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• D�e-30-97 17 :21 AESI Kirkland 4�58?75424 <br /> P.O1 <br /> �f►O�A7E O/IIC[ <br /> ����rr�T�� 711 F'iM An��w.SuiM 100 <br /> �TN KLkI..�.VYb�Aipw MOJi <br /> SGIENCE'.i. INC r����y�s�y� <br /> (,.. <br /> , Nrreuoce isuwo omc� <br /> 179 tibdwr l.e.hbnA <br /> laibridp�41ond,1A9�90110 <br /> 120617lo-9770 <br /> December 30, 1997 F�(2061790-94'1! <br /> ProjectNo. G95103A <br /> Seaaay Development Company <br /> c/o W&H Pecific <br /> 3025 112`�Avenue NE <br /> Bcllcvue, Washingten 98009-9304 <br /> Attrntion: Mr. Rendy Blair <br /> Subject Ravine Fill Coneepts <br /> Seaway Center Lot 3 <br /> Dcar Mr.Blair: <br /> lt is our understandin� that preliminar�,�v��opment plans for the Seaway Centa Lot 3 call for <br /> filling the upper portions of several draiaege ravines in the westem portion of the siu, adjacent <br /> w the Easc Fork of Powder Mip Cmk We hnve coaducted a reconnaissance of these ravina <br /> and preseat below our preliminary recommendations for placemeat of fill in these arcae. <br /> �rcvious work conducted by Associated Earth Sciences,Ine. (AESn indusated that the azea at the <br /> � top of the mvina is undedain by giacially consolidated �raveAy sand (Vashon Advana <br /> Outwash). Altlwuah oo subs�•face exploruion was conducted withia ti►e stecply sloP+�B <br /> portions of the raviaa, it was infetred that the yashon Advmce Outwash underlies �11 of the <br /> sceeply sloping areas in tl�e western portion of the siu. Durin�our recent monmissance, hand <br /> pmbing indiu�ted that surficial soils within yu ravina rypically consist of at least two ro three <br /> feet of loosr, colluvial sedimenu. <br /> Preparation of the ravine areac for placement of fill should include removal of all trees, bnuh, <br /> debris>topwii,aod other deleterious mamials, The loose.coUuvial sediments should be stripped <br /> down co the underlYing 5nn and unyieldin� naflve soils. The ba�e of 6ll placed on the slopes <br /> should be tied to the firm, smble,natuni soils yy app�opriate keying and benchinQ. ?he keyway <br /> wi11 embed the toe ofthe new fiU into the hillside. Gecerally,the keyway for hillside fills sho�ld <br /> be at least eight feet wida Leve! beacha should then be cut horizontaliy across the hiil, <br /> following the contours of the slope. Presented be�ow aze three optioas for placement of fill in die <br /> ravine areas. <br /> DEC 30 '97 17: 10 4258275424 PiiGE.001 <br />