Tagenvironmental assessment(30)

This September 2025 Environmental Assessment evaluates three alternatives for near-term development projects at Seattle-Tacoma International Airport, comparing a No Action scenario against a Proposed Action and a Hybrid Terminal Option through analysis years 2032 and 2037. The study finds that while both action alternatives would increase aircraft operations to approximately 475,655 by 2032 and 509,892 by 2037, resulting in higher emissions and some biological resource impacts, none of the increases are considered significant. Mitigation measures, where warranted, include post-construction stormwater controls and nest protection protocols during construction activities.

This section of the Seattle-Tacoma International Airport (SEA) Environmental Assessment describes the airport's physical setting and surrounding communities as they existed in 2022, serving as the baseline for evaluating potential impacts from near-term expansion projects. SEA occupies approximately 2,800 acres in the City of SeaTac, bordered by state routes and residential neighborhoods in cities including Burien, Des Moines, and Tukwila. The assessment defines a General Study Area of 3,692 acres where direct or indirect impacts from proposed actions may reasonably be expected to occur.

The Port of Seattle held a public meeting on December 3, 2024 in Des Moines, WA to present highlights from the Environmental Assessment (EA) for Seattle-Tacoma International Airport's Sustainable Airport Master Plan (SAMP). The SAMP outlines a wide range of near-term construction and expansion projects across the airport, including airside, landside, terminal, cargo, and support facilities. The meeting provided an opportunity for community members to learn about the plan's environmental findings and submit public comments.

This section of the Seattle-Tacoma International Airport Environmental Assessment lists the individuals and organizations responsible for preparing the document, including staff from the FAA, Port of Seattle, and several consulting firms. The team covered a wide range of technical areas, with specialists handling noise analysis, air quality, surface transportation, wetlands, cultural resources, and public engagement. The assessment was produced in October 2024 as a draft under the airport's Sustainable Airport Master Plan for near-term projects.

This section of the Seattle-Tacoma International Airport Environmental Assessment examines cumulative impacts from past, present, and reasonably foreseeable future development projects at and around SEA airport, covering the period from 2017 through 2032. It reviews actions by the Port of Seattle and surrounding cities and agencies — including hotel construction, terminal expansions, and flight procedure changes — to assess how their combined environmental effects, such as noise, emissions, and land use changes, may affect nearby communities. Projects beyond 2032 or those in the long-term vision phase are excluded from detailed analysis due to insufficient specificity.

This October 2024 draft Environmental Assessment evaluates the potential environmental impacts of near-term construction and operational projects at Seattle-Tacoma International Airport under three alternatives: No Action, a Proposed Action, and a Hybrid Terminal Option. The analysis covers impacts through 2032 and an out-year of 2037, finding that increases in air quality emissions and effects on biological resources are not considered significant, with mitigation measures proposed for stormwater management and migratory bird nesting. Farmlands and Wild and Scenic Rivers were determined to have no presence in the study area and required no further analysis.

This draft Environmental Assessment from October 2024 examines the existing conditions around Seattle-Tacoma International Airport (SEA) as part of the Sustainable Airport Master Plan Near-Term Projects. Using 2022 as the baseline year, it describes SEA's location on approximately 2,800 acres in the City of SeaTac, situated 12 miles south of downtown Seattle and surrounded primarily by residential neighborhoods. The study covers a General Study Area of 3,692 acres to identify where proposed airport development actions could have direct or indirect environmental impacts on nearby communities.

This draft Environmental Assessment chapter from October 2024 outlines the process used to evaluate alternatives to proposed construction and expansion projects at Seattle-Tacoma International Airport (SEA). Using a two-step screening process, planners assessed public suggestions — such as building a new airport, using high-speed rail, or limiting growth — against the project's core purpose of serving 56 million annual passengers at an optimal level of service, rejecting most suggestions as unfeasible or insufficient. A No Action Alternative is also included, which assumes none of the proposed improvements would be built, though several independent projects already underway or planned by 2032 would still proceed.