EXH2206034783

As requestedby the Portof Seattle,thismemo and the attachedfiguresprovideconceptual design and supportinginformationfor the proposeddrainageswaleto protectwetlandsin Borrow Area 3. We alsoprovidea brief explanationof the hydrologythat supportsthe wetlands, includingwhy excavationof Borrow Area 3 will not drainthesewedands. Figure shows the locationof BorrowArea 3 to the Southof Sea-TacAirport. REVIEW OF BORROW AREA 3 WETLAND HYDROLOGY le,_yci_ The firstsectionof thismemoprovidesa review and _xplanationof the hydrologythat currentlysupportsandsustainswetlandsin BorrowArea 3. Understandingthesehydrologic factorsisimportantinensuringthe long-termpreservationof thewetlandsduringandafter Juneau excavation of the fillmaterialscontainedin BorrowArea 3. Factors Promoting Preservation of the Wetlands Existingwetlandsandcurrenttopographyin BorrowArea 3 areshown on Figure2; the LongSeach proposed area of miningandresultingcontoursfor finalexcavatioriareshownon Figure3. The seriesof wetlandsmappedin BorrowArea 3 follow a lineof shallowdepressionsin the southcentralpart of the site,extendingto the southeastfromWetland29 throughWetlands po,_and Bg, 30, B7, B6, andB5. Thesewetlandsexist in anarea of relativelypermeablesubsoils where the main groundwatertable is at a dej_thof 10 to 15 feet below the wetlands. Depth of the water table indicatesthe Wetlandsare supported by othersourcesof Water. The sources of water appearto includesurficialrunoffand shallow interflow,aswell as Seattle '0 Fair,view Avenue East - ,ttle, Washington 98102-3699 206.3211.5581 2o_.3_,t953o ECY'00022165 Exhibit-2206 AR 034783 ..J ta_ .c_ _ (3Q. • C" ,¢ ¢,q ¢N o _ J-4978-08 8/01 _ IL_ Figure B-2 ECYO0022166 AR 034784 .c oU _1 0 tf) _J - "_" 0 J-4978-08 8/01 I_. Figure B-3 ECYO0022167 .... AR 034785 _J t.. ,_¢. _- oU C'_ C_ tn I-- J-4978-08 6/01 °_ 0 (/) I1. ECYO0022168 Figure B-4 _J AR 034786 t • o ..J LJ. c_ _. •_ o E _ _o_ •... )< J-4978-08 8/01 LLI Figure B-5…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]