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22401 98TH AVE W.PDFlill 11111111 9703 22401 98TH AVE W SOUTH FORK GEOSCIENCES, PLLC PO Box 1275 NORTH BEND, WA 98045 (425) 831-2023 ANDREWeSFGEO.COM VREET FILE December 3, 2015 Project #15062 The Leren Company Inc. DEC 2 8 2015 PO Box 12863 Mill Creek, WA 98082 BUILDING DEpARWENT GM of EDMONDS Attention: Mr. Tom Leren Subject: Additional Supplemental Information Soil Assessment for Stormwater Infiltration/Low Impact Development BMP Simplified Sizing Proposed Addition — Strayer Residence Parcel #00450701200007 2240198"' Avenue West, Edmonds, WA 98020 Mr. Leren: The purpose of this letter is to provide some additional clarification with respect to our previous work on the project, which was documented in the referenced letter (South Fork Geosciences, August 11, 2015). It is our understanding that through the course of the project design, the stormwater flow control measures for the proposed addition were changed from an infiltration drywell to a "rain garden" type of facility. This proposed rain garden will be constructed approximately 25 to 30 feet north of our previous soil exploration. Based on our phone discussions and e-mail correspondence with Mr. Leren and Mr. Jeff Haynes, PE (CSP Engineering), it is our understanding that City of Edmonds staff has requested additional soils information for the new location. Based on our previous site reconnaissance, we observed native Vashon lodgement till soils on the subject property. Due to the relatively flat topography, and how the grades on the property compared to adjacent properties and streets, we did not observe any signs of significant fill soils. Based on these observations, the nearby location of our previous exploration, and in combination with our knowledge of the regional geologic setting, it is our opinion that our previous work that was documented in the referenced letter suitably characterizes the shallow subsurface soils with respect to infiltration in the new rain garden location. Though we mentioned this in our previous letter, the roof runoff currently generated by the site discharges from downspouts directly onto the ground surface. This would be considered a substandard stormwater best management practice by current standards, yet this has been performing without observed problems or impacts since the home was constructed. It stands to reason that similarly sized drainage areas routed to modern best management practices such as rain gardens or infiltration facilities will function properly upon construction. SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045,(425) 831-2023 Closure We have enjoyed working with you on this project and are confident that the information provided in this letter will aid in the design of your project. If there are any questions about this letter, please feel free to contact us. Sincerely, Andrew L. Glandon, LEG, CPESC Geologist / Owner South Fork Geosciences, PLLC References: "Soil Assessment for Stormwater Infiltration/Low Impact Development, BN1P Simplified Sizing, Proposed Addition — Strayer Residence, Parcel #00450701200007, 2240198' Avenue West, Edmonds, WA 98020", South Fork Geosciences, PLLC, August 11,2015 2 SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045,(425) 831-2023 a7t!�) t��- - 0 & 07 SOUTH FORK GEOSCIENCES, PLLC PO Box 1275 NORTH BEND, WA 98045 (425) 831-2023 AGLANDON@COMCAST.NE'r The Leren Company Inc. PO Box 12863 Mill Creek, WA 98082 Attention: Mr. Tom Leren August 11, 2015 Project #15062 L �43 SEP 18 2015 BUILDYIN,G DEPARTMENT aT DF EDMONDS Subject: Soil Assessment for Stormwater Infiltration/Low Impact Development BMP Simplified Sizing Proposed Addition — Strayer Residence Parcel #00450701200007 2240198' Avenue West, Edmonds, WA 98020 Mr. Leren: The purpose of this letter is to summarize our assessment of the onsite soils for stormwater infiltration. Based on our phone discussions and e-mail correspondence, it is our understanding that the City of Edmonds uses the referenced document (#E72B) for Low Impact Development Best Management Practices (LID BMP) facility sizing. Based on our review of this document, the sizing for these facilities can be determined by using the USDA soil textural classification of the receptor soil, in accordance with the long-term infiltration rates set forth in the 2005 DOE Stormwater Management for Western Washington (2005 DOE Manual). The following sections will briefly describe the property, the shallow subsurface conditions, and our conclusions with respect to LID BMP sizing. Site Description The property was located at 22401 98h Avenue West in Edmonds, Washington. According to the King County Assessor Records, the property was 8,400 square feet (0. 19 acres) in size. There was an existing single family residence and garage on the property, with associated landscaping and grading for the driveway and yard areas. The property was flat to very gently sloping and we estimate that the total relief on the property was on the order of 3 feet. The property was bordered by 224th Street SW to the north, 98th Avenue West to the west, and by residential properties to the south and east. 1 SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045,(425) 831-2023 Subsurface Conditions Subsurface conditions on the property were inferred from a visual reconnaissance of the property, a review of the referenced geologic map (Minard, 1983), and one hand auger boring. The hand auger boring was logged by the undersigned licensed engineering geologist. The location of the hand auger boring is shown in the attached Site and Exploration Plan and the log are attached to this report. Our interpretation of the near surface, native soils as Vashon lodgement till sediments is in agreement with the referenced geologic map. Stratigraphy Vashon Lodgement Till Based on our hand auger boring, our review of the referenced geologic map, and our knowledge of the area, we interpret the near surface native soils on the subject property as Vashon lodgement till sediments. Lodgement till sediments are a dense, poorly sorted mixture of clay, silt, sand, and gravel that was deposited at the sole of the Vashon glacial ice. These sediments typically possess high strength, low permeability, and low compressibility characteristics as a result of consolidation from being overridden by several thousand feet of glacial ice. Vashon lodgement till sediments, due to their glacially consolidated nature, are relatively dense in place and erosion resistant. Hydrology There was no groundwater seepage observed or signs of past high groundwater table such as mottling or oxidation observed in the hand auger boring. Though groundwater conditions are subject to change seasonally, based on the sediments observed and the geologic setting it is our opinion that the likelihood of a static groundwater table at less than 8 feet below the ground surface is extremely low. USDA Soil Textural Classification A sample of the soil from the depth interval from 2 to 2.5 feet was obtained from the hand auger boring for laboratory testing. A sieve analysis with hydrometer was performed on the sample. The results of this grain size analysis is attached to this report. After normalizing the percentages for the material passing the #4 sieve (fine gravel/coarse sand threshold), the USDA Soil Texture Triangle classification was determined to be "sandy loam", as shown in the USDA Soil Textural Classification attachment. LIB BMIP Sizing As previously stated, we determined that the receptor soil is classified as a "sandy loam" using the USDA Textural Classification. In Table 3.7 "Recommended Infiltration Rates based on USDA Soil Textural Classification" in Volume III of the 2005 DOE Manual, the Estimated Long -Term (Design) Infiltration Rate for a "sandy loam" is 0.25 inches per hour. 2 SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045,(425) 831-2023 Observations of Eidstinix Downspouts During our site reconnaissance, we observed the gutter downspouts on the existing home. These downspout pipes were routed directly to the ground surfacewithout any splash pad or dispersion - type BMP in place. We did not observe signs of significant surface flow or erosion from these downspout locations. Since the subject property is relatively flat and there are no signs of significant surface flow or erosion associated with the existing downspouts, it is our opinion that the roof runoff from the proposed addition could be dispersed using splash pads, as long as the impervious surface drained per each new downspout is similarly sized to that of the existing house. It is our opinion that this alternative would be functionally equivalent to drywells or infiltration trenches and based on the historical performance of the exiting downspouts, it would not adversely affect the subject or adjacent properties. Closure We have enjoyed working with you on this project and are confident that the information provided in this letter will aid in the design of your project. If there are any questions about this letter, please feel free to contact us. Sincerely, Andrew L. Glandon, LEG, CPESC Geologist / Owner South Fork Geosciences, PLLC Attachments: Vicinity Map Site and Exploration Plan Hand Auger Boring Logs Grain Size Analysis USDA Soil Textural Classification References: "City of Edmonds Development Information, Low Impact Development (LID) Stormwater Best Management Practices (BMPs) Simplified Sizing" #E72B "Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, Washington", Minard, James P., 1983, United States Geological Survey, Miscellaneous Field Studies, Map MF-1541, Scale 1:24,000 . 3 SOUTH FORK GEOSCIENCES, PO Box 1275, NORTH BEND, WA 98045,(425) 831-2023 Not to Scale f 4 Site Pr _q. &IDIOM Vicinity Map Strayer Residence Addition, 22401 98 1h Avenue West, Edmonds, WA Project #15062 Site Plan SCALE: ["=20.00' 0. 10' 20' 50' 40' 50' Site Address 22401 q&TH AVE KEST EDMON05, KA qb02O Owner Compost Soil Note ALL OISTUR5ED SOILS 5KALL W = CAOMPOST AMENDED PER BW TS.15 Or THE STOR141LATER RANUAL. ii, 60' Cut and Fill — CJJT, 60 YOS. FILL� 20 YDS. (APPRO>O Height Calculations A 102.15 IS 105.5 1045 1045 AVERAGe 105.D2' MAX HEIew: 12bb2' ACTUAL RIP615 KT. 125,152' EASTINS MAIN FLOOR� 106.001 DP. AT SEIAER MR. IN ROAD SET 0 100,00, MELINDA 4 TIMOTHY STRAYER 22401 q&TH AVE NEST EDMONDS, KA c15020 Filter Socks Slit Fence FILTER SOCKS PER CITY OF SIL FENCES AS INDIOATED ON 51TE Assessoes Parcel No. EDMONDS STANPARD DETAIL E1.5. PLAN PER CITY OF EDMONDS 00450`70Q�M STANDARD DETAIL EI.I. Conventional SWM T Stockpile AS INDICATED ON SITE PLAN. F)CATIWr, GFV4rQ MH Excess Material - Excavation TO BE USED AROUND PERIMETER AND AS PILL. Drainaue NIEN IMPERVIOUS UNDER 2000 5F TO BE HITH 5PLA5HELOCK5. AREA OVER 2000 TO BE INFILTRATED IN 4' VIA. x 60" INFILTRATION PIT PER 5117E PLAN. Erosion Control EX15TINC, LANDSCAPE TO REMAIN. AREA OF DISTURBANCE TO BE COVERED WITH 5TR.AA AND SILT FENCE PERIMETER. Lot Size &400 50. FT. Building Footprint HOUSE (EXISTINS.) c04 50. FT. NEH ADDITION 1245 TOTAL 50 1 F T. 22211 LOT COVERArDE 26.5% F09N, e and Exploration Plan il Assessment for Stormwater Infiltration aver Residence Addition -J L- — — — — — — — — — — - —LAHNr EASTINC7 "S— "S— "S w RE4loENCE Imnervious surface calca Type Area (sq. ft.) 1 Non -regulated 2§49 Exarnpl jm�empt 2 'Replaced 754 3 New (P��1977) 1615 4 Total Regula6kimpe-1-d- Area MidgatIon mqked If In alqmq� al 2369 5 Total area mIdg3A"xIstIng storm.tr managementsystem. 2000 6 Regula��rea not yet m1fil d. 369 7 Ares,proposed to be mitigated by )Zw'mpa ct Development Tech. Z7 Area proposed to be mitigated by echniques. ' NEK DRVEMY 'E" 'VE'1AY 5 '!Z Emo Exi5T X 5TOCKPIL I ,-SILT PENCE ... ....... .. . k M. 3 �;OROI`05EV ADDITION Ali 10 'DIA x 60" DEEP - INFILTRATION I PIT K/ CRUSHED I ROCK ---- -- ---------- 1 0.00 X15 11116 PATIO Tj BE REMOVED SILT 111111-M Strayer Residence Addition Edmonds, WA Date: 7-30-2015 Depth Number: HB-1 (it) 0 Sod/Topsoil (0-2") Vashon Lodgement Till loose to medium dense, dry, light brown silty fine SAND with gravel (SM) 1 - roots present to 1.5ft 2 d Idense, dry to damp, light gray silty fine SAND with gravel (SM) Total Depth = 2-5ft Refusal due to density 3 No groundwater seepage observed No caving observed Sample taken @ 2-2.5ft for grain size analysis 2 5 2 7 Hand Auger Boring Log IThe subsurface conditions shown on this field log represent our observations at the time and location of excavation, twdified by geologic intetpretation and judgment, and where noted, by engineering analysis and laboratory testing. The conditions shown may not be representative of conditions at other tirms. South Fork Geosciences will not be responsible for use or intetprelation by others of inforrnation presented on these logs. Project # 15062 SouTH FoRK GEOSCIENCES PO Box 1275 NORTH BEND, WA 98045 PHONE: (425) 831-2023 10C 9C 8C 70 Particle Size Distribution Report d . ..e 0 0 0 d 6 6 S G co 0 C� -It M- V a 8 �! ;! C, U :11 * :2, 9 TEST RESULTS Opening Percent Spec.* Pass? Size Finer (Percent) (X=Fail) 2 100.0 1 82.0 3/4 78.0 3/8 67.0 #4 62.0 #10 56.0 #40 47.0 #60 40.0 #100 31.0 #200 22.8 #270 18.9 #325 17.3 0.0344 turn. 13.6 0.0222 nun. 11.8 0.0131 mm. 9.3 0.0094 mm. 8.0 0.0067 nun. 6.8 0.0048 mm* 5.6 0.0033 mm. 4.9 Material- Description Lt. Grey silty sand with gravel Afterberg Limits (ASTM D 4318) PL= NP LL= NV PI= NV Classification USCS (D 2487)= SM AASHTO (M 145)= A- I -b Coefficients D,O: 01114117 D,5= 019.60079 D60 3:053146 D50 .61 5 D3 = .14 2 D IS: 0 82 D10= 0.0151 cu� 232.41 Cc= 0.37 Remarks Equipment: 53, 66, 58, 141 Date Received: 7/30/2015 Date Tested: 8/5/2015 Tested By: J. Hoover Checked By: Mike Blackwell Title: Laboratory Manager . (no specification provided) Source of Sample: Strayer Residence #15063 Depth: 2'- 2.5' Date Sampled: 7/30/2015 Samale Numbdr: HB-I - A.A.R. Client: So. Fork Geosciences Testing Project: Misc. Lab Laborato!y, Inc. Proig-d NP: 15-103 Figure -- 15-165 too RLAAMAMAII M MWA INX I ZWA 0 0, -00 10, '0 `b 4 Sande'7, USDA Soil Textural Classification Strayer kesidence Addition, 22401 98 th Avenue West, Edmonds, WA Project #15062 PLANNING DATA SINGLE FAMILY RESIDENTIAL :F[L:E:] Name: Date: tz, t( Site Address: Plan Check #: Project Description: Reduced Site Plan Provided: (YES /)10) Zoning: Map Page: --------- —". Corner LoVJ5R NO) Flag Lot: (YES /QEOD Critical Areas Determination #: El Study Required U4-141= M—Waiver SEPA Determination: Exempt Needed (for over 500 cubic yards of grading) 0 Fee 0 Checklist 0 APO List with notarized form Required Setback5 ('10 St t: Sid Sid. - Actual Setback5 Street: S t7d e: Detached Structures: Rockeries: Fences/Trellises: El Bay Windows/ Projecting Modulation: El Stairs/Deck: Height Datum Point: 4\ Datum Elevation: Maximum Height Allowed: Actual Height: ZJ7 -F Other Parking Required: 2- Parking Provided: e.-I d.,,c -7-0 Lot Area: S t'Ll 0 C9 Maximum Lot Coverage: 35% Proposed: 7 Lot Coverage Calculations: I-ILI V /11S ADU Created: (YES Subdivision: k.JV,1-4"u-C, Vonles+e0fd AtY- Legal Nonconforming Land Use Determination Issued: (YES / NO) LLig 14 Comments 10 lo 3 .5- Z_57 -- t 2, V 0070 -Z a,4 CP-fqrLK1U re /Gy. Pla n Review By: A &A 6*� I , wte�)(Pv- //) �-Arrl- Planning Data Form 04-11-06.doc Site Plan 50ALE: I"=20.00' 01 101 20, 501 4o' 5o' bol Site Address 22401 cWH AVE 1-*,E5T EDMONDS, KA c15020 Owner MELINDA 4 TIMOTHY STRAYER 22401 41bTH AVE NEST EDMONDS, KA 11b02O AssessoesParcel No. 00450-10120000-1 Stockpile AS INDICATED ON SITE PLAN. Excess Material - Excavation TO BE USED AROUND PERIMETER AND AS FILL. Drainage PER CIVIL PLAN (BY OTHERS) Erosion Control EX15TIN6 LANDSCAPE TO REMAIN. AREA OF DISTURBANCE TO BE COVERED NITH STRAIN AND SILT FENCE PERIMETER. Lot Size 5400 50. FT. Building Footprint HOUSE (r=X15TINC7 Wilt Icl:299 cl&4 50. FT. NEN ADDITION 1245 TOTAL 50. FT. 222cl LOT COVERA&E 26.5% Compost Soil Note ALL P15TUREWD SOILS SHALL 5E COMPOST AMENDED FER 5MF T5.15 OF THE STORMKATER MANUAL. Cut and Fill CUT: bo Ylrm. FILL: 20 YDS. (APPROX) Height Calculations A 102.15 B 1055 0 1045 0 1045 AVERASE 10�.621 MAX �EIOW-- 126.62, ACTUAL RIVC7E HT. 125,D2' EXISTIN6 MAIN FLOOR: 106.00, D.P. AT SE)AIER M.H. IN ROAD SET a 100.00' Filter Socks Silt Fence FILTER SOCKS PER CITY OF SILT FENCES AS INDICATED ON SITE EDMONDS STANDARD DETAIL EI.5. PLAN PER CITY OF EDMONDS STANDARD DETAIL EI.I. EX15TINO SENER M.H. DATV POINT @ 100.00- Appll�,nt sha� rep&/ 0�' ftn�age hpnovz��Qn'iz-' U�v r a pr Ci,,,y StEg;�eF- or occurt, durlig 0WHER/CONTFUCT0.9 IS RESPONSIBLE FOR P � 0-Q! ON TR C-'- .4 PTI D P2,! � -16. r�- -�� 224TH ST. S.H. Zone J��-F Comer Fla& — Setback Reauired Actual 4,- a10.-\ Front,v/vj -i-67-77g- SidesF/� 2- 7- Rear Other ENGNEF-RiNG DIVL90N AIr ED AS NOTEQ Date.J1926(0 0%44516 AvbO Sox Ct, F09- fAW(pNtV6IkJ O6-S-1CQU 0111LIFAM-So. ASPHALT DRIVE IN R.O.A. (SEE CIVIL) 4---RAIN OARVEN 11 PER CIVIL NCE 0*129 H III E e L-b 2D(�-060� BUILDING DEPARTMENT CITY OF EDMONDS STORMWATER MANAGEMENT PLAN "M ........... GENERAL SPECIFICA71ONS ALL MATERIALS, WORK, AND CONSTRUCTION WORKMANSHIP SHOWN ON THESE PLANS SHALL CONFORM TO THE APPROVED STANDARD PLANS AND SPECIFICATIONS OF THE LOCAL GOVERNING AUTHORITY. EXCEPT WERE ADOPTED LOCAL STANDARDS PROVIDE OTHERWISE, ALL MATERIALS, WORK, AND CONSTRUCTION WORKMANSHIP SHOWN ON THESE PLANS SHALL ALSO CONFORM TO THE CURRENT EDITIONS OF THE FOLLOWING SPECIFICATIONS AND CODES, AND ALL OTHER APPLICABLE LOCAL MUNICIPAL, STATE, AND FEDERAL CODES, RULES AND REGULATIONS. -INTERNATIONAL BUILDING CODE -WSDOT/APWA STANDARD SPECIFICATIONS FOR ROAD, BRIDGE AND MUNICIPAL CONSTRUCTION -WASHINGTON STATE DEPARTMENT OF ECOLOGY STORMWATER MANAGEMENT MANUAL FOR WESTERN WASHINGTON THE ABOVE REFERENCED DOCUMENTS SHALL BE CONSIDERED AS INCORPORATED INTO THIS PLAN SET BY REFERENCE. SELECTED STANDARD DETAILS AND NOTES FROM THE ABOVE REFERENCED DOCUMENTS ARE ILLUSTRATED ON THESE PLANS TO FACILITATE CONSTRUCTION OF THIS PROJECT HOWEVER NOT ALL OF THE INFORMATION REFERENCED ABOVE IS INCLUDED. THE CONTRACTOR IS RESPONSIBLE FOR OBTAINING COPIES OF THE ABOVE REFERENCED DOCUMENTS AND COMPLYING WITH THE SPECIFICATIONS AND STANDARD DETAILS IDENTIFIED THEREIN. PERMITS 1. THE CON TRACTOR/DEVELOPER/OWNER SHALL BE SOLELY RESPONSIBLE FOR OBTAINING ALL NECESSARY LOCAL, STATE, AND FEDERAL PERMITS NECESSARY FOR THE IMPLEMENTA71ON OF THE PROJECT ILLUSTRATED ON THESE PLANS. AS -BUILT RECORDS 1. A COPY OF THESE APPROVED PLANS MUST BE ON THE JOBSITE WHENEVER CONSTRUCTION IS IN PROGRESS. 2. DEVIATIONS FROM THESE PLANS MUST BE APPROVED BY THE ENGINEER OF RECORD AND THE LOCAL GOVERNING AUTHORITY. 3. THE CONTRACTOR SHALL RECORD ALL DEVIA71ONS FROM THESE PLANS ON A SET OF "AS -BUILT" DRAWINGS AND SHALL SUMMARIZE ALL AS -BUILT CONDITIONS ON ONE SET OF REPRODUCIBLE DRAWINGS FOR SUBMITTAL TO THE APPROPRIATE PERMITTING AGENCIES PRIOR TO PROJECT COMPLETION AND ACCEPTANCE. SURVEY INFORMATION / EXISTING U71LITIES AND SITE FEATURES 1. LEGAL DESCRIPTION, VERTICAL DATUM, BASIS OF BEARING, BENCHMARKS & MONUMENT TIES ILLUSTRATED ON THESE PLANS HAVE BEEN PROVIDED BY OTHERS OR OBTAINED FROM ONLINE, DESIGN, ANDIOR AS -BUILT RECORDS. 2. THE LOCATIONS OF EXISTING UTILITIES AND SITE FEATURES ILLUSTRATED ON THESE PLANS HAVE BEEN PROVIDED BY OTHERS BY FIELD SURVEY OR OBTAINED FROM ONLINE, DESIGN, ANDIOR AS -BUILT RECORDS AND SHOULD THEREFORE BE CONSIDERED APPROXIMATE ONLY AND NOT NECESSARILY COMPLETE. 3. CSP ENGINEERING ASSUMES NO RESPONSIBILITY FOR THE COMPLETENESS OR ACCURACY OF INFORMATION ILLUSTRATED ON THESE DRAWINGS WHICH HAS BEEN PROVIDED BY OTHERS OR OBTAINED FROM OTHER SOURCES. 4. IT IS THE SOLE RESPONSIBILITY OF THE CONTRACTOR TO INDEPENDENTLY VERIFY THE ACCURACY OF ALL UTILITY LOCATIONS ILLUSTRATED ON THESE PLANS AND TO FURTHER DISCOVER AND PROTECT ANY OTHER UTILITIES NOT SHOWN HEREON WHICH MAY BE AFFECTED BY THE IMPLEMENTATION OF THIS PLAN. 5. THE CONTRACTOR IS RESPONSIBLE FOR VERIFYING ALL CONDITIONS AND DIMENSIONS AT THE PROJECT SITE, INCLUDING THE LOCATION, DEPTH, SIZE, TYPE, CONDITION, AND CONFIGURATION OF EXISTING UTILITIES AT CONNECTION OR CROSSING POINTS, BEFORE TRENCHING FOR NEW UTILITIES, CONSTRUC71NG ANY SITE FEATURES, OR ORDERING ANY PRECASTIPREFABRICATED ITEMS ASSOCIATED WITH THE IMPLEMENTATION OF THIS PROJECT. 6. THE CONTRACTOR SHALL NOTIFY THE OWNER'S REPRESENTATIVE AND CSP ENGINEERING OF ANY DISCREPANCIES FOUND IN THE FIELD WHICH MAY AFFECT THE IMPLEMENTATION OF THIS PROJECT. 7. CONTRACTOR SHALL PROTECT ALL UTILITIES DURING CONSTRUCTION AND SHALL CONTACT THE UNDERGROUND UTILITIES LOCATION SERVICE (1-800-424-5555) AT LEAST TWO (2) BUSINESS DAYS PRIOR TO CONSTRUCTION. SHOP DRAWINGS / REQUESTS FOR INFORMAT10N / FIELD REVISIONS 1. SHOP DRAWINGS FOR ALL PRECAST ANDIOR PREFABRICATED ITEMS, CAST -IN -PLACE DRAINAGE STRUCTURES, AND GENERIC ITEMS (I.E. YARD DRAINS) SHALL BE SUBMITTED TO CSP ENGINEERING FOR REVIEW PRIOR TO FABRICATION, INSTALLATION, ANDIOR DELIVERY TO THE SITE. 2. SHOP DRAWING SUBMITTALS, REQUESTS FOR INFORMATION OR CLARIFICA77ON OF DESIGN DOCUMENTS, AND PROPOSED FIELD REVISIONS MUST BE SUBMITTED TO CSP ENGINEERING IN WRITING VIA FAX, EMAIL, OR U.S. POSTAL SERVICE. ALL CORRESPONDENCE SHALL BE ROUTED THROUGH, REVIEWED AND COORDINATED BY THE ARCHITECT OF RECORD OR THE OWNER'S SITE REPRESENTATIVE PRIOR SUBMISSION TO CSP ENGINEERING. CUT / FILL / SITE STRIPPINGS / SOIL CONDITIONS 1. CUT, FILL, AND SITE STRIPPING QUANTITIES DELINEATED ON THESE PLANS WERE CALCULATED IN WHOLE OR IN PART UTILIZING COMPUTER SOFTWARE COMPARING EXISTING GRADE CONTOURS TO FINISH GRADE CONTOURS AND CLEARING LIMITS ILLUSTRATED ON THE PLANS AND DO NOT ACCOUNT FOR THE INSTALLATION OF UNDERGROUND UTILITIES OR STRUCTURES, SOIL SWELLING OR SHRINKAGE, OR FOR UNSUITABLE MATERIAL WHICH MAY BE PRESENT ON THE SITE. CUT, FILL, AND SITE STRIPPING QUANTITIES SHOULD BE CONSIDERED APPROXIMATE ONLY AND SHOULD NOT BE RELIED UPON FOR BIDDING PURPOSES. 2. CONTRACTOR SHALL BE RESPONSIBLE FOR CALCULATING ANDIOR VERIFYING THE CUT, FILL AND SITE STRIPPING QUANTITIES NECESSARY FOR THE IMPLEMENTA71ON OF THIS PROJECT. BOTH EXPORT AND IMPORT OF SOIL AND ROCK MATERIALS WILL BE REQUIRED. 3. CONTRACTOR SHALL OBTAIN A COPY OF THE PROJECT GEOTECHNICAL REPORT (IF APPLICABLE) AND PERFORM ALL SITE WORK IN STRICT COMPLIANCE WITH THE RECOMMENDATIONS CONTAINED THEREIN. 4. ANY DISTURBED, SOFT, OR LOOSE SOIL OR ORGANIC MATERIAL ENCOUNTERED DURING CONSTRUCTION SHALL BE EVALUATED BY A GEOTECHNICAL ENGINEER TO PROVIDE REMOVAL ANDIOR REPLACEMENT RECOMMENDATIONS. 5. ALL Fit I SHALL BE PLACED ON SUITABLE NATIVE MATERIAL AS APPROVED BY GEOTECHNICAL ENGINEER WITH TOP 12" COMPACTED TO A MINIMUM OF 95% RELATIVE COMPACTION. 6. FILL MATERIAL SHALL BE SUITABLE NATIVE MATERIAL APPROVED FOR USE BY A GEOTECHNICAL ENGINEER OR COMMON GRAVEL BORROW (WSDOT 9-03.14) PLACED IN MAX 8" LIFTS AND COMPACTED TO 90% MAX DRY DENSITY (AASHTO T180) TO WITHIN 2' OF FINISH SUBGRADE. TOP 2' OF FILL MATERIAL SHALL BE PLACED IN MAX 4" LIFTS AND COMPACTED TO 95% MAX DRY DENSITY (AASHT0 T180). SITE GRADING / EROSION CONTROL 1. AS A MINIMUM REQUIREMENT, ALL DISTURBED AREAS WITHIN RIGHT-OF-WAYS SHALL BE RETURNED TO THE EQUIVALENT OF THEIR PRECONSTRUCTION COND17ION IN ACCORDANCE MTH APPROPRIATE REQUIREMENTS AND STANDARDS. 2. ALL DISTURBED SOIL AREAS SHALL BE SEEDED OR STABILIZED BY OTHER ACCEPTABLE METHODS FOR THE PREVENTION OF ON -SITE EROSION AFTER THE COMPLETION OF CONSTRUCTION. SEE EROSION CONTROL PLANS FOR SPECIFIC GRADING AND EROSION CONTROL REQUIREMENTS. 3. THE CONTRACTOR SHALL KEEP OFF -SITE STREETS CLEAN AT ALL TIMES BY SWEEPING. WASHING OF STREETS WILL NOT BE ALLOWED WITHOUT PRIOR APPROVAL. 4. SLOPE OF FINISHED GRADE SHALL BE CONSTANT BETWEEN SPOT ELEVATIONS SHOWN. TOPOGRAPHIC CONTOURS SHOULD BE CONSIDERED APPROXIMATE ONLY AND SHOULD NOT BE RELIED UPON FOR FINAL SITE GRADING. 5. FINISHED GRADE OF LANDSCAPED AND OTHER PERVIOUS SURFACES SHALL SLOPE AWAY FROM BUILDINGS AT A MINIMUM OF 57. FOR A MINIMUM DISTANCE OF 10 FEET. 6. CONTRACTOR SHALL BE RESPONSIBLE FOR AND SHALL INSTALL, MAINTAIN, AND REMOVE SHORING AND BRACING AS NECESSARY TO PROTECT WORKERS, EXISTING BUILDINGS, STREETS, WALKWAYS, UTILITIES, OTHER EXIS77NG AND PROPOSED IMPROVEMENTS AND EXCAVATIONS AGAINST LOSS OF GROUND OR CAVING EMBANKMENTS. U711JTY CONNECTIONS / U71UTY INTERRUPTIONS 1. ALL WATERISEWERISTORMILITILITY CONNECTIONS, RELOCATIONS ANDIOR SERVICE INTERRUPTIONS SHALL BE ARRANGED FOR AND COORDINATED IN ADVANCE WITH THE AFFECTED OWNERS AND APPROPRIATE GOVERNING AUTHORITIES INCLUDING THE FIRE DEPARTMENT. CONNECTIONS TO EXISTING WA TERISEWERISTORMIUTILI TIES SHALL BE MADE ONLY WITH PRIOR WRITTEN APPROVAL OF THE AUTHORITIES GOVERNING SAID UTILITIES. 2. EXISTING WATERISEWERISTORMIU71LI71ES WHICH ARE DAMAGED DUE TO CONSTRUCTION WORK SHALL BE REPAIRED AT CONTRACTOR'S EXPENSE AND INSPECTED AND ACCEPTED BY THE LOCAL SITEIBUILDING INSPECTOR AND GOVERNING AUTHORITY OF THE AFFECTED WATERISEWERISTORMILITILITY PRIOR TO BACKFILLING. FINISH FLOOR ELEVATIONS 1. FINISH FLOOR ELEVATION (FFE) SHOWN ARE FOR GARAGE SLAB OF BUILDING. ELEVATIONS ARE APPROXIMATE AND ARE INTENDED ONLY TO FACILITATE ROUGH GRADING OF SITE. ACTUAL FINAL DESIGN FINISH FLOOR ELEVATIONS SHALL BE COORDINATED IN THE FIELD TO ACCOUNT FOR AS -BUILT CONDITIONS OF THE ROAD AND SITE WORK, FINAL BUILDING CONFIGURATIONS, AND GARAGE LOCATION. UNLESS OTHERMSE NOTED, FINAL GARAGE FINISH FLOOR ELEVA71ONS SHALL BE SET TO MAINTAIN POSITIVE DRAINAGE TOWARDS 'ME ACCESS ROAD. CALL BEFORE YOU DIG 1-800-424-5555 SE 1/4, SECTION 25, TOWNSHIP 27 NORTH, RANGE 03 EAST, W.M. REPLACE EXISTING GRAVEL/CONCRETE DRIVEWAY WITH PERMEABLE CONCRETE PAVEMENT WIMAX 2.0% SUBGRADE SLOPE (261 SF) fNON-REGULATEDI EXISTING SEWER M.H. DATUM POINT @ 100.00' EPLACE EXISTING ASPHALT DRIVEWAY (239 SF) fREPLACED EXEMPTI Ld 3: Lj 00 M SLOPE PAVEMENT TO VEST (TYP) 224TH ST. S.W. STORMWATER MANAGEMENT PLAN P=ff""!Mn' I SCALEI"=2 ill 0 f# i \ CLEARING LIMITS NEW ASPHALT PAVEMENT (333 SF) PROFILE TO ACCOMODATE EXIS71NG SHEET FLOW ADJACENT TO PAVEMENT EDGE IREGULATEDI NEW PERMEABLE CONCRETE PAVEMENT WIMAX 2.07. SUBGRADE SLOPE (777 SF) �R�EGULATE 3'xSx3' WASHED ROCK DRYWELL FOR FOOTING DRAINS 4' PVC 2.00% OVERFLOW RAINGARDEN [I/Cl] 86 SF BOTTOM AREA WIMINIMUM BTM ELEV 104.4 (VERIFY 1.0' BELOW FE) "`�414" PVC 2.007a 1 CD CONNEC71ON POINT FOR ROOF DOWNSPOUTS NEW ROOF (1,439 SF) ,�v I EGULATED1 IN. �_ - _� 'A.T1 --- TEMP STOCKPILE NEW PERMEABLE CONCRETE (4 SF) IREGULATEDI I ROOF DOWNSPOUT RISER PER ARCH PLANS - SET INI ET 0.5' MIN ABOVE FFE (TYP) I S-1vt f-r-pt-v. -ro %a 11UfP-rAw'%V c--p�AoripS 5,L4N0A?_v OwtAw NOTES. 1. RAINGARDEN PLANTINGS SHALL BE AS RECOMMENDED BY A QUALIFIED NURSERY CONSISTING OF A MINIMUM OF 3 DIFFERENT SPECIES OF DEEP ROOTED, DENSE, DROUGHT TOLERANT SHRUBS ANDIOR HERBACEOUS PLANTS. 2. FLOOR OF RAINGARDEN SHOULD BE PLANTED WITH ZONE I TREES, SHRUBS AND GROUND COVER. SEE APPENDIX 3 - "BIORETENTION PLANT LIST" IN THE LID TECHNICAL GUIDANCE MANUAL FOR PUGET SOUND (CURRENT EDITION). 3. SIDE SLOPES SHOULD BE PLANTED WITH ZONE I OR 2 GROUND COVERS. 4. BIORETENTION SOIL, COMPOS17ION AND pH LEVELS SHALL MEET THE STANDARDS SET FORTH IN THE LID TECHVICAL GUIDANCE MANUAL FOR PUGET SOUND (CURRENT EDITION). 5. PLANTING SHALL CONSIST OF NATIVE SPECIES ABLE TO TOLERATE VARIABLE SOIL MOISTURE CONDITIONS, P%DING WATER FLUCTUATIONS, AND VARIABLE SOIL MOISTURE CONTENT. 6. RAINGARDEN SHALL BE LINED WITH AT LEAST 12 INCHES OF BIORETENTION SOIL MIX COMPACT SUBSOILS MUST BE SCARIFIED AT 4 INCHES BELOW THE AMENDED LAYER. 2"-4" QUARRY SPALL SPILLWAY 2.0' WIDE BY 0.3' DEEP 8 n DI DOMED DROP -IN GRATE [HARCO 2013-002 OR EQUAL] DOWNSPOUT INLET RISEP, ACCEPTABLE TIGHTLINE SDR 35 MATERIAL SCH 40 N-12 F810 HANCOR Appflwnt shal',4 repdrlfropfact� dl darriep to Lfti4ties re?rontage tmprov "no nin In 0htj rlgN-of-way per City standardn 5mt �s camod or occurs durl-ing thn p=nq1ed prqjs-.t RAINGARDEN MAINTENANCE. 1. THIS PROJECT INCORPORATES A STORMWATER MANAGEMENT FLOW CONTROL BMP (BEST MANAGEMENT PRACTICE) CALLED A 'RAIN GARDEN," WHICH WAS INSTALLED TO MITIGATE THE STORMWATER QUANTITY AND QUALITY IMPACTS OF SOME OR ALL OF THE IMPERVIOUS OR NON-NATIVE PERVIOUS SURFACES ON THE PROPERTY. RAIN GARDENS, ALSO KNOWN AS "BIORETENTION," ARE VEGETATED CLOSED DEPRESSIONS OR PONDS THAT RETAIN AND FILTER STORMWATER FROM AN AREA OF IMPERVIOUS SURFACE OR NON-NATIVE PERVIOUS SURFACE THE SOIL IN THE RAIN GARDEN HAS BEEN ENHANCED TO ENCOURAGE AND SUPPORT VIGOROUS PLANT GROWTH THAT SERVES TO FILTER THE WATER AND SUSTAIN INFILTRA71ON CAPACITY. DEPENDING ON SOIL CONDITIONS, RAIN GARDENS MAY HAVE WATER IN THEM THROUGHOUT THE WET SEASON AND MAY OVERFLOW DURING MAJOR STORM EVENTS. 2. THE SIZE, PLACEMENT, AND DESIGN OF THE RAIN GARDEN AS DEPICTED ON THIS PLAN MUST BE MAINTAINED BY THE HOMEOWNER AND MAY NOT BE CHANGED WITHOUT WRITTEN APPROVAL FROM THE CITY OF EDMONDS. PLANT MATERIALS MAY BE CHANGED TO SUIT TASTES, BUT CHEMICAL FERTILIZERS AND PESTICIDES MUST NOT BE USED. MULCH MAY BE ADDED AND ADDITIONAL COMPOST SHOULD BE WORKED INTO THE SOIL OVER TIME 3. RAIN GARDENS MUST BE INSPECTED ANNUALLY FOR PHYSICAL DEFECTS. AFTER MAJOR STORM EVENTS, THE SYSTEM SHOULD BE CHECKED TO SEE THAT THE OVERFLOW SYSTEM IS WORKING PROPERLY. IF EROSION CHANNELS OR BARE SPOTS ARE EVIDENT, THEY SHOULD BE STABILIZED WITH SOIL, PLANT MATERIAL, MULCH, OR LANDSCAPE ROCK. A SUPPLEMENTAL WATERING PROGRAM MAY BE NEEDED THE FIRST YEAR TO ENSURE THE LONG-TERM SURVIVAL OF THE RAIN GARDEN'S VEGETATION. VEGETATION SHOULD BE MAINTAINED AS FOLLOWS. A) REPLACE ALL DEAD VEGETATION AS SOON AS POSSIBLE, B) REMOVE FALLEN LEAVES AND DEBRIS AS NEEDED; C) REMOVE ALL NOXIOUS VEGETATION WHEN DISCOVERED; D� MANUALLY WEED WITHOUT HERBICIDES OR PESTICIDES, E DURING DROUGHT CONDITIONS, USE MULCH TO PREVENT EXCESS SOLAR DAMAGE AND WATER LOSS. TRAINGARDEN SCALE 1 3' 0 12" BIORETENTION SOIL MIX I' ENVELOPE WASHED DRAIN ROCK -'-4" PVC INLET x 8"x4" P VC TEE W10PEN BOTTOM FILTER FABRIC ELEV 105.9 ,mK FFE 105.4 VICINITY MAP NTS OWNER/APPLICANT MELINDA & TIMOTHY STRAYER 22401 98TH AVE WEST EDMONDS, WA 98020 CONTACT CSP ENGINEERING INC PS 1037 NE 65TH ST #153 SEATTLE, WA 98115 TAX ACCOUNT NO 00450701200007 PROJECT DATA PARCEL AREA: 0.19 ACRES DISTURBED SITE AREA: 4,460 SF NEWIREPLACED IMPERVIOUS SURFACE. Z605 SF RAINGARDEN DESIGN RAINGARDEN IS DESIGNED TO ACCOMMODATE 1,439 SF OF ROOF AREA AND 72 SF OF UNMITIGATED NEW IMPERVIOUS SURFACE IN THE RIGHT OF WAY BASED ON AN UNFACTORED INFILTRA71ON RATE OF 1.O'1HOUR (DESIGN LONG TERM RATE PER GEOTECH REPORT IS 0.25"IHOUR WITH A 4.0 FACTOR OF SAFETY). A 5.7% SIZING FACTOR WAS INTERPOLATED FROM HANDOUT #E72B TA13LE 5, 6" PONDING DEPTH. RAINGARDEN SIZE 1,511 SF x 0.057 = 86 SF BOTTOM AREA. ADDITIONAL PROJECT/SITE DEVELOPMENT INFORMATION THIS STORMWATER MANAGEMENT PLAN ENCOMPASSES ONLY A PORTION OF THE ENTIR&-SET OF PLANSIkEPORTS NECESSARY FOR IMPLEMENTATION OF TH6-PROJECT. THE ARCHITECTURAL PLANS, RELATED REPORTS ANDIOR STUDIES CONTAIN ADDITIONAL PROJECT INFORMATION ESSENTIAL TO THE PROPOSED IMPROVEMENTS AND SHALL BE CONSIDERED AS INCORPORATED INTO THIS PLAN SET BY REFERENCE. IT IS THE CONTRACTOR'S RESPONSIBILITY TO OBTAIN ALL THE ABOVE REFERENCED INFORMATION AND THE LOCAL PERMITTING AUTHOR17YS "APPROVED FOR CONSTRUCTION" VERSIONS OF THESE PLANS FOR USE IN IMPLEMENTATION OF THIS PROJECT. Line Type Area (square feet) Non -Regulated 2. Replaced Exempt Regulated i I_; ' ' ' 1, 'S 0' U ARAGE & PAT101916 3. 4. New (Post 1977) 4 4 4 4 4 4 Total Regulated Impervious Mitigation required ifin excess of 000sf 19689 '29605_: 5. 6. Total Area Mitigated by Existing Stormwater Management System(s) Regulated Area Not Yet Mitigated 0 2,605, 7. Area Proposed to be Mitigated by Low Impact Development Techniques 21605 8. Area Proposed to be Mitigated through Conventional SWM Techniques 0 RZIT-0- YJAY CCNIS) 7FIXOT Ka'14 TERIPIT AND 1N2'-PECTf0,N REQUIRED 3" DEPTH ASTM #57 4" DEPTH ACI LEVELING COURSE 522 1-08 CONCRETE 77 MINIMUM 3" DEPTH 0.5n TO UNIFORMLY GRADED CRUSHED (ANGULAR) THOROUGHLY WASHED STONE (ASTM #3) PERMEABLE CONCRETE IL N PAVEMENT SECTION NTS 0 APPROVED FOR CONSTRUCTION rA CITY ENGINEER DWIS16PJ 1JATLf CITY OF EDMONDS z 0 E Uj z z 00 � z W Q a Uj LU LL. U. 00 WIWI I I I I I L LU W C> z I LU � � � � 3 az CL th, A at: !Ali L4 r= E Ln SO 08 Ln 00'.'D 04 ra IS %_ 1A 04 '00 Oj C Z Ln rim NO Uj z @j tA M k * ?-Vf VjV- 'TO -5rrE 91APJ C-09- e9b%jeA) tdAft"L