TagACC(1534)

This section of the Sea-Tac Airport Master Plan Update Environmental Impact Statement examines how proposed airport expansion alternatives would affect water quality and hydrology in the surrounding area, particularly Miller Creek and Des Moines Creek. The analysis finds that increased impervious surfaces would raise stormwater runoff volumes and peak flow rates, potentially causing downstream flooding and erosion, but that required detention storage facilities and mitigation measures would largely prevent significant water quality degradation. Both creeks, while classified as Class AA extraordinary waters, already show some pollution from urban stormwater runoff, though deeper regional groundwater used for drinking remains unaffected.

This figure from the Sea-Tac Airport Stormwater Management Plan maps current fish habitat in the Des Moines Creek, Miller Creek, and Walker Creek watersheds near Sea-Tac Airport. It identifies the fish species present in various streams and lakes in the area, including Coho, Cutthroat, Steelhead, Chum, Chinook, Bull Trout, and Pumpkinseed Sunfish. The map also highlights piped stream segments and areas of potential Chinook and Bull Trout habitat within these interconnected watershed basins adjacent to Puget Sound.

This 2001 Memorandum of Agreement between the U.S. Army and the EPA outlines the policies and procedures for determining what types of mitigation are required when issuing permits for discharging dredged or fill material into waters under Clean Water Act Section 404. It establishes a three-step mitigation sequence — first avoiding impacts, then minimizing unavoidable impacts, and finally providing compensatory mitigation for any remaining harm — with a goal of no overall net loss of wetlands. The document provides guidance to Army Corps of Engineers and EPA field personnel on how to evaluate standard permit applications in compliance with these environmental protection standards.

This legal declaration by fish biologist Donald E. Weitkamp was submitted to Washington's Pollution Control Hearings Board in a case involving Seattle-Tacoma International Airport's expansion, including a proposed third runway. Weitkamp argues that the project's stormwater controls and water quality conditions under the §401 Certification are adequate to protect nearby streams, and disputes claims that salmon species are present near the airport's property along the headwaters of Miller, Walker, and Des Moines Creeks. He contends that these streams have already been significantly altered by surrounding urban development, making them more suitable for warm-water fish species than for salmonids.

Fish biologist Donald E. Weitkamp submitted this declaration opposing a legal challenge to Sea-Tac Airport's expansion plans, arguing that the airport's stormwater controls and water quality measures adequately protect nearby streams. He concluded that the headwater portions of Miller, Walker, Des Moines, and Gilliam Creeks near the airport are unlikely to support chinook or chum salmon, as urbanization has altered those streams to favor warm-water species instead. The declaration supports the Port of Seattle's position that its Master Plan Update projects meet environmental standards and will not significantly harm local aquatic resources.

This document is a professional biography and project experience summary for Dr. Don Weitkamp, a fisheries biologist with a Ph.D. from 1976, who has spent decades studying salmon habitat, water quality, and shoreline restoration in the Pacific Northwest. His work has focused on rivers, estuaries, and coastal areas including Commencement Bay, the Green-Duwamish River, and Elliott Bay, involving biological assessments, habitat restoration, and hydroelectric dam impacts. This document does not contain information related to Sea-Tac Airport noise policy.

This document contains the Port of Seattle's formal objections and responses to interrogatories filed by the Airport Communities Coalition (ACC) before Washington State's Pollution Control Hearings Board (Case No. 01-160). The Port identifies over a dozen expert witnesses it intends to use, including specialists in geotechnical engineering, toxicology, hydrology, and groundwater science from firms such as Parametrix, Inc. and Hart Crowser, Inc. The case involves a dispute between the ACC and the Port of Seattle regarding environmental and pollution control issues related to Sea-Tac Airport operations.

In this 2001 declaration filed with Washington State's Pollution Control Hearings Board, fisheries biologist Dr. John A. Strand argues that proposed modifications to the Port of Seattle's stormwater discharge permit would harm Walker and Gilliam Creeks near Sea-Tac Airport, which support salmon, trout, and other aquatic life. Dr. Strand contends that Ecology failed to identify specific locations of new construction-related stormwater outfalls, denying the public a meaningful chance to assess environmental impacts. He supports a stay of the permit modification until its compliance with the Clean Water Act can be fully reviewed.

In this 2001 legal declaration, Washington Department of Ecology official Kevin Fitzpatrick addresses water quality concerns raised by the Airport Communities Coalition regarding stormwater discharges from Seattle-Tacoma International Airport during its Third Runway expansion. Fitzpatrick explains that while stormwater discharges have shown elevated levels of copper, lead, and zinc, these instantaneous exceedances do not necessarily constitute violations of state water quality standards, since stormwater fluctuates rapidly by nature. He further outlines steps the Port of Seattle was taking to address pollution, including rerouting de-icing runoff, replacing zinc-emitting metal roofs, and conducting required studies to establish specific effluent limits under the Clean Water Act 401 Certification.

This document outlines Washington State water quality standards for surface waters, including criteria for total phosphorus levels in lakes across different ecoregions (Cascades and Columbia Basin) and limits for toxic substances such as heavy metals, pesticides, and radioactive materials. It establishes trophic state classifications and action values that trigger lake-specific studies when exceeded, and sets numerical criteria for aquatic life protection in both freshwater and marine environments.