Appendix M: Water Resources — Wetland and Stream Delineation Technical Report, Seattle-Tacoma International Airport SAMP Near Term Projects

This technical report, prepared by Parametrix for the Port of Seattle in February 2024, documents the wetlands and streams found within and around Seattle-Tacoma International Airport as part of the Sustainable Airport Master Plan (SAMP) Near Term Projects. It covers the delineation of aquatic critical areas, assessments of potential project impacts on wetlands and waterways, proposed mitigation measures, and the permitting approach needed to address those impacts. The report also includes analysis of impervious surface changes and Federal Flood Risk Management Standard (FFRMS) compliance worksheets.

Notes

Wetlands and Streams Report prepared by Parametrix for Port of Seattle, February 2024, as part of the Seattle-Tacoma International Airport (Sea-Tac Airport) Sustainable Airport Master Plan (SAMP) Near Term Projects environmental review. Appendix M to the 2024 Draft Environmental Assessment covers water resources including wetland and stream delineation, impacts assessment for aquatic critical areas, impacts and mitigation summary, proposed permitting approach, impervious area impacts and mitigation measures, and FFRMS (Federal Flood Risk Management Standard) worksheets. Filed during the 2024 Draft EA public comment period (October 21 – December 13, 2024).

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