TagDes Moines Creek(169)

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.

Exhibit 175 (AR018443) summarizes wetland mitigation credit for Sea-Tac Airport Master Plan Update improvements. Tables detail in-basin mitigation (102.27 acres, 29.80 credit) and out-of-basin mitigation (65.38 acres, 42.91 credit) for a total of 167.65 acres and 72.71 mitigation credits. Specific mitigation sites include Vacca Farm, Miller Creek Wetland and Riparian Buffer, Tyee Valley Golf Course,

This declaration by stormwater engineer Paul S. Fendt, filed in a Washington State Pollution Control Hearings Board case, explains how Sea-Tac International Airport's Master Plan Update will increase impervious surfaces and alter stormwater runoff into Miller, Walker, and Des Moines Creeks. The document outlines mitigation measures, including 344.1 acre-feet of new detention storage and controlled low-flow water releases, to offset increased peak flows and reduced summer stream flows caused by airport expansion. It provides technical background on the affected watersheds and the Port of Seattle's stormwater management strategy.

This figure (2.1-3) is a map showing wetlands located in the Des Moines Creek Basin near Seattle-Tacoma International Airport (STIA). It identifies delineated wetlands verified by the Army Corps of Engineers (ACOE), water features, streams, and piped streams across the area, with individual wetlands labeled by alphanumeric codes. The map was submitted as part of a supplemental natural resources mitigation plan related to airport development activities in the region.

Pre-filed testimony of Thomas R. Luster submitted on behalf of Airport Communities Coalition (ACC) in PCHB No. 01-160, ACC & CASE v. Department of Ecology & Port of Seattle, dated February 22, 2002. Luster, formerly Ecology’s senior expert on water quality certifications, challenges the Section 401 Clean Water Act certification issued by Ecology for Sea-Tac

Pre-filed written testimony of Dr. John Strand, Ph.D. (Principal Biologist, Columbia Biological Assessments; Adjunct Professor, Washington State University Tri-Cities), submitted on behalf of Appellant Airport Communities Coalition (ACC) in PCHB No. 01-160, ACC & CASE v. Dept. of Ecology & Port of Seattle, dated February 22, 2002. Strand’s testimony covers ecological risk assessment of stormwater

Handwritten notes dated 2/22/02 from a telephone call with Eliz. Leavitt outline five follow-up issues, including evaluation of biological impacts after implementation (involving USFWS/NMFS), a 60-day Walker Creek matter related to WL 44A, a July Des Moines Creek discussion about vaults of the same size, pH vault monitoring and recent science/technical papers, and concerns about how float vaults are designed.

This document is an agenda for a Low Streamflow Analysis Meeting held on February 19, 2002, at the Department of Ecology in Bellevue, Washington. The meeting covered technical modeling and water flow topics for three local waterways — Walker Creek, Miller Creek, and Des Moines Creek — including reviews of land cover tables, groundwater routing, and calibration. General topics such as water quality monitoring, channel hydraulics, and embankment modeling were also on the agenda.

This February 2002 supplement lists the technical documents relied upon by environmental scientist John A. Strand, Ph.D., when assessing the potential environmental impacts of proposed improvements outlined in Seattle-Tacoma International Airport's Master Plan Update. The documents primarily consist of laboratory analysis letters from Columbia Analytical Services and Analytical Resources, Inc., covering water quality sampling results collected between 2000 and 2002. An email regarding turbidity measurements in Des Moines Creek is also included, suggesting a focus on water quality impacts near the airport.