Notes
GeoSyntec Consultants, retained by the Airport Communities Coalition (ACC), submitted technical comments to the U.S. Army Corps of Engineers regarding the Port of Seattle’s Low Flow Analysis for the Third Runway Expansion Project at Sea-Tac Airport. The letter critiques the Pacific Groundwater Group’s November 2001 embankment fill modeling report, identifying key deficiencies including failure to account for initial years of reduced water flow through the embankment, unreliable long-term flow estimates, and unvalidated assumptions. GeoSyntec concludes that the storage vaults may be substantially under-designed and that insufficient water will be available to mitigate impacts to low stream flows during the initial years of operation.