Port Of Seattle Low Streamflow Analysis Technical Review Letter

Notes

Northwest Hydraulic Consultants, Inc. (nhc), retained by the Airport Communities Coalition (ACC), submitted a technical review letter to the U.S. Army Corps of Engineers identifying flaws in the December 2001 ‘Low Streamflow Analysis and Summer Low Flow Impact Offset Facility Proposal’ prepared by Parametrix, Inc. for the Port of Seattle. The letter details specific errors in the Miller Creek low flow analysis, including double-counting of groundwater discharges in the HSPF model, flawed embankment seepage methodology, and failure to account for updated embankment construction methods. Additional concerns are raised regarding Walker Creek and Des Moines Creek modeling inadequacies.

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