1505 INDUSTRY ST Geotech Report 2018-01-02 MF Import

and thc munituring wclls wcrc drillcd to dcpths ranging from 35 to 7� fect. Soil toring SB-7 and monitoring wcll �IW-3 wcrc dcllcd ihrough structural fill that was pl�ced in the formcr mined pit on thc casl sidc of thc sitc. Dc�ailcd logs of thc soil borings and monitorin� wclis as wcll as thcir locstions �rc includcd in :\ppcndix 13. SITE CONDITIONS Thc fullo«�ing scctioiw dcsuribc thc gcncral xurfacc nnd subsurfacc conditions ut tnc sitc. fntcrprctnLons ' „P thc sitc conditions arc bascd un a sitc rcconn;�issancc, prcvious cxpericncc during ;itc grading, and �ul:surEicc explorations performcd by IiNSR Corpur.iliun. EXISTING SURFACE CONDITIONS �1'r visitcd thc sitc on January 23, 2005 to obscrvc cxisting surfncc conditions. 'I'he ground surCacc is roughly �lat and is genernlly devoici oi veget:uion other than scaRcred wecds and stnall shmbs sca[tered across the site. Sevcr.d shalluw cuts (I to 3 fcet decp) havc becn made across the site to collect and wnvcy sud'ace water runo(( ro lemporary detaition pands. Thrce tcmporary detenlian ponds werc obscrvcd on the siic, including a large pond about 2 io 3 fect decp ncar the center of the site, an S- ro 10-I'oot-da:p pond in the noRhwest arca of thc sitc ;md a smaller dctention pond in the southwest arc;i of thc site. Thc pond in the middle uf the site was pnrtially fillcd with w.�le[ es[im�ted to be OS �o I toot dccp, wi�ilc thc pond in thc northwcst :�re:� o(lhc silc hnd abuut 2 to 3 Ccct of watcr in i[. Scvenl �- lo 3-foot-high so;l stockpiles are lucated in the southcas[corner of the site and along the east property line. A G- lo S-('oobhigh soil berm exists along thc r; !i?i side of thc site adjacent to blcrrill Creck Parkway. Thc soil bcrtn is approsimatcly d0 fcct ��idc and has 31C I V sidc slopes. Thc bcmi is gcncrally covcrcd with grass, except on the east half'whcre much of!he vegetation has bc�•n rcmuved. A stomi drainpipe was rcccndy installed in the bemi along thc northcast �rea. The trcndi bnckfill nppcars to h�vc sctNcd up to G inches anel 2- to 4-inch-tvide cracks �sere obscrved along dic en!ire Icngih u( dre trench back(ill, , which indicatcs that thc backfill was likcly poody compactcd. "I'he west side of the site is locatcd adjacent to the pemr.mcnt storm�e:ucr dctemion Ei�ility. An ft-foo�-high rocky was constmcted along thc property linc. Thu rockery uppcareJ tu be adcquatcly cunstructed and tl�c rock sizes appcared ro he appropriate. Scvcral utilitics, incluJing cicclrical, communication, and gas,wcrc obscrvcd running paraflcl to thc north siJc oC Industry SireeL Thc utilitics appe:ired to be within about 20 Icet of the curb line. A low mound of lill wil, about I to 3 I'cet abuve the street surface, was ubscrved in this arca and it extends about 40 f'ect nurth of the curb line. A drainage ditch�vas located nlong the nortl�side of the meunded till area. SITE GEOLOGY Prioi lo mining and site gmding by Rinker Materi�ls, geolueic maps for the Sca�ea}' I3usiness Center vicin�ty indicatc qi;�[ Ihc surficiul soils consisted of'Vashon glucinl till. Glacial till lypically consisls of a vcry compaci, poorly sartcd, nonstraUficd mixWrc of cl:ry, silt, sand, gravcl and cobblcs-. [Jnweathcred glacial till typically appcars gray or 61uc un a f'resh surfacc, �chil�: wcadtcred glacial till m;iy bc brown tu vcllow in colue Glacial till is known locally as "hardpan" and ranges from abou! 10 to 100 feet thick in ihc vicinity oCthr. Seaway L3usines, Park. F3asc� on our kno�sledgc of tlu site, the native glacial till wati completely removed irom the eastem portian of Ihe property during tnining aclivities to expose the underlying sand and onvel resources. Dense W ��cry dense glacinl till deposiu were exposed in the ccntral por�iuns of lhc piuperty. �vhilc till :md uutwash dcpusits wcrc expostd in thc wcstcrn poRion of ihc ,fic. F�l� �>� i_�,7a��ol.��i� �� 5�'� GEOENGINEEIIS� J�:rwa.r'S, :JUj