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I Itr ur���:r �hrrc Icct ��� c���li�r,di�,n pi� I�I'-.' cn �sis���l iif�luu�c. dr��, hni�•.n. silt�� �;md ai�h somc <br /> '.r;��cl. urganic �+:istc :md constnictiun ruhhlc. 'I hc till suil cncuuntcrcd in this c�plurati�,n �ii�f <br /> not originalc t�om this property nor was it placcd sWcturally. It was also visually apparcnt ih:u <br /> ihc cast slopc of l3road�uay, adjaccnt to ihc wcst cnd of the property, wxs compriscd of fil! s��i I. <br /> Yresumably, since this soil is supporting a City slrcet, this fill slopc should Ix striectural fill. <br /> 11���Jcrlying the fill soil in EP-2 anJ undcr n thin laycr of topsoil in I:P-1 was a dcnsc sand unit. <br /> I�hc subsurfacc conJitions at depth in Iwth cxploratiou pils consistcd of dense, damp, light <br /> hrown-brey, medium sttnd wilh ir�cc gravcl. "I�he up�:r 2 to 3 fect was wcathercd tn a slightl� <br /> Icvs dense condition. '1'he sanJ extended Leyond lhe tettnination depths �f the explurations cu 1 � <br /> to 1 G fcct bclow existing ground surfacc, '1'his sand hyc bccn intcrprctcd to bc Vashon adv.+n�� <br /> uutwash. 77�c Vashon advancc outwash was depositcd prior to the advance of the IaSt glaci.�I i:.� <br /> sheet in the Puget Sound rcgion. 1'hc sand and 6ravcls wcre deposited by (luvial processes <br /> associated with runotT from the icc shr.ct. 'I'he sand and gravel deposits were subscyucnUy o��•r- <br /> run by scveral Uiousand fcet of glacia] icc resulting in thcir dense condition. <br /> l'I�ero was no ground watcr encounlercd in the exploration pit completed tiv this study. I h,• <br /> sand and grsvcl sedimcnts havc a good pcnncability and allow surfacc runof't'lo infiltrni. <br /> vcrtically. 'fhc permca�blc sand ar,d gravcl should allow thc infiltration of thc mujnrit� ��i <br /> putcntial stonn watcr during construction cxc.pt from largc slortn cvents or storm cvcm. o� I�mi� <br /> dur.uion. The pern�eable sand and gravel will h�� ahlc t�, su�,�,nrt inlil�rrtinn nf>t��rm �c:urr <br /> nm�1T frum thc planncd imrcnnr:�hlc surf.iccs <br /> Gcolugic Naz:�rds <br /> I'he following di�,.u�..i�,n ,�I����,tr,��u,ii r���l�,�•ic h:v:u�I:: ir, !�;c.rJ �,n Ih� ��ir,ual r�corur,:i,;�;uu'� ��f <br /> ��1C SItC� ���C$�l�l:illl��:l�'t' �" '��tiL::��'�II`�. :II71� Il'V ICl1•: t�� ;'Cll:i� ���l��hl;'ill���l: :III�� �C�r1Ull{1� !1��)l�f'f8J`.�IIC <br /> �11J�5 Of�Q1C iilC�1. <br /> SICC�S�ODC H.IV.::i��' <br /> I'l�e property is considercd to be a steep slopc hazard area due to thc inclination ��f ti�c sl����r. <br /> I'he slope;was nt inclinations of about 45 perccnt:uid was about 40 feet high. "l hc slopc �i:i> <br /> underlain by densc,glacially consolidnted,�dvancc outwash sand scdimcnt:,. "1'hc slope was �c�ll <br /> vcgctatcd �vith good gmund cover. Then:was no evidence of rcccnt crosion or slope instahiliiy <br /> ubscrvcd on 1he sloEx;. <br /> I'hc advwicc outwash sand and gravcl scdimcnts cncountcred on the sitc are not prone to dcc�� <br /> scatcd, rotational failures due to thcir high intcmal strcngili :u�d good permeability. 'I'licrc wcrr <br /> no indications of past debris flow or rotation�il fuiluro occurrenccs on this or thc ad.jaccnt <br /> properlies. 17�e pinnnecl development pro�ses to construct a retaining wall that will bc <br /> cmbedded into the dense sand soil ncar Q�c toc of il�c slopc. �� Uuttress oCgcogrid reinti,rcr till <br /> will bc notched into thc slopc to cmate stcpped building pad fi�r tlic liousc a��d garage arc.u. <br /> Provided thal consWction of the rctainirg wall and structural fill are done in accordancc with the <br /> recommendations cnntained in this report, it is our proCessional opinion that thc risk of a debris <br /> Ilow or other mass wasting events occurring on this property ufter consuuction �vould be low. <br /> Ii(iC, �illc l.}:'h7 .'U�!'�' ,Avenuc NI�. W�nulinvill�'. �1':A ')ft077 (d75) 27;-SU6� '�� �� <br />