Letter to U.S. Army Corps of Engineers regarding Port Of Seattle low flow mitigation deficiencies

Notes

Northwest Hydraulic Consultants, retained by the Airport Communities Coalition (ACC), writes to the U.S. Army Corps of Engineers Seattle District identifying serious deficiencies in the Port of Seattle’s proposed low flow mitigation plans for Miller, Walker, and Des Moines Creeks related to the Sea-Tac third runway. The letter highlights flaws in the Port’s analysis of runway secondary recharge, arguing that embankment recharge volumes are overstated, stream low flow impacts are understated, and mitigation storage volumes are undersized. Additional concerns are raised about the Port’s failure to address outstanding public comments and certification conditions.

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