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APPROVED STM RESUB 3-BLD2023-1355+Storm_Drainage_Report+10.18.2024_3.31.39_PM+4569304BLD2023-1355 MOMENTUM CIVIL ENGINEERING CONSULTANTS 1145 BROADWAY, SUITE 115 TACOMA, WA 98402 MOMENTUMCIVIL.COM (253) 319-1504 RESUB Oct 18 2024 FULKEPSON SINGLE FAMILY RESIDENCr- MC# VILL0001 Fulkerson single family residence 2024-10-09 VILL0001-Drainage Report.docx Drainage Report COMPLIES WITH APPLICABLE CITY STORMWATER CODE 11 /25/2024 MC# VILL0001 October 9, 2024 Drainage Report Page 1 of 25 Drainage Report October 9, 2024 Prepared for: Signature Homes by Village Life, LLC Point of Contact: Kevin Ballard Village Life, Inc 19020 33rd Ave W Suite 450 Lynnwood, WA 98036 Email: kevin@avillage-life.net Phone: (425) 530-6700 Civil Engineer: Momentum Civil 1145 Broadway, Suite 115 Tacoma, WA 98402 Prepared by: Jazmin Santos Email: jazmins@momentumcivil.com Q/A by: Drew Harris, P.E. Email: drewh@momentumcivil.com Phone: 253-319-1506 ",\ Atik� MC# VILL0001 Drainage Report Fulkerson single family residence Page 2 of25 2024-10-09 VILL0001-Drainage Report.docx Table of Contents Project Overview 3 Conditions and Requirements 5 Minimum Requirements 6 Offsite Analysis 8 Resource review 8 Upstream basin 8 Downstream analysis 9 Other Permits 9 Operations and Maintenance Manual 9 Appendices Appendix A Resource Review Documents 14 Appendix B Existing Offsite Flow Path 16 Appendix C Site Maps 22 Appendix D ESNW Report for ES-9363 Dated September 29, 2023 23 Appendix E S411 BMP's for Landscaping and Lawn/Vegetation Management 24 Appendix F Flow Frequency Calculation for MR7 25 MC# VILL0001 Fulkerson single family residence 2024-10-09 VILL0001-Drainage Report.docx Drainage Report Page 3 of 25 Project Overview Project Site Areas Total Project Area 15,056 SF Total Hard Surface Area 5,159 SF New NPGIS (Roof) Area 3,259 SF New PGIS 1,900 SF Existing Impervious Area 4,994 SF Existing Impervious Area to be removed 4,994 SF Site Location The site is located at 8503 200th St SW, Edmonds, WA 98026. Existing Adjacent Development Existing development around the site is listed below. North -Single family homes zoned RS -8 West- Single family homes zoned RS -8 South- Maplewood Parent Cooperative zoned RS-8 East- Single family homes zoned RS -8 Pre -Developed Site Conditions The site currently has a house and 3 sheds located on the site. There is a mixture of gravel driveway and lawn on the site. Post -Development Site Conditions The site will have a single family house and associated concrete driveway on the site. There will be a mixture of grass lawn and landscaping on the remainder of the site. Roof drains are to be routed to a detention tank onsite. A dispersion trench will be installed to manage most of the driveway, with the remaining area that is not feasible to be routed to the detention tank. This tank outfalls into the City's Municipal stormwater system in 200th Drainage Review Type This project is a new development site which proposes more than 5,000 SF of new or replaced hard surface area and is classified as a Category 2 project. As a Category 2 project, it will be subject minimum requirements #1-9 per the flowchart in the Conditions and Requirements section. MC# VILL0001 Drainage Report Fulkerson single family residence Page 4 of25 2024-10-09 VILL0001-Drainage Report.docx IER i.85 ING PLAN-` 24"FAPLEE(�) 7.50, I BSBL 1 I OOF LINE I A PORTION OF THE NW 1/4, SECTION 19, TOWNSHIP 27 NORTH, RANGE 4 EAST, W.M. °04'20"E 80.00' " QEC 30" DECK Do NORTH 10 0 5 10 20 \ ( FEET ) SURFACE COVERAGE SUMMARY I 1 I L— ID O Lu \ / 00 O (V 4i o I RO PoiED NEW SWGL� o� z FAMILY HOUSE N M - j Z 6" H i n .. ..... j u e RE pR1�}EVJA.J TOW YESi SO .:' . _ gRD5 SOU Y Sao.--J FIR 14, 44 zo.00, ° — — PATH a 4 '° FLOW . � I 4 — — " Qj Ili, �--- --•1 � I �---- 1 I I I Y 4.4 Y o cv H m 75LA DS oV Hw S Tod , ----------I 4 8aFl4.4 SD� 2 8„ / A 4'20"E 99.25' A SURFACE DESCRIPTION AREA (SQ. FT) IMPERVIOUS SURFACE ROUTED TO R-TANK 3,718± IMPERVIOUS SURFACE ROUTED TO FLOW 1,516± DISPERSION TRENCH GRASS LAWN/LANDSCAPE 10,052± TOTAL LOT AREA 15,286± IMPERVIOUS CALCULATIONS LOT AREA =15,056 SF HOUSE = 2,974 SF LOTCOVERAGE =19.8% ROOF AREA = 3,259 SF DRIVEWAY/WALKWAY/PATIO -1,900SF TOTAL = 5,159 SF IMPERVIOUS =3'Z% DRIVEWAY BM P T5.12 SHEET FLOW =1,516 SF DRIVEWAY LOCATED WITHIN ROW = 310 SF (TO BE DRAINED TOWARD YD#1) REMAINING IMPERVIOUS FOR DETENTION =3,615 SF R-TAN K VOLUME REQUIRED =72.3 SF X3'DEPTH = 216.9 CF R-TANK DETENTION PROVIDED = 3.08 SF X 25 MODULES X 3DEPTH X 9S % POROSITY = 219.3 CF MAX. ALLOWED IMPERVIOUS =5,1665E EG MAJOR CONTOUR —100.0— — EGMINORCONTOUR — — 101.0 — — — J O o �Tg� 11 Z w— W W W W W— 200T i a Qp — — — — - — —Q — a o — o —/ — — — a oz— �~ 03 ou o ou o pO v f o O \ VER NEW DRY UTILITYC UITS 0- xN SS ��SS SS 55 SS SS � SS SS SS SS SS SS SS'7' - SS SS 'lS l`II o3 ROUWD�ITILITY PERMIT z a 3 Z 0 LL V7 LL Y L. D J LL J_ /Z_A N Q = o M O Z mo W � m Ln a a� 1145 BRO�)� SUITE 115 TACOMA, WA 98402 PHONE: 253.319.1504 CHECKED BY: D. HARRIS DESIGNED BY: D.HARRIS DRAWN BY: 7.SANTOS HORZ. DATUM:NAV83/91 VERT. DATUM: SSHM ON 200 DATE: 10/10/24 PRO]ECTNO. VILL-001 SHEET NO. 1-1 REFERENCE NO. EX.1 Conditions and Requirements This project triggers minimum requirements #1-9 per the flowchart below. Flowchart from Edmonds Stormwater Ada(-idum Adopted 0&0112022 Does the project result in 2,0tKI 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 Requircments No. 1 through 5 apply I I Minimum Requirement No_ 2 applies Piext Question l 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? Yea I is this a rood related project? I All Minimum Raluiroments Ytm apply to the new and replaced hard surfaces and convened 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 more of new hard surfaces:' Yes Do new hard surfaces add 50% or more to the existing hard surfaces within the project limits? Figure 3.1. Flow C hart for Determining Requirements for Development. I No additional I nquirtments_ MC# VILL0001 Drainage Report Fulkerson single family residence Page 5 of25 2024-10-09 VILL0001-Drainage Report.docx Minimum Requirements MR1: Preparation of Stormwater Site Plans Stormwater plans have been prepared and are to be submitted along with this Drainage Report. MR2: Construction Stormwater Pollution Prevention Plan (SWPPP) An erosion and sediment control plan has been prepared for this site which will minimize soil erosion/sedimentation during construction. This plan is included in the drainage plan sheet set. MR3: Source Control of Pollution The project is not a high -use site and is not expected to have significant point -sources of pollution requiring source control methods. However, BMP's for Landscaping and Lawn/Vegetation Management will need to be followed per Appendix E. MR4: Preservation of Natural Drainage Systems and Outfalls The site currently flows unconcentrated to the southwest. This is via the storm ditch on the north side of 200th, as well as the property to the west. This downstream parcel has a collection and detention system built as part the building permit BLD20060992. This detention system combines with the storm ditch and connects into the downstream storm on the south side of 2001h St SW approximately 150 feet to the west of the project. The new outfall from this site is to be connected to the city's stormwater system on the south side of 2001h St SW. The stormwater originally flowing west onto the neighbor property will meet up with the original flowpath within the % mile allowed diversion distance.All existing impervious surfaces are to be removed so no additional retrofitting of impervious is necessary. MR5: On -Site Stormwater Management The site has the option of using LID BMP's from List #2 for all surfaces or using flow control BMP's to achieve the LID performance standard. This site is electing to use the LID BMP's from List #2 to comply with MR#5. The feasibility of these BMP's from List #2 as well as detention has been evaluated in the table below. The site is proposing to utilize Detention for the roof drains and is located on the south side of the house. The site is proposing to use BMP T5.12 Sheet Flow Dispersion for a portion of the driveway where the flow path can be maintained on private property. All other hard surfaces will be routed to the same R-Tank as used for roof drains located on the south side of the site. The detention system is sized using simplified methodology for a detention vault in the City Storm Drainage addendum Section 6.3.1 and applying a volume correction factor to account for the 95% void ratio in an R-Tank. The contributing area remaining for impervious detention is 3,615 square feet, which requires a volume of 72.3 cubic feet at a depth of 3 feet. The R-Tank system provides 3.08 square feet of detention per module with 25 modules at a 3-foot depth and 95% porosity, ensuring compliance with the maximum allowable impervious area of 5,166 square feet. MC# VILL0001 Drainage Report Fulkerson single family residence Page 6 of25 2024-10-09 VILL0001-Drainage Report.docx REMAINING IMPERVIOUS FOR DETENTION VAULT INTERIOR BOTTOM AREA PER CITY OF EDMONDS ADDENDUM DETENTION SYSTEM VOLUME REQUIRED 216.9 CF PROVIDED <2 19.45 CF REQUIRED MAX. ALLOWED IMPERVIOUS Lawn and landscape Areas BMP T5.13: Post -Construction Soil Quality and Depth Feasible = 3,615 SF = 2% OF CONTRIBUTING SURFACE = 72.3 SF X 3 DEPTH = 216.9 CF = 3.08 SF X 25 MODULES X 3 DEPTH X 95% POROSITY = 219.45CF =5,166 SF Roofs Infeasible -The required 100 foot flowpath for dispersion is not possible on BMP T5.30: Full Dispersion or BMP this site. Infeasible -There is not at least 3 feet of more of permeable soil T5.10A: Downspout Full Infiltration from the proposed final grade to an impermeable soil layer. Infeasible -The measured soil saturated hydraulic conductivity is less than BMPT7.30: Bioretention 0.30 inches per hour. Infeasible- The downspouts do not have any suitable downhill dispersion BMP T5.10B: Downspout Dispersion paths. House height pushes yard into a bowl shape, where flowpath would Systems be contained and create flooding potential to house. BMP T5.10C: Perforated Stub -out Infeasible -There is not 1 foot of clearance between a proposed perforated Connections stub out connection and an impermeable soil layer Detention Feasible Other Hard Surfaces Infeasible -The required 100 foot flowpath for dispersion is not possible on BMP T5.30: Full Dispersion this site. Infeasible -The measured soil saturated hydraulic conductivity is less than BMP T5.15: Permeable Pavements 0.30 inches per hour. Infeasible -The measured soil saturated hydraulic conductivity is less than BMPT7.30: Bioretention 0.30 inches per hour. Feasible (Partially) -Driveway has been designed to sheetflow to the extent BMP T5.12 Sheet Flow Dispersion or BMP feasible. Infeasible for areas where flowpath would be located within the T5.11: Concentrated Flow Dispersion ROW. Detention Feasible MC# VILL0001 Drainage Report Fulkerson single family residence Page 7 of 25 2024-10-09 VILL0001-Drainage Report.docx MR6: Runoff Treatment This project does not have 5,000 SF or more of pollution -generating hard surface and does not have 3/4 of an acre or more of pollution -generating pervious surfaces and is therefore exempt from this requirement. MR7: Flow Control This project does not have 10,000 square feet or more of effective impervious surfaces, nor does it convert 3/4 acre or more of native vegetation, pasture, scrub/shrub, or unmaintained non- native vegetation into lawn or landscaped areas. It also does not convert 2.5 acres or more of native vegetation into pasture. Additionally, the project does not result in an increase of 0.15 CFS or more in the 100-year flow frequency. This is based on WWHM12 WS-DOT data, comparing the project's current site conditions, as of July 6, 1977—the effective date of the City's first drainage control ordinance (per the Edmonds Addendum) —to the proposed runoff from the project. The current 100-year flow is 0.041 CFS, and the proposed flow is 0.143 CFS, representing an increase of 0.102 CFS, which remains below the 0.15 CFS threshold. Calculations for Minimum Requirement #7 have been conducted separately and do not include the detention system. Please refer to Appendix F for further details. MR:8 Wetlands Protection There is an inventoried wetland downstream of the site a couple hundred feet past the % mile mark. This requires this project to comply with the General Protection and Protection from Pollutants requirements of this section. Most of the General Protection pertain to the actual wetland, which is far offsite from the project site and therefore will be followed by having no disturbance or work near the wetland. This site is implementing the one General Protection of Flow Control BMP's that pertain to this project onsite, over % mile away from any buffers. Protection from Pollutants requires the site to comply with MR:2,3,5, and 6. These requirements are detailed in the preceding sections. MR:9 Operation and Maintenance This project is to be maintained per the Operations and Maintenance manual section discussed later in this report. Offsite Analysis to address MR#1 Resource Review See FEMA Firm Flood Map showing this site well away from any flood zones in Appendix A. Upstream Basin There is no area that is tributary to this site. The house to the west is already constructed and drains away to the road. Other parcels to the north and east do not slope towards this project. MC# VILL0001 Drainage Report Fulkerson single family residence Page 8 of 25 2024-10-09 VILL0001-Drainage Report.docx Downstream Analysis A level one downstream analysis was performed on 8/24/2023. This is detailed in Appendix B later in this report. The detention tank will discharge to the city stormwater system on the south side of 200th St. Other Permits This project will require a building permit from the City of Edmonds for the new single family home as well as for the demolition of the existing structures onsite. Operations and Maintenance Manual The onsite stormwater control and conveyance system will be privately owned and maintained. The following pages detail the maintenance needs of the system. MC# VILL0001 Drainage Report Fulkerson single family residence Page 9 of25 2024-10-09 VILL0001-Drainage Report.docx N -n OC In�� # O in < < L. O r- Q q O (Q O (D O N 7 N � N — (D (D -0 D O N ; Q O 0 X A N N � � (Q (D (D O � — O � rf Table V-A.2: Maintenance Standards - Infiltration (continued) Maintenance Component Defect Conditions When Maintenance Is Needed Results Expected When Maintenance Is Per- formed (A percolation test pit or test of facility indicates facility is only working at 90 % of its designed capabilities. Test every 2 to 5 years. If two inches or more sediment is present, remove). Filter Bags if applicable) 9( pp ) Filled with Sediment and Sediment and debris fill bagmore than 1/2 full. Filter bag is replaced or stem is redesigned. 9 P y 9 Debris Rock Filters Sediment and Debris By visual inspection, little or no waterflows through filter during heavy min storms. Gravel in rock filter is replaced. Side Slopes of Pond Erosion See Table V-A. Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten- tion Ponds Tree Growth See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten- Emergency Overflow Spillway tion Ponds and Berms over feet in height. See Table V-A.1: Maintenance Standards - Deten- Piping See Table V-A.1: Maintenance Standards - Detention Ponds tion Ponds Rock Missing See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten- Emergency Overflow Spillway tion Ponds Erosion See Table V-A.1: Maintenance Standards - Detention Ponds See Table V-A.1: Maintenance Standards - Deten- tion Ponds Facility or sump filled Pre -settling Ponds and Vaults with Sediment and/or 6" ordesigned sediment trap depth of sediment. Sediment is removed. debris Table V-A.3: Maintenance Standards - Closed Detention Systems (Tanks/Vaults) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Per - Component formed Plugged Air Vents One-half of the cross section of a vent is blocked at any point or the vent is damaged. Vents open and functioning. Accumulated sediment depth exceeds 10% of the diameter of the storage area for 1/2length of storage vault or any point depth exceeds 15% of diameter. All sediment and debris removed from storage Debris and Sediment (Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than 1/2length of area. Storage Area tank.) Any openings or voids allowing material to be transported into facility. Joints Between Tank/Pipe Section All joint between tank pipe sections are sealed. (Will require engineering analysis to determine structural stability). Tank Pipe Bent Out of Shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. (Review required by engineer to determine Tank/pipe repaired or replaced to design. structural stability). Cracks wider than 1/2-inch and any evidence of soil particles entering the structure through the cracks, or main- Vault replaced or repaired to design spe- Vault Structure Includes Cracks in Wall, Bottom, tenance/inspection personnel determines that the vault is not structurally sound. cifications and is structurally sound. Damage to Frame and/or Top Slab Cracks wider than 1/2-inch at the joint of any inlet/outlet pipe or any evidence of soil particles entering the vault through the No cracks more than 1/4-inch wide at the joint of walls. the inlet/outlet pipe. 2019 Stormwater Management Manual for Western Washington Volume V - Appendix A - Page 1007 N -n OC n �� # O�" < C L-O r- Q q O (II O (D O N 7 v � (D — (D (D -0 D O N ;; Q O 0 X N 0) N (Q lD N O (D— � O rf Table V-A.3: Maintenance Standards - Closed Detention Svstems (Tanks/Vaults) (continued) Maintenance Defect Conditions When Maintenance is Needed Results Expected When Maintenance is Per - Component formed Cover Not in Place Cover is missing or only partially in place. Any open manhole requires maintenance. Manhole is closed. Manhole Mechanism cannot be opened by one maintenance person with propertools. Bolts into frame have less than 1/2 inch of Locking Mechanism Not Working thread (may not apply to self-locking lids). Mechanism opens with proper tools. Cover Difficult to Remove One maintenance person cannot remove lid after applying normal lifting pressure. Intent is to keep coverfrom sealing off Cover can be removed and reinstalled by one access to maintenance. maintenance person. Ladder Rungs Unsafe Ladder is unsafe due to missing rungs, misalignment, not securely attached to structure wall, rust, or cracks. Ladder meets design standards. Allows main- tenance person safe access. Catch Basins See Table V-A.5: Maintenance Standards -Catch See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards - Basins Catch Basins Table V-A.4: Maintenance Standards - Control Structure/Flow Restrictor Maintenance Com- Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed ponent Trash and Debris (Includes Sediment) Material exceeds 25% of sump depth or 1 foot below orifice plate. Control structure orifice is not blocked. All trash and debris removed. Structure is not securely attached to manhole wall. Structure securely attached to wall and outlet pipe. General Structure in correct position. Structure is not in upright position (allow up to 10 %from plumb). Structural Damage Connections to outlet pipe are not watertight and show signs of rust. Connections to outlet pipe are watertight; structure repaired or replaced and works as designed. Any holes - other than designed holes - in the structure. Structure has no holes other than designed holes. Cleanout gate is not watertight or is missing. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Cleanout Gate Damaged or Missing Chain/rod leading to gate is missing or damaged. Chain is in place and 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 missing, out of place, or plate is in place and works as designed. bent orifice plate. Obstructions Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions Any trash or debris blocking (or having the potential of blocking) the Pipe is free of all obstructions and works as designed. overflow pipe. Manhole See Table V-A.3: Maintenance Standards - Closed Detention Systems See Table V-A.3: Maintenance Standards - Closed Detention Systems See Table V-A.3: Maintenance Standards - Closed Detention Systems (Tank- s/Vaults (Tanks/Vaults) (Tanks/Vaults) Catch Basin See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards - Catch Basins See Table V-A.5: Maintenance Standards - Catch Basins 2019 Stormwater Management Manual for Western Washington Volume V - Append&A - Page 1008 N -n OC n �� # O�; < < L r- 5-0 O O (Q O (D O N 7 v � (D — (D (D -0 D O N ;; Q O n x 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 or debris. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals orvegetation 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 To slab has holes la erthan 2 square inches or cracks wider than 1/4 inch. Intent is to make sure no material is running into basin P r9 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 3/4 inch of the frame from the top slab. Frame not securely attached Frame is sitting flush on the riser rings or top slab and finely 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 longerthan 1 foot at thejoint of any inlet/outlet pipe or any evidence of soil particles entering pipe is regrouted 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 growing in inlet/outlet pipe joints that is more than six inches tall and less than six inches apart. No vegetation or root growth present. Contamination and Pal- lution See Table V-A.1: Maintenance Standards - Detention Ponds No pollution present. 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 Locking Mechanism Mechanism cannot be opened by one maintenance person with proper tools. 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 coverfrom 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 widerthan 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) Damaged or Missing. Gate missing or broken members) of the grate. Grate is in place, meets the design standards, and is installed and aligned with the flow path. 2019 Stormwater Management Manual for Western Washington Volume V-AppendixA - Page 1009 N -n OC n �� # O in < 0 7 r C Ln• O � � O O O fD O N 7 v � (D � (D — A 0- (D (D O7 N ;; b- O n x N N N Q tQ lD (D W � -- O Lrl f+ Table V-A.10: Maintenance Standards - Filter Strips Maintenance Defect or Prob- Condition When Maintenance is Needed Recommended Maintenance to Correct Problem Component lem Sediment Accu- mulation on Sediment depth exceeds 2 inches. Remove sediment deposits, re -level so slope is even and flows pass evenly through strip. Grass When the grass becomes excessively tall (greaterthan 10- Vegetation inches); when nuisance weeds and other vegetation starts Mow grass, control nuisance vegetation, such that flow not impeded. Grass should be mowed to a height between 3-4 inches. to take over. General Trash and Debris Trash and debris accumulated on the filter strip. Remove trash and Debris from filter. Accumulation Eroded or scoured areas due to flow channelization, or For ruts or bare areas less than 12 inches wide, repair the damaged area by filling with crushed gravel. The grass will creep in over the rock in time. If Erosion/Scouring higherflows. bare areas are large, generally greater than 12 inches wide, the filter strip should be regraded and re -seeded. For smaller bare areas, overseed when bare spots are evident. Flow spreader Flow spreader uneven or clogged so that flows are not uni- Level the spreader and clean so that flows are spread evenly over entire filter width. formly distributed through entire filterwidth. Table V-A.11: Maintenance Standards - Wetponds Maintenance Component Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Water level First cell is empty, doesn't hold water. Line the first cell to maintain at least 4 feet of water. Although the second cell may drain, the first cell must remain full to control tur- bulence of the incoming flow and reduce sediment resuspension. Trash and Debris Accumulation that exceeds 1 CF per 1000-SF of pond area. Trash and debris removed from pond. Inlet/Outlet Pipe Inlet/Outlet pipe clogged with sediment and/or debris material. No clogging or blockage in the inlet and outlet piping. Sediment Accu- Sediment accumulations in pond bottom that exceeds the depth of sed- mulation in Pond Bot- iment zone plus 6-inches, usually in the first cell. Sediment removed from pond bottom. tom General Oil removed from water using oil -absorbent pads orvactortruck. Source of oil located and corrected. If chronic low levels of oil per- sist, plant wetland plants such as Juncus effusus (soft rush) which can uptake small concentrations of oil. Erosion Erosion of the pond's side slopes and/or scouring of the pond bottom, that Slopes stabilized using proper erosion control measures and repair methods. exceeds 6-inches, orwhere continued erosion is prevalent. Settlement of Pond Any part of these components that has settled 4-inches or lowerthan the Dike/berm is repaired to specifications. Dike/Berm design elevation, or inspector determines dikelberm is unsound. Internal Berm Berm dividing cells should be level. Berm surface is leveled so that waterflows evenly over entire length of berm. Overflow Spillway Rock is missing and soil is exposed at top of spillway or outside slope. Rocks replaced to specifications. Table V-A.12: Maintenance Standards - Wetvaults Maintenance Defect Condition When Maintenance is Needed Results Expected When Maintenance is Performed Component General I Trash/Debris Accumulation Trash and debris accumulated in vault, pipe or inlet/outlet (includes floatables Remove trash and debris from vault. 2019 Stormwater Management Manual for Western Washington Volume V - Appendix A - Page 1012 Appendix A - Resource Review Documents MC# VILL0001 Drainage Report Fulkerson single family residence Page 14 of25 2024-10-09 VILL0001-Drainage Report.docx Existing 1 Mile Flowpath. North is to the left. MC# VILL0001 Drainage Report Fulkerson single family residence Page 16 of 25 2024-10-09 VILL0001-Drainage Report.docx Figure shows 1/3 mile flowpath to Northstream Creek, where flowpath continues for the next 2/3 mile. Looking south from the site at the next catch basin downstream of the connection CB. Looking west at piped system on the south side of 2001" flowing west. MC# VILL0001 Drainage Report Fulkerson single family residence Page 17 of25 2024-10-09 VILL0001-Drainage Report.docx Continuing to look west along 2001n MC# VILL0001 Drainage Report Fulkerson single family residence Page 18 of 25 2024-10-09 VILL0001-Drainage Report.docx Looking west at southeast corner of 2001" St SW and 881" Ave W. MC# VILL0001 Drainage Report Fulkerson single family residence Page 19 of 25 2024-10-09 VILL0001-Drainage Report.docx Looking north at southwest corner of 891h PI W and 2001h St SW. MC# VILL0001 Fulkerson single family residence 2024-10-09 VILL0001-Drainage Report.docx Drainage Report Page 20 of 25 End of 1 mile flow path. MC# VILL0001 Drainage Report Fulkerson single family residence Page 21 of25 2024-10-09 VILL0001-Drainage Report.docx Appendix C - Site Map MC# VILL0001 Drainage Report Fulkerson single family residence Page 22 of 25 2024-10-09 VILL0001-Drainage Report.docx MAIN FLOOR ELEVATION (MFE) BOTTOM OF EXCAVATION FRONT GARAGE ELEVATION HOUSE HEIGHT CALCULATIONS HOUSE RECTANGLE EXISITNG CORNER ELEVATIONS 417.10 413.60 416.67 POI NT A 416.78 POINT B 416.40 POI NT C 415.23 POINT D 415.99 AVERAGE EXISTING GRADE 416.10 MAXIMUM ROOF HEIGHT 441.10 VERTICAL FEET BETWEEN MAX AND PROPOSED 000.34 HEIGHT SURVEY REQUIRED AS LESS THAN 1 FOOT DIFFERENCE MAIN FLOOR ELEVATION 417.10 FRONT GARAGE ELEVATION 416.67 NOTE: CONTRACTOR SHAL POTHOLE TO VERIFY EXISTING SEWER INVERT ELEVATIONS FOR SANITARY SEWER AND CONTACT ENGINEER IF ELEVATIOKNS VARY FROM THIS SHOWN NOTE: CONTRECTOR TO GRADE SITE TO PROVIDE POSITIVE DRAINAGE AWAY FROM STRUCTURE AROUND ENTIRE BUILDING PERIMETER. A PORTION OF THE NW 1/4, SECTION 19, TO D C* 1 CONCRETE PAD FOR HEAT PUMP 1 I I c cfl I I W I O CV CD I PROPOSED NEW SINGLE o z 1 I FAMILY HOUSE I MFE = 417.10 �L... 3 pATH - -R17----Im- d °. OW ZO F L I / d n °. d- ° d. a . . . . . . . . . . . . . . d Al 1% SLOp S SOUTHWEST d TOWARD ° . . . . . . . . . . .I ° d d d0 . ° d ° FLOW DISPERSION TRENCH 2' WIDE X 6" DEEP 10.81'. EXISTING DRIVWAY 4" SEWER I.E. AT BU I LDI NG 411. I . 20.00' . . . d A 7 FLOW PATH. I as a - I a. °ROOF DRAIN CONNECTION i I d A. '.. 6"PVCIE415.51° I r. .. a - - I . I A d a ° 8 LF 6" PVC 8 3% .. a 8.3.00' 1 I 1 ........J ° 1 .............. d I. 'd d ° d 6" PVC IE 414.68- -- i 9 .. . . . . . . . . . . . . . V EW Alr --------- I 311 �GEOGRID� u 2%SLOpE S ARpS UTHW I I I cI o w o w m. . . . . . . . . . TOW . . . . . . . . . dd .' °.. i I I 2, N Cn w . . . . d 6" PVC E 412.8 SIDE BACKFILL . L ' '°. d " d I a' 16"PkIE41285 . . ° , 1 . °'� ° P G @- - - - - - - - --I . FLOW PATH T ELF 6 7 LF 6" PVC @ 4.86% L� cn 20_ dr �� 11 �� ,_ cn / L DE AT PROPERTY CORNER 416.27 - EXISTING DRIVEWAY\ 20.38' YD#1 R I M 416.35 6" PVC (NE) 413.85 ' 417 -1 a r- �21' UPIVEWAY WITH WINGS NEW 6" PVC �Zww 14 D _ r- I_>z it �07)<< 0 r w oF- J EX. PAINTED z o v SKIP C/L Y z - o~ aa) - SS SS SS w Z w w 3S SS SS n �U)< rw� Dlt _ SD �1- SD S D S SD SD SD- 0 l� G G IMPERVIOUS CALCULATIONS OHP OHP OHP HP OHP EX. CURB AND GUTTER Y LOT AREA=15,056 SF i �o o\-C6 O �ti 'OF ::EN89' 11 4'20"E 99.25' �Q CB#2 -TYPE 2 48" J 16.00' `r RIM 417.18 6" PVC (E) 412.51 6" PVC (W) 412.51 HOUSE = 2,974 SF J LOT COVERAGE = 19.8% > ROOF AREA = 3,259 SF i� DRIVEWAY/WALKWAY/PATIO = 1,900 SF °' TOTAL = 5,159 SF DATUM POINT IMPERVIOUS = 34.1% ELEV=416.53' 3 SSMH RIM=416.53' a DRIVEWAY BMP T5.12 SHEET FLOW = 1,516 SF IE=407.18' (8" IN E) DRIVEWAY LOCATED WITHIN ROW = 310 SF IE=407.08, 8„ W OUT (TO BE DRAINED TOWARDYD#1) ( ) REMAINING IMPERVIOUS FOR DETENTION = 3,615 SF r R-TANK VOLUME REQUIRED = 72.3 SF X 3' DEPTH r = 216.9 C F 4 R-TANK DETENTION PROVIDED = 3.08 SF X 25 MODULES X 3' DEPTH X 95 % POROSITY 3 = 219.3 CF I MAX. ALLOWED IMPERVIOUS = 5,166 SF SANITARY SEWER I SERVICE AT 7.8% MIN SLOPE 12" WATER BOTTOM OF PIPE 414.92 6" SEWER TOP OF PIPE=410.41 4.51' CLEARANCE BETWEEN PIPES s SS SS APPROX INVERT=408.69 - 10 A \ SD Si G1 Sp Pi27 NORTH, RANGE 4 EAST, W.M. i O \ NORTH \ 10 0 5 10 20 (FEET) NOTE: R-TANK IS NOTTRAFFIC-BEARING AND LANDSCAPING OR ROCK FEATURES SHALL BE INSTALLED TO PREVENT VEHICLES FROM DRIVING OVER THE TANK. A MINIMUM OF 3' HORIZONTAL SEPARATION AND 1' VERTICAL SEPERATION IS REQUIRED BETWEEN DRY UTILITIES AND SEWER, WATER, STORM AND 5' HORIZONTAL SEPERATION FROM ANY CITY MAIN LI N ES. MAINTAIN 2' COVER OVER DRY UTILITIES CONDUITS C - SD - - SD - SD -SD- - SD SD G G- G- - G G - -OHP OHP OHP OHP OHP OHP �OHP PEDESTRAIN CROSSWALK / ACROSS SCHOOL DRIVEWAY `� CB T-1 RIM=417.00' IE=411.48' (12" CONC E) IE=411.48' (12" CONC W) TYPEOFAREA AREA(SF) STORVNUAT RFACIUTY LAWN AND LANDSCAPE 9938 RTANKDETENTION ROOFS 3259 R TANKDETENTION DRIVEWAY 1516 BMPT5.12 SHEET FLOW DRIVEWAY 293 R TANKDETENTION %RETROFIT 134231 REMOVAL FOOTING DRAIN CONNECTION 6" PVC I E 413.60 O a F_- NOTE: ROOF DRAINS SHALL Lu En 0 uj RUN SEPERATELY FROM o 0 a w FOOTING DRAINS. ao 0 <LLI a�w a PROPOSED PRIVATE DRAINAGE EASEMENT EXTENTS - G P - 10.75 PROPOSED EASEMENT N89°04'20"E 78.39' GRADE AT PROPERTY CORNER 417.68 �- CB#1 -TYPE 2 48" \KITH-SQU-ID-LID- - RIM 417.86 6" PVC (W) 412.30 12"CPEP (S) 411.80 W - - W - -200TH ST SW_ _ _ 12" STORM TOP OF PIPE 412.66 12" WATER BOTTOM OF PIPE 414.42 1.76' CLEARANCE BETWEEN PIPES PROVIDED SS SS SS SS SS 8" SANITARY SEWER PIPE 408.69 12" STORM BOTTOM OF PIPE 411.6 2.64' CLEARANCE BETWEEN PIPES PROVIDED - SD SD -SD- 3D -_� SD - G G OHP OHP OHP OHP OHP -OHP- CB T-1 RIM=418.14' IE=411.62' (12" CONC E) IE=411.62' (12" CONC W) IE 411.62' (12" CPEP) NEW SEE APPROVED CIVILS FOR ENGINEERING REQUIREMENTS DATUM NAVD 88 UTILITY KEYNOTES OTHE ROOF DRAINS ARE TO BE CONNECTED TO THE R-TANK. O2 THE FOOTING DRAINS TO BE CONNECTED INTO CATCH BASIN #1. G) DRIVEWAYTO BE SLOPED TOWARD SHEET FLOW DISPERSION TRENCH ON WEST SIDE OF DRIVEWAY. SHEET FLOW DISPERSION TRENCH TO USE DETAIL SD-635 ON SHEET C4.0. DRIVEWAY LOCATED WITHIN ROW TO BE SLOPED TOWARDS YARD DRAIN #1 AT EDGE OF ROW. INSTALL SHALLOW BERM ON WEST SIDE OF DRIVEWAY WITHIN ROW IF NECESSARYTO MAKE STORMWATER FLOW TO YARD DRAIN #1. EX CHARGING STATION TO BE LOCATED WITHIN THE GARAGE. 0 OINSTALL R-TANK PER MANUFACTURER SHOP DRAWINGS ON PAGES C4.2 5 AND C4.3. R-TANK HD 25 DOUBLE + MINI (2.5) MODULES GRAVEL BASE FROM 412.26 TO 412.51 INSTALL R-TANK MODULES AT 41231 TOP OF R-TANK 416.05 12" COVER ALLOWED WHERE ALL VEHICLE LOADING IS RESTRICTED MINIMUM GRADE OVER TANK 417.05. GEOGRID SHOULD EXTENTS' BEYOND EXCAVATION FOOTPRINT.CONTRACTOR TO PROVIDE SHOP DRAWINGS MATCHING PROPOSED GEOMETRY. (DNEW 1" METER TO BE INSTALLED BYTHE CITY OF EDMONDS PUBLIC WORKS DEPARTMENT IN PROPOSED ROW PER WA-130. OINSTALL NEW 1 %2" POLY WATER LINE WITH TRACER WIRE. TO BE INSTALLED BY CITY OF EDMONDS PUBLIC WORKS. ORESTORE TRENCH PAVEMENT DEMOLITION AREA PER GU-410. SEE DETAIL GU-400 ON SHEET C4.0. ALL PAINT/STRIPING PER CITY OF EDMONDS PUBLIC WORKS STANDARDS TO MATCH ADJACENT PAVEMENT. ORE -LAY SEWER AND INSTALL 4" SSCO WITHIN 2' OF HOUSE. APPROX I.E. _ 411.86 S10 INSTALL 6" SSCO ON NEW SEWER SERVICE AT EDGE OF ROW PER DETAIL SS-200. APPROX I.E. = 410.87. 6CB # 2 CONTROL STRUCTURE WITH ONE 0.5" DIAMETER ORIFICE . ORIFICE 6 TO USE DETAIL SD-301 WITH OVERFOW AT 415.51. INSTALL UNDERGROUND NEW DRY UTILITY. LINES FROM EXISTING POLE 3" 12 CONDUIT-PSE POWER. 1" CONDUIT COMCAST.1" CONDUIT-ZIPLY. UTILITY BORING BY SNOHOMISH COUNTY PUD #1. 13 CONNECT TO EXISTING CB. IE= 411.62 G DRIVEWAY TO BE CONSTRUCTED OF 3" HMA CL Z" (OVER 6" CRUSHED SURFACING) WITHIN ROW, AND 6" CONCRETE OVER 4" CRUSHED SURFACING ON PRIVATE PROPERTY. PROPOSED UTILITY LEGEND BUILDING OVERHANG RD ROOF DRAIN W W WATER SERVICE UGP UNDERGROUND POWER SERVICE FD FOOTING DRAIN WATER METER CB T-1 RIM=419.51' IE=412.46' (12" CONC E) IE=412.46 (12 CONC W) IE=412.56,(12„CONC N) DATUM INFORMATION IS DERIVED FROM SSHM ON 200TH STREET ELEV = 416.53' YD, CB TYPE 2 O SEWER CLEANOUT NOTES: 1. REPLACE ALL DISTURBED HARD SURFACES NECESSARY FOR SIDE SEWER CONSTRUCTION WITH LIKE MATERIAL PER GU-410. 2. FINAL SURFACE RESTORATION WITHIN RIGHT-OF-WAY TO BE COMPLETED BY CONTRACTOR NOT CITY OF EDMONDS. 3. UTILITY PATCHES WITH LESS THAN 20 FEET OF SEPARATION TO BE COMBINED AND FULL WIDTH OR HALF WIDTH OVERLAY WILL BE REQUIRED DEPENDING ON THE EXTENT OF DISTURBANCE. WHERE UTILITY PATCHES FALL ENTIRELY WITHIN ONE TRAVEL LANE, THE OVERLAY SHALL EXTEND TO THE CENTERLINE OF THE ROADWAY. WHERE UTILITY PATCHES EXTEND INTO BOTH TRAVEL LANES THEN A FULL WIDTH OVERLAY IS REQUIRED. 4. EXISTING FAILING OR DAMAGED ROW IMPROVEMENTS SHALL BE REMOVED AND REPLACED AS DETERMINED BY THE CITY ENGINEERING INSPECTOR. S. A MINIMUM OF 3' HORIZONTAL SEPARATION AND 1' VERTICAL SEPARATION IS REQUIRED BETWEEN DRY UTILITIES AND SEWER, WATER, STORM AND 5 FROM ANY CITY MAINLINES. 6. UTILITY CROSSINGS WITHIN THE ROW TO BE RESTORED TO EXISTING CONDITIONS PER GU-400 AND GU-410. 7. 10' PROPOSED ROW SHOWN ONLY AS REFERENCE TO CITY OF EDMONDS OFFICIAL STREET MAP. NO ROW IS PROPOSED TO BE DEDICATED AS PART OF THIS PERMIT. 8. MATAIN A MINIMUM OF 3' OF HORIZONATAL SEPERATION BETWEEN THE WATER SERVICE AND DRY UTILITIES. APPROVED FOR CONSTRUCTION CITY OF EDMONDS DATE: BY: CITY ENGINEERING DIVISON z O w z z w w a o 2 2 u p O O C) w ~ ~ z 0� U U O g O � � U < < N N N w I--m N O < N M O �q o V N Cy) PERMIT z a u J 3 Z Z Vi w LL J Q O J DLL W 4V Z Q O N M W J > W O o V z AA AACMENTUM CIVIL 1145 BROADWAY, SUITE 115 TACOMA, WA 98402 PHONE: 253.319.1504 CHECKED BY: D. HARRIS DESIGNED BY: D.HARRIS DRAWN BY: J.SANTOS HORZ. DATUM:NAV83/91 VERT. DATUM: SSHM ON 201 DATE: 10/10/24 PROJECT NO. VILL-001 SHEET NO. 2 of 9 REFERENCE NO. C2.0 Appendix D - Geotechnical Report MC# VILL0001 Drainage Report Fulkerson single family residence Page 23 of 25 2024-10-09 VILL0001-Drainage Report.docx September 29, 2023 ES-9396 Signature Homes by Village Life, LLC 19020 — 33rd Avenue West, Suite 450 Lynnwood, Washington 98036 Attention: Lucas Kragt, P.E. Subject: Geotechnical Evaluation Fulkerson Property 8427 and 8503 — 200t" Street Southwest Edmonds, Washington Greetings, Lucas: Earth Solutions N W «C Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation for the proposed short plat residential development. To complete the geotechnical scope of services, ESNW completed a subsurface exploration, laboratory and engineering analyses, review of the referenced documents, and this letter summarizing our findings and recommendations for the proposed project. Project Description Based on ESNW's understanding of the proposed development, the existing structures will be demolished and the site will be redeveloped with three residential lots, an access road, and associated improvements. Grading plans were not available for review. Given the relatively level nature of the site, we anticipate minimal grading will be required to achieve design elevations. At the time this report was prepared, specific building load values were not available. However, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads on the order of 1 to 2 kips per linear foot, column loads of up to about 20 kips, and slab -on -grade loading of 150 pounds per square foot (psf). If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW has reviewed the referenced plans as part of this report preparation. 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711 Signature Homes by Village Life, LLC September 29, 2023 Surface Conditions ES-9396 Page 2 The subject site is located at 8427 and 8503 — 200th Street Southwest in Edmonds, Washington, as illustrated on the attached Vicinity Map (Plate 1). The site consists of two tax parcels (Snohomish County parcel numbers 27041900202900 and 27041900211400) totaling about 0.60 acres. The site is bordered to the north, east, and west by single-family residences, and to the south by 200th Street Southwest. The site is currently developed with two single-family residences, outbuildings, and associated improvements; the remainder of the site consists of grass -covered yard areas with mature trees. Site topography is relatively level with less than five feet of elevation change. Subsurface Conditions An ESNW representative observed, logged, and sampled the excavation of three test pits on August 14, 2023. The test pits were excavated using a trackhoe and operator retained by our firm. The test pits were excavated for purposes of assessing soil conditions, classifying site soils, and characterizing groundwater conditions within the proposed development area. The approximate locations of the test pits are depicted on the attached Test Pit Location Plan (Plate 2). Representative soil samples collected at the explorations locations were analyzed in general accordance with Unified Soil Classification System (USCS) and United States Department of Agriculture (USDA) methods and procedures. Topsoil Where encountered, topsoil was generally observed extending about four inches below the ground surface (bgs). Deeper pockets of topsoil may be encountered locally across the site. The topsoil was characterized by its dark brown color, presence of fine organic material, and small root intrusions. Fill Fill was observed at one of the test pit locations (TP-3) located within the western portion of the subject site. The fill was observed to extend to a depth of roughly two and one-half feet bgs. The fill was characterized primarily as loose and moist silty sand (USCS: SM), and contained bricks, concrete, and wood debris. Fill may also be present within proximity to existing structural improvements. Where encountered, fill soils intended for reuse as structural fill should be free of organics and other deleterious materials, and should be evaluated by ESNW for suitability at the time of construction. Native Soil Underlying existing topsoil and fill, native soil was encountered primarily as silty sand (Unified Soil Classification System: SM), consistent with the typical makeup of glacial till. The near -surface, loose to medium dense deposits may be characterized as "weathered", and the underlying, dense to very dense and cemented deposits may be characterized as "unweathered". The upper, loose to medium dense weathered glacial till deposits were observed generally extending to depths of about two to three feet bgs, transitioning to a dense to very dense, cemented, and unweathered condition at depth. Overall soil relative density generally increased with depth. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Geologic Setting ES-9396 Page 3 Geologic mapping indicates the site is underlain by glacial till deposits (Qvt). As reported on the geologic map resource, the glacial till consists of a nonsorted mixture of silt, sand, pebbles, cobbles, and boulders and commonly is referred to as "hardpan." The till was deposited directly from the glacier as it advanced over bedrock and older Quaternary sediment. Additionally, the Web Soil Survey (WSS) identifies Alderwood-Urban land complex (2 to 8 percent slopes) within the proposed development area. The Alderwood series was formed in glacial till plains. Based on our field observations, on -site native soils are generally consistent with glacial till deposits and Alderwood series soil. Groundwater Groundwater seepage was not observed at the test pit locations during the fieldwork (August 2023). However, seepage should be expected in deeper excavations at this site, particularly during the winter, spring, and early summer months. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. Geologically Hazardous Areas Assessment As part of this geotechnical engineering study, the referenced chapter of the Edmonds City Code (ECC) was reviewed. Based on our investigation and review, there are no geologically hazardous areas present on or adjacent to the site. Geotechnical Considerations Based on our evaluation, the proposed project is feasible from a geotechnical standpoint. The information presented in the following sections is intended to aid site designs and construction. In -situ and Imported Soils On -site soil exposed during site mass grading will likely consist of glacial till. The glacial till is moisture sensitive and may not be suitable for use as structural fill unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. If the on -site soils cannot be successfully compacted, cement treatment and/or the use of an imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for export of soil that cannot be successfully compacted as structural fill if grading activities take place during periods of rainfall activity. We recommend avoiding construction -equipment tracking across the on -site soil and generally active site work during periods of heavy rainfall, as such disturbance has the potential to degrade the on -site soil beyond a workable state. Imported soil intended for use as structural fill should consist of a well -graded, granular soil with a moisture content that is at (or slightly above) the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well -graded, granular soil with a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three -quarter -inch fraction). Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Wet Season Grading ES-9396 Page 4 If grading takes place during periods of wet weather, a contingency in the project budget should be included to allow for treatment of the on -site soils or export of on -site soils and import of structural fill as described below. Additional surface control and drainage measures will be necessary to control and detain runoff. Stormwater collection tanks may be necessary to detain stormwater. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab -on -grade, roadway, permanent slope, retaining wall, and utility trench backfill areas. The following recommendations are provided for soils intended for use as structural fill: • Structural fill material • Moisture content • Relative compaction (minimum) • Loose lift thickness (maximum) Granular soil* At or slightly above optimum 95 percent (per ASTM D1557) 12 inches Existing site soil may only be considered suitable for use as structural fill if a suitable moisture content is achieved at the time of placement and compaction. If the on -site soil cannot achieve the above specifications, the use of imported structural fill material will likely be necessary. Concerning underground utility installations and backfill, local jurisdictions will likely dictate soil type(s) and compaction requirements. Excavations and Slopes Excavation activities across the site are likely to expose loose to medium dense native soil within the upper approximately two to three feet bgs, transitioning into dense glacial till ("hardpan") with depth. Based on the soil conditions observed at the subsurface locations, the following allowable temporary slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The applicable Federal Occupation Safety and Health Administration and Washington Industrial Safety and Health Act soil classifications are also provided: • Areas exposing groundwater seepage 1.5H:1V (Type C) • Loose soil 1.5H:1 V (Type C) • Medium dense soil 1H:1V (Type B) • Dense to very dense "hardpan" native soil 0.75H:1V (Type A) Earth Solutions NW. LLC Signature Homes by Village Life, LLC ES-9396 September 29, 2023 Page 5 Permanent slopes should be planted with vegetation to enhance stability and to minimize erosion, and should maintain a gradient of 2H:1V or flatter. The presence of perched groundwater may cause localized sloughing of temporary slopes. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Foundations The proposed residential structures can be supported on conventional spread and continuous footings bearing on undisturbed, competent native soil, recompacted native soil, or new structural fill. Provided site earthwork activities are completed in accordance with our recommendations, suitable soil conditions should be exposed in building pad structural subgrade areas. Due to the high moisture sensitivity of the site soils, foundation subgrade areas should be protected from wet weather or areas of remediation should be anticipated; a layer of crushed rock can be considered to protect foundation subgrade areas. If structural building pads are disturbed during wet weather, remediation measures such as cement treatment or overexcavation and replacement with rock may be necessary in some areas. Provided the structures will be supported as described above, the following parameters can be used for design of the new foundations: • Allowable soil bearing capacity 2,500 psf • Passive earth pressure • Coefficient of friction 300 pcf (equivalent fluid) M1 The passive earth pressure and coefficient of friction values include a safety factor of 1.5. A one- third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of about one-half inch. The majority of the settlements should occur during construction, as dead loads are applied. Seismic Design The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically with respect to earthquake loads. Based on the soil conditions encountered at the test pit locations, Site Class D should be used for seismic design. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Liquefaction ES-9396 Page 6 Liquefaction is a phenomenon where saturated, loose, and cohesionless fine sand or silt soil suddenly loses internal strength and behaves as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered negligible. The composition and relatively dense characteristics of the native soil were the primary bases for this opinion. Slab -on -Grade Floors Slab -on -grade floors should be supported on a firm and unyielding subgrade consisting of competent native soil or at least 12 inches of new structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to construction of the slab. A capillary break consisting of a minimum of four inches of free - draining crushed rock or gravel should be placed below the slab. The free -draining material should have a fines content of 5 percent or less defined as the percent passing the number 200 sieve, based on the minus three-quarters inch fraction. In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If used, the vapor barrier should consist of a material specifically designed to function as a vapor barrier and should be installed in accordance with the manufacturer's specifications. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for design: • Active earth pressure (unrestrained condition) • At -rest earth pressure (restrained condition) • Traffic surcharge* (passenger vehicles) • Passive earth pressure • Coefficient of friction • Seismic surcharge * Where applicable. t Where H equals the retained height (in feet). 35 pcf (equivalent fluid) 55 pcf 70 psf (rectangular distribution) 300 pcf (equivalent fluid) ME 8H psft The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The above design parameters are based on a level backfill condition and level grade at the wall toe. Revised design values will be necessary if sloping grades are to be used above or below retaining walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant loads should be included in the retaining wall design. Earth Solutions NW. LLC Signature Homes by Village Life, LLC ES-9396 September 29, 2023 Page 7 Retaining walls should be backfilled with free -draining material that extends along the height of the wall and a distance of at least 18 inches behind the wall. The upper 12 inches of the wall backfill may consist of a less permeable soil, if desired. A perforated drainpipe should be placed along the base of the wall and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the wall design. Drainage The presence of groundwater seepage should be expected in excavations. Where zones of groundwater seepage are encountered, temporary measures to control groundwater seepage may be needed. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve passive elements such as interceptor trenches and sumps, as necessary. Surface water should not be directed to the top or toe of slopes, modular block walls, or rockeries; wall and rockery drainage should not be used to temporarily control surface water during construction. Surface grades must be designed to direct water away from structures and slopes. The grade adjacent to structures and slopes should be sloped away at a gradient of at least 2 percent for a horizontal distance of at least 10 feet or as setbacks allow. In our opinion, perimeter footing drains should be installed at or below the invert of the building footings. A typical footing drain detail is provided on Plate 4 of this report. Infiltration Evaluation In -situ testing was completed in accordance with the Small-scale Pilot Infiltration Test (PIT) procedure, as outlined in Volume III, Chapter 3, Page 526 of the 2014 Stormwater Management Manual for Western Washington (2014 SMMWW). The testing was completed at a depth of approximately four feet at TP-1. The infiltration test was located within undisturbed unweathered glacial till deposits. The measured PIT rate was negligible, with no measurable drop over the course of the test. The very low hydraulic capacity is attributed to both the presence of relatively high in -situ fines content of the native soil and underlying hardpan glacial till which is relatively impermeable. In this respect, infiltration should be considered infeasible for the project. On -site Stormwater Management Pursuant to City of Edmonds stormwater management requirements, implementation of on -site stormwater BMPs are required for proposed developments in accordance with specified thresholds, standards, and lists. The intent of BMP implementation is to infiltrate, disperse, and retain stormwater runoff on site to the extent feasible. The table below summarizes our evaluation of low impact development methods, as outlined in the referenced stormwater manual, from a geotechnical standpoint. It is instructed in the referenced stormwater manual that BMPs are to be considered in the order listed (from top to bottom) for each surface type, and the first BMP that is determined to be viable should be used. For completeness, however, we have evaluated each listed BMP for the proposed surface types. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 ES-9396 Page 8 BMP Viable? Limitations or Infeasibility Criteria Lawns and Landscaped Areas T5.13: Post -construction soil quality Yes None. and depth (Volume V, Chapter 5) Roofs T5.30: Full dispersion (Volume V, Maybe* Adequate vegetative flow paths will likely not be available. Chapter 5) T5.10A: Downspout full infiltration Infeasible due to shallow depth to low permeability hardpan systems (Volume III, Chapter 3) No soil. Roofs T5.10A: Bioretention (Volume V, NO Infeasible due to shallow depth to low permeability hardpan Chapter 7) soil. T5.10B: Downspout dispersion systems (Volume III, Chapter 3) Maybe* Adequate vegetative flow paths are likely not available. Based on proposed grades, the bottom of the perforated stub- T5.10C: Perforated stub -out Maybe* out connection trenches would likely be within the underlying connections (Volume III, Chapter 3) unweathered till, which will likely have perched groundwater during the wet season. T5.30: Full dispersion (Volume V, Maybe* Adequate vegetative flow paths are likely not available. Chapter 5) T5.15: Permeable pavement Infeasible due to shallow depth to low permeability hardpan soil (Volume V, Chapter 5) No which would cause saturation and instability of soil directly supporting the pavement. T5.10A: Bioretention (Volume V, NO Infeasible due to shallow depth to low permeability hardpan Chapter 7) soil. T5.12: Sheet flow dispersion T5.11: Concentrated flow dispersion Maybe* No flooding or erosion impacts are anticipated. However, (Volume V, Chapter 5) adequate vegetative flow paths are likely not available. * Viability stated from a geotechnical standpoint and should be determined by site storm designer with respect to setbacks and flow paths. Utility Support and Trench Backfill The soils observed at the subsurface locations are generally suitable for support of utilities. In general, the soils observed at the test locations will not be suitable for use as structural backfill in the utility trench excavations unless the soil is at or slightly above the optimum moisture content at the time of placement and compaction. If native soil is placed below optimum moisture levels, settlement will likely occur once wet weather impacts the trenches. Native soil will be difficult or impossible to use as utility trench backfill during wet weather conditions. Moisture conditioning or treatment of the soils may be necessary at some locations prior to use as structural fill. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable requirements of presiding jurisdiction. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 Limitations ES-9396 Page 9 This letter has been prepared for the exclusive use of Signature Homes by Village Life, LLC and their representatives. No warranty, express or implied, is made. The recommendations and conclusions provided in this letter are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. If the design assumptions outlined in this letter either change or are incorrect, ESNW should be contacted to review the recommendations provided in this letter. The information provided in this letter does not cover unforeseen of changed conditions. Additional Services ESNW should review the final design to verify the geotechnical recommendations provided in this letter have been incorporated into the plans. Additionally, ESNW should be retained to provide observation and testing services during construction, where necessary. Earth Solutions NW. LLC Signature Homes by Village Life, LLC September 29, 2023 ES-9396 Page 10 We trust this letter meets your current needs. Should you have questions, or if any additional information is required, please call. Sincerely, EARTH SOLUTIONS NW, LLC Adam Z. Shier, L.G. Project Geologist T. W WA a it 53803 4, O�F`SS��NA ST L 09/29/2023 Henry T. Wright, P.E. Associate Principal Engineer Attachments: Plate 1 — Vicinity Map Plate 2 — Test Pit Location Plan Plate 3 — Retaining Wall Drainage Detail Plate 4 — Footing Drain Detail Test Pit Logs Grain Size Distribution References: • Soil Summary and Preliminary Geotechnical Recommendations, prepared by ESNW, ES- 9396, dated August 23, 2023 • Topographic Survey, provided by the client, dated August 9, 2023 • Geologic Map of the Edmonds East and part of the Edmonds West Quadrangles, Washington, compiled by James P. Minard, dated 1983 • WSS, maintained by the Natural Resources Conservation Service under the USDA. • 2014 SMMWW, prepared by Department of Ecology • Chapter 23.80 (Geologically Hazard Areas), ECC Earth Solutions NW. LLC Perrinville � Q Puget �x 86th Street Southwest X s Sound V 187th Street Southwest l`.s, 111 3 `Due e� 188th Street Southwest MCI (yQIP t4 Pork - '7° 189th Place South N Blake Placen ^ 190th Street Sout Cherry Street Q 191st SAeer Southwest 192nd Street Southwest J, 3 192nd Place Sou%e5 °a�r'le NOf chstream / t�ltdole CpP D 193rd Place S Lanouthwest n m �,th place`t'lest lane L _/ Puget ori,e - -- Piyep`9 �196th Street 5--O theses[_ _ _. _ _ _ WA 524 ----- get_Dr� to - - -- ^! LanFT e ➢ m „Hindley Lane C viewland Way m o � m A c 3 2 v m ,Z - 199th Street Southwest � n N ^ WA 524 - SITE • 00th Street Southwest Edmond _ DVisfa Place L N 201 st Street Southwest _ College [reel Carol Wa ° 3 202nd Street Southwest 202nd Place Southwest y� 1. > I '3 a' a Edmonds 8 ti y E.a 203rd Street Southwest ZGleo Street Glen Street o r 'o y Lynnwood a Daley scree[ 1.- m Munlbpal a W Golf Course Street ' °� Sprague Street > v n y-- o ➢ ^ Pine Ridgej^� -_ S206th Street Southwest -, - -.College Edmonds Street _ park r ^ Place Middle School Main Street _ Main Street — " 208th Street Sou a 3 u a °r Map Maple Way ... T O ➢ Maple Street 210th Street Southwest fD Yost Pork ,,'- '�6Pa v Ider Street alnut Street Walnut Street Sher] 3� Cedar Street I 9 Park 212 11 Spruce Street A ~ v Edmonds/ street - - a' Woodway Apartments c, so,,,, ^ y 1z f High School Way n'y`' beet 215thSccee[Sout�`aes[ ➢ o D m F� r ?Pone Street Chose Lake 216[h Street Southwest 2161h Street Southwest m Elementary WA 99 ^ School 0 < 217th Street Southwest o ❑� ' • / /�c�Q� eec s a v zlacnStreet Southwest Y NORTH Earth i E 'AllN111., Reference:00� Snohomish County, Washington Observation/Testing Open Strell p. org40 Vicinity Map Fulkerson Property Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drawn CAM Date 09/21 /2023 Proj. No. 939E responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked AZS Date Sept. 2023 Plate 1 416 '-I Shed I � i Shed I � — i I House TP-1 � 4 I 'I , I i I TP-3 Driveway I ' House I / I � I i TP-2 Driveway 4161 �hed I 418 200TH STREET S.W. LEGEND TP-1 Approximate Location of — ■ — ESNW Test Pit, Proj. No. ES-9396, Aug. 2023 Subject Site Existing Building NOTE: The graphics shown on this plate are not intended for design purposes or precise scale measurements, but only to illustrate the approximate test locations relative to the approximate locations of existing and / or proposed site features. The information illustrated is largely based on data provided by the client at the time of our study. ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. NORTH NOT - TO - SCALE Test Pit Location Plan Fulkerson Property Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drawn CAM Date 09/21 /2023 Proj. No. 9396 responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked AZS Date Sept. 2023 Plate 2 18" Min. 0 0 o 0 o O °o o �p � �° �0 .0 po o °o�0 0o0 ° ��o 0 �oo 0 0 0 00° 0000�oo 00000 o 0 0 0 0 oo .0 o, o 8 0 00 o o oo O 0 0 0 0 o o o o O o0 o oo op o° 0 o o 0 0 0 0 o 0 0 0 o0 00° 0 o o 00 0 op oo 0 o o o 0 0 0o Oo 0 0 Oo0o O oo o 00 00 0 0 oo o p o o�oo ...0. 00 0 0 8 0 0 0 0 oo 0 0 0 000 o0 o 000 o 0 0 0 g o Ooop o 0 0o 00 p o oo 0 0 o So o0 0 0 0 0 o 0 0 00 o o 00 0 000 8 Oo 0 & o p 0o0o o Oo .0 0 0�?, NOTES: • Free -draining Backfill should consist of soil having less than 5 percent fines. Percent passing No. 4 sieve should be 25 to 75 percent. • Sheet Drain may be feasible in lieu of Free -draining Backfill, per ESNW recommendations. • Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Q 00o O p o000 Free -draining Structural Backfill -inch Drain Rock %. of of of ti Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING Retaining Wall Drainage Detail Fulkerson Property Edmonds, Washington Drawn CAM Date 09/21/2023 Proj. No. 9396 Checked AZS Date Sept. 2023 Plate 3 Perforated Rigid Drain Pipe (Surround in Drain Rock) NOTES: • Do NOT tie roof downspouts to Footing Drain. • Surface Seal to consist of 12" of less permeable, suitable soil. Slope away from building. LEGEND: Surface Seal: native soil or other low -permeability material. B.* - _- - - _... " - " 1-inch Drain Rock SCHEMATIC ONLY - NOT TO SCALE NOT A CONSTRUCTION DRAWING Drawn CAM Date 09/21 /2023 Proj. No. 9396 Checked AZS Date Sept. 2023 Plate 4 W I ,1� �� Well -graded gravel with Moisture Content Symbols m CU > GW or without sand, little to 0 c no fines Dry - Absence of moisture, dusty, dry to Cement grout U U j L 11 the touch ATD = At time surface seal 0 O o o of drilling g Bentonite o p o01 00(lo Poorly graded gravel with Damp Perceptible moisture, likely below chips o Z v UU o 0 0 0 GP or without sand, little to optimum MC Static water i LO C o Q�oQ no fines level (date) eall Co ° Moist - Damp but no visible water, likely o a) H a) at/near optimum MC - Filter pack with 65 0 a) tav, 0 0 uD op o GM Silty gravel with or without Wet - Water visible but not free draining, blank casing section o 0 2 � O Q 0 sand likely above optimum MC Screened casing o or Hydrotip with U) ° 0 .0 o Saturated/Water Bearing - Visible free filter pack o U) 0 � Clayey gravel with or water, typically below groundwater table End cap O -0-0 � ° L L LL C7 ^ GC without sand Terms Describing Relative Density and Consistency _ 0 co Z Coarse -Grained Soils: Test Symbols & Units Well -graded sand with u� O SW or without gravel, little to = Density SPT blows/foot Fines Fines Content ( ) oo N o c IL o°o°o°o°o°o °°°°°°°°°°° no fines Very Loose < 4 O LO U ._ U (n o MC =Moisture Content (%) Loose 4 to 9 ':: ca � 0 to , •:: •..:•.;: , . Poorly graded sand with DD = Dr Density cf Medium Dense 10 to 29 Y Y (P ) a)o v Sp or without gravel, little to o Z no fines Dense 30 to 49 Str = Shear Strength (tsf) 0 a)Very Dense _> 50 O U) PID = Photoionization Detector (ppm) co a� '.:' . SM Silty sand with or without o Lo c c :;: .::'•:. ;.. gravel Fine -Grained Soils: OC = Organic Content (%) e . •;. Consistency SPT blows/foot CEC = Cation Exchange Capacity (meq/100 g) : Very Soft < 2 � � SC Clayey sand with or LL = Liquid Limit (%) Soft 2 to 3 ^ without gravel Medium Stiff 4 to 7 PL = Plastic Limit (%) (%) Stiff 8 to 14 PI = Plasticity IndexLO CD Silt with or without sand IVIL or gravel; sandy or Very Stiff 15 to 29 gravelly silt Hard _> 30 0 0 0 U 0 F/// Clay of low to medium Y Component Definitions > a)—.1 plasticity; plasticity; lean clay with cn M t. or without sand or gravel; Descriptive Term Size Range and Sieve Number 00 cn E sandy or gravelly lean clay Boulders Larger than 12" — — _ � rn . — J U .5 Cobbles 3" to 12" �o _ OL Organic clay or silt of Zo — low plasticity Gravel 3" to No. 4 (4.75 mm) -0 to J �_ — Coarse Gravel 3" to 3/4" Fine Gravel 3/4" to No. 4 (4.75 mm) Elastic silt with or without d Sand No. 4 (4.75 mm) to No. 200 (0.075 mm) 0 0 o MH sand or gravel; sandy or Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm) c O (n g gravelly elastic silt Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm) IL 2 >, - Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm) 0 °o U O Clay of high plasticity; Silt and Clay Smaller than No. 200 (0.075 mm) o -0 LO CH fat clay with or without Modifier Definitions o E sand or gravel; sandy or J gravelly fat clay —_ Percentage by fn Weight (Approx.) Modifier CY OH Organic clay or silt of medium to high plasticity < 5 Trace (sand, silt, clay, gravel) 5 to 14 Slightly (sandy, silty, clayey, gravelly) o> ca o PT Peat, muck, and other 15 to 29 Sandy, silty, clayey, gravelly = �U) — = highly organic soils Q _> 30 Very (sandy, silty, clayey, gravelly) Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual — field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and ii FILL Made Ground plasticity estimates, and should not be construed to imply field or laboratory testing unless presented herein. Visual -manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an identification guide for the Unified Soil Classification System. Earth Solutions NW L�c Earth Solutions NWLLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services EXPLORATION LOG KEY Y Earth Solutions NW, LLC TEST PIT NUMBER TP-1 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81816 LONGITUDE-122.34815 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION w _ CL ~Lu _ wJ CO TESTS Q O MATERIAL DESCRIPTION p d7 ry Q Z 0 0.0 TPSL .`=: `. 0.3 Dark brown TOPSOIL Brown silty SAND, loose to medium dense, moist -probed 2" SM GB MC=6.4 20 Gray silty SAND, dense, moist 2.5 -moderately cemented, light iron oxide staining GB MC = 8.6 infiltration test at 4' Fines = 41.3 [USDA Classification: slightly gravelly sandy LOAM] -probed 0-1" 5.0 SM GB MC = 8.2 7.5 GB MC = 10.3 9.0 [USDA Classification: slightly gravelly sandy LOAM] Fines = 39.4 Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. J J W d F 2 0] J Q Uj W Z W Y Earth Solutions NW, LLC TEST PIT NUMBER TP-2 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 PAGE 1 OF 1 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81792 LONGITUDE-122.34793 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION W _ CL ~W _ wJ CO TESTS Q O MATERIAL DESCRIPTION p d7 ry Q Z 0 0.0 TPSL .`=: `. 0.3 Dark brown TOPSOIL Brown silty SAND, medium dense, moist -probed 1" SM Z. [USDA Classification: very gravelly sandy LOAM] GB MC = 5.3 2.5 Fines = 30.0 3.0 Gray silty SAND, dense, moist -moderately cemented GB MC - 5.3 -probed 0" 5.0 SM GB MC = 9.9 75 9.0 GB MC=6.6 Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. Y Earth Solutions NW, LLC TEST PIT NUMBER TP-3 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property DATE STARTED 8/14/23 COMPLETED 8/14/23 GROUND ELEVATION EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.81810 LONGITUDE-122.34839 LOGGED BY AZS CHECKED BY HTW GROUND WATER LEVEL: NOTES SZ AT TIME OF EXCAVATION SURFACE CONDITIONS Grass AFTER EXCAVATION w _ ~W _ wJ CO TESTS Q O MATERIAL DESCRIPTION p CL ry Q Z 0 0.0 Brown silty SAND with gravel, loose, moist (Fill) -probed 2-3", bricks, concrete, wood SM 12.5 roots 2.5 SM Brown silty SAND, medium dense, moist 3.0 GB MC - 8.7 Gray silty SAND, dense, moist -probed 0-1" -moderately cemented, light iron oxide staining 5.0 GB MC = 9.0 SM 7.5 GB 9.0 MC = 9.6 Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. Earth Solutions NW, LLC GRAIN SIZE DISTRIBUTION b..!Rml15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 PROJECT NUMBER ES-9396 PROJECT NAME Fulkerson Property U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER 6 4 3 2 1 5 1 1/2W 3 4 6 810 1416 20 30 40 50 60 100140 200 100 95 90 85 80 75 70 65 H x 60 w � 55 m w 50 z LL 45 z w 40 w a 35 30 25 20 15 10 5 0-11 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS k___ COBBLES GRAVEL SAND SILT OR CLAY fine coarse medium fine Appendix E - S411 BMPs For Landscaping and Lawn/Vegetation Management MC# VILL0001 Fulkerson single family residence 2024-10-09 VILL0001-Drainage Report.docx Drainage Report Page 24 of 25 S411 BMPs for Landscaping and Lawn / Vegetation Management Description of Pollutant Sources: Landscaping can include grading, soil transfer, vegetation planting, and vegetation removal. Examples include weed control on golf course lawns, access roads, and utility corridors and during landscaping; and residential lawn/plant care. Proper man- agement of vegetation can minimize excess nutrients and pesticides. 2019 Stormwater Management Manual for Western Washington Volume IV - Chapter 4 - Page 523 MC# VILL001 Drainage Report 7/17/2024 Fulkerson Single Family Residence 23 2024-07-16 Drainage Report.docx Pollutant Control Approach: Maintain appropriate vegetation to control erosion and the dis- charge of stormwater pollutants. Prevent debris contamination of stormwater. Where practicable. grow plant species appropriate for the site, or adjust the soil properties of the site to grow desired plant species. Applicable BMPs: • Install engineered soil/landscape systems to improve the infiltration and regulation of storm - water in landscaped areas. • Select the right plants for the planting location based on proposed use, available main- tenance,soil conditions, sun exposure, water availability, height, sight factors, and space avail- able. • Ensure that plants selected for planting are not on the noxious weed list. For example, but- terfly bush often gets planted as an ornamental but is actually on the noxious weed list. The Washington State Noxious Weed List can be found at the following webpage: https://www.nwcb.wa.gov/printable-noxious-weed-list • Do not dispose of collected vegetation into waterways or storm sewer systems. • Do not blow vegetation or other debris into the drainage system. • Dispose of collected vegetation such as grass clippings, leaves, sticks by composting or recyc- ling. • Remove, bag, and dispose of class A & B noxious weeds in the garbage immediately. • Do not compost noxious weeds as it may lead to spreading through seed or fragment if the composting process is not hot enough. • Use manual and/or mechanical methods of vegetation removal (pincer -type weeding tools, flame weeders. or hot water weeders as appropriate) rather than applying herbicides, where practical. • Use at least an eight -inch "topsoil' layer with at least 8 percent organic matter to provide a suf- ficient vegetation -growing medium. 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 indef- initely. • Select the appropriate turfgrass mixture for the climate and soil type. Certain tall fescues and rye grasses resist insect attack because the symbiotic endo- phytic fungi found naturally in their tissues repel or kill common leaf and stem -eating lawn insects. 2019 Stormwater Management Manual for Western Washington Volurne IV - Chapter 4 - Page 524 MC# VILL001 Drainage Report 7/17/2024 Fulkerson Single Family Residence 24 2024-07-16 Drainage Report.docx ■ The fungus causes no known adverse effects to the host plant or to humans. ■ Tall fescues and rye grasses do not repel root -feeding lawn pests such as Crane Fly larvae. ■ Tall fescues and rye grasses are toxic to ruminants such as cattle and sheep 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 Exten- sion 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: BMP C 120. Temporary and Permanent Seeding, BMP C121: Mulching, BMP C123: Plastic Covering, and BMP C124: Sodding. . Adjusting the soil properties of the subject site can assist in selection of desired plant species. Consult a soil restoration specialist for site -specific conditions. Recommended Additional BMPs: • Conduct mulch -mowing whenever practicable. • Use native plants in landscaping. Native plants do not require extensive fertilizer or pesticide applications. Native plants may also require less watering. • Use mulch or other erosion control measures on soils exposed for more than one week during the dry season (May 1 to September 30) or two days during the rainy season (October 1 to April 30). • 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. • Apply an annual topdressing application of 318" compost. Amending existing landscapes and turf systems by increasing the percent organic matter and depth of topsoil can: Substantially improve the permeability of the soil. o Increase the disease and drought resistance of the vegetation. Reduces the demand for fertilizers and pesticides. • Disinfect gardening tools after pruning diseased plants to prevent the spread of disease. • Prune trees and shrubs in a manner appropriate for each species. . If specific plants have a high mortality rate, assess the cause and replace with another more appropriate species. • When working around and below mature trees, follow the most current American National Standards Institute (ANSI) ANSI A300 standards (see 2019 Storm water Management Manual for Western Washington Volume IV - Chapter 4 - Page 525 MC# VILL001 Drainage Report 7/17/2024 Fulkerson Single Family Residence 25 2024-07-16 Drainage Report.docx http://www.tcia.org/TCIA/BUSINESS/ANSI A300 Standards /TCIA/BUSINESS/A300 Standards/A300 Standards. aspx?hkey=202ff566-4364-4686-b7cl-2a365af59669) and International Society of Arboriculture BMPs to the extent practicable (e.g., take care to min- imize any damage to tree roots and avoid compaction of soil). Monitor tree support systems (stakes, guys, etc.). • Repair and adjust as needed to provide support and prevent tree damage. • Remove tree supports after one growing season or maximum of 1 year. o Backfill stake holes after removal. . When continued, regular pruning (more than one time during the growing season) is required to maintain visual sight lines for safety or clearance along a walk or drive, consider relocating the plant to a more appropriate location. • Make reasonable attempts to remove and dispose of class C noxious weeds. • Re -seed bare turf areas until the vegetation fully covers the ground surface. • Watch for and respond to new occurrences of especially aggressive weeds such as Him- alayan blackberry, Japanese knotweed, morning glory, English ivy, and reed canary grass to avoid invasions. • Plant and protect trees per BMP T5.16: Tree Retention and Tree Planting. . Aerate lawns regularly in areas of heavy use where the soil tends to become compacted. Con- duct aeration while the grasses in the lawn are growing most vigorously. Remove layers of thatch greater than'/, -inch deep. • 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. Mowing is a stress -creating activity for turfgrass. Grass decreases its productivity when mowed too short and there is less growth of roots and rhizomes. The turf becomes less tolerant of environmental stresses. more dis. ease prone and more reliant on outside means such as pesticides, fertilizers, and irrig- ation to remain healthy. Additional BMP Information: . King County's Best Management Practices for Golf Course Development and Operation (King County, 1993) has additional BMPs for Turfgrass Maintenance and Operation. • King County, Seattle Public Utilities, and the Saving Water Partnership have created the fol- lowing natural lawn and garden care resources that include guidance on building healthy soil with compost and mulch, selecting appropriate plants, watering, using alternatives to pesti- cides, and implementing natural lawn care techniques. 2019 Stormwater Management Manual for Western Washington Volume IV - Chapter 4 - Page 526 MC# VILL001 Drainage Report 7/17/2024 Fulkerson Single Family Residence 26 2024-07-16 Drainage Report.docx ■ Natural Yard Care -Five steps to make your piece of the planet a healthier place to live (King County and SPU. 2008) • The Natural Lawn & Garden Series: Smart Watering (Saving Water Partnership, 2006) • Natural Lawn Care for Western Washington (Saving Water Partnership, 2007) ■ The Natural Lawn & Garden Series: Growing Healthy Soil: Choosing the Right Plants; and Natural Pest. Weed and Disease Control (Savino Water Partnershio. 2012) The International Society of Arboriculture (ISA) is a group that promotes the professional prac- tice of arboriculture and fosters a greater worldwide awareness of the benefits of trees through research. technology. and education. ISA standards used for managing trees. shrubs, and other woody plants are the American National Standards Institute (ANSI) A300 standards. The ANSI A300 standards are voluntary industry consensus standards developed by the Tree Care Industry Association (TCIA) and written by the Accredited Standards Com- mittee (ASC). The ANSI standards can be found on the ISA website: www.isa-arbor.- com/education/publications/index.aspx Washington State University's Gardening in Washington State website at http://garden- ing.wsu edu contains Washington State specific information about vegetation management based on the type of landscape. Seethe Pacific Northwest Plant Disease Management Handbook (Pscheidt and Ocamb, 2016) for information on disease recognition and for additional resources. MC# VILL001 Drainage Report 7/17/2024 Fulkerson Single Family Residence 2024-07-16 Drainage Report.docx 27 Appendix F - Flow Frequency Calculations MC# VILL0001 Drainage Report Fulkerson single family residence Page 25 of 25 2024-10-09 VILL0001-Drainage Report.docx WWHM2012 PROJECT REPORT MINIMUM REQUIREMENT #7 CHECK FOR 0.15 CFS INCREASE General Model Information WWHM2012 Project Name: MR#7 Site Name: Fulkerson Site Address: 8503 200th Street SW City: Edmonds Report Date: 10/16/2024 MGS Region: Puget East Data Start: 1901 /10/1 Data End: 2058/09/30 Timestep: 15 Minute DOT Data Number03 Version Date: 2024/06/28 Version: 4.3.1 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year MR#7 10/16/2024 4:22:30 PM Page 2 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.28 Pervious Total 0.28 Impervious Land Use acre ROOF TOPS FLAT 0.05 DRIVEWAYS FLAT 0.02 Impervious Total 0.07 Basin Total 0.35 Element Flow Componants: Surface Interflow Componant Flows To: POC 1 POC 1 Groundwater MR#7 10/16/2024 4:22:30 PM Page 3 Mitigated Land Use Basin 1 Bypass: Yes GroundWater: No Pervious Land Use acre C, Pasture, Flat 0.23 Pervious Total 0.23 Impervious Land Use acre ROOF TOPS FLAT 0.08 DRIVEWAYS FLAT 0.01 Impervious Total 0.09 Basin Total 0.32 Element Flow Componants: Surface Interflow Componant Flows To: POC 1 POC 1 Groundwater MR#7 10/16/2024 4:22:30 PM Page 4 Lateral I Basin 1 Bypass: No Impervious Land Use acre DRIVEWAYS FLAT 0.03 Element Flow Componant: Surface Componant Flows To: POC 1 MR#7 10/16/2024 4:22:30 PM Page 5 Routing Elements Predeveloped Routing MR#7 10/16/2024 4:22:30 PM Page 6 Mitigated Routing MR#7 10/16/2024 4:22:30 PM Page 7 Analysis Results POC 1 ff i 4- 0.0 u o.a 0 J IL 0.0 0,0 1 If, nri Percent Time Exceeding + Predeveloped Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.28 Total Impervious Area: 0.07 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.23 Total Impervious Area: 0.12 10 Cumulative Pmbabilily 10 0.1 xxx x °n LL x++ 0.01 0.01 0.5 1 2 5 10 20 30 50 70 80 90 95 96 99 99.5 1 x Mitigated Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.028951 5 year 10 year 0.045562 PRE -DEVELOPED CONDITION CAN MATCH 0.06009 25 year 0.083298 EXISTING (CURRENT) CONDITIONS SINCE 50 year 0.104702 HOUSE WAS CONSTRUCTED PRIOR TO 1977 100 year 0.130185 1�, Flow Frequency Return Periods for Mitij@ted. POC #1 Return Period 2 year Flow(cfs) 0.038334 NOTE: THERE IS NOT AN INCREASE OF 0.15 CFS 5 year 0.052266 BETWEEN THE PREDEVELOPED AND MITIGATED 10 year 0.062725 CONDITION IN THE 100-YEAR STORM. THEREFORE, 25 year 0.077423 FLOW CONTROL IS NOT REQUIRED. THERE IS A 50 year 0.089501 DECREASE IN THE 100-YEAR STORM DUE TO ALL 100 year 0.102591 LANDSCAPED AREAS RECEIVING TOPSOIL AMENDMENT WHICH CAN BE MODELED AS PASTURE Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1902 0.025 0.043 1903 0.030 0.046 1904 0.058 0.056 1905 0.019 0.025 1906 0.017 0.027 1907 0.033 0.039 1908 0.024 0.032 1909 0.025 0.039 1910 0.037 0.040 1911 0.029 0.040 MR#7 10/16/2024 4:22:30 PM Page 8 Disclaimer Legal Notice 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, 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. 2005-2024; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com MR#7 10/16/2024 4:23:42 PM Page 32