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APPROVED STM RESUB2 BLD2022-1025+Storm_Drainage_Report+10.24.2022_11.05.16_AM+3180985BLD2022-1025 DECCIO Engineering Inc. RES U B 17Bothell, 7th Avenue W. Bothell, WA. 98012 Oct 25 2022 Fax: (4225) 7411-8214 CITY OF EDMONDS DEVELOPMENT SERVICES COMPLIES WITH APPLICABLE DEPARTMENT CITY STORM CODE 1 /25/2022 Duffy SFD Edmonds App # BLD2022-1025 Drainage Design Report, O&M Manual & SWPP Report Property Location: 23511 74" Ave W. Edmonds, WA September 5, 2022 Revised: October 11, 2022 Prepared for: Brian and Nancy Duffy Duffy 23511 741" Ave W, Edmonds STORMWATER DRAINAGE REPORT TABLE OF CONTENTS Page Introduction.......................................................................................................................................... 2 Section 1: Project Overview 7 Section2: Existing Site Conditions.................................................................................................... 2 Section 3: Offsite Analysis Off -Site Analysis and Mitigation................................................................................................... 5 Section4: Minimum Requirements..............................................................................................8 Section 5: Stormwater Control Plan...........................................................................................10 Section 6: Pollution Prevention Plan Section 7: Special Reports and Studies Section 8: Wetlands Protection ................. Section 9: Operations and Maintenance List of Figures: Site Location and Vicinity Map Existing Site Conditions Developed Site Conditions Downstream Analysis and Sub -Basin Map APPENDIX A Soils Management Form Soils Option 3 12 14 14 14 Introduction This report has been prepared at the request of Brian and Nancy Duffy in support of a single family residential building permit for a site located on the east side of 74t'1 Ave W. Edmonds, Washington in the NE 1/a of the SE'/a Section 32, Township 27 North, Range 04 East W.M. The site address is 23511 74' Avenue W, Edmonds WA. (Parcel #27043200200100) (Refer to Site Location and Vicinity Map). This report addresses the drainage report contents and organization of MR 1 to MR 9 per DOE 2019 Stormwater Management Manual as adopted by the City of Edmonds Stormwater Coe effective July 1, 2022. Specifically we have designed the drainage using a review of the LID applications as outlined in Volume 1, Chapter 2, Table Z5.1 of the DOE 2019 Stormwater Management Manual. Section 1: Project Overview The project consists of the construction of a new home on a 25,976 sf site. The existing lot contains a house and garage which will be removed to construct the new home. The existing rockeries and driveways will remain. The site cover is landscaping and lawn is located on Lake Ballinger. . Once developed, the site will add a new home with a total of 3,100 sf of new impervious area in the form of a roof for the home. Approximately 220 sf of existing gravel driveway will be paved in front to the new garage. The existing rockeries and driveway will remain. All of the proposed improvements are outside of the wetlands and the associated buffers. The area of disturbance is 4,640 sf. Duffy SFD Revised: October 11, 2022 Page 2 s 3 � ' Esperance 01fyrjipic View Arena IV x w - Park & ro m Off Leash / Mercury Lea Q eserIdeal Senior Care Dog Area Pharmacy Services© QThe Nock Point r ve 99 Ranch Market Boo Han Oriental Market y� Three Holy© 226th St SW £ s Esperance f Hierarchs Romanian.. e, 226th PI SW f Q Q McKeown James M Stained Glass Studio 228th St SW Andorra ate Chapel Michaels Traveling Notary < Arariment Homes Dominos Pizza St Michael / c a Ethiopian Orthodox_ 9 2 s' S" 3 Bethel Chapel 231.1 S1 SW Les Schwab Tire 1// ndsa a b Ballinger Park Another Castle �3y4 a -SW �. 2281h St SW D An t`e :E 230th S N I Sl` Ass, Casc Holly Ln Video Games, y Fantasy Flights Q Maple to A / � r 2341h SI SW � Lake Ballinger Estates Q 234th Pl sw WhidyBall� Edmonds Lutheran 2a511 74th AvetW, A Edmonds WA 98026 Learning Center L ke Ba tinge 2361h St SW 2361h St SW Franco Pa Services L 0 Mountlake Transit Safeway ® ; i Beach Lakeview or Exclusively v° s \\ �/ r McAleer boat lau 238th St SW `�` 238th StsW ©Hosoonyi Korean >; Nile Nightmares =dDl0un Haunted House \\ / \ van Haunted Evergreen A 1 SY2 240th St sw Mo Burlingt6riO _ 104 (\ 242nd St SW it I Y , 9q 242nd St sw a De,rny s artments Panera Bread UWMedicinePrimary Q o� r Care at Shoreline O Holyrood Cemetery,oa — N 203rd St The: Home Depot Q N 202nd S Costco WholesaleQ N 200th St Echo Lake Park -- gzsia NE 2041h St D to iD = _ m Northrid e Swim Club Q Shamrock Living Services • Ballinger Commons Q Apartment Homes ry SCh001 n N 198th St 0 Days In y ndham - D Seattle,Awrpr�a !I Echo Lake N1e6thPl S T Studio E trre ake Mexicar Untiake (rage Q Lond g NE 2001h St n i ; Kindergarten Readiness Goog Preschool WeeCare �,/� VICINITY MAP Section 2: Existing Site Conditions The project consists of construction of a new home on a 25,967 sf site. The existing lot contains a house and garage which will be removed to build the new home. The site cover is landscaping and lawn. The site has slopes around 4 to 10 percent with runoff flowing east into Lake Ballinger. Duffy SFD Revised: October 11, 2022 Page 3 Existing Site Conditions Duffy SFD Revised: October 11, 2022 Page 4 Section: 3 Offsite Analysis Report Per Section 2.5, Stormwater site plans and SWPP Plans have been prepared for the site and are included with this storm drainage report. BMP's are proposed for the site since the runoff from the roof impervious area is under 5,000 s£ OFF SITE ANALYSIS AND MITIGATION An Off Site Analysis and Mitigation Study meeting requirements outlined in Section 2.5.1 was performed on September 1, 2022. The weather was clear and warm at the time of the field inspection. See Downstream Analysis Map. TASK L• PROJECT OVERVIEW & STUDYAREA DEFINITION Existing Site Conditions: The existing lot contains a house and garage. The site cover is landscaping and lawn with slopes around 4 to 10 percent. The site itself drains towards to the east into Lake Ballinger. TASK 2: REVIEW OF AVAILABLE INFORMATION ON STUDY AREA Resource Review: The following is a description of the resources that were reviewed for the preparation of this Level 1 Drainage Study: A. Basin Recognizance Summary: Enclosed within are downstream and upstream basin area map which clearly define the flow pass and the drainage basins related to this project. See (Downstream Analysis Map ) Evidence of Existing and Predicted Problems Lack of capacity or constrictions in the existing drainage system. 0 On -site: No evidence of any problem. O Off -site: Stream/Lake None noted Culverts/pipes None known (no evidence of capacity or any other problems) Overtopping, Scouring, Bank, Sloughing of Sedimentation 0 On -site: No evidence of any problem. O Off -site: C 12-inch pipes: None noted C Stream Channel: none noted Flooding etc. O None Noted Significant Destruction of Aquatic Habitat or Organisms Duffy SFD Revised: October 11, 2022 Page 5 0 None Noted B. Adopted Basin Plans: None Known C. Floodplain/Floodway (FEMA Maps): The proposed improvements do not appear to be located within the flood plain of the lake as determined by the FEMA maps. D. Other Off -Site Analysis Issues: None Noted TASK 3 & 4: FIELD INSPECTION AND DESCRIPTION OF DRAINAGE SYSTEM WITH EXISTING AND PREDICTED PROBLEMS A Level 1 drainage analysis and "Off Site Analysis and Mitigation Study" meeting requirements outlined in Section 3.2.0 was performed. See Downstream Analysis Map. Level 1 Downstream Drainage Analysis: Section 1: Upstream Drainage Analysis: Based on the site contours there is little if any off -site runoff draining onto the site with all upstream runoff being intercepted by 74' Ave W. and therefore the drainage is limited to the site itself. A review of the upstream area indicated that there were no indications of problems observed. Section 2: On -site Drainage Considerations: All runoff from the site drains to the east and into Lake Ballinger. Section 3: Site to Lake Ballinger 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, or up to one -quarter mile, whichever is less. Runoff from roof areas will be managed via downspout dispersion trenches. Runoff from other impervious areas will enter the City's MS4 within one -quarter mile since the project proposes to connect into the public storm main along at the south end of the lake, south of the property. The receiving water is Lake Ballinger which is adjacent to the site. The downstream flowpath is outlined below in "Downstream Analysis" Figure. TASK 5: LEVEL 1 MITIGATION OF EXISTING PROBLEMS In order to mitigate the site improvements, the project proposes the following BMP. • The site proposes the use of dispersion trenches Water Quality Requirements: With less than 5,000 sf of PGIS area, water quality is not proposed for the site improvements. Duffy SFD Revised: October 11, 2022 Page 6 Downstream Analysis Map Duffy SFD Revised: October 11, 2022 Page 7 Section 4: Minimum Requirements 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. A full DOE SWPPP that addresses the 13 elements of Construction Stormwater Pollution Prevention has been prepared. See Section 6 and the civil drawings. 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. All single-family residential projects shall, at a minimum, incorporate required BMPs from SWMMWW Volume IV, S411 — BMPs for Landscaping and Lawn/Vegetation Management. The Operation & Maintenance Manual found in Section VII addresses Lawn/Vegetation management. 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 3. Minimum Requirement #5: On -Site Stormwater Management: The proposed project is a Category 1 project per ECDC 18.30 that discharges to the City's MS4. It shall either use On -Site Stormwater Management BMPs from List No. 1 (per ECDC 18.30.060.D.5.d) for all new plus replaced hard surfaces and land disturbed or demonstrate compliance with the LID Performance Standard (per ECDC 18.30.060.D.5.c). This project will use On -Site Stormwater Management BMPs from List No. 1. Please see Section 5 for feasibility review. 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 Minimum Requirement #6: Runoff Treatment. Since the PGIS area is under 5,000 sf, runoff treatment is not required. Minimum Requirement #7: Flow Control. The project is under 5,000 sf therefor flow control is not required. Minimum Requirement #8: Wetlands Protection. All proposed improvements are outside of both the wetlands and the buffers, thereby providing protection of the wetlands. Minimum Requirement #9: Operations and Maintenance. Not required. Duffy SFD Revised: October 11, 2022 Page 8 EDMONDS STORMWATER ADDENDUM J U N E 2017 Does the project result in 2,000 square feet, or greater, of new plus replaced hard surface area? OR Does the land disturbing activity total 7,000 square feet or greater? Yes No Minimum Requirements No. 1 throu2ji 5 apply Minimum Requirement No. 2 applies Next QaesAon Does the project add 5,000 square feet or more of new plus replaced hard surfaces? OR Convert 0.75 acres or more of vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? No Yes Is this a road related project? All Minimum Requirements 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 add 5,000 square feet or No more of new hard surfaces? I Yes Do new hard surfaces add 501/6 or more to the existing hard surfaces within the project limits? No Figure3.1. Flow Chart for Determining Requirements for Development. 8 1 APPLICABILITY OF THE MINIMUM REQUIREMENTS No additional requirements. Duffy SFD Revised: October 11, 2022 Page 9 Section: 5 Stormwater Control Plan As discussed above, once developed the site will contain a new home only. The total impervious area including the home is under 5, 000 sf in size Under the On -Site Stormwater Management Requirements" the "Low Impact Development Performance Standards" specifically List 2 of the DOE 2014 Stormwater Management Manual, Volume 1, Chapter 2, Table 2.5.1, and BMP T5.13 requires that each item must be review and analyzed for use. The BMP's listed below were reviewed using City of Edmonds "Appendix A: On -Site Stormwater Management BMP Infeasibility Criteria" as follows: TABLE 2.5.1 LIST #2 BMP FEASIBILITY Lawn and landscaped areas: 1. Post -Construction Soil Quality and Depth in accordance with BMP T5.13 in Volume V, Chapter 5 of this manual (Will be used) 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 is infeasible because groundwater seepage was discovered at 3.5' below grade by the geotechnical engineer. 2. Rain Gardens in accordance with BMP T5.14A and Bioretention in accordance with Chapter 7 are infeasible because groundwater seepage was discovered at 3.5' below grade by the geotechnical engineer. 3. Downspout Dispersion Systems in the form of dispersion trenches in accordance with BMP T5.1013 are feasible and will be implemented for the building roof and impervious decks which will be down spouted to the building roof drains. Other Hard Surfaces: Full Dispersion in accordance with BMP T5.30 in Volume V, Chapter 5 of this manual. The site cannot meet the 100-fto flow paths for the site 2. Permeable pavement in accordance with BMP T5.15 in Chapter 5 of Volume V, (Permeable Pavement will not be used.) 3. Driveway dispersion will be used. Since the proposed existing driveway gravel area will only be paved, This runoff will continue to sheet flow towards the lake. Water quality: Since there is no new PGHS areas water quality is not required. BMP T5.13 "Post Construction Soil Quality and Depth" The top soils will be stockpile on -site and reused per "Implementation Options #3 per BMP T5.13 "Post Construction Soil Quality and Depth" which requires "Stockpile existing top soils during grading and replace it prior to planting... " (See work sheets "List of Figures") Duffy SFD Revised: October 11, 2022 Page 10 DS Ia FOO .-............... a-avc ROOF O � II rie Mi,UU3E j TING DRAIN PIPE + S �FTG DRAIN -. -.J 'DISCHARGE FLOW " \\ \ NEWTVPE ICB RIM 286,20 IE IN 284 0" PVC " IE OUTT 281.50 0" PERF OUT D o'PVC ._j ROOF DRN Y -05- SOFT LONG FLOW PATH INSTALL IP I ,M FODTING II" I -:' DRAINPIPE Ill �J TRENCH SOFT LONG DISPERSION 3 IL TRENCH QI EXISTING AC TO REMAIN r ti � ear f FLOW FLOW PL 21 EL Ot NA, L_.._.._....._ CITY LIMITQ: 1 _ I 1 1 O j jj I O; j Q I 7 _ i 4-0 jj V I I jj v i fj Q I 1 It V/ W j1 Q /1 I + f V ICI 1 I 7 + jl yI li +t i +1 L i 1 ++ I ___ .I .F _ _ (" SOU-H i--�-F - r --c-n a-. Section 6: SWPP Plan Narrative The topography of the site containing the proposed site improvements has moderate slopes. The soils have identified as atype C . With minimal disturbance and standard erosion control measures such as silt fence, straw mulching and hydro -seeding, the risk of erosion can be minimized. The limits of clearing will be restricted to the building site and lot. Greater source control measures would have to be taken during winter construction such as mulching or plastic sheeting. Good construction practices will prevent any sediment from leaving the site. The following are BMP measures to limit adverse impact upon the off -site drainage system: • Filter fabric fences, as required • Limited clearing area • Rock construction entrance pad • Seeding/ landscaping of any bare areas • Limited months of construction • On -Site Fueling (N/A No re -fueling will take place on -site) • Concrete Wash -out (per BMP C-151) Duffy SFD Revised: October 11, 2022 Page 12 THE 13 ELEMENTS OF A CONSTRUCTION SWPPP 1. Preserve Vegetation/Mark Clearing Limits: The clearing limits are indicated on the plan sheet. Furthermore, clearing and grading will be limited to only areas that need to be disturbed for grading/construction of the road surface to preserve as much natural vegetation as possible. Field marking the clearing limits shall be completed prior to clearing and grubbing activities. BMP's: Preserve Natural Vegetation (VEG) Field Marking Clearing Limits (CL) 2. Establish Construction Access: Access to the construction site shall be limited to the rock construction entrance. The construction entrance shall be extended to provide access to the construction vehicle/equipment staging and employee parking areas. BMP's: Stabilized Construction Entrance (CE) The project will use the existing paved driveway as the construction access. The project is not proposing to export soils from the site and will only be importing construction materials, therefore the amount of sediment is minimal. In addition, to install a rock construction pad would involve tearing up good pavement and having to haul in rock, then removal of the construction entrance resulting in more sediment than if the existing asphalt was left in place. 3. Control of Flow Rates: Storm water detention: No detention is proposed for the site since the increase in volume is less minimal 4. Installation of Sediment Controls: Sediment control will be provided through a combination of filtration through the surround on -site vegetation, filter fence, straw bails, BMP's: Silt Fence (FF) If required 5. Soils Stabilization: Temporary and permanent soil stabilization will be provided. Temporary stabilization will be provided through the application of straw and/or plastic sheeting to exposed, worked earth. From October 1 until April 30, no exposed soil may remain exposed and unworked for more than two days; after May 1, no exposed soil may remain exposed and unworked for more than seven days. BMP's: Plastic Sheeting, 6. Slope Protection: Slopes shall be protected from erosion through cover and prevention of concentrated surface runoff flows. BMP's: Plastic Sheeting, 7. Protection of Permanent Drain Inlets: Inlet protection will pe provided for all catch basins. BMP's: inlet protection will be provided on and downstream of site. 8. Stabilization of Channels and Outlets: All channel slopes shall be constructed and protected against erosion in accordance with City E.D.D.S. BMP's: None required 9. Pollutant Control: Pollutants shall be controlled as described in the Potential Pollutants section of this SWPPP. 10. Dewatering Control: De -watering: Interception of the water table is not expected to occur, even if there is an increase in precipitation. However, should ground water flows be encountered, the flows can be directed to on site native vegetation for cleanup. BMP's: Native vegetation (As Required) 11. BMP Maintenance: All BMP's and SWPPP elements shall be inspected daily and maintained as required. 12. Project Management: The project shall be managed in a cooperative effort by the project manager, contractor, engineer, and the City inspector. During the construction process, if unforeseen issues arise that cannot be resolved on site, construction activity (other than SWPPP maintenance) shall be halted and the City inspector and the project engineer are to be contacted and informed of the situation. 13. Protect On -Site Stormwater Management BMPs For Runoff From Roofs And Other Hard Surface On -site stormwater management BMPs used for runoff from roofs and other hard surfaces include: full dispersion, roof downspout full infiltration or dispersion systems, perforated stubout connections, rain gardens, bioretention systems, permeable pavement, sheetflow dispersion, and concentrated flow dispersion. The areas Duffy SFD Revised: October 11, 2022 Page 13 on the site to be used for these BMPs shall be protected from siltation and compaction during construction by sequencing the construction in a fashion to install these BMPs at the latter part of the construction grading operations, by excluding equipment from the BMPS and the associated areas, and by using the erosion and sedimentation control BMPs. BMP C 102: Buffer Zone Water Pollution Source Control Since the project is for residential lots, the project does not fall under the "High Use Sites" covering commercial or industrial sites. BMP C-151: Concrete Handling (Design and Installation Specifications) Concrete truck chutes, pumps, and internals shall be washed out only into formed areas awaiting installation of concrete or asphalt. Unused concrete remaining in the truck and pump shall be returned to the originating batch plant for recycling. Hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels shall be washed off only into formed areas awaiting installation of concrete or asphalt. Equipment that cannot be easily moved, such as concrete pavers, shall only be washed in areas that do not directly drain to natural or constructed stormwater conveyances. Washdown from areas such as concrete aggregate driveways shall not drain directly to natural or constructed stormwater conveyances. When no formed areas are available, washwater and leftover product shall be contained in a lined container. Contained concrete shall be disposed of in a manner that does not violate groundwater or surface water quality standards Maintenance Standards Containers shall be checked for holes in the liner daily during concrete pours and repaired the same day None required Section 7 Special Reports and Studies Section 8 Wetlands Protection All of the proposed improvements will be outside of the buffer area, thereby protecting the existing wetlands. Section 9 Operations and Maintenance The proposed stormwater system consists of a dispersion trench and catch basin. Duffy SFD Revised: October 11, 2022 Page 14 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 27 — GRAVEL FILLED DISPERSION TRENCH BMP Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Preventative Blocking, obstructions Debris or trash limiting flow to dispersion trench Dispersion trench able to receive full or preventing spreader function, flow priorto and during wet season. Site Trash and debris Trash or debris that could end up in the No trash or debris that could get into dispersion trench is evident. the dispersion trench can be found. Pipes Inlet is plugged The entrance to the pipe is restricted due to The entrance to the pipe is not sediment, trash, or debris. restricted. Vegetation/roots Vegetation/roots that reduce free movement of Water flaws freely through pipes. water through pipes. Plugged Sediment or other material prevents free flow of Water flaws freely through pipes. water through the pipe. Broken joint orjoint Damage to the pipe or pipe joints allowing water Pipe does not allow water to exit leaks. to seep out. other than at the outlet to the trench. Cleanout caps Cleanout caps are broken, missing, or buried. Cleanout caps are accessible and intact. Structure Flow not reaching Flaws are not getting into the trench as designed. Water enters and exits trench as trench designed. Perforated pipe Flaw not able to enter or properly exit from Water freely enters and exits plugged perforated pipe. perforated pipe. Flow not spreading Outlet flows channelizing or not spreading evenly Sheet flow occurs at the outlet of the evenly at outlet of from trench. trench. trench CleanoutAnspection The cleanout/inspection access is not available. CleanoutAnspection access is access does not allow available. cleaning or inspection of perforated pipe Filter Media Filter media plugged Filter media plugged. Flow through filter media is normal. Inspection Frequency Annually and prior to and following significant Inspect dispersion trench system for storms. any defects of deficiencies. 4/24/2016 A-36 2016 Surface Water Design Manual — Appendix A Duffy SFD Revised: October 11, 2022 Page 15 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 — CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60% of the depth from the Sump of catch basin contains no bottom of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than % cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch '/3 the depth from the bottom of basin to invert basin. the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases (e.g., methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Corner of frame extends more than 3/, inch past Frame is even with curb. and/or top slab curb face into the street (If applicable). Top slab has holes larger than 2 square inches Top slab is free of holes and cracks. or cracks wider than % inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than % inch of the frame from the top slab. Cracks in walls or Cracks wider than % inch and longer than 3 feet, Catch basin is sealed and is bottom any evidence of soil particles entering catch structurally sound. basin through cracks, or maintenance person judges that catch basin is unsound. Cracks wider than % inch and longer than 1 foot No cracks more than '/4 inch wide at at the joint of any inlet/outlet pipe or any the joint of inlet/outlet pipe. evidence of soil particles entering catch basin through cracks. Settlement/ Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than % inch at the joint of the No cracks more than '/<-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the catch basin at the joint of the inlet/outlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than % inch at the joint of the No cracks more than Y.-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 2016 Surface Water Design Manual — Appendix A A-9 4/24/2016 Duffy SFD Revised: October 11, 2022 Page 16 APPENDIX A Soils Management Form Soils Option 3 Duffy SFD Revised: October 11, 2022 Page 17 Use Achieving the Post -construction Soil Standard booklet Project Information Complete all information on page 1, onlysite address and permitnumberon additional pages. Site address/Lot Snoh No. Permit Type Single Family Permit Number Permit Holder Phone Mailing Address Contact Person Richard Deccio P.E. Phone 206-390-8374 Plan Prepared By Richard Deccio P.E. Attachments -attach the following to this plan: * Scale stormwater site plan drawings that include areas to be treated with Soil Treatment Options 1, 2, 3,4. * Completed Compost and Topsail Calculation Worksheet results. * Original compost and/or topsoil test results reports demonstrating that products contain adequate organic matter (for soil treatment options 2) and meet topsoil soil quality standard. Note. Retain original delivery tickets for compost and/or topsoil products for verifi cation purposes. Soil Treatment Options for Areas Identified on Site Plan Soil treatment options available: *Option 1 - Leave native soil undisturbed, and protect from compaction during construction. *Option 2 - Amend existing soil in place. *Option 3 - For native soil: stockpile site duff and topsoil, and reapply after grading and construction. *Option 4 - Import topsoil mix with 8-13%soil organic matter content. FC)R Pr), I ICF ()NI v Plan Approval Record I Reviewer. Required: Approved: Area: 1 Square footage: 2,600 Print Form (refer to lettered areas mapped on site plan) Selected soil treatment option: Option 1 ® Option 3 If using option 2, select type of amendment rate: Pre -approved (2") Custom with Organic Matter Option 2 Option 4 % Target Soil Area: (refer to lettered areas mapped on site plan) Square footage: Selected soil treatment option: ❑ Option 1 ❑ Option 2 ❑ Option3 ❑ Option4 If using option 2, select type of amendment rate: ❑ Pre -approved (2") ❑ Custom with % Target Soil Organic Matter Area: (referto lettered areas mapped on site plan) Square footage: Selected soil treatment option: ❑ Option 1 ❑ Option 2 ❑ Option 3 ❑ Option 4 If using option 2, select type of amendment rate: ❑ Pre -approved (2") ❑ Custom with % Target Soil Organic Matter Record the compost and/or topsoil products to be used Compost Product #1: Test Results % organic matter: Quantity in cubic yards Supplier Compost Product #2: Test Results % Quantity in cubic yards organic matter: Supplier Topsoil Product #3: Test Results Quantity in cubic yards organic matter: Supplier r Topsoil Product #4: Date: Reviewer: Approved: Test Results % Revisions Required: organic matter: Supplier Totalcubicyards compost: Quantity in cubic yards Total cubic yards topsoil: Duffy SFD Revised: October 11, 2022 Page 18 Option 4 Native Soil — stockpile site duff and topsoil and reapply after grading and construction. • Enter lettered areas from site plan where this option will be used: LOT A • Enter combined square footage of lettered areas in thousands 2.5 (example: for 4,525 sq ft, enter 4.525; for 500 sq ft, enter 0.5) • Multiply combined square footage by 25 and enter product in box B B 65 CYDS AMOUNT OF TOPSOIL TO BE STOCKPILED AND REAPPLIED IN THESE AREAS Import topsoil. • Enter lettered areas from site plan where this option will be used: • Enter combined square footage of lettered areas in thousands (example: for 4,525 sq ft, enter 4.525; for 500 sq ft, enter 0.5) • Multiply combined square footage by 25 and enter product in box C: Cj =Cubic Yards AMOUNT OF IMPORTED TOPSOITHESE NEEDED FOR THESE AREAS Order These Amounts: • Enter amount in Box A: Cubic Yards of Compost • Enter amount in Box C : Cubic Yards of Topsoil Note: MR 5 is triggered on sites with more than 2,000 sq. ft. of new, replaced, or new plus replaced impervious surface, or 7,000 sq. ft. or greater of land disturbing activity. Effective September 30, 2010 S:ICSCIDocument WarehouselFORMSICurmnt FormslCompostond Topsoil Calculation Worksheet 9 13 10.docx Duffy SFD Revised: October 11, 2022 Page 19