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southwcst corncr uf the lol. It is our opinion that thc c�ploration pits represent the suhsurfacc <br /> conditions across thc entirc lot. <br /> F.xploration pit (EP) logs of the completed e�plorations are attached to this report. The suhsurface <br /> canditions consisted of a minor amount of fill soil or prcviously disturhed r.arth ovcrlying Vashon <br /> aged advance ouhvash sand sediments. <br /> Stratigraphy <br /> 11ie upper soils in all thrce explorations were comprised of topsoil or fill soil. The fill soil was <br /> comprised of the silt and sac�d sediments from the leveling of the adjacent lot to die south. Therc <br /> was �ui excavation adjacent to the shop huilding on the adjacent south lot with the same sediment <br /> conditions as described below for thc subject lot. The fill gener.�lly consisted of inedium dense, dry <br /> to damp, light �Rey-brown, silry sand with some small gravels and organic fr�gments. Thc fiU soils <br /> werc found to bc bctwecn 2 to 4 feet thick in thc thrce exploration pi�s. <br /> Undcrlying thc fill soils wcre sedimcnts consisting of mcdium dcnse to dcnsc witl� incmusing dcpth, <br /> dry te damp, light grcy-brown, silty a��h some finc sand in the upper 1 to 2 feet 6Tading to fine to <br /> mcdiwn sand with tracc gnvcl cxtcnding bcyond thc tcrtninaGon depth of thc pits. Thesc scdimcnts <br /> cxtcnded below the tcrmination dcpths of our cxplontion pits at G l0 7 feet hclow ground surfacc. <br /> 'I'his material was interpretcd to be Vashon adv,�tnce outwash sand that was de�sited as tui outwash <br /> alluvium in fmnt of thc advancing icc shcet during thc last glacial advancc inro thc Pugct Sound <br /> n;gion. l'hc silt laycr in thc upper portion of thc dcposit represcnts an ovcr-bank floodplain typc <br /> dcposit. 'l�he outw�.sh sediments wcre sub�equcntly over-run by several tho�is:uid feci of glacial ice <br /> resulting in a dcnsc scdimcnt with good strcngth and modcratc pertneability ch.lnctcristics. <br /> (;ruund Watcr <br /> l�hcre was no ground wetcr secpagc cncounlcrcd in Ihc cxploration pits at thc timc of our field <br /> cxploratinns. Wc do not anticipatc cncuuntcring any suhsurfacc ground wa�cr conditions during thc <br /> dcvclopmcnt ol this projcct. Surfacc runoff watcr aprcars to infiltratc through thc sitc scdimcnts <br /> with c�:ccss ninoff flowing as shcct wash down slopc. 71�c shcct w�.sh h�s not causcd rilling or any <br /> othcr erosional fe�wros onsitc. <br /> (:colaRic Hatards <br /> Tlic f��llowing Jiscussion of putenti�il geologic harvds is b:ued on the visual reconn:+issance of thc <br /> sitc, thr subsurlace cxploralions, :+nd a rcvicw of acrial phc�b�graphs and n�gi��n:il topo�;raphic maps <br /> of thc arca. <br /> Slecp Slope and Landslide Hcv.u�ls <br /> l hc silc was locatcd ncar thc top of a histuric drainapc from an upland arca Jown to thc Pu�ct <br /> S�und ll�c moderrdc slopc of ttle tup of this historic dr.iinage cha�incl was created by erosion <br /> Ihrougli prcvi�us dcposition rathcr than mas� wasting evcnts. Thc slopc was compriscd of dcnsc, <br /> modcratcly t}cc draining udimcnts wilh no cvidcncc of pasl slopc inst.�n�i�ty. t� �� ���,<<,������,�, o��� <br /> Ihc slo�c is considcred to bc stablc hascd on currcnt gcotcchnical cnginccring practia; and thc ris4� of <br /> slupc inst,�hility is lo�v. "I hc dcvclopmcnt of a sin�lc farnily residcncc onsitc will n��t a(Tcct Ihc <br /> BGC, pllc 1A267 209"' Avenue NF Wnodinvdle, WA 9A077 (425) 27:1-SOG � <br /> �a'1����j� <br />