TagEnvironmental Impact Statement(328)

This section of the May 2026 Draft Environmental Impact Statement for Seattle-Tacoma International Airport examines how the airport's near-term construction projects may combine with other past, present, and planned developments to create cumulative environmental effects. The analysis covers 58 projects in the surrounding area—including housing, road improvements, and airport expansions—completed or expected between 2017 and 2032, within a study area defined by the airport grounds, the 65 DNL noise contour, and the surface transportation zone. Long-term airport expansion proposals beyond 2032 are excluded from the analysis because they lack sufficient detail and funding approval to allow meaningful review.

This document is the References section of the Draft Environmental Impact Statement (EIS) for Seattle-Tacoma International Airport's Sustainable Airport Master Plan Near-Term Projects, published in May 2026 under Washington State's Environmental Policy Act (SEPA). It lists the sources cited across the EIS's chapters, covering topics such as aviation activity forecasts, terminal facility requirements, air quality standards, greenhouse gas emissions, geological surveys, and federal FAA design guidelines. The references draw from federal agencies (FAA, EPA), state bodies (WSDE, WDNR, WDFW), regional organizations (Puget Sound Regional Council), and consulting firms that informed the airport's environmental review and planning process.

This appendix outlines the traffic mitigation measures required for the Seattle-Tacoma International Airport Sustainable Airport Master Plan Near-Term Projects, as mandated by the FAA's Record of Decision and the Port of Seattle's State Environmental Policy Act Environmental Impact Statement. It details specific intersection improvements across multiple jurisdictions—including the City of SeaTac, City of Burien, City of Des Moines, and WSDOT—such as new traffic signals, roundabouts, and turn lane additions, along with proportionate-share cost contributions where full mitigation is not required. The measures are designed to address projected traffic impacts through 2037 and maintain acceptable levels of service at affected intersections near the airport.

The Port of Seattle is advancing a set of Near-Term Projects under its Sustainable Airport Master Plan (SAMP) for Seattle-Tacoma International Airport, covering infrastructure improvements such as new gates, taxiway extensions, runway blast pads, and cargo facilities. The plan is subject to both federal (NEPA) and state (SEPA) environmental review, with a Draft Environmental Impact Statement being prepared to assess potential impacts. Public and regulatory next steps include finalizing the EIS and communicating outcomes to stakeholders and surrounding communities.

This document is the agenda for the Port of Seattle Regular Commission Meeting held on March 24, 2026, covering routine governance matters such as approval of meeting minutes, claims and obligations totaling over $144 million, and several authorization requests for contracts and collective bargaining agreements. The meeting was held both in person at Seattle-Tacoma International Airport and virtually via Microsoft Teams. No specific noise policy items appear on this agenda; primary topics include environmental support contracts, a water reservoir rehabilitation project, Oracle software licensing, and labor agreements for airport staff.

Port Of Seattle Commission presentation (Item 8j supp) dated March 24, 2026 requesting $1,000,000 additional contract authorization for the Sustainable Airport Master Plan (SAMP) Near-Term Projects Environmental Review. Total authorizations including this request reach $9,750,000, following previous authorizations of $3,000,000 (11/10/2015), $3,400,000 (2/25/2021), and $2,350,000 (6/27/2023). Budget increase justified by enhanced outreach and engagement in

This document outlines principles and steps for conducting cumulative effects analysis in environmental impact assessments. It covers identifying cumulative effects issues, establishing geographic and temporal boundaries, and determining which effects are important from a cumulative perspective. https://ceq.doe.gov/docs/ceq-publications/ccenepa/sec2.pdf

This document introduces the concept of cumulative environmental effects analysis under NEPA, explaining how multiple minor actions can combine to create significant environmental impacts. It defines cumulative effects as impacts resulting from incremental effects of actions combined with past, present, and future actions, and discusses the purpose and implementation of cumulative effects analysis by federal

This document is a formal response to public comments on the Sea-Tac/Communities Plan Draft Environmental Impact Statement, addressing concerns about the airport's Noise Remedy Program. It explains that noise program classifications for petition signers were upgraded due to factors such as summer flight patterns and proximity to approach paths, and that most signers were moved into the Purchase Guarantee area or recommended for the Cost Sharing Insulation Program. The response also notes that no specific schedule exists for noise remedy implementation due to uncertainties in federal funding, and that detailed land-use planning for acquisition areas will involve full citizen participation after properties are acquired.