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APVD STM RESUB 3-BLD2023-0168+Storm_Drainage_Report+10.12.2023_1.42.38_PM+3838121WESI Land Use "Consultants PLANNING • ENGINEERING • SURVEYING 9740 Evergreen Way • Everett, WA 98204 425-356-2700 INFO@WESLCO RESUB Oct 12 2023 CITY OF EDMONDS DEVELOPMENT SERVICES DEPARTMENT TARGETED STORMWATER DRAINAGE REPORT for Bolotin Addition BLD2023-0168 18230 911t Avenue W Edmonds, WA 98026 BLD2023-0168 ISSUE DATE: February 7, 2023 REVISIONDATE: September 21, 2023 ORIGINAL PREPARED & REVIEWED BY - TIMOTHY A. SARKELA, P.E. REVISED BY.- NICK BRESKE, E.T. REVIEWED BT RANDOLPH R SLEIGHT, P.E. OWNER Sofia & Vladimir Bolotin 18230 91st Avenue W Edmonds, WA 98026 Office: (425) 551-9193 Email: sofikland@gmail.com 70--12-23 ENGINEER WESI Land Use Consultants. Job # 22-0801-A COMPLIES WITH APPLICABLE CITY STORMWATER CODE 10/20/2023 WESI Land Use Consultants, LLC ©2023 Bolotin Addition TABLE OF CONTENTS SITE OVERVIEW Page ExecutiveSummary.......................................................................... 2 ExistingConditions........................................................................... 2 VicinityMap...................................................................................... 3 Impervious Area Exhibit .................................................. 4 Figure 3.1 Applicability....................................................5 MINIMUM REQ. #1 MINIMUM REQ. #2 SWPPP Narrative .................................................... 7 MINIMUM REQ. #3 Water Pollution Source Control ............................. 8 MINIMUM REQ. #4 Natural Drainage System & Outfalls..................... 8 Upstream/Downstream Analysis...................................................... 8 DrainageComplaints........................................................................ 8 Basin& Aerial Maps......................................................................... 9 MINIMUM REQ. #5 On -Site Storm Water Management ....................... 8 MINIMUM REQ. #6 Runoff Treatment .................................................... 9 MINIMUM REQ. #7 Flow Control...........................................................10 MINIMUM REQ. #8 Wetland Protection................................................10 MINIMUM REQ. #9 Operations & Maintenance ................................... It APPENDIX I — Drainage Plan...................................................................14 APPENDIX II — Soil Information.............................................................16 WEST Land Use Consultants, LLC I PROJECT: 22-0801-A Bolotin Addition Site Overview Executive Summary The proposed project consists of clearing/grading for the construction of a new single- family residence addition, and an associated driveway and drainage improvements. Drainage management for new roof areas is to consist primarily of BMP T5.1 OB. Drainage management for new driveway and walkway areas will consist of dispersion per BMP T5.11. The project is to be designed to the DOE 2019 Stormwater Management Manual for Western Washington along with city of Edmonds 2022 Stormwater Manual Addendum, and is classified as Category 1 in the City of Edmonds 2022 Stormwater addendum. Existing Conditions Summary The property is a one tax parcel and currently contains a single-family residence with driveway and patio improvements. Vegetation on -site consists of residential lawn areas, and partial tree covering. Slopes on -site are moderate, ranging from 8% to 20%, and sloping northwesterly. From a Snohomish County Soil Survey done by USDA the soils on -site consist of Alderwood Urban Land Complex type soils. Refer to Appendix II for soil information. Surrounding parcels are developed with existing SFRs and driveways. Vegetation in the surrounding area is comprised primarily of residential lawn and second/third growth forest. WESI Land Use Consultants, LLC 2 PROJECT: 22-0801-A Bolotin Addition VICINITY MAP 01d?WSJ: tt Park 187th St SW MAP TAKEN FROM GOOGLE MAPS WESI Land Use Consultants PLANNING • ENGINEERING • SURVEYING 1851h PI SW BOLOTIN ADDITION EDMONDS 98026 SCALE: DATE: 02/07/23 1" = 500' JOB NUMBER: BY: TAS 22-0801-A 186th PI SW CHECKED: TAS FILE NAME: 220801A/VICINITYMAP WESI Land Use Consultants, LLC 3 PROJECT: 22-0801-A PROPOSED ROOFTOP = 1,586 SF PROPOSED CONCRETE DRIVEWAY = 98J SF PROPOSED DECK = J72 SF EXIS77NG ROOFTOP = 2,061 SF EXIS71NG BRICK WALK = 807 SF EXIS77NG GRAVEL DRIVE = 3,417 SF EXISTNG SHED ROOF = 150 SF EXISTING ASPHALT = 374 SF TOTAL NEW IMPERVIOUS AREA = 2,919 SF TOTAL EXIS7NG IMPERVIOUS AREA = 6,809 SF -0.25 RE77?0 => 1,702.5 SF REPLACED ROOFTOP AREA (Existing House) = 1,536 SF PREPARED BY.• WEST LAND USE CONSULTANTS 9740 EVERGREEN WAY EVERETT, WA 98204 PHONE. (425) 356-2700 WWW. WESI. CO MITIGA7ED IMPERVIOUS TOTAL = 6,157 SF IMPERVIOUS AREA EXHIBIT TAX NO.00528600000700 S17E ADDRESS. • 182JO 91ST AVE W, OWNER. SOFIA BOL07IN EDMONDS, WA ISSUE DA7F• 02-28-23 Bolotin Addition BASIN AND AERIAL MAPS WESI Land Use Consultants, LLC 5 PROJECT: 22-0801-A 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 I No Minimum Requirements No. 1 through 5 apply I Minimum Requirement No. 2 applies Next Question Does the project add 5,000 square feet or more of new plus replaced hard surfaces? OR Convert 0.75 acres or more of vegetation to lawn or landscaped areas? OR Convert 2.5 acres or more of native vegetation to pasture? No Yes Is this a road related project? All Minimum Requirements apply to the new and replaced Yes hard surfaces and converted vegetation areas. All Minimum Requirements apply to the new hard surfaces and converted vegetation areas. No Yes Does the project add 5,000 square feet or No more of new hard surfaces? Yes Do new hard surfaces add 50% or more to the existing hard surfaces within the project limits? No Figure 3.1. Flow Chart for Determining Requirements for Development. No additional requirements. 8 3. APPLICABILITY OF THE MINIMUM REQUIREMENTS Bolotin Addition Minimum Requirement #1: Preparation of Site Plan Site plan prepared in accordance with 2019 SWMMWW requirements. Minimum Requirement # 2: SWPPP Narrative Element #1: Mark Clearing Limits Clearing limits have been shown on the Temporary Erosion and Sedimentation Control Plans. To be marked with Hi-Vis orange fencing per BMP C-103 Element #2: Establish Construction Entrance The existing driveway will serve as temporary construction entrance. All vehicles shall be free of debris prior to leaving the site. BMP C-105 Element # 3: Control Flow Rates Flow rates during construction are to be contained through the installation of silt fencing along the northwestern clearing limits and Sediment traps per BMP C-240. Element # 4: Install Sediment Controls Sediment controls mainly consist of installing silt fencing along the northwestern clearing limits along with sediment traps per BMP C-240 Element # 5: Stabilize Soils All soils disturbed during site grading will be stabilized by use of the most appropriate BMP method available. Methods consist of straw covering over the soils or permanent/ temporary seeding. At this time no wintertime grading or construction activities will occur. During construction periods longer than 1 working week (7 days) where the soils are exposed and un-worked will use the proscribed methods in the Storm Water Management Manual for Western Washington to reduce sedimentation transported offsite. If winter grading is conducted, all exposed soils shall be covered within 2 days. BMP C-121 Mulching, BMP C-123 Plastic covering. Element # 6: Protect Slopes Mulching of exposed soils BMP C-121. Element # 7: Protect Drain Inlets Downstream inlets will be protected with catch basin inserts or equivalent. BMP C-220 Element # 8: Stabilize Channels and Outlets The need for channel stabilization is not expected but, existing channels or drainage outlets located within 500-feet of the property of the property should be routinely inspected for debris that may dam and/or aid erosion. Element # 9: Control Pollutants All pollutants from construction vehicles will be contained and disposed of in the approved manner consistent with state environmental policies. Any vehicle maintenance will be performed by authorized mechanics using drip pans and waste containment vessels. All pollutants will be disposed offsite at approved facilities. BMP C-153 WESI Land Use Consultants, LLC 7 PROJECT: 22-0801-A Bolotin Addition Element # 10: Control De -Watering De -watering of the site is not expected. If dewatering of the site is needed, all groundwater removed shall be retained and recharged into the ground after de -watering has been finalized. Element # 11: Maintain BMPs All Temporary Erosion and Sedimentation Control (TESC) devices and equipment will be inspected and maintained on a weekly basis if not sooner, based on storm events contributing to runoff. When construction is complete and the site is stabilized, any existing sediment will be removed and stabilized onsite. BMP C-150 Element # 12: Manage the Project A general construction manager will manage the project for or by the owners. The construction manager shall maintain all of the above items in order to minimize sediment transport and turbid water leaving the site. His job will entail continual observation of the grading operations to ensure minimal effects to adjacent properties and offsite waterways. BMP C-150 Element # 13: Protect On -Site Stormwater Management BMPs Stormwater management mainly consists of dispersion and soil amendment BMPs. Soil amendment areas will be protected from siltation and compaction when feasible. BMP C- 103 Minimal Requirement # 3: Water Pollution Source Control ECDC 18.30.060.D.3 and SWMMWW Volume IV. Note that all single-family residential projects shall incorporate required applicable source control BMPs from SWMMWW Volume IV, which may include: • S411 — BMPs for Landscaping and Lawn/Vegetation Management. • S433 - BMPs for Pools, Spas, Hot Tubs, and Fountains • S438 - BMPs for Construction Demolition • S440 - BMPs for Pet Waste • S441 - BMPs for Fertilizer Application • S452 - BMPs for Building, Repair, Remodeling, Painting, and Construction Minimum Requirement # 4: Preservation of Natural Drainage Systems and Outfalls, and provisions of off -site mitigation Upstream Analysis From available topographic elevation information acquired, upstream runoff will originate in the form of both sheet flows as well as subsurface flows coming from the adjacent parcels to the east majority of which consist of residential lawn, driveway, and roof areas. No other runoff appears to enter the site and no erosion due to existing runoff was observed. WESI Land Use Consultants, LLC 8 PROJECT: 22-0801-A Bolotin Addition Downstream Analysis Refer to the aerial map in the next section of this report for a depiction of runoff paths. The entire property tends to slope westerly towards adjacent parcels to the west. Runoff then continues approximately 300 feet northwesterly towards Olympic View Drive. The runoff continues approximately 2,500 feet southerly to the intersection of Wharf Street. The runoff then flows approximately 800 feet westerly into Puget Sound. As this is the closest receiving water, no further downstream analysis is required. Drainage Complaints There are no known drainage complaints for this site. No changes to the existing drainage systems and outfalls are proposed with this development. All proposed runoff from the project area is to be mitigated with LID BMPs and is assumed "lost" at features' extents. Minimum Requirement #5 On -Site Storm Water Management Due to the project proposing less than 5,000 sf of new hard surfaces, the project is considered Medium Impact and 2019 DOE Manual Minimum Requirements 1 through 5 must be evaluated. Per 2019 Stormwater Management Manual for Western Washington Volume 1 Section 2.5.5 the project will fulfill the requirements of List #1 of that section and the following BMPs must be implemented when feasible: Lawn and landscaped areas: • Post -Construction Soil Quality and Depth in accordance with BMP T5.13 in Chapter 5 of Volume V. WESI Land Use Consultants, LLC 9 PROJECT: 22-0801-A Bolotin Addition Roofs feasibility description: 1. Full Dispersion per BMP T5.30 or Downspout Full Infiltration per BMP T5.10A. i. Full Dispersion is infeasible due to a lack of native vegetation. The site consists almost entirely of residential lawn, which does not allow for the retention of 65% of the site in a forested or native condition. ii. Full Infiltration is infeasible for most of the site. Within 50 feet of the top of slopes greater than 15 percent. 2. Rain Gardens per BMP T5.14 or Bioretention per BMP T7.30. i. Rain Garden infiltration is infeasible for most of the site. Where the site cannot be reasonably designed to locate bioretention/rain garden areas on slopes less than 8 percent. 3. Downspout Dispersion Systems in accordance with BMP T5.1 OB. i. New residential roof drains & existing Garage will drain to downspout splash blocks with 50' vegetated flow paths 4. Perforated Stub -out Connections in accordance with BMP T5.1 OC. i. N/A, previous BMPs selected for roof areas. Other Hard Surfaces feasibility description: 1. Full Dispersion per BMP T5.30 i. As noted above, Full Dispersion is infeasible due to a lack of native vegetation. On -site vegetation is almost entirely residential lawn, which does not allow for the retention of 65% of the site in a forested or native condition. 2. Permeable Pavement per BMP T5.15, or Rain Gardens per BMP T5.14, or Bioretention per BMP T7.30. i. Permeable Pavement, Rain Garden, and Bioretention infiltration is infeasible for most of the site. the site cannot be reasonably designed to locate bioretention/rain garden areas on slopes less than 8 percent. 3. Sheet Flow Dispersion in accordance with BMP T5.12 or BMP T5.11. i. Driveway areas will be directed towards transition zones to vegetated flow paths or compost amended flow paths as prescribed on the corresponding drainage plan. BMP T5.10B Downspout Dispersion Systems has been selected for proposed roof areas and will consist of four (4) downspout splash blocks with 50' flow paths for most of the SFR roof areas. See below for sizing: Downspout Splash block Mitigation Existing and Proposed Roof Area to Splash Blocks x 4 1 Required Per 700 SF Roof Area x 3 = 2,100 SF Mitigated rooftop + 526 SF ex garage trade off = 2,626 SF mitigated roof New Rooftop = 1,586 SF Replaced Rooftop = 1,536 SF Total rooftop to be mitigated = 3,122 SF — 2,626 = 496 SF to be traded off for mitigation of existing unmitigated driveway. See below. WESI Land Use Consultants, LLC 10 PROJECT: 22-0801-A Bolotin Addition Other Hard Surface Mitigation Proposed Concrete Driveway= 962 SF Existing Hardscape=6,809 SF x 25% retrofit = 1,702.5 SF for mitigation Rooftop Mitigation Remaining = 496 SF Proposed Deck Trade off = 372 SF Total Proposed Other hard Surface mitigation = 3,532.5 SF Retrofit/Trade off Catchment Area = 2,577 SF existing gravel drive Total area mitigated by BMP T5.11= 3,537 SF > 3532.5 Required ok Additionally, all disturbed pervious areas are to be amended per BMP T5.13. Minimum Requirement # 6: Runoff Treatment Due to less than 5,000 sf of pollution generating hard surfaces and less than 3/4 of an Acre of pollution -generating pervious surfaces, runoff treatment is not required. WESI Land Use Consultants, LLC 11 PROJECT: 22-0801-A Bolotin Addition Minimum Requirement # 7: Flow Control Due to the project proposing less than 5,000 sf new/replace hardscape and less than 3/4 acres conversion of native vegetation to lawn, flow control requirements do not apply. Minimum Requirement # 8: Wetland Protection No known wetlands onsite, however potential downstream wetlands will be protected with onsite BMP's. Wetland protection is not required. Minimum Requirement # 9: Operation and Maintenance WESI Land Use Consultants, LLC 12 PROJECT: 22-0801-A Table V-A.S: Maintenance Standards - Catch Basins Maintenance Defect Conditions When Maintenance is Needed Results Expected When Maintenance is per - Component formed Trash or debris which is located immediately in front of the catch basin opening or is blocking inletting capacity of the basin by more than 10%. No Trash or debris located immediately in front of Trash or debris (in the basin) that exceeds 60 percent of the sump depth as measured from the bottom of basin to invert of the lowest pipe into or out of the catch basin or on grate opening. basin, but in no case less than a minimum of six inches clearance from the debris surface to the invert of the lowest pipe. No trash or debris in the catch basin. Trash & Debris Trash or debris in an inlet or outlet i blocking more than 1/3 of its height. Y pipe 9 9 Inlet and outlet pipes free of trash ordebris. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within the catch basin. Sediment (in the basin) that exceeds 60 percent of the sump depth as measured from the bottom of basin to invert of the lowest pipe into or out of the Sediment basin, but in no case less than a minimum of 6 inches clearance from the sediment surface to the invert of the lowest pipe. No sediment in the catch basin General Structure Damage to T slab has holes lar er than 2 square inches or cracks wider than 1/4 inch. Intent is to make sure no material is running into basin W 9 Q ( 9 )� Top slab is free of holes and cracks. Frame and/or Top Slab Frame not sitting flush on top slab, i.e., separation of more than 314 inch of the frame from the top slab. Frame not securely attached Frame is sitting flush on the riser rings or top slaw and firmly attached. Fractures or Cracks in Maintenance person judges that structure is unsound. Basin replaced or repaired to design standards. Basin Walls/ Bottom Grout fillet has separated or cracked wider than 1/2 inch and longer than 1 foot at the joint of any inleVoutlet pipe or any evidence of soil particles entering Pipe is regrouled and secure at basin wall. catch basin through cracks. Settlement/ Mis- alignment If failure of basin has created a safety, function, or design problem. Basin replaced or repaired to design standards. Vegetation growing across and blocking more than 10% of the basin opening. No vegetation blocking opening to basin. Vegetation Vegetation gnawing in inleUoullel pipe joints that is more than six inches tall and less than six inches apart. No vegetation or root growth present. Contamination and Pd- See Table V-A.1: Maintenance Standards - Detention Ponds No pollution present. INion Cover Not in Place Cover is missing or only partially in place. Any open catch basin requires maintenance. Cover/grate is in place, meets design standards, and is secured Catch Basin Lacking Mechanism Mechanism cannot be opened by one maintenance person with propertools. Bolts into frame have less than 1/2 inch of thread. Mechanism opens with proper tools. Cover Not Working Cover Difficult to One maintenance person cannot remove lid after applying normal lifting pressure. Cover can be removed by one maintenance per - Remove (Intent is keep cover from sealing off access to maintenance.) son. Ladder Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, not securely attached to basin wall, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows main- tenance person safe access. Grate opening Unsafe Grate with opening wider than 7/8 inch. Grate opening meets design standards. Metal Grates Trash and Debris Trash and debris that is blocking more than 20% of grate surface inletting capacity- Grate free of trash and debris. (If Applicable) Grate is in place, meets the design standards, and Damaged or Missing. Grate missing or broken member(s) of the grate. is installed and aligned with the flow path. Table V-A.6: nance Standards - Debris Barriers (e.g., Trash Racks) Maintenance Components Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed General Trash and Debris Trash or debris that is plugging morethan 20% of the openings in the barrier. Barrier cleared to design flow capacity. Bars are bent out of shape more than 3 inches. Bars in place with no bends more than 314 inch. Damaged[ Missing Bars. Bars are missing or entire barrier missing. Bars in place according to design. Metal Bars are loose and rust is causing 50% deterioration to any part of barrier. Barrier replaced or repaired to design standards. Inlet/OutletPipe Debris barrier missing ornot attached to Pipe Barrier firmly attached to pipe Table V-A.7: Maintenance Standards - Energy Dissipators Maintenance Com- Defect Conditions When Maintenance is Needed Results Expected When Maintenance is ponents Performed External Rock Pad Missing or Moved Rock Only one layer of rock exists above native soil in area five square feet or larger, or arry exposure of native sal. Rock pad replaced to design standards. Erosion Soil erosion in or adjacent to rock pad. Rock pad replaced to design standards. Pipe Plugged with Sediment Accumulated sediment that exceeds 20% of the design depth. Pipe cleaned/flushed so that it matches design. Not Discharging Water Propedy Visual evidence of water discharging at concentrated points along trench (normal condition is a "sheet flow" of water along trench). Trench redesigned or rebuilt to standards. Intent is to prevent erosion damage. Dispersion Trench Perforations Plugged. Over 1/2 of perforations in pipe are plugged with debris and sediment. Perforated pipe cleaned or replaced. Water Flogs Out Top of "Distributor" Maintenance person observes or receives credible report of waterflowing out during any storm less than the design storm or its causing Facility rebuilt or redesigned to standards. Catch Basin. or appears likely to cause damage. Receiving Area Over -Saturated Water in receiving area is causing or has potential of causing landslide problems. No danger of landslides. Internal_ Wore or Damaged Post, Baffles, Side Structure dissipating flow deteriorates to 112 of original size or any concentrated worn spot exceeding one square foot wl i _ ` :: _ u I d Structure replaced to design standards. ManholeChamber of Chamber make structure unsound. Other Defects See Table V-A.S: Maintenance Standards -Catch Basins See Table V-A.S: Maintenance Standards _ Catch Basins Bolotin Addition BMP T5.13 Post -Construction Soil Quality and Depth Maintenance • Soil quality and depth should be established toward the end of construction and once established, should be protected from compaction (i.e. from large machinery use and/or erosion) • Soil should be planted and mulched after installation. • Plant debris or its equivalent should be left on the soil surface to replenish organic matter. WESI Land Use Consultants, LLC 15 PROJECT: 22-0801-A Bolotin Addition APPENDIX I Drainage Plan WESI Land Use Consultants, LLC 16 PROJECT: 22-0801-A 2' MIN. R DRIVEWAY r FILTER FABRIC CLEAN (<57. FINES) BOTTOM & SIDES 1-1/2" - 3/4' WASHED DRAIN ROCK 6" MIN. AMENDED SOIL 0 nI TRANSITION ZONE DETAIL WIRE / FENCE SET REBAf /CAP h / o' APPR� PE U) U) N. T. S. if NW 114, NW 114, SEC. 18, T.27N, R. 04E, W.M. CITY OF EDMONDS, WASHINGTON FOUND REBAR/CAP N 83°38'23 LS# 35978 o ° w , 40"CED 0.33'N OF LINE & I FOUND 1.5" IP — D"�'� , F'� °�� / 8' C �� 7' DEED)11 01 O 0.2� OF PROP COR I /� 0.45' OF LINE / — _ "�' 32' ED a — / -t FACE ENDS 0.5'N lr�,.OF rROP CORp Q; _ _ / _ 0 10 OF\ LINE & 5.1'W I // 8' //• / — _ — — _ OIjL''NE 1. FF OM PROP COR I / / p / GRAVEL / I / � FOUN 1" IP DRIVE o 1.48'S F LINE I 1 /_ .. •/ � � / \ \ 4.70'� FROM I 40'CED / \ \ PROP COR / 0 (FOUND 1.5" IP / 1.5,6'S OF LINE R/ S D ` 4�8'W FROM J / �v F'PROX. LOC. — — — /r OP 6R LECTRIC EASEMENT / I / PER REC. NO. 992937 12 HL / cNo INGRESS, L/GR SS, o tK / `r UTILITIES EA9EM T PE Izo / �REC./N0. 07 684 TED I \\ I If 10' / I' 5'CE I� of / I F - \� 14 ED / � FI / ( 72'CED / F IPA/ �\. : I O'CEDO / 12 ED O WOOD RICK // GR�W I / L STAIR �/ o T . SITI N ZONE / � 44' D Y I / / / ROUTE SPLASH BLOCK TO SHEET F _ / ye OVER BRICK INTO VEGETATION I l l REMOVE BRICK VID EGETATE / I cK / / 36'CED O \ 00� / FLOW PATH OF/ TRADE-OFF GARAGE "' ''� CATCHMENT AREA / WIRE 1,369 SF FENCE DECK / �tK• / \ JF/ ROAD EASEMENT PAR RE ,v cV Y / MODULAR BLOCK / ADDITIO �'L �P F I a0 WALL PER / �, / NO.' 809468 do 989780 o / ARCHITECTURAL / / �' 1 / - / PLANS / / � EL=259.90 C, I L,� 8' C E Id 2' GRAVEL I I / T SITION ZONE.. EL=262.00 I / 2' GRAVEL TRANSITION ZONE 9 L Q / 2' GRAVEL / l 10' � I Z _. NTER� COMPOS TRANSITION ZON / VE EIA QHOUSE N. 1 .29 o FOOTPRINTO1,12830SF / // S R? STRIP -rI I \ _ FOUND REBAR/CAP APPROX.PER AS BULL' / \ / // / F %K I 0\ 9'EOOFOLINE / / \ SPLASH BLOCK / F��2S d b 00 / - / / EL=259. 75 Q HIMNEY / PROPOSED Q / I I I 40',16'CED / �'DRIVEWAY ��OZ � / 10' ' : � I I O 30'C�D CS F D REBAR/CAP `L _ / / WIRE Q EL_260,09 D�� EGETATE SSMH / 2969 %/ / /�° I 4 SQ LS1 / LTER III I I RIM=265.42' / \ //`� // Oa �PG�� // 1 I I ----- I E(N) 8"CONC .° 0.62' E OF LINE& / `�' (TBR) � � � P a IE(S,E) 6"GONG / 6 D 0.74' E OF �,� oa W00 �/ ` ro o 30 C �/ I' I \ I=257.17'(C.C.) 50C/ELL MR%d�l / SPLA H BLOCK <" �( o O F F I ) T� 4'CED 6 CED / / ��ON / // 34'CED TZ m 4'EVG 0' OWP EL 6RIC EASEMENT PER 2 o RC. N0. 199910250185 SHED TO INCLUDE ONE ITULAVLOCK WALL I >> I I / EV-READY STALL PER / ECDC 17.115.040 SHED cL/ ANTICIPATED WATER SERVICE / k, LOCATION. CONTRACTOR TO CALL' LOCATE SERIVCES AND VERIFY / I .. I O / 8s�R� / PRIOR TO WORK ON -SITE. / I I I ro FENCE END 0.4'S (METER ON 184TH ST SIN // I o I- 0 F CE END / // `tio/ .2'S OF LI / SPLA BLOCK /E 10' I I I ELECTRIC EASEMENT PER LRL / / VEGETATED Z I i REC. NO. 199910250186 ° / / FLAPW PATH o I ' I . o' 8',6'L/RL / !y / I I STEVERTTBM N 6 O 8'L L / / E I I ELEV=269.11' �s9, 0 i \ / WOOD4.4 8 00' tv 2� 10'LRL Ty F o I 111I���666 CA 8 07' O / `L/ WIRE C) <- / a FENCE / / i i I SANITARY/STORM EASEMENT (PER I TITLE) PER REC. N0. 1964433 COMPOST AMENDED EN CE AL o I � . VEGETATED FILTER STRIP N LINE / F 2' MIN. DRIVEWAY 1-2% / I / 1. /\/�\\,�\\/\/ / o / �. F I 6" COMPOST 77LLED INTO' ._ _ \\� 44 �.~ \� FILTER FABRIC I l / 1.2 ' NATIVE SOIL FOR CAFVS \\ BOTTOM & SIDES � / CLEAN <59 FINES \ 6' MIN. AMENDED SOIL 1-1/2" - 3/4" WASHED\\�\\i\\\i\\\� 72'CED I / SET DRAIN ROCKTRANSITION ZONE W/ COMPOST AMENDED VEGETATED FILTER STRIP DETAIL N. T. S. Know what's below. Call 811 two business days before you dig. REBAR/CAP 1. GVL. 'AS � a� I a � 7.7' �I � a a 02-08-2023 PROPOSED NEW ROOFTOP = 1,586 SF PROPOSED CONCRETE DRIVEWAY = 983 SF — — PROPOSED DECK = 372 SF EXISTING ROOFTOP = 2,061 SF Jill EXISTING BRICK WALK = 807 SF EXISTING GRAVEL DRIVE = 3,417 SF EXISTING SHED ROOF 150 SF F EXISTING ASPHALT - - 374 SF TOTAL NEW IMPERVIOUS AREA = Z919 SF TOTAL EXISTING IMPERVIOUS AREA = 6,809 SF 0.25 RETRO => 1,702.5 SF REPLACED ROOFTOP AREA = 1,536 SF M171GATED IMPERVIOUS TOTAL = 6,157 SF IMPERVIOUS AREA EXHIBIT 8" Min. Well Draining Soil Keystone Cap Unit /Keystone Compac Unit Unit Drainage Fill 1" - 1 114" 1-j" Washed _ 8" Finished Grade Rouned Rock) r N Filter Fabric top, side, & bottom i Unreinforced Concrete or 6" Perforated PVC Crushed Stone Leveling Pad Drainage with holes up. MODULAR BLOCK (KEYSTONE) WALL N. T. S. SCALE. 1" = 10' 0 10 20 LE_ EXISTING BUILDING EXISTING GRAVEL EXISTING PROPERTY BOUNDARY EXISTING EDGE OF ASPHALT ,,, - — — — — — — - EXISTING EASEMENT EXISTING SANITARY SEWER LINE SS PROPOSED BUILDING W/ ROOF OVERHANG PROPOSED DRIVEWAY TAX ACCOUNT NO. (S): SITE ADDRESS: 27041800200300 18230 91ST AVENUE W EDMONDS, WA 98026 COPMGHT © 2023 JWESI (425) GRADING, DRAINAGE AND LANDSCAPE PLAN FOR: LAND USE BOLOTIN ADDITION CONSULTANTS 356-2700 NW 114, NW 114, SEC 18, T.27N, R.04E, W.M. CITY OFEDMONDS, WASHINGTON PLANNINGOENGINEERING OSURVEYING DRAWN BY DATE REV. BY DATE PROJECT MANAGER SCALE * 9740 EVERGREEN WAY * EVERETT * WA * 98204 * TAS 02/07/23 T. SARKELA 1 "=10, DRAWING FILE NAME CHECKED BY F.B. NO. JOB NUMBER SHEET NO. VISIT OUR WEBSITEAT.• WWW.WESI.CO 220801ABASEDWG TAS - 22-0801-A 3 OFS Bolotin Addition APPENDIX II SOIL INFORMATION WESI Land Use Consultants, LLC 18 PROJECT: 22-0801-A Bolotin Addition USDA Soil Man: Snohomish County Area, Washington (WA661) Snohomish County Area, Washington (WA661) Map Acres Percent of Unit Map Unit Name in A0I A01 Symbol 3 Alderwood 0.7 90.7% gravelly sandy loam, 15 to 30 _ percent slopes 6 Iderwood-Urban 0.1 9.3% land complex 8 to 15 ercen • slo es Totals for Area of 0.7 100.0% t � Interest 4 t 40 � r 00 WESI Land Use Consultants, LLC 19 PROJECT: 22-0801-A Bolotin Addition Snohomish County Area, Washington 3—Alderwood gravelly sandy loam, 15 to 30 percent slopes Map Unit Setting • National map unit symbol: 2t627 • Elevation: 0 to 1,000 feet • Mean annual precipitation: 25 to 60 inches • Mean annual air temperature: 46 to 52 degrees F • Frost -free period: 160 to 240 days • Farmland classification: Farmland of statewide importance Map Unit Composition • Alderwood and similar soils: 85 percent • Minor components: 15 percent • Estimates are based on observations, descriptions, and transects of the mapunit. Description of Alderwood Setting • Landform: Hills, ridges • Landform position (two-dimensional): Backslope • Landform position (three-dimensional): Nose slope, side slope, talf • Down -slope shape: Convex, linear • Across -slope shape: Convex • Parent material: Glacial drift and/or glacial outwash over dense glaciomarine deposits Typical profile • A - 0 to 7 inches: gravelly sandy loam • Bw1 - 7 to 21 inches: very gravelly sandy loam • Bw2 - 21 to 30 inches: very gravelly sandy loam • Bg - 30 to 35 inches: very gravelly sandy loam • 2Cd1 - 35 to 43 inches: very gravelly sandy loam • 2Cd2 - 43 to 59 inches: very gravelly sandy loam Properties and qualities • Slope: 15 to 30 percent • Depth to restrictive feature: 20 to 39 inches to densic material • 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 37 inches • Frequency of flooding: None • Frequency of ponding: None • Available water supply, 0 to 60 inches: Very low (about 2.7 inches) WEST Land Use Consultants, LLC 20 PROJECT: 22-0801-A Bolotin Addition Interpretive groups • Land capability classification (irrigated): None specified • Land capability classification (nonirrigated): 4e • Hydrologic Soil Group: B • Ecological site: F002XA004WA - Puget Lowlands Forest • Forage suitability group: Limited Depth Soils (G002XN302WA), Limited Depth Soils (G002XF303WA), Limited Depth Soils (G002XS301WA) • Other vegetative classification: Limited Depth Soils (0002XN302WA), Limited Depth Soils (G002XF303WA), Limited Depth Soils (G002XS301WA) • Hydric soil rating: No Minor Components Everett • Percent of map unit: 5 percent • Landform: Moraines, eskers, kames • Landform position (two-dimensional): Backslope • Landform position (three-dimensional): Side slope • Down -slope shape: Convex • Across -slope shape: Convex • Hydric soil rating: No Indianola • Percent of map unit: 5 percent • Landform: Terraces, kames, eskers • Landform position (three-dimensional): Tread • Down -slope shape: Linear • Across -slope shape: Linear • Hydric soil rating: No Shalcar • Percent of map unit: 3 percent • Landform: Depressions • Landform position (three-dimensional): Dip • Down -slope shape: Concave • Across -slope shape: Concave • Hydric soil rating: Yes Norma • Percent of map unit: 2 percent • Landform: Drainageways, depressions • Landform position (three-dimensional): Dip • Down -slope shape: Linear, concave • Across -slope shape: Concave • Hydric soil rating: Yes 6—Alderwood-Urban land complex, 8 to 15 percent slopes Map Unit Setting • National map unit symbol: 2hzn • 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 WEST Land Use Consultants, LLC 21 PROJECT: 22-0801-A Bolotin Addition Map Unit Composition • Alderwood and similar soils: 60 percent • Urban land: 25 percent • Minor components: 5 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: 8 to 15 percent • Depth to restrictive feature: 20 to 40 inches to densic material • 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 supply, 0 to 60 inches: Low (about 3.0 inches) Interpretive groups • Land capability classification (irrigated): None specified • Land capability classification (nonirrigated): 4s • Hydrologic Soil Group: B • Ecological site: F002XA004WA - Puget Lowlands Forest • Forage suitability group: Limited Depth Soils (G002XN302WA) • Other vegetative classification: Limited Depth Soils (G002XN302WA) • Hydric soil rating: No Minor Components Norma, undrained • Percent of map unit: 5 percent • Landform: Drainageways • Other vegetative classification: Wet Soils (G002XN102WA) • Hydric soil rating: Yes WEST Land Use Consultants, LLC 22 PROJECT: 22-0801-A