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Geotcchnicnl Gnginccring Report <br /> l lousinc I lopc <br /> Dccemt er i, 2004 <br /> RMI PileNo. 21704 <br /> Pagc 5 <br /> permcable soils consist of the topsoil, fill, nnd wcathcred advance ��'hvash. The less permeable <br /> soils consis[ of compact unwcathered advance out��'ash. It is our espeiience tha[ the advance <br /> outwnslt wili infiltrate, but occasionally �vater will perch on the unv.eathered ouh�:�sh if thc <br /> compaciness mid/or ihe silt content incrcascs. <br /> Perched water does nol represent a regional gro�nd wa[er "tabld' within [I�e upper suil horizons <br /> nnd[ends to vary spa[ially. Perched watcr is usually dependent upon the amount of rainfall. We <br /> would c:cpcc[ thc amount of ground water to dccrcase during drier times of'the year and incrcase <br /> during wetter periods. <br /> SrNSITIVE ARGA F.VALUATION <br /> Scismic Hazard <br /> I'he projcct is located within "/_one 3 of the Seismic %one Map shown as Figure 16-2 of the 1997 <br /> Unifonn Building Code (UDC). �'his corresponds to a Seismic Z.one Factor, Z, of 030. This, in <br /> turn, corresponds to an effective peak horizontal ground acceleration of 03g. Since medium <br /> dense to dense advance out�vash was encountered at dic site, the site condiLiens best tit the UI3C <br /> description for Soil Profile Type S�. <br /> Hazards associated with seismic activity indude liqucfaction po�ential, slope instability and <br /> ampliticatiun of eround motion duc to soft soil. The medium dense to den,e outwash soils that <br /> are inten�reted to underlie this sitc Jo not have a signiticant potential for liquefaction, slope <br /> in,tability or amplitication of ground mo[ion. <br /> Grosion 1{azard <br /> 'll�c critcria uscd for �valuation of erosion hazards include soil rypc, slope gradient, vegetation <br /> cover,and eroundwater conditions. The surface soil types(group clussification)are related to[he <br /> underlying gcologic soil uni[s. The Suil Survey of Snohomish County Area, Washington, by the <br /> Soil Conservation Service(SCS), was reviewed to evaluate the erosion hazard of[he on-site soils. <br /> l'he subsurface soils at the site wcre mapped as Aldernood-Urban, bu[ we found soils consis[ent <br /> ��ith Ihe Everett gravclly sandy loam (0 to 3 percen[ slopes). These soils are derived from die <br /> advance ouhvash deposits mapped in thc site area. The crosion hazard for Evcrett Series is listed <br /> as slight. <br /> RM! ASSOC/ATES, LTD. <br />