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Geotech_Response_Comments_06.03.13.pdfLIU & ASSOCIX'r� ES, IN(,-,-,,, lk. lAch 011p chang 17 134 FA hot Road kknonds, MAN 98026 Dear TY Chan-,-.�: Ergmwq Geowgi Aphl 1 1. 2013 I�EIRRIGMN j t r"'Ax C 5 t I ) I - 1� - 1 0. 11 � � I �' , M Cvmnpww"�' ("'A �111111R)11'31 u 106 . :�� 1 1 1 Unmg ReOdowe 17134 "F,,Obotkoad Fdrnond,:3, L&A Regarding the comillwas in CUy of Edincmids 11 lelter ll,'y Mr Cltigswn .md Ow IIVI013 luiler by Nls. jenrlhor Larribem Vie fi�lve the F0110witlg rupousus: "L -Y LIM _Lv C K 14003 Illylew LOW Chw remmimendmion of sabaA of 35 fuct nym the ciem of the acep WE Or the prcp_)sed rt,sjdellce indudCS ',t t a.ie r �')Llffer of 2() feet from tho cresa of llv� Nul' ,ind ;,1 15 foot �,ctback 1'rom this b-,uffi,-n 31# 2013 Letter IS cKience of a swriii drAn Joe of Mg MAng house ClUTUlly OCCUPYing. the site and its proper and, cideq'wutc ft. nctioll bt,, vcrified before it cati be LlSed Or discharEQ, ccilcued storrmvater A Ille prol.,mse'd nee %" residencQ.sl'cmtlnv�rte r ended by ON dridn Ent 4 awdlahle anti thwimAng, is u) be diposcd through 19213 Kenlake Place ?JF,__' Kenmorfe,, WA, 98028 Phone �426) 483,9134 Fnm (426) 486-7746, Apri I I t. 210 13 Dn Lieh Ching Chang T -&A Job No. 12-083 Page 2 an elevated dispersion pipe system installed at the base of the bluff, If this dispersion pipe system is located within the railroad right-of.'-WLN". z1 pennissioll wouldhay e to be setired froni the railroad company. We understand that the adjacent residence to the north has a sionii drain line which carries and disebarges storunwatcr onto a rock spall splash piid at the base of the bluff, We also undtrstand that the owner; of this residence have given verbal consent to .Dr, Chang to allolv storniNvater of subject new residence to be discharged into their starer;: drain line, If this is the case, then it would be a Mable and safe iv -,t to dispose swunwatcv collcoted from the Chang residence. b, If neither of the above options, is feyislble, then Vvo e:lcvated dispersion pipe systems (with typical scaioa sho-wri on Plate 3 in our 9i 1512012 report'), one along each of the Nvo side fringes of the backyard. may be used to &spo!,e roolrunoff of the peruse. These elevated spreader pipe syswrns �Noujd allow disposed Morins titer tea evaporate into the arnbient and be absorbed by the root system of gruss and t, 'planted shrubs., with nuninial infiltration int© the around. Drquina,ce -1tein 6 We anticipatc the a.111t7ant of collected into footing drain system to be miniinal, and may be discharg-,':Qd through the dispi;rsion pipe systems unrVor the rain gardcn. Water in footing drains shoiild be tightlined stfparaaclv from other subsurface drain lines to discharge bast IINFIV b� lied to the a long a sume stormwater disposal sy-sten-i s S the discharge point is at least 12 is che.s lower than the low point Of the f00thIg drai-n systern, If necessan,', a rain garden may be located in the front yard (o dispose roof runoff of the garage and runoff' of the, paved drivelkN7,iv, Water storcd in rain gardens, is mostly evaporated into the ambient and absorbed by tile rocit. systems oCveyctation planted in rain P-ardens, with rninin-sal infiltrating, into the ground.. Therefore, it is our LIU & ASSOCIATES, INCa April 11, 2013 Dr. Lich China Chanc, T,&A Job No. 12-083 Page 3 recorrimendatlon that the rain -ardon of the subjeet project be sized based on a pzscudo infiltration raw of 05 iph A typical section of rain gardcn6 is shop �,n on Plaw I attachcd hei-eto. Storm runoff over the driveway should he routed into a catch basin equipped with an oil/water sepatator befora eing discharged into the nin garden. -11� rain garden should be approximatcly3 to 5 feet deep. 'Ilio bank slopes of rain V-1rdens -should be no sl-A--eper I - than 22-511:1V tbr cut banks and no steeper than 311:1V I -of fill tinbanh-ments. Topsoil and surficial ikeak soil within footprint ofpond fill ernbanknients should be stripped down to the underlying, native, firm'. stable deposit. The exposed %oil should be compacted to as non-vielding- state ��vith a vibrator t r 'Me ib y mechani.cal conipac o , bottom of till einbanknients of the rain garden should he keyed at least 12 inches into tile till soil, Fill ernbanknitnts shOLAd be constructed 1",ith snit comaining at least 35% of frae-graincd material (silt and clay cornhined), no more than 2155,£) passing ilw No. 20 Sieve, and Nvith partiele size no larger than 111". inch. Fill embankments should he coustructM in lifts no moru than 10 inches thick in loose state, ivith each lift compacted ividi is non -yielding state with an clephant-foot or sheep-foGt mechanical compactor. Soil to be Used for fill cnibanknient construction should have a moisture content within 0.5%X) of its OptinIUM jjjoj- ,,tul-e content. OptiRIUM MOiStUre content is tile moisture contcn.t of soil that enable the soil to be compacted to thmaxi inium dry .e density, for as giVCn COMPIWiOTI efrort. The pond of the rain garden should be lined With a layer of amended soil ai least 18 inches thicL The ainendcd soil should have 30 to '35 percent of compost. tilted into the rain garden embanknicnt soil to achieve an organic content of I Vift' by dry ~ eidmt. Plants of the rain. garden should be toleram of ponding Nvater and saturated soil c0nditions in the -,.vinter months sand drouoht in the summer monflis. M general, the predominant plants should be of facultative specles adapted to mrosscs a,,sociated with vvel and dry condiflons. T pically. the rain garden plants may comprise of red J. . & ASSOCIATES, INC, April 11. 2013 Dr. Lich Ching Chang L&A Job No. 12-083 Page 4 mig dogvvoodl. rushes., sedges, salmonbetry. and twinbcrr�y and ornamentals such as royal ferns, [gig -leaved figularias or virious prinwoses- Draina c - fwii 7 it' the recommendations in our 91115 201.2 geotechnical. report and in his response leiter are (filly jillplenitnted during construction, dicre should be minimal int- 51tration of stonmvatcr into tht ground. Please feel tree to contact. us if you have questions, One plate attached Yours very truly, L SSOCTJ.S, JNC.- J, S, (Julian) Liu. Pb,D.- P.E. Consulting Geotechnical Engineer MU & ASSOCIATES, INC. L IU & ASSOCIATES, INC. 41 FV.Wj CHANE RESIDENCE 17134 TALBOT ROAD EDMONDS, WASHINGTON DATE