Impacts from SEA Airport Expansion
Response to the Sustainable Airport Master Plan (SAMP)
The City recognizes the impacts on our community due to our proximity to Seattle-Tacoma International Airport (SEA). The City is responding to the Port of Seattle’s plan to expand SEA, which will increase airport impacts on our community.
The Port's planned expansion to handle more passengers and flights is outlined in the Sustainable Airport Master Plan (SAMP). Under this plan, SEA will add gates, build a new terminal and increase flights.
An assessment released in 2024 under the National Environmental Policy Act (NEPA) found that the airport expansion will not have any additional negative impacts on our communities. The City is appealing that finding, working with the cities of Burien and SeaTac. The cities have filed a petition for review of the “finding of no significance” under NEPA.
In early 2026, we anticipate the state will release a draft Environmental Impact Statement, required by the Washington State Environmental Policy Act (SEPA). This document outlines how the airport's proposed expansion would impact the surrounding area and the measures the Port must take to mitigate this. We are partnering with the cities of Burien and SeaTac to ensure our interests are represented.
Community Involvement
The Council has established the Airport Committee, made up of Des Moines residents. This is an advisory body to the City Council, providing input and recommendations on key airport-related topics.
In December 2024, the City held a public meeting in response to the release of the NEPA Environmental Assessment finding of no significance. A recording of that meeting is linked below.
Read on to learn more about the City’s work regarding airport impacts.
Background
The City of Des Moines held a Public Meeting on Tuesday, December 3, 2024 where City consultants gave a power point presentation on how the public can comment to the Port of Seattle on the Sustainable Airport Master Plan Environmental Assessment.
December 3, 2024 Meeting Video
December 3, 2024 Power Point Presentation
Sample/Template Letter to the Port of Seattle/FAA to respond to the EA
SAMP Website: https://www.airportprojects.net/sampntpenvironmentalreview/
Accessing the Document
The FAA’s NEPA draft EA is available online and will also be available at public libraries and at the SEA Airport Conference Center; including Des Moines Library (21620 11th Ave S., Des Moines, WA 98198).
Environmental Review Process
An environmental review is a process to assess how projects at Port of Seattle facilities may impact the environment in a variety of categories that include air quality and climate, water resources, biological resources, and noise, among others. If impacts are identified, the analysis evaluates the extent of those impacts, and if required, identifies ways to reduce or avoid them. A project may require both federal and state environmental reviews, but not always both are required for every project
The purpose of an environmental review is to assess the potential environmental impacts of a proposed project before it is undertaken. Key objectives include:
- Informed decision-making
- Full transparency and public engagement in the decision-making process
- Compliance with laws and regulations
- Identification of ways to avoid, minimize, or mitigate impacts
The SAMP NTP environmental review includes 31 proposed projects, which is being conducted to comply with the National Environmental Policy Act (NEPA) and State Environmental Policy Act (SEPA). The FAA is the lead agency for NEPA, and the Port follows their guidance under FAA Order 1050.1F.
Steps in the NEPA Environmental Review Process
The typical environmental assessment process includes:
- Developing the purpose and need for the project and determining potential alternatives that provide a solution.
- Undertaking scoping to understand agency and public concerns that are then addressed in National Environmental Policy Act (NEPA) documentation.
- Analyzing and documenting the environmental consequences for all alternatives detailed in the NEPA document.
- Conducting public meetings through the analysis process to advise and continue to collect input from agencies, the community and general public, including a public meeting or hearing at the issuance of the draft EA document.
- Addressing comments on the draft NEPA document, which will aid in the preparation of a final NEPA document.
- Ending with either the lead federal agency – in this case, the FAA – issuing a Finding of No Significant Impact/Record of Decision or the lead agency determining that an EIS is required.
Public comment during the environmental review process is provided during formal comment periods. The purpose of public input during this process is to fully understand the potential impacts related to the proposed projects and consider community concerns before a federal agency makes a final decision.