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Gcotcchnical �nginecring Lcucr <br /> l lcuingcr Grading and Drainagc Rcvic�a <br /> Gvcrcu, \Vasliington <br /> NGA Pilc No. 7S I GOS <br /> July 29, 2009 <br /> Paec 2 <br /> short rockcry along thc casicrn property linc, as wcll fill placcmcnt to thc noilhwcst of thc housc <br /> bctwccn thc housc and thc top of Ihc stccp slopc. <br /> SITE COND17'IONS <br /> Yau inlonucd us thal 4-inch solid draivagc pipcs �vcrc inslallcd along tl�c �ecstcrn sidc of thc <br /> housc. thc southcrn sidc of thc drivc�vay, and in �ront of thc garagc, as sho�vn on Silc Plan A, to <br /> crnrvcy rool'nmofl'into undcrground inliltration trcnches. At tlic cnds of thc solid pipcs, 10-1'oot <br /> lang perforatcd pipc scctions wcrc installcd and wnppcd with filtcr fabric. '1'hc cud of thc <br /> southcrn pipc and thc n�n� in fronl of �hc garagc is locatcd along thc southcrn cnd of thc <br /> driveway, as shown on Ihc silc plan. '1'hc cnd of Ihc pipc along tlre wcstcrn sidc of thc housc is <br /> tcrminatccl within a modcratcly sloping portion of thc slopc n�.rthwcst of thc residcncc. It is our <br /> undcrstnnding that a minimum of 12 inchcs of 1-1/2-iuch gravcl was placcd bclow and abovc thc <br /> perl'oratcd pipcs. Il is also ow�uudcrstanding that a tightlinc pipc Gom thc northcastcrn corncr of <br /> ihc housc is dirccicd to a perfi�ra�cd drain pipc that u�as installcd undcrncath thc nc�e rockcry <br /> along lhc caslcrn property linc. <br /> Nc obscn�cd thal lill malcrial ���as pl,iccd on thc castcrn sidc of thc housc, as sliown on Sitc Plan <br /> 13. 7�hc m•ca slopcs drnvn from a short rockciy to titc backyard arca. It is our underslanding that <br /> thc majoriry of thc fill material cousists of rack spalls, and thc rock spalis ha��c been covercd aith <br /> saud. Pill matcrial �eas also placccl along thc no�lliwcstcrn sidc of thc housc abovc tlic top of Ihc <br /> stccp slopa Also, an olcl block wall Iliat csistcd along Ihc norlhcastcrn portion of tlic stccp slopc <br /> lias bccn rcmm�cd. Nall rcmoval lias resultcd in a small stccp cut in that arca. <br /> CONCLUSIONS AND RLCO�1�11'sNDA'I'fONS <br /> �Vc �vcrc not imohcd in thc most rcccnt sitc impro�cmcnts including grading nnd drainagc. <br /> la�ginceriug or dcsign lor the intilu�atirni system or grading liacl not becn comple�cd; however, <br /> bascd oii our prior knowlcdgu oCthc sitc, cun�cnt sitc obscn�ations, mid discussions with you, it is <br /> our upiniou that tlic grading and dr:iinagc syslems should perfonn adcquatcly undcr nonnal <br /> conditions. 71�cse syslcros may tail or bccomc ovcrn�helmed during estrcmc ���cather. �Vc <br /> rccommcnd that any cxposcd areas of soil bc covcrcd ���ith jutc nctting aud perniancnt <br /> landscapinc �cgctation as snon :is possiblc. 'I'hc rockcry along thc castern properly linc is <br /> NELSON GEOTECHNICAL ASSOCIATES, INC. � <br />