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22415 100TH AVE W.PDF22415 1 OOTH AVE W 0 0 ADDRESS: TAX ACCOUNT/PARCEL #: LK07 005- Qa) 1007-- BUILDING PERMIT (NEW STRUCTURE) #: COVENANTS(RECORDED)FOR: CRITICAL AREAS #: DETERMINATION: [-I Conditional Waiver El Study Requ7ire--d�Waiver CRITICAL AREAS #: DETERMINATION: El Conditional Waiver E]StudyRequired E)Waiver DISCRETIONARY PERMIT #'S: DRAINAGE PLAN DATED: PARKING AGREEMENTS DATED: EASEMENT(S) RECORD FOR: PERMITS (OTHER — list permit #'s): PLANNING DATA CHECKLIST DATED: SCALED PLOT PLAN DATED: SEWER LID FEE $: ID #: SHORT PLAT FILE: LOT: IBLOCK: SIDE SEWER AS BUILT DATED: SIDE SEWER PERMIT(S) #: GEOTECH REPORT DATED: STREET USE/ENCROACHMENT PERMIT #: FOR: WATER METER TAP CARD DATED: OTHER: L:\TEMP\DST's\Forms\Jana's Street File Checklist 5-14-08.doc PLANNING DATA STREETFILE SINGLE FAMILY RESIDENTIAL I Name: Date: 0, Site Address: Plan Check #: Project Description: lnki- il o,,-", --SFP— 4 / Reduced Site Plan Provided: (YES / NO) Zoning: Map Page: Corner Lot: (YES 0) Flag Lot: (YE(/ N?)? Critical Areas Determination #: 0 Study Required XW—aiver SEPA Determination: 11 Exempt El Neededj,(.fdro�ver 500 �cubic yards of grading) 0 Fee 0 Checklist El APO List with notarized form Required Street: Side: --7 Side: —75 1/ Rear: Actual Setbacks Street: Side:, Rear: A/0- Detached Structures: El Rockeries: V,Fences/Trellises: --,7,7D 10611k, oc'�kl 11 Bay Windows/Projecting Modulation: El Stairs/Deck: He�7ht Datum Point: -Da4im �evatiion: Maximum Height Allowed: Actual Height: Other Parking Required: Lot Area: -��vided. Maximum Lot Coverage: 35% Proposed: Lot Coverage Calculations: ADU Created: (YES / ONO) Subdivision: Legal Nonconforming Land Us e Determination Issued: (YES comft�ts r -eel; r� V p, . f 01 Plan Review By: Planning Data Fonn 04-11-06.doc Applicant shall rqp&lr/r9Pl0Ce all 4anjo 9 t9'. utilities or frontage ftwwonm im A C right -of -WAY per CRY standaro thgt Ig caueec or 0001.1re during thO Pwrntftd project. WELL '--F V i.- i- -96,-o s6- PT '04, 0-- Y-Eh- t YARD I RAIN— L-LiDR WAY & PA lNc-L S IPNIN PLA F - E ,- I T t L S C CON2 : LLL _L LLI 261 SO, FT POSSIBLE V) NP U REMITTI 0 ADDITION- - L L L L U I S - FT IMPERAOUS OF SURFACE t L LL �-LL L L `­ LL 11 i I I -�- IL -LLLLL.LL -LLLLLLL 7 LLLLLLL EXISTING 1-1- 1, L.I L I- RGCKERY I-A-L I. I .-LLLL'-LL LLLL � L-LLLLLL-L LL-LLF L L LLLLL L LI-L LI L FT OF NEW P WALK WAY J T J ROCKERY ENDS 12*-0' SOUTH PROPERTY LINE 3' -1 D3 LL — - H LINE DRAINAGE PLAN SCALE: 1/8"-l'-O' EROSION CONTROL "LL BE IMPLEMENTED IN ACCORDANCE WITH THE CITY OF EDMONDS REQUIREMENTS 'on e�-f Comer Flag ;',etb cks �red Rgu: Actual F nt -- z 5- s i c k-,s I%& -7.5-7--7i:7— Rear 7 Other Rei .J�DPFTAIL -ULL-LL�LL +LLLLLL,L,i _LLLi-L�— -L.LL L-LLLI L LL EXISTING RET NING WALL TO REM IN ­LLI L LLLLL-1- IL L L L L L I i 1040 0. FT. OF NEW LLLI-LLL'- RAVI S TO REPLACE A-L 1-1- 1XIS NG CONCRETE PATIO L L L L :LLLL -LLL(- -LLL -LLL. ON RETAINING —EXISTING WALL TO REMAIN 156 INEAR TET OF N TR7A TRENCH Da, t w- Ile OPATTE j-N 2DD9 AND FOR 4� D1?4 IAIA GE NC PATTEN ARCHITECTS INC.. 401S "U15314. "I'" IB eat . .' 9.. Ph.— (206i 248-4596 a IMPERVIOUS SURFACE - EXISTING BUILDING ROOF OUTLINE: 2.827 SQ. FT. (CONSTR. 1950'S) EXISTING BUILDING ROOF OUTLINE ADDITIONS: 373 SO, FT. (CONSTR. UNKNOWN ?) EXISTING DRIVEWAY THAT HAS BEEN REPLACED: 900 SQ, FT. (CONSTR. 2oo9) EXISTING PATIO THAT HAS 8EEN REPLACED: 1.040 SQ. FT. (CONSTR. 2009) EXISTING WALKWAY THAT HAS BEEN ADDED: 248 SO. FT. (CONSTR. 2009) LOT COVERAGE: 5.3158 SO, FT. (39X) LOT AREA: 13,522 SO. FT. 'ROVED AS NOTED I LOT SLOPE: 10% 4' CONCRETE DRIVEWAY �Lc��6'76 6R�"f" SLOPED TO DRAIN 6*.6' PAVER OVER SAND BED I' D111 COVER 4' PERFORATED DRAIN DRAIN LINE *YARD 4' PERFORATED t2' DRAIN LINE WASH ROCK E: . 4 P� PERFORAZTED DRAIN LINE ,ASH ROCK W/ LTER FABRIC WRAP W/ FILTER FABRIC WRA t WASH RGCKIW/ FILTER FABRC:!�� INFILTRATION TREN CH 1 2 1 IYARD DRY WELL 3 1DRIVEWAY DRY WELL SCALE: 3/4'-1'-0' FsCALE —314--V-." SCALE: 3/4*-1'-0' �7� Zubair Residence 224151 A. a— +1 �05 —9- DAM: 25 FIA � SHEET NO 0, .0D[IPt n 1 1E— or 1.11 P1 ANN G I-FAW r7 JIJ14 112009 STREET FIMILDING DEPAWMENT CITY OF EDMONDS It I 0 CAW NO. qq— V Critical Areas Checklist ------------------------------------------------------------ RECIE11VE, Site Information (soil s/topography/hydrology/vegetation) Site Address/Location: :)a4li;_ ItYj'h ilk- LJ, e-0 M C:>'V\ A !:�2 MAY 10 1999 Property Tax Account Number: - 4 5_0 3 - C) Q 5-- 000 -.100-7 LX ENT.SERVIC, 3. Approximate Site Size (acres or square feet): 13 -i 5-oo --,a 4. Is this site currently developed? _.y yes; — no. If yes; how is site developed? Lj R Q, (�� IR-00 w\ AyV\ 8 5. Describe the general site topography. Check all that apply. Flat: less than 5-feet elevation change over entire site. Rolling: slopes on site generally less than I ' 5% (a vertical rise of 1 0-feet over a horizontal distance of 66-feet). Hilly: slopes present on site of more than 15% and less than 30% a vertical rise of I 0-feet over a horizontal distance of 3 3 ) to 66-feet). Steep: grades of greater than 30% present on site (a vertical rise of 10-feet over a horizontal distance of less than 3.3 )-feet). Other (please describe): NO e-k-JAI-toys C-V%AA6e- IOF(- 7VX ,�k 0 t") I MI 0 I\J 6. Site contains areas of year-round standing, water: 00 Approx. Depth: 7. Site contains areas of seasonal standing water: Approx. Depth: What season(s) of the year? 8. Site is in the floodway \0 (D floodplain IJ 0 of a water course. 9. Site contains a creek or an area where water flows across the grounds surface? Flows are year- - round? Flows are, seasonal? (What time of year? 10. Site is primarily: forested meadow shrubs mixed urban landscaped (lawn,shrubs etc) X 11. Obvious wetland is present on site: �j 0 :DETtftM.-1NAT10N.::: CONDMONAL WAtVEk 6ate %a_chk.dm R� 10103/97 City of Edmonds NAW CRITICAL AREAS CHECKLIST The Critical Areas Checklist contained on this form is to be filled out by any person preparing a Development Permit Application for the City of Edmonds prior to his/her submittal of a development permit to the City. The purpose of the Checklist is to enable City staff to determine whether any potential Critical Areas are, or may be, present on the subject property. The information needed to complete the Checklist should be easily available from observations of the site or data available at City Hall (Critical Areas inventories, maps, or soil surveys). An applicant, or his/her representative, must fill out the checklist, sign and date -it, and submit it to the City. The City will review the checklist, make a precursory site visit, and make a determination of the subsequent steps necessary to complete a development permit application. Please submit a vicinity map along with the signed copy of this form to assist City staff in finding and locating the specific piece of property described on this form. In addition, the applicant shall include other pertinent information (e.g., site plan, topography map, etc.) or studies in conjunction with this Checklist to assist staff in completing their preliminary assessment of the site I have completed the attached Critical Areas Checklist and attest that the answers provided are factual, to the best of my knowledge (fill out the appropriate column below), Owner/Applicant: 6 P, I f� Name aca�i":'7- Poe, Li, Street Address 1A city State Zip Telephone Signature/ Date 4_2 / A!� Applicant Representative: Name Street Address City State Zip Telephone Signature Date (over) c:recepfion\janaXcac1.doc DA Zone J S.E. 1/4, SEC. 25 T27N., R.3 E.W.M. 104 417 gig 2180"1 1805 21802 .7 21807 21806 1 Z1802 218 "1 PL. 218DI 211302- 21807 zlect5i le 1108 of 1109 4T 2ig 19 21816 01 21810 2605 805 JJV 916 f 910 216)2 1 218 7 918M 2 i - - ? 1812 2180 21812 n — — — all'. 1819 21818 2/819 > t ?jolt "Is 21821 H36 m 21820 21621 ?J82P K 2192 18)3 2183 2102S 21bu- 1 219,26 2)92 21 2/82-31 S? 218?'9 21829 Z1926 21823 11111L 718276 b 1131 cr WaTiv CT. -- - 190 't v900 1915 1901 2)832 v 21910 21 901 110S 21821 21923 21905 ,Z) 911 21900 19. 21916. 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C211 q222a 211 223 L, J7 213201 '21 12327 T. S. W. 4 -T 22?- �210 2401 Zp 22.4 0 22,q 07 Z24oti, r2,2405 -,,j 0+ \9 04 Z24jr Z2,q I 1 12, 1 + 117 724 A U415 4 11A 22406 r'. '901 cr 1 22408 09 0- 22406 13 z"Zi 22421 Avu ?.3 =424 '"1 22 224 11; 22412 =1 1 3 1 22,116 224/31 22"! 11 l3 - 1 1 2 — PZZ-44 23 2428 AZ427 2429 #33 22,12912VPin 431 224-12 — 22,121 22 4 20 22120 22421 �2420 r Z2431 -Zqljol �50�1,114 505 439 '-�04 124" 22501. Z2507 Z2506 22507 2250Q, EDMONDS 22,Y)l 225/0 Z2511 22510 49 22SIS pRairsavreit'Aw C, vAcA ir 12 22523 )i - -4 2516 2267 2261A 225/5 72C S'w ZZ506 22521 253) 225M 21570 2*2519 2.2516 22517 22-5/8 40 22(a 2Z(o 2607 Or. 22601 2U04 2960:F 22(oo4 22AD5 '22&0.f 07 05 6157 -m 0I z 6 PL. 22615' 60 92609 22(.08 926,09 22608 2621 Z26/9 N =619 22612 > Lua"? 126/2 31 x lu 22162 "K 277,0/ 22629 22629 21620 2ZG 9 224-20 22619 2276,q ?2710 V7tO 22711 227016 22706 227C5 Z2706 711 a. r� 2UV718 719 2271C, co 227/2 , 114 FARKINO 2271--PL. S. 2'271,7 Do 'n 140M . 2726 — -- 21 0 2 1 46 22714 22727 -7 1 - 'a" T 226" T - - -- S -w- -Z z a 15 zz 22806' %n 22811 CID 01 7 PL. S.W. cr Ia- (D 1229 2261 - 915 . w I . () 229oi 1v I wEsn;Arw Ir 9,p 228* 2202 CU m 00 IQ a, "o 0 I � �) 1) C. 1 S9 Kris Pederson 22415 1 00th Avenue West Edmonds, WA 98020 CITY OF EDMONDS 121 5TH AVENUE NORTH . EDMONDS, WA 98020 - (425) 771-0220 - FAX (425) 771-0221 DEVELOPMENT SERVICES DEPARTMENT Planning - Building - Engineering May 27,1999 Subject: Determination regarding Critical Areas Checklist # 99-130 BARBARA FAHEY MAYOR Dear Applicant: Enclosed please find a copy of the Critical Areas Checklist you submitted. The "DETERMINATION" reached by the City is located on the reverse side of the form (bottom of page). It is very important for you to retain a copy of this Critical Areas Checklist "DETERMINATION" for. your records. ...... . . ..... .. TION TO BE NO TED: i 6ATANT INFORMA PLEASE EXAMINE THIS" DETERMINATION" FOR ADDITIONAL REQUIREMENTS. YOU MAY NEED TO SUBMIT ADDITIONAL INFORMATION SUCH AS AN ENWRONMEJYTAL CHECKLIS OR CRITICAL AREAS STUDY, The 'DETERMINATION' for the Critical Areas Checklist you submitted is a site -specific determination not a project -specific determination. NO. You must submit a covy of the CRITICAL AREAS CHECKLIST and DETERMINATION KITH ALL -411111111 PERMIT APPLICATIONS or YOUR APPLICATION WILL NOT BE PROCESSED. Peffnit applications include the following: Enc: Determination * Architectural Design Board C:Rer,eptIonUana\CRLTR.d0C Building Permits Conditional Use Peffnits Subdivisions Variances Applications to the ADB* Land Use Applications Any other development permit applications. Thank you. Planning Secretary Incorporated August 11, 1890 Sister City - Hekinan, Japan Message Page I of I Zulauf, JoAnne From: Shuster, Jerry Sent: Thursday, July 02, 2009 2:23 PM To: Zulauf, JoAnne Subject: Zubair-22415 1 00th Ave W-BLD#20080651 STREET FILE JoAnne, I've reviewed the submittal date June 23, 2009 for Gary A. Flower, PLLC regarding the drainage requirement for this project and suggestions in a June 15, 2009 correspondence from the City to the Permittee. In response to Mr. Flowers comments on our suggestions, I will back up a little a give the project some context relative to the City's stormwater requirement in Edmonds Community Development Code 18.30. This code requires stormwater controls for projects that create 2,000 square feet or more of new impervious surface. The City has repeated asked for information on the amount of new impervious surface added since 1977 and has not received a complete answer. As such, it is difficult for us to know exactly what drainage requirements to require on this property which is further confounded by the fact that most of work has been completed without records of how some of the features have been constructed (i.e. infiltration trench and drywell). In addition, without a pre-setting catch basin, the sand separating the paving stones has a high potential for running off and clogging the on -site infiltration systems. That said, given the site constraints of steep slopes and rockeries, and an assurance by Mr. Flowers that the existing drainage system will function as intended, the City is willing to accept the most recent plan as is. This plan includes a new infiltration well trench at the bottom of the new driveway. Jerry Shuster, P.E. Stormwater Engineering Program Manager City of Edmonds 121 5th Ave N. Edmonds, WA 98020 Desk Phone: 425-771-0220 x1323 Fax: 425-672-5750 shuster@ci.edmonds.wa.us 7/2/2009 Jun 23 09 04:17p Gartl FJWer 206-417-fO p.2 GARY A. FLOWERS, PLLC GEOLOGICAL & GEOTECHNICAL CONS ULTINJ%eCe%4fw 1�% 2, & 10S Technical Memorandum SE%RCfS Date: June 23, 2009 To: JoAnne Zulauf Project Zubair Residence City of Edmonds, Engineering Name: 22415 1 00'b Ave W From: Gary Flowers, P.E.G. Project No: 2008-0651 Subject: Driveway Drainage Requirements I have reviewed your plan review corrections dated June 15, 2009 and need some clarification and explanations. I ) You have requested a yard drain in the "lowspot " on thesouthside oj'lhe driveway where it tapers to the narrower part qf the driveway". You say this drain "would catch a majority of the runoffftom the upper portion of the drivewayl�arking area". Based on actual runoff observations of water on the driveway this drain would possibly catch water from an area about 190 sf. The other apporoximate 200 sf of upper driveway to the south flows due west and the water runs directly into the landscape area. 2) You request that "this drain can be connected to an infiltration french placed between the lower driveway and the rockery". How do you propose to have an infiltration trench on a 15% or greater slope? You will not get any infiltration value and you will lose all storage value of the trench due to the slope. 3) You state that the "trenchshould be 15 - 20ft long, 18 " deep� 24 " wide, lined with geotextilefabric andfiller with 1 112 " to 1314, " washed rock. Connectionftom yard drain should be 4 " perforated pipe. Pipe should have 6 " cover measuredftom base of pipe ". Besides the above stated problem of trying to infiltrate on a steep slope area and losing all storage value of the trench, the distance between the driveway and the existing rockery is 18 to 20 inches. I do not recommend digging an 18" deep trench at the base of any rockery and a 24 inch wide trench would undermine the rockery. Is the city willing to take responsibility if the rockery collapses into the trench or if the storm water saturates the bearing soils for the rockery and causes future problems? I'm not? If you insist on having this drain, which does not seem reasonable for approximately 190 sf of impermeable surfacing, it would be much better to add the infiltration trench in the lawn area directly south of the yard drain. This drain would be far enough removed from the lower rockery as to not be a concern. 4) You state that "the yard drain proposed at the base oj*the driveway can still be added to catch the runofffrom the remaining area of the driveway. To ensure that this drain captures the majority ofrunoffasphalt berms approximately 2 " high and 6 " wide should Phone; 206-417-7640 19532 12"' Avenue N).,., Shoreline, WA 98155-1100, F:206-686-3834 OT Q I RED FILE Jun 23 09 04:17p Gartj FiWer 206-417-WO p.3 Technical Memorandum Zubair Residence Drainage Page 2 of 2 be added to guide water into drain". I believe that a channel drain would be abetter option but the asphalt berms will certainly work. Please understand, regardless of a yard drain with asphalt berms or a channel drain, the soils at the base of the driveway are much less permeable than the soils in the back yard area. As such, the infiltration trench or pit that you insist on having at the bottom of the driveway will likely fill quickly and overspill into the soils underlying the street where they may or may not infiltrate further. Wouldn't it be much better to have the water atop the asphalt layer and flowing into the storm water system as it always has in the past instead of beneath the asphalt layer where it can potentially softcn the subgrade soils and have an adverse impact on the condition of the street pavement? Why do you not want the water from the Zubair driveway to flow into the street as it does for everyone else in the area? In addition to the above comments I would sincerely like to understand why so much issue is being made of the new driveway. Every driveway along 100"' Ave W drains to the street. Why is this one being treated differently? Is the city storm water system overloaded and undersized and this is the proposed fix — to make homeowners attempt to infiltrate water even in areas that are not suitable to infiltration. I believe that infiltration is wonderful and should be used where the soils are suitable. Where the soils are not suitable alternative methods must be used. I do not ask these questions facetiously. I came into this project very late in the game and undoubtedly have little knowledge of everything that has transpired. I truly would like to understand as it will help my consulting practice in the future. Thank you for your time. Please email (glj!m crs() I it coniCist nct). fax or call me with any questions. We truly would like to get this project wrapped up. Phone: 20&-417-7640 19532 12"' Avenue NE, Shoreline. WA 98155-1106 1::206-686-3834 0 0 June 9, 2009 Project No. 09014 Mr. Aneil Zubair c/o Patten Architects 401 SW 153rd, Suite B Seattle, WA 98166 Subject: Geotechnical Evaluation 22415 1 00`h Ave W Edmonds, Washington Gary A. Flowers, PLLC Geological & Geotechnical Consulting 19532 12th Avenue NE Shoreline. WA 98155-1106 ? As requested and agreed, we have completed our limited geotechnical evaluation at your property at the above noted address in Edmonds, WA. Our scope of services was to address the geotechnical soils and drainage issues requested by the City of Edmonds in their Plan Review Corrections Notice to Mr. Patten dated April 28, 2009. The subject property consists of a single family building lot with an existing single story home. The home is located on a relatively gentle west facing slope. The house building pad appears to have been created by excavating a level pad on the slope face. Retaining walls on the order of 4 feet in height support the slope cut on the east side of the property. A 4 to 5 foot tall rockery provides g'rade separation along the west side of the property between the yard area and sidewalk. Recent remodeling has reportedly included significant landscape work such as removing the concrete driveway, parking strip and sidewalk on the west side of the house and replacing them with new paving stones. Due to past drainage issues (i.e. standing water) in the back of the house (east side) additional subsurface drainage has been added and a new patio built of paving stones. The new drainage system is located beneath the new paving Stone patio in the back of the house and reportedly includes an infiltration trench and a dry well. The location and details of these drainage items are presented on the attached Drainage Plan by Patten Architects dated 2/25/09 with revision dates of 4/10/09 and 6/l/09. During the course of our site investigation we met with Chris Stevens of Around The House Handyman, LLC. who installed the new drainage system. Mr. Stevens' description of the new system closely matches the location and details as shown on the plan from Patten Architects. Storm water runoff from the roofs on the southeast and southwest portions of the house reportedly tie into this new system. Storm water runoff from the northern portion of the house reportedly ties into an existing pipe system that has been in place for many years along the north side of the house. The discharge point for this existing storm water pipe is apparently unknown. Gary A. Flowers, PLLC. —RESUa 19532 12'h Avenue NE Shoreline, Washington 98155-1106 JUN 112009 206-417-7640 BUILDING MPARWENT C17Y OP C-DMQ�Jzgj 0 0 Zubair Pro erty Geotechnical Services LeUer 22415 1001fAve W Edmonds, Washington Mappings We have reviewed both the Composite Geologic Map of the Sno-King Area, Central Puget Sound Lowland, Washington, by Booth, Troost, Cox and Shimel, Seattle Area Mapping Project, University of Washington and the United States Geological Survey, January 5, 2004 and the Geologic Map of the Edmonds East and part of the Edmonds West Quadrangles, Washington, Minard 1983, United States Geological Survey, Miscellaneous Field Studies, Map MF-1541 ' Both of these published maps of the geology of the project area indicate that the site is near the contact between the Vashon age glacial till (Qvt) and the Vashon age advanced outwash deposits (Qva). We have also reviewed the National Resources Conservation Service soil survey information for the site. According to this document the mapped soils are the Alderwood Urban -land complex on 8 to 15 percent slopes. The soil is typically 20 to 40 inches thick before the dense confining layer is reached. The soil is moderately well drained. A typical soil profile is gravelly sandy loam over very gravelly sandy loam. According to the Soil Survey of Snohomish County, Washington the permeability of this soil unit is 2 to 6 inches per hour. Hand Explorations While on site we hand excavated several shallow test holes to further evaluate the on -site sediments that are the receiving soils for the infiltration trench and dry well. Encountered soils consisted of dense, gray to brownish -gray, silty fine to medium sand to fine to medium sand with some silt and gravel. Since we were unable to excavate very deep into these soils we were unable to determine if they belong to the till or outwash deposits. This soil would be classified as either a loamy sand or sandy loam as per the USDA Soil Textural Classification. Infiltration Potential Based on the USDA Soil Textural Classification the encountered soils would have a short-term infiltration rate of I to 2 inches per hour with no correction factor. We also performed an informal, infiltration test in one of the hand dug holes. The hole was approximately 18 inches deep in the back yard area near the southeast comer of the house. The sides of the hole was scarified to remove "glossing" from the shovel sliding over the soils and then was filled with water for a soak period of 30 minutes. The water level was then adjusted to approximately 6" deep and was allowed to infiltrate over the next 30 minutes. The water level dropped by 3.25 inches in 34 minutes. Although the soils were not allowed to soak for a full 4 hours, this informal test indicated an infiltration rate of about 6 inches per hour. Therefore, based on the USDA textural triangle and the field infiltration it appears that the on -site soils have an infiltration potential between I and 6 inches per hour short term or .5 to 3 inches per hour long term with a correction factor of 2 applied. Gary A. Flowers, PLLC. 19532 12'h Avenue NE Shoreline, Washington 98155-1106 206-417-7640 2 0 0 'Zubair Pr erty Geotechnical Services Letter 22415 10;Ave W, Edmonds, Washington CONCLUSIONS AND RECOMMENDATIONS During most normal storm events surface water failing on the paving stones will naturally infiltrate through the sand separating and supporting the paving stones. Most of this water will naturally infiltrate into the upper portion of the site soils. Water that doesn't infiltrate will eventually flow into the new infiltration trench and either infiltrate at a deeper depth (24") at the bottom of the trench or will be picked up in the perforated pipe that has been installed in the trench. Water that flows along the bottom of the infiltration trench or in the pipe will eventually be deposited into the new dry well located just downslope of the southwest comer of the house. This dry well will serve as both an infiltration facility and retention facility. Should this dry well ever become full the water will simply flow out of it along the soil/sod interface in the yard area and will ftirther infiltrate into the near surface soils in the western yard area. Based on our observations on the site during a moderate rainfall event, no water was transferred from the back yard area into the dry well and no water was observed flowing off of the paving stones. Therefore it is our opinion that the system as installed will function as intended during most storm events. During periods of long term or intense rainfall, it is possible that some water will flow off of the paving stones and out of the dry well into the western yard area. We anticipate that this condition is similar to what has occurred at the site for the many decades since the house was originally constructed. The existing rockery along the west side of the property appears to have been in place since the original construction on the site many decades ago. The rockery was not originally constructed to meet any current rockery standards as it does not appear to have a drainage layer behind it and some of the rocks are stacked instead of interlocked. Also, some of the rocks have severely deteriorated and will ultimately have to be replaced. Finally, it is our understanding that Around The House Handyman, LLC did replace or extend some of the rockery at the far northern end of the property along the driveway. This new area of rockery was not evaluated for our study as it is far removed from the dry well and City concerns of impacts to the rockery. There are two rockeries downslope of the new dry well. The upper rockery appears to be new but is only 12 to 18 inches in height. This small rockery is not part of our evaluation and is too small to be impacted by the drainage system. The lower rockery, along the west side of the property, is not in good condition and will have to be replaced at some time in the future. As shown on the Site Drainage plan attached, this rockery does not extend to the south property line but stops about 12 feet to the north. As such, the rockery is not present in the area directly below the new dry well. Given the distance between the dry well and the existing rockery, the fact that the rockery is not directly downslope of the dry well, and the fact that runoff from the yard area for many decades has not impacted the existing poorly constructed rockery, it is our opinion that the potential for storm water runoff from the new drainage system to impact the lower rockery is very small. We do not recommend any mitigation for this issue other than anticipating that a new rockery will need to be installed at some time in the not to distant future. The new rockery will Gary A. Flowers, PLLC. 19532 12'h Avenue NE Shoreline, Washington 98155-1106 206-417-7640 3 .Zubair Pro y Geotechnical Services Letter ',fert 22415 100' Ave W, Edmonds, Washington be a result of continued deterioration of the existing rockery and not due to impacts from the new drainage system. The new sidewalk, parking area and driveway on the west side of the house have been constructed with paving stones and reportedly replaced old concrete structures. As such, the runoff from the pavers will be substantially less than it was from the solid concrete. As for the backyard patio area, rainfall from most storm events onto the new pavers will simply infiltrate through the sand that separates and supports the pavers and infiltrate into the near surface soils or flow along topographic contours atop the underlying soils downslope of the residence where infiltration will eventually occur. During long term or very intense rainfall events some runoff from the pavers will occur. This is no different than has been occurring at the site since the original construction of the house. In order to eliminate, further slow or delay any storm water from reaching the surface street on the west side of the house, we would recommend constructing another dry well near the base of the driveway. The dry well can either constructed as shown on the Drainage Plan attached, with the driveway sloping into the catch basin, or it could extend the entire width of the driveway with a full width channel drain. In either case the drainage structure should be deep enough to allow sediment to settle out and be properly maintained and cleaned on a regular basis. SUMMARY Based on our observations of the encountered soils it is our opinion that the new drainage system will function as intended and will not have any adverse impacts to the existing lower rockery. A new infiltration well/trench should be installed at the bottom of the new driveway. Our findings and recommendations provided in this report were prepared in accordance with generally accepted principles of engineering geology as practiced in the Puget Sound area at the time this report was submitted. We make no other warranty, either express or implied. Respectfully submitted, %, 'WI Gary A. Fl ers, P.G., P.E.G. Principal Engineering Geologist Attachments: Drainage Plan from Patten xc: Roger Patten, Patten Architects, Inc., 401 SW 153rd, Suite B, Seattle, WA 98166 Gary A. Flowers, PLLC. 19532 12'h Avenue NE Shoreline, Washington 98155-1106 206-417-7640 4 CITY OF EDMONDS 121 5TH AVENUE NORTH * EDMONDS, WA 98020 * 425-771-0220 - FAX 425-771-0221 Website: www.cLedmondsma.us PUBLIC WORKS DEPARTMENT Engineering Division June 30, 2009 Aneil Zubair 9033 Lk Washington Blvd NE Bellevue, WA 98004 RE: Request for driveway slope waiver at 22415 1 00th Ave W Dear Mr. Zubair; GARY HAAKENSON MAYOR sjtts iWt We have reviewed your request for a driveway slope waiver for over 26% due to the limited distance between the street and the existing garage. Edmonds Community Development Code Section 18.80.060D requires the slope of a driveway to not exceed 14%. We understand that due to the grade of the existing garage and 1 00th Ave W that it would be impossible to meet this slope requirement for the driveway grade. Therefore considering the challenges of this lot, we will approve the subject waiver request. The driveway slope is granted to the existing slope of 26%. If you have any questions please call JoAnne Zulauf at 425-771-0220, ext 1324. Sincerely, lh4' a Robert S. English, P.E. City Engineer Cc: street file permit file bld2008O651 Incorporated August 11, 1890 Sister Citv - Hekinan. Janan