5300 GLENWOOD AVE 2018-01-02 MF Import

f � Glemvood Tecrace Pilc Numbcr 126994 May 12. 1993 Vage 7 llydrolo�ic Conditions: Sapage was encountered in all of Uie tcst pits cxcept for TP-2 through TP-0. "Ihc H:.Icr Icvcls rangcd from 3.0 to 9.0 feet in depth. W'at�r levels were near the surface in the perforeted pipcs IocateJ along lhe existing cut slope. We could not determine the source(subsur}ace or surface)of the water collecting in perforatcd pipe. We suspect lhat it is some type of cut-off�rench. 71�c amount of sapage ranges from very slight in Uu fill slopc portion of tlie site (north) to hcavy in the vicinity of the rubble and cut slopc (south). \Ye suspcct that the ground water is a perchcd condition on the less pertncablc undcrlying soils,such as silt layers of lhe tr,utsitional beds. Ground�vater should bo expccted to be witLin the oubvash during mon of the ycar and may not tluctuate significantly between wet und dry periods oCthe year. Shallow ground water should be expecled Uvoughout lhe sitc even in tlic fill arcas. SENSITIVE AREA EVALUATIOIV Scismic HazArd 71ie Puget Sound Rcgion ir classified as a Zone 3 by tlic Uniform Building Caia. Hazards associated with seismiciry include liquefsction,ground movement attcnuation and reduction of siope stability. Liquefaction is caused by a risc in pore pressures in a loose sand deposit. The medium dense consistency and the higli rclativc pcmicnbility, in our opinion, indicalcs tlic w�derlying nativc deposits have a law potcnlial for liquefaction. The dcnsc nature of die soil conditions arc not expexted to prescnl problems azsociat�d with scismic huards ilml would c[tect U�e improvcn ats. The fill could exl�ibit some settlement follo«�ng a scismic evcn[. Since U�e sttuctures ovcr fill are to be founded through lhc fill, this sctQement should not significa�rtly impact Uie plann�d dcvclopmcnt. If the recoirmicndations are follavcd in this repart, wc would nat expect problems associatcd wilh ground movemetrt attenuation mid reduction of slope stability �ti�hich��ould significandy impact the pl�nncd improvemcnts. Erosion Ilazard Tlie erosion hazard criterin uscd for dctertninalion of atiected arcas include soil type, slope gradicnt, vegeL�lion covcr,and ground watcr wnditions. 'fltc crosion sensitivity is rclated to vcgetativc cover and the specific surface soil ty�cs (group classification), which arc related to dw underlying gcologic soil units. The follo«�ng G�ble outlines lhe crosion hazard for tLe on-site soils that have been stdppcd of vegetatian. 'Il�c soils have bcen classificd in accord:uice wilh tlro Soil Conscrvation Service (SCS) classification system �nd have been grouped��ith respect b the corresponding geologic unit. ¢colo ig•c Unit Surfncc Soil Sensitivity At Slopc 0-IS%16-39%>40% Qvt(Vaslion Till) Aldcnvood Med Med High Qva(Vashon Outwnsh) Aldenvood Med High High Qtb(Transitional Beds) Aldcrn�oocUEvcreR Med Med Iligh NELSON-COUVRETTE&ASSOCIATES, INC. FFA-23-1�9C 12�n4 205 481 2510 96i �'•�79 �