Notes
Memorandum dated November 27, 2000 from Dave Garland, NWRO Water Quality, Washington State Department of Ecology, to Ann Kenny and Kevin Fitzpatrick regarding Sea-Tac Third Runway Borrow Area 3 wetland impacts. Addresses Port Of Seattle proposal to excavate sand and gravel from Borrow Area 3 south of Sea-Tac Airport for Third Runway fill embankment. References Pacific Groundwater Group (PGG, 2000) hydrologic study concluding excavation ‘would likely have substantial impacts to wetland water flows, and possibly biota.’ Document covers seven wetlands in Borrow Area 3, perched water-bearing zone interception, proposed drainage swale along northwest margin of borrow pit, flow control structure, wetlands 29 and 30, Hart Crowser reports (2000a, 2000b), Section 401 Water Quality Certification, and recommendations including minimum 50-foot undisturbed buffer, HDPE-lined drainage swale, and semi-annual swale inspection.