Notes
Memorandum dated July 9, 1999 from Reese P. Hastings and Michael J. Bailey, P.E. (Hart Crowser, Inc.) to Barbara Hinkle, Port Of Seattle, regarding Third Runway Project Borrow Areas 1, 3, and 4 and projected impacts to wetlands. Document J-4978-02 quantifies potential wetland resource impacts from excavation of borrow areas providing 7.9 million bank cubic yards (BCY) of glacially deposited silty sands and gravels for the Third Runway embankment (requiring 17 million cubic yards total compacted fill). Borrow Area 1 (121 acres, City of Des Moines/City of SeaTac, 1.79 acres wetlands, Des Moines Creek, 3.8–4.8 million BCY); Borrow Area 3 (60 acres, City of SeaTac, 2.35 acres wetlands, 1.0–1.5 million BCY); Borrow Area 4 (40 acres, no wetlands, 2.1 million BCY, west of Tyee Golf Course). Also evaluates conceptual truck and conveyor haul routes aligned to avoid wetlands, with road grades under 8% for trucks and 15 degrees for conveyors, crossing Tyee Golf Course to regional detention facility (RDF). References FEIS, FSEIS, SR-509 WSDOT extension, South 216th Street, 24th Avenue South, South 200th Street, 18th Avenue South.