • Rinseate from equipment cleaning and/or triple -rinsing of pesticide containers should be used as product or recycled into product. For more information, contact the Washington State University (WSU) Extension Home -Assist Program, (253) 445-4556, or Bio-Integral Resource Center (BIRC), P.O. Box 7414, Berkeley, CA.94707, or EPA to Volume IV - Source Control BMPs — December 2014 2-24 obtain a publication entitled "Suspended, Canceled, and Restricted Pesticides " which lists all restricted pesticides and the specific uses that are allowed. Applicable Operational BMPs for Vegetation Management: Use at least an eight -inch "topsoil' layer with at least 8 percent organic matter to provide a sufficient vegetation -growing medium. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can substantially improve the permeability of the soil, the disease and drought resistance of the vegetation, and reduce fertilizer demand. This reduces the demand for fertilizers, herbicides, and pesticides. Organic matter is the least water-soluble form of nutrients that can be added to the soil. Composted organic matter generally releases only between 2 and 10 percent of its total nitrogen annually, and this release corresponds closely to the plant growth cycle. Return natural plant debris and mulch to the soil, to continue recycling nutrients indefinitely. Select the appropriate turfgrass mixture for the climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endophytic fungi found naturally in their tissues repel or kill common leaf and stem -eating lawn insects. However, they do not, repel root -feeding lawn pests such as Crane Fly larvae, and are toxic to ruminants such as cattle and sheep. The fungus causes no known adverse effects to the host plant or to humans. Endophytic grasses are commercially available; use them in areas such as parks or golf courses where grazing does not occur. Local agricultural or gardening resources such as Washington State University Extension office can offer advice on which types of grass are best suited to the area and soil type. • Use the following seeding and planting BMPs, or equivalent BMPs to obtain information on grass mixtures, temporary and permanent seeding procedures, maintenance of a recently planted area, and fertilizer application rates: Temporary and Permanent Seeding, Mulching, Plastic Covering, and Sodding as described in Volume II. Adjusting the soil properties of the subject site can assist in selection of desired plant species. For example, design a constructed wetland to resist the invasion of reed canary grass by layering specific strata of organic matters (e.g., composted forest product residuals) and creating a mildly acidic pH and carbon -rich soil medium. Consult a soil restoration specialist for site -specific conditions. • Aerate lawns regularly in areas of heavy use where the soil tends to become compacted. Conduct aeration while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than 3/4-inch deep. Volume IV - Source Control BMPs — December 2014 2-25 Mowing is a stress -creating activity for turfgrass. Grass decreases its productivity when mown too short and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses, more disease prone and more reliant on outside means such as pesticides, fertilizers, and irrigation to remain healthy. Set the mowing height at the highest acceptable level and mow at times and intervals designed to minimize stress on the turf. Generally mowing only 1/3 of the grass blade height will prevent stressing the turf. Irrigation: The depth from which a plant normally extracts water depends on the rooting depth of the plant. Appropriately irrigated lawn grasses normally root in the top 6 to 12 inches of soil; lawns irrigated on a daily basis often root only in the top 1 inch of soil. Improper irrigation can encourage pest problems, leach nutrients, and make a lawn completely dependent on artificial watering. The amount of water applied depends on the normal rooting depth of the turfgrass species used, the available water holding capacity of the soil, and the efficiency of the irrigation system. Consult with the local water utility, Conservation District, or Cooperative Extension office to help determine optimum irrigation practices. Fertilizer Management: Turfgrass is most responsive to nitrogen fertilization, followed by potassium and phosphorus. Fertilization needs vary by site depending on plant, soil, and climatic conditions. Evaluation of soil nutrient levels through regular testing ensures the best possible efficiency and economy of fertilization. For details on soils testing, contact the local Conservation District, a soils testing professional, or a Washington State University Extension office. Apply fertilizers in amounts appropriate for the target vegetation and at the time of year that minimizes losses to surface and ground waters. Do not fertilize when the soil is dry. Alternatively, do not apply fertilizers within three days prior to predicted rainfall. The longer the period between fertilizer application and either rainfall or irrigation, the less fertilizer runoff occurs. Use slow release fertilizers such as methylene urea, IDBU, or resin coated fertilizers when appropriate, generally in the spring. Use of slow release fertilizers is especially important in areas with sandy or gravelly soils. Time the fertilizer application to periods of maximum plant uptake. Ecology generally recommends application in the fall and spring, although Washington State University turf specialists recommend four fertilizer applications per year. Volume IV - Source Control BMPs — December 2014 2-26 • Properly trained persons should apply all fertilizers. Apply no fertilizer at commercial and industrial facilities, to grass swales, filter strips, or buffer areas that drain to sensitive water bodies unless approved by the local jurisdiction. Integrated Pest Management An IPM program might consist of the following steps: Step 1: Correctly identify problem pests and understand their life cycle Step 2: Establish tolerance thresholds for pests. Step 3: Monitor to detect and prevent pest problems. Step 4: Modify the maintenance program to promote healthy plants and discourage pests. Step 5: Use cultural, physical, mechanical or biological controls first if pests exceed the tolerance thresholds. Step 6: Evaluate and record the effectiveness of the control and modify maintenance practices to support lawn or landscape recovery and prevent recurrence. For an elaboration of these steps, refer to Appendix IV-F. 5412`BM.Ps for Loading and Unloadin Ar s ..ferLiqui: or S'blid Material ; Dt ri io f P ut t ur s: era rs is y c du og/ oa g li d a s d er' s a 'nd ria nd c in cia aci ' ies s pi an ec in , ou de ora in are , et . ria tra fe d c in de ro cts aw ate Is e di pr uc , w e ter' s, eis, cra et s, e . L s d sp' so el ,oil , po er or ics ea m als alt aci , al lis c. rin ra er ay us to a co a ati . S is om h ra c li br s e a in obl a oa g cks Po to C tr Ap oa ver nd nt ' th oa 'ng/ to in ea er nec sar to eve ru on st w er d of f c a at sto w er. A is a er io B s• At L di / U oa ' g ea sig ' is a un f d ris an cu lat at o si , un ve d o ng/ to in re a . S ep ese rf es qu tly re ove ose at ial at c ld on in e st ter. we ar s to or ily ve d a r r ov of e c ta' ers ogs r o er at al ve r' g t gr nd ace rip ans or o er pr ria to or co ai en ev' e, a to do w re 1 s sp' s y o ur ch ho co ec 'ons ose eel nd le oz s. wa us dri a wh in in nd Volume IV - Source Control BMPs — December 2014 2-27 S417 BMPs for Maintenance of Stormwater Drainage and Treatment Systems Description of Pollutant Sources: Facilities include roadside catch basins on arterials and within residential areas, conveyance systems, detention facilities such as ponds and vaults, oil/water separators, biofilters, settling basins, infiltration systems, and all other types of stormwater treatment systems presented in Volume V. Oil and grease, hydrocarbons, debris, heavy metals, sediments and contaminated water are found in catch basins, oil and water separators, settling basins, etc. Pollutant Control Approach: Provide maintenance and cleaning of debris, sediments, and oil from stormwater collection, conveyance, and treatment systems to obtain proper operation. Applicable Operational BMPs: Maintain stormwater treatment facilities per the operations and maintenance (O&M) procedures presented in Section 4.6 of Volume V in addition to the following BMPs: • Inspect and clean treatment BMPs, conveyance systems, and catch basins as needed, and determine necessary O&M improvements. • Promptly repair any deterioration threatening the structural integrity of stormwater facilities. These include replacement of clean -out gates, catch basin lids, and rock in emergency spillways. • Ensure adequacy of storm sewer capacities and prevent heavy sediment discharges to the sewer system. • Regularly remove debris and sludge from BMPs used for peak -rate control, treatment, etc. and discharge to a sanitary sewer if approved by the sewer authority, or truck to an appropriate local or state government approved disposal site. • Clean catch basins when the depth of deposits reaches 60 percent of the sump depth as measured from the bottom of basin to the invert of the lowest pipe into or out of the basin. However, in no case should there be less than six inches clearance from the debris surface to the invert of the lowest pipe. Some catch basins (for example, WSDOT Type 1 L basins) may have as little as 12 inches sediment storage below the invert. These catch basins need frequent inspection and cleaning to prevent scouring. Where these catch basins are part of a stormwater collection and treatment system, the system Volume IV - Source Control BMPs — December 2014 2-37 owner/operator may choose to concentrate maintenance efforts on downstream control devices as part of a systems approach. • Clean woody debris in a catch basin as frequently as needed to ensure proper operation of the catchbasin. • Post warning signs; "Dump No Waste - Drains to Ground Water," "Streams," "Lakes," or emboss on or adjacent to all storm drain inlets where possible. • Disposal of sediments and liquids from the catch basins must comply with "Recommendations for Management of Street Wastes" described in Appendix IV-G of this volume. Additional Applicable BMPs: Select additional applicable BMPs from this chapter depending on the pollutant sources and activities conducted at the facility. Those BMPs include: • S425 BMPs for Soil Erosion and Sediment Control at Industrial Sites • S427 BMPs for Storage of Liquid, Food Waste, or Dangerous Waste Containers • S406 BMPs for Spills of Oil and Hazardous Substances • S410 BMPs for Illicit Connections to Storm Drains • S430 BMPs for Urban Streets . S418 BMPs for Manuf'ctu'ring Act.tr itieg ut de, D 'scr' 'tio 'of `llu 'nt our `s: V�a 'ng /hi urc me de tsi pr ess rea , sta e a ...../R/anu ctu 'ng tiv' h tak pl e st nt posed p o to ma rial re in.`` of do Co ro p oac Corer d c ta' ou ''de manufacturing.: d p ve sto w r-on.and e'ont in on here feasible' pli le pe do al $VIP;: ' • w p p ed reayfefgularly;'as needed; to:preverit contamiiiatierii o at ; +' er e a vit y mi din or m in he nt in on sto w r. p ca S ct al ur C tr s: cl e t act' rty ( e F' re .2. If ss' e, clo th a fac rin act' ty ' a ui in ov th cti ' y d c ne flo dr ' s t as ita se r, i a rov d b he ca ew au orit . B o slo th oo as ee d t• prevent ai e o po to to tsi ar s. u Volume IV - Source Control BMPs — December 2014 2-38 S ck ea eri s, s a rooms,..dustpans,..and vacuum swe er ea e ora ar f S430 BMPs for Urban Streets Description of Pollutant Sources: Urban streets can be the source of vegetative debris, paper, fine dust, vehicle liquids, tire and brake wear residues, heavy metals (lead and zinc), soil particles, ice control salts, domestic wastes, lawn chemicals, and vehicle combustion products. Street surface contaminants contain significant concentrations of particle sizes less than 250 microns (Sartor and Boyd, 1972). Pollutant Control Approach: Conduct efficient street sweeping where and when appropriate to minimize the contamination of stormwater. Do not wash street debris into storm drains. Facilities not covered under the Industrial Stormwater General Permit may consider a minimum amount of water washing of streets. All facilities must comply with their local stormwater requirements for discharging to storm sewers. Municipal NPDES permittees are required to limit street wash water discharges and may have special conditions or treatment requirements. Recommended BMPs: For maximum stormwater pollutant reductions on curbed streets and high volume parking lots, use efficient vacuum sweepers. Note: High -efficiency street sweepers utilize strong vacuums and the mechanical action of main and gutter brooms combined with an air filtration system that only returns clean air to the atmosphere (i.e., filters very fine particulates). They sweep dry and use no water since they do not emit any dust. High -efficiency vacuum sweepers have the capability of removing, 80 percent or more of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and reasonably expected accumulation conditions. For moderate stormwater pollutant reductions on curbed streets use regenerative air sweepers or tandem sweeping operations. Note: 4 tandem sweeping operation involves a single pass of a mechanical sweeper followed immediately by a single pass of a vacuum sweeper or regenerative air sweeper. - 4 regenerative air sweeper blows air down on the pavement to entrain particles and uses a return vacuum to transport the material to the hopper. Volume IV - Source Control BMPs — December 2014 2-57 - These operations usually use water to control dust. This reduces their ability to pick up fine particulates. These types of sweepers have the capability of removing approximately 25 to 50 percent of the accumulated street dirt particles whose diameters are less than 250 microns. (Sutherland, 1998). This assumes pavements under good conditions and typical accumulation conditions. For minimal stormwater pollutant reductions on curbed streets use mechanical sweepers. - Note: The industry refers to mechanical sweepers as broom sweepers and uses the mechanical action of main and gutter brooms to throw material on a conveyor belt that transports it to the hopper. - These sweepers usually use water to control dust. This reduces their ability to pick up fine particulates. Mechanical sweepers have the capability of removing only 10 to 20 percent of the accumulated street dirt particles whose diameters are less than 250 microns (Sutherland, 1998). This assumes pavements under good condition and the most favorable accumulation conditions. • Conduct vacuum sweeping at optimal frequencies. Optimal frequencies are those scheduled sweeping intervals that produce the most cost-effective annual reduction of pollutants normally found in stormwater and can vary depending on land use, traffic volume and rainfall patterns. • Train operators in those factors that result in optimal pollutant removal. These factors include sweeper speed, brush adjustment and rotation rate, sweeping pattern, maneuvering around parked vehicles, and interim storage and disposal methods. • Consider the use of periodic parking restrictions in low to medium density single-family residential areas to ensure the sweeper's ability to sweep along the curb. • Establish programs for prompt vacuum sweeping, removal, and disposal of debris from special events that will generate higher than normal loadings. • Disposal of street sweeping solids must comply with "Recommendations for Management of Street Wastes" described in Appendix IV-G of this volume. • Inform citizens about eliminating yard debris, oil and other wastes in street gutters to reduce street pollutant sources. Volume IV - Source Control BMPs — December 2014 2-58 Blow'. Clean A forterra Compaq Northwest OPERATION & MAINTENANCE MANUALA 1�� WETLANDS- Inspection Guidelines for Modular Wetland System - Linear Inspection Summary o Inspect Pre -Treatment, Biofiltration and Discharge Chambers — average inspection interval is 6 to 12 months. ■ (15 minute average inspection time) . o NOTE: Pollutant loading varies greatly from site to site and no two sites are the same. Therefore, the first year requires inspection monthly during the wet season and every other month during the dry season in order to observe and record the amount of pollutant loading the system is receiving. System Diagram Access to separation chamber and pre -filter cartridges ndi"" U_A;� rEf Cart Curb Inlet =r Cartridge Vertical Underdrain Manifold UI�Mtz! I EEN 1O Pre-treatment Chamber O2 Biofiltration Chamber ODischarge Chamber Access to discharge er and orifice control 'land/ Drain -Down Lined �'�r/ED 1 A Flow Control Riser { j � Outlet Pipe www.modularwetlands.com Inspection Overview 1�� WETLANDS - As with all stormwater BMPs inspection and maintenance on the MWS Linear is necessary. Stormwater regulations require that all BMPs be inspected and maintained to ensure they are operating as designed to allow for effective pollutant removal and provide protection to receiving water bodies. It is recommended that inspections be performed multiple times during the first year to assess the site specific loading conditions. This is recommended because pollutant loading and pollutant characteristics can vary greatly from site to site. Variables such as nearby soil erosion or construction sites, winter sanding on roads, amount of daily traffic and land use can increase pollutant loading on the system. The first year of inspections can be used to set inspection and maintenance intervals for subsequent years to ensure appropriate maintenance is provided. Without appropriate maintenance a BMP will exceed its storage capacity which can negatively affect its continued performance in removing and retaining captured pollutants. Inspection Equipment Following is a list of equipment to allow for simple and effective inspection of the MWS Linear: • Modular Wetland Inspection Form • Flashlight • Manhole hook or appropriate tools to remove access hatches and covers • Appropriate traffic control signage and procedures • Measuring pole and/or tape measure. • Protective clothing and eye protection. • 7/16" open or closed ended wrench. • Large permanent black marker (initial inspections only — first year) • Note: entering a confined space requires appropriate safety and certification. It is generally not required for routine inspections of the system. www.modularwetlands.com 1�� WETLANDS Insoection Steos The core to any successful stormwater BMP maintenance program is routine inspections. The inspection steps required on the MWS Linear are quick and easy. As mentioned above the first year should be seen as the maintenance interval establishment phase. During the first year more frequent inspections should occur in order to gather loading data and maintenance requirements for that specific site. This information can be used to establish a base for long term inspection and maintenance interval requirements. The MWS Linear can be inspected though visual observation without entry into the system. All necessary pre -inspection steps must be carried out before inspection occurs, especially traffic control and other safety measures to protect the inspector and near -by pedestrians from any dangers associated with an open access hatch or manhole. Once these access covers have been safely opened the inspection process can proceed: • Prepare the inspection form by writing in the necessary information including project name, location, date & time, unit number and other info (see inspection form). • Observe the inside of the system through the access hatches. If minimal light is available and vision into the unit is impaired utilize a flashlight to see inside the system and all of its chambers. • Look for any out of the ordinary obstructions in the inflow pipe, pre-treatment chamber, biofiltration chamber, discharge chamber or outflow pipe. Write down any observations on the inspection form. • Through observation and/or digital photographs estimate the amount of trash, debris and sediment accumulated in the pre-treatment chamber. Utilizing a tape measure or measuring stick estimate the amount of trash, debris and sediment in this chamber. Record this depth on the inspection form. www.modularwetlands.com 1�� WETLANDS • Through visual observation inspect the condition of the pre -filter cartridges. Look for excessive build-up of sediments on the cartridges, any build-up on the top of the cartridges, or clogging of the holes. Record this information on the inspection form. The pre -filter cartridges can further be inspected by removing the cartridge tops and assessing the color of the BioMediaGREEN filter cubes (requires entry into pre-treatment chamber — see notes above regarding confined space entry). Record the color of the material. New material is a light green in color. As the media becomes clogged it will turn darker in color, eventually becoming dark brown or black. Using the below color indicator record the percentage of media exhausted. New Exhausted BioMediaGREEN I BioMediaGREEN 0% -- Percent Clogged -- 100% • The biofiltration chamber is generally maintenance free due to the system's advanced pre- treatment chamber. For units which have open planters with vegetation it is recommended that the vegetation be inspected. Look for any plants that are dead or showing signs of disease or other negative stressors. Record the general health of the plants on the inspection and indicate through visual observation or digital photographs if trimming of the vegetation is needed. • The discharge chamber houses the orifice control structure and is connected to the outflow pipe. It is important to check to ensure the orifice is in proper operating conditions and free of any obstructions. Generally, the discharge chamber will be clean and free of debris. Inspect the water marks on the side walls. If possible, inspect the discharge chamber during a rain event to assess the amount of flow leaving the system while it is at 100% capacity (pre- treatment chamber water level at peak HGL). The water level of the flowing water should be compared to the watermark level on the side walls which is an indicator of the highest discharge rate the system achieved when initially installed. Record on the form is there is any difference in level from watermark in inches. www.modularwetlands.com 1�� WETLANDS NOTE: During the first few storms the water level in the outflow chamber should be observed and a 6" long horizontal watermark line drawn (using a large permanent marker) at the water level in the discharge chamber while the system is operating at 100% capacity. The diagram below illustrates where a line should be drawn. This line is a reference point for future inspections of the system: 41 Water Level Marks �� wa NZ itoo- Water Level Mark Using a permanent marker draw a 6 inch long horizontal line, as shown, at the higher water level in the MWS Linear discharge chamber. • Water level in the discharge chamber is a function of flow rate and pipe size. Observation of water level during the first few months of operation can be used as a benchmark level for future inspections. The initial mark and all future observations shall be made when system is at 100% capacity (water level at maximum level in pre-treatment chamber). If future water levels are below this mark when system is at 100% capacity this is an indicator that maintenance to the pre -filter cartridges may be needed. • Finalize inspection report for analysis by the maintenance manager to determine if maintenance is required. www.modularwetlands.com 1�� WETLANDS - Maintenance Indicators Based upon observations made during inspection, maintenance of the system may be required based on the following indicators: Missing or damaged internal components or cartridges. • Obstructions in the system or its inlet or outlet. • Excessive accumulation of floatables in the pre-treatment chamber in which the length and width of the chamber is fully impacted more than 18". • Excessive accumulation of sediment in the pre-treatment chamber of more than 6" in depth. www.modularwetlands.com 1�� WETLANDS- • Excessive accumulation of sediment on the BioMediaGREEN media housed within the pre- filter cartridges. The following chart shows photos of the condition of the BioMediaGREEN contained within the pre -filter cartridges. When media is more than 85% clogged replacement is required. New BioMediaGREEN 0% -- Percent Clogged -- 100% • Overgrown vegetation. Exhausted BioMediaGREEN • Water level in discharge chamber during 100% operating capacity (pre-treatment chamber water level at max height) is lower than the watermark by 20%. www.modularwetiands.com 1�� WETLANDS - Inspection Notes 1. Following maintenance and/or inspection, it is recommended the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms. 2. The owner should keep maintenance/inspection record(s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time. 3. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. 4. Entry into chambers may require confined space training based on state and local regulations. 5. No fertilizer shall be used in the Biofiltration Chamber. 6. Irrigation should be provided as recommended by manufacturer and/or landscape architect. Amount of irrigation required is dependent on plant species. Some plants may not require irrigation after initial establishment. www.modularwetlands.com Can 1�� WETLANDS - Maintenance Guidelines for Modular Wetland System - Linear Maintenance Summary o Remove Sediment from Pre -Treatment Chamber - average maintenance interval is 12 to 24 months. ■ ( 10 minute average service time). o Replace Pre -Filter Cartridge Media - average maintenance interval 12 to 24 months. . ( 90- 15 minute per cartridge average service time) . o Trim Vegetation - average maintenance interval is 6 to 12 months. ■ ( Service time varies) . System Diagram Access to separation chamber and pre -filter cartridge Curb -r Cartridge (j) ___T7 Vertical Underdrain Manifold UlUMediaGREEN 1O Pre-treatment Chamber O2 Biofiltration Chamber O3 Discharge Chamber r!► Qn } Drain -Down LineXE'D I A Plow Control Riser O 3 Outlet Pipe www.modularwetiands.com Maintenance Overview 1�� WETLANDS The time has come to maintain your Modular Wetland System Linear (MWS Linear). To ensure successful and efficient maintenance on the system we recommend the following. The MWS Linear can be maintained by removing the access hatches over the systems various chambers. All necessary pre -maintenance steps must be carried out before maintenance occurs, especially traffic control and other safety measures to protect the inspector and near -by pedestrians from any dangers associated with an open access hatch or manhole. Once traffic control has been set up per local and state regulations and access covers have been safely opened the maintenance process can begin. It should be noted that some maintenance activities require confined space entry. All confined space requirements must be strictly followed before entry into the system. In addition the following is recommended: Prepare the maintenance form by writing in the necessary information including project name, location, date & time, unit number and other info (see maintenance form). • Set up all appropriate safety and cleaning equipment. • Ensure traffic control is set up and properly positioned. • Prepare a pre -checks (OSHA, safety, confined space entry) are performed. Maintenance Equipment Following is a list of equipment required for maintenance of the MWS Linear: • Modular Wetland Maintenance Form • Manhole hook or appropriate tools to access hatches and covers • Protective clothing, flashlight and eye protection. • 7/16" open or closed ended wrench. • Vacuum assisted truck with pressure washer. • Replacement BioMediaGREEN for Pre -Filter Cartridges if required (order from manufacturer). www.modularwetlands.com 1�� WETLANDS - Maintenance Steps 1. Pre-treatment Chamber (bottom of chamber) A. Remove access hatch or manhole cover over pre-treatment chamber and position vacuum truck accordingly. B. With a pressure washer spray down pollutants accumulated on walls and pre -filter cartridges. C. Vacuum out Pre -Treatment Chamber and remove all accumulated pollutants including trash, debris and sediments. Be sure to vacuum the floor until pervious pavers are visible and clean. D. If Pre -Filter Cartridges require media replacement move onto step 2. If not, replace access hatch or manhole cover. Removal of access hatch to gain access below. Removal of trash, sediment and debris. Insertion of vacuum hose into separation chamber. Fully cleaned separation chamber. www.modularwetlands.com 2. Pre -Filter Cartridqes (attached to wall of pre-treatment chamber A. After finishing step 1 enter pre-treatment chamber. B. Unscrew the two bolts holding the lid on each cartridge filter and remove lid. /? 9 ,Z2,07 /M" Pre -filter cartridges with tops on. 1�� WETLANDS- Inside cartridges showing media filters ready for replacement. C. Place the vacuum hose over each individual media filter to suck out filter media. Vacuuming out of media filters. D. Once filter media has been sucked use a pressure washer to spray down inside of the cartridge and it's containing media cages. Remove cleaned media cages and place to the side. Once removed the vacuum hose can be inserted into the cartridge to vacuum out any remaining material near the bottom of the cartridge. www.modularwetlands.com 1�� WETLANDS- E. Reinstall media cages and fill with new media from manufacturer or outside supplier. Manufacturer will provide specification of media and sources to purchase. Utilize the manufacture provided refilling trey and place on top of cartridge. Fill trey with new bulk media and shake down into place. Using your hands slightly compact media into each filter cage. Once cages are full removed refilling trey and replace cartridge top ensuring bolts are properly tightened. Refilling trey for media replacement. i Refilling trey on cartridge with bulk media. F. Exit pre-treatment chamber. Replace access hatch or manhole cover. 3. Biofiltration Chamber (middle vegetated chamber) A. In general, the biofiltration chamber is maintenance free with the exception of maintaining the vegetation. Using standard gardening tools properly trim back the vegetation to healthy levels. The MWS Linear utilizes vegetation similar to surrounding landscape areas therefore trim vegetation to match surrounding vegetation. If any plants have died replace plants with new ones: www.modularwetlands.com 1�� WETLANDS - Inspection Notes 1. Following maintenance and/or inspection, it is recommended the maintenance operator prepare a maintenance/inspection record. The record should include any maintenance activities performed, amount and description of debris collected, and condition of the system and its various filter mechanisms. 2. The owner should keep maintenance/inspection record(s) for a minimum of five years from the date of maintenance. These records should be made available to the governing municipality for inspection upon request at any time. 3. Transport all debris, trash, organics and sediments to approved facility for disposal in accordance with local and state requirements. 4. Entry into chambers may require confined space training based on state and local regulations. 5. No fertilizer shall be used in the Biofiltration Chamber. 6. Irrigation should be provided as recommended by manufacturer and/or landscape architect. Amount of irrigation required is dependent on plant species. Some plants may not require irrigation after initial establishment. www.modularwetlands.com 1�� WETLANDS - Inspection Form Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com www.modularwetlands.com 1�� WETLANDS - Maintenance Report Modular Wetland System, Inc. P. 760.433-7640 F. 760-433-3176 E. Info@modularwetlands.com www.modularwetlands.com