EXH1126042613

PCHBPollution Control Hearings Board of the State of Washington

FROM: ReeseP. Hastingsand Michael J.Bailey, P.E.,Hart Crowser, Inc. RE: Third Runway Project, Borrow Areas I, 3, and 4 Projected Impacts to Wetlands J-4978-02 CC: JamesC. Kelley, Ph. D., Parametrix, Inc. J.Thomson, P.E.,HNTB On-site Borrow A ctivities This memorandum quantifies the potential impacts to wetland resources resulting from development of Borrow Areas 1, 3, and 4, and an on-site haul route for use in the construction of the Third Runway embankment. Completion of the Third Runway embankment will require about million cubic yards of compacted earth fill. Use of borrow sites owned by the Port of Seattle (Port) to provide this material will significantly reduce air quality and local traffic impacts associated with haulage from off-site sources. The Final Environmental Impact Statement (FEIS)(prepared for Sea-TacInternational Airport's Proposed Master Plan update development actions) discussed development of construction fill material borrow areasfrom eight identified sources within property controlled by the Port. Based on several factors (wetlands impacts, material types, operational costs) the FinalSupplemental Environmental Impact Statement (FSEIS)indicated that four of these eight on-site resource areas could likely be used to extract a maximum quantity of 15.45 million cubic yards of fill material. Further study by the Port has focused on the Borrow Areas designated 1, 3, and 4, which are proposed to provide a combined total of 7.9 million cubic yards. Figure 1 - Site Location Map shows the location of Borrow Areas 1, 3, and 4. AR 042613 Port of Seattle J-4978-02 July 9, 1999 Page 2 Original resource estimates for two…
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