TagEnvironmental Impact Statement(325)

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.

This appendix lists the individuals and organizations responsible for preparing the environmental review documents for Seattle-Tacoma International Airport's Sustainable Airport Master Plan Near-Term Projects. It includes two tables: one covering contributors to the State Environmental Policy Act (SEPA) Environmental Impact Statement, and one listing those who prepared the National Environmental Policy Act (NEPA) Environmental Assessment. Key contributors include staff from the Port of Seattle, consulting firms such as Parametrix, Landrum & Brown, CDM Smith, Concord Engineering, and RS&H, covering areas such as air quality, noise, climate change, safety, and biological resources.

The Port of Seattle has released a Draft Environmental Impact Statement (EIS) under Washington State's environmental review law for 31 near-term construction projects at Seattle-Tacoma International Airport (SEA). The projects, which include a new 19-gate terminal and an elevated busway system, are designed to handle up to 56 million passengers by 2032. While a prior federal review found no significant environmental impacts requiring mitigation except for surface transportation, this state-level review evaluates two action alternatives alongside a no-action scenario.

The Port of Seattle has released a Draft Environmental Impact Statement for its Sustainable Airport Master Plan (SAMP), outlining 31 near-term construction projects at Seattle-Tacoma International Airport aimed at handling a projected 56 million passengers by 2032. Key proposals include a second terminal with 19 new aircraft gates, an elevated busway connecting terminals, expanded cargo facilities, airfield safety upgrades, and new sustainable aviation fuel infrastructure. The plan addresses longstanding capacity shortfalls in parking, check-in, security, and gate areas that were already undersized as of 2018.

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.

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 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.