EXH1125042527

404 Permitprocessfor theThird RunwayProject. The site is located at the Sea-TacInternationalAirport in SeaTac,Washington(refer to Figure1, Vicinity Map). Figure1 showsspecificareaswithin the airport vicinitywhere we have performed explorationsfor thisstudy. Theseareasare presentedas siteand explorationplans,Figures2 and3. Crosssectionsshowing inferredgeologic conditionsare providedon Figures4 through6. Finally,a groundwater elevationcontourmap for the RegionalShallowAquiferisshown on Figure7. Thisreport providesthe data usedin engineeringanalyseswhich will be presentedin other reports.We have organizedthisreport into severalsections. The maintextstartswith a discussionof sitesurficialgeology and subsurface conditions.This isfollowedby a discussionof the hydrogeologicconditionsand testinginformationwe have obtainedfrom our explorationsto date. AppendicesA and Bfollow the maintextandpresentresultsof our subsurface explorationsand laboratorytesting,respectively. PURPOSE AND SCOPE Thisreportprovidesinformationon subsurfacesoiland groundwaterconditions for the plannedThirdRunwaywithin the areasrepresentedby our explorations. Thisdocumentsaddressesscope itemTask2.3, "Characterizationof Subsurface Conditions"discussedin our proposaldatedJanuary28, 1999. Additional informationon subsurfaceconditionswill be obtainedto supportcompletionof design.Tasks2.1, "SubsurfaceExplorations,"and 2.2 _LaboratorySoilsTesting." alsopartof the Januaryproposal,were completedto provide informationfor thisreport. GENERALIZED GEOLOGIC DESCRIPTION AND SUBSURFACE SOIL CONDITIONS Thissectionprovidesa descriptionof the geologicand subsurfacesoil conditionswithin the areasshownon Figures2 and3 basedon our recent explorationsat the siteand explorationsby others. Previousstudiesinto the Hart Crowser _97s.o6 Page I AR 042530 local geologic conditions at the Third Runway have been accomplished by AGI Technologies (AGI, 1998 and 1996) and CivilTech (1997). Generalized Geologic Conditions The site is located on the Des Moines Drift Plain in the Puget Sound Lowland. Glacial soilshave been deposited and extensively reworked by glacial episodes. the most recent being the Vashon glaciation. This section presents the geologic conditions within the study areas shown on Figures2 and 3. In summary, the following geologic units have been identified at the Third Runway project site: • Fill (loose to medium…

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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 [...]