TagSea-Tac Airport(2027)

This engineering cross-section diagram from Sea-Tac International Airport illustrates the dramatic 179-foot elevation drop adjacent to the proposed Third Runway, showing how a massive retaining wall and new embankment would be constructed alongside Miller Creek. The exhibit depicts key infrastructure features including a permanent chain-link security fence, rock underdrain, silt fence, inner collection swale, and a minimum 50-foot creek buffer zone designed to protect the existing waterway. The drawing is part of the Miller Creek Instream and Buffer Enhancements project documentation associated with the Third Runway expansion.

This document is an NPDES (National Pollutant Discharge Elimination System) permit fact sheet for Sea-Tac International Airport, issued by the Washington State Department of Ecology. It details the locations of numerous water discharge outfalls across the airport property, covering industrial wastewater, stormwater from industrial activities, and stormwater from construction activities. The discharges flow into several local waterways including Des Moines Creek, Miller Creek, Walker Creek, Gilliam Creek, and Puget Sound.

The Pollution Control Hearings Board ruled largely in favor of community groups ACC and CASE in their challenge to Sea-Tac Airport's water pollution permit, ordering stricter wastewater treatment standards and rejecting most of the Port's appeals. Key victories included requiring the airport to meet long-overdue water quality standards for its industrial wastewater discharged into Puget Sound, mandating improved toxicity testing during de-icing season, and directing a professional wetlands analysis of Lake Reba. Of the seven final directives issued by the Board, six favored the community appellants and only one favored the Port.

This document explains the Washington State Department of Ecology's review process for Sea-Tac Airport's applications to fill wetlands as part of its third runway project. Sea-Tac submitted three separate applications between 1996 and 2000, with the third ultimately receiving a Section 401 water-quality certificate that was later put on hold after the Airport Communities Coalition appealed. The Pollution Control Hearings Board identified three key concerns driving the stay: contaminated fill material, insufficient water rights for dry-season stream flow, and inadequate wetlands mitigation plans.

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.