EXH0274019516

"- The IW$ collects and u'eatsindusu'iaJwastcwata';z2the 1W$ serves as a spiU-conu'olB_. The _$ was initially cons,_Jcted in 1963 to collect runoff fi-omterminalaprons, _xiways, hangm's, portions of the termmal root"top," the parking garage, the toll plaza, aircra/_ and ve._/cle maintenance arras, and some parking lots in the W cargo area. Runoff fi'omthese areasmay be contam/natedby accidentalfuel spills, de.icing chemicals,and washwaterfrom cleaningof aircraft and ground supportvehicles. A comprehensiveengineeringevaluationof the rWS system was conductedin 1995 ('Kennedy/Jenks1995) anda programforupgradingthe system is ongoing. The originalIWS syst=n hasbeengraduallyexpandedover theyears to includelargerareas of terminal apronplusnewlydevelopedareassubjecttoindusu'ialactivities.Many pansofthecurrentIWS systemoriginallybelongedto_eSDS,butwa_ laterconnectedtotheIWS. Runofffi-omthe IWS catchmentareas is collecmdbytlmIWS conveyance system. The IWS is divided into two primarydrainageareas: the air cargo/runwaysystem and the terminalsystem. Runoff fromthese areasis conveyed to the IWTP via separatepipeline routes. With upcoming plannedimprovements,the [WS conveyancesystemwill be sized to handleapproximatelythe25- yeardesign storm. Because the U,VSdoes not dischargeto the su'cams,it is not included in the hydrologicmodelinganalysis forthe SMP. However, five pumpstations,which normallydrainto theIWS,overflowm theSDS underhighflowconditions(seeSection4.2.3below).These ovcdlowsarcincludedinthehydrologicmodeloftheSDS andreceivingstreams. - Threelagoons(LagoonsI,2,and3)inthesouthwestcornerofSTIAprovidestorageforthe indus_al wastewaterpriorto U'eannentin the IWTP. Treateddischargeflows to an outfall pipeline thatjoms the MidwayWastewaterTrcau'nentPlanteffiucmpipe fordischargeinto Puget Soundvia a marine outfall. The dischargeis author/zealby the Port's NPDES Permit. IWS treaunent performance and the Port's dcterrn/nationof all known available and reasonable treatment (AKART) fortheIWS arediscussedin Sections4.5.3 and7.5, respectively. 4.2.2.1 IWS Storage Capacity The 2006 configurationofthe IWS (land use, lagoon stonge capacity,treaunentrate,and outfa]l discharge capacity) is summarizedin Table 4-2. A continuous simulation of the IWS was performedusing KCRTS (KingCounty Regional Time Series) to demonsuate that overflows will '_ As defined m STIA's NPDES Pon_t WA-002465-1. "'[ndusmd…

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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 [...]