TagEnvironmental Impact Statement(400)

This U.S. Army Corps of Engineers Record of Decision evaluates a permit application from the Port of Seattle (case 1996-4-02325) for construction work in the Seattle area, assessing environmental impacts including effects on wetlands, fish habitat, water quality, air quality, and noise. The document reviews compliance with numerous federal and state laws—such as the Clean Water Act, Endangered Species Act, and National Environmental Policy Act—and addresses public and agency concerns, including those related to airport and aircraft safety. It ultimately documents the Corps' findings and determinations regarding whether to issue, conditionally issue, or deny the requested permit.

This document assesses the ecological functions of wetlands and aquatic resources in the Miller Creek and related basins near Sea-Tac Airport, evaluating their roles in water quality, flood storage, and wildlife habitat. Wetlands in the Runway Safety Area and Vacca Farm areas are rated across functions such as nutrient trapping, groundwater exchange, and habitat for fish, waterfowl, amphibians, and small mammals. The assessment finds that interconnected wetland complexes like Lake Reba provide high-value flood attenuation and baseflow support for Miller Creek, while farmed wetlands perform at lower functional levels due to sparse vegetation and agricultural runoff.

This U.S. Army Corps of Engineers document reviews the environmental impact of construction projects at Seattle-Tacoma International Airport, including the Third Runway and related Master Plan Update improvements, focusing on impacts to wetlands and waterways. The Corps conducted an independent assessment of wetland functions and evaluated whether the Port of Seattle's proposed mitigation plans adequately compensated for the destruction or alteration of aquatic resources. After finding the Port's initial December 2000 mitigation plan insufficient, the Corps worked with the Port to develop a revised plan, accepted in November 2001, that better addressed the loss of wetland functions caused by airport construction.

This document classifies and describes the various wetland types found within the Sea-Tac Airport project area, using both the Cowardin (1979) and Hydrogeomorphic (HGM) classification systems. It identifies forested, scrub-shrub, emergent, aquatic bed, and riverine wetlands across three drainage basins — Miller Creek, Des Moines Creek, and Walker Creek — listing the specific wetland units belonging to each category. The classifications support environmental impact assessment and mitigation planning associated with airport development activities.

This document tabulates public comments received during a permit review process, likely related to a construction or development project near Sea-Tac Airport. A total of 509 individuals opposed the permit, while 101 supported it, with additional concerns raised across topics including MSE wall integrity, wetlands, hydrology, air and noise pollution, and airport/aircraft safety. The index identifies specific commenters — ranging from environmental consultants to aviation industry groups — and maps each comment to a designated paragraph number for formal review response.

This document analyzes the environmental impacts of construction projects at a north airfield area on wetlands and waterways in the Miller Creek Basin. It details how filling approximately 2.75 acres of wetlands and 980 linear feet of Miller Creek will affect water quality, hydrology, fish habitat, wildlife, and plant communities. It also describes a compensatory mitigation plan at the nearby Vacca Farm site, where Miller Creek will be relocated and wetlands restored to offset the project's ecological losses.

This document summarizes the environmental wetland impacts associated with airport expansion projects near Sea-Tac Airport, detailing acreage affected across four creek basins — Miller Creek, Walker Creek, Des Moines Creek, and Green River. It breaks down impacts by wetland vegetation type (forested, shrub, emergent, and open water) and hydrological classification (depressional, riverine, and slope), with total impacts ranging from 4% of the Walker Creek project area to 100% of the Green River area. The tables also distinguish between temporary and permanent wetland impacts as determined by the U.S. Army Corps of Engineers, covering features such as the Third Runway and Runway Safety Area extensions.

This map document illustrates the planned Third Runway expansion at Seattle-Tacoma International Airport, showing the proposed runway location, construction staging area, and fill 'borrow' areas in the Sea-Tac region. The map covers surrounding communities including Burien, Normandy Park, and Des Moines, and highlights nearby waterways such as Des Moines Creek, Miller Creek, and Walker Creek that could be affected by construction. Based on the 1996 Port of Seattle EIS Sea-Tac Airport Master Plan and 1997–1998 King County Wetlands Maps, the document provides geographic context for environmental and land-use planning related to the runway project.

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