Des Moines committee targets airport noise, data and outreach while awaiting federal EIS

Members of a Des Moines City advisory committee on (start-related airport issues) spent most of their meeting outlining a work plan to press for stronger study, more data and broader community outreach around Seattle‑Tacoma International Airport noise and related impacts. Committee members agreed to gather and share data, pursue coordinated legal review of environmental review processes, and hold neighborhood meetings and a citywide survey after the first of the year. The committee approved the minutes of the previous meeting by head nods.

Committee members said they want to avoid “reinventing the wheel” by reusing past studies and data but stressed gaps remain in measures of noise, vibration and ultrafine-particle pollution. Rebecca Deming, Des Moines City community development director, told the group that staff are working with other cities through an interlocal arrangement to retain legal counsel experienced in NEPA and SEPA work and that the SEPA process — which will contain the local EIS — is expected to follow the federal NEPA review. Deming said the NEPA document is due next month and SEPA is expected to begin after the new year.

The discussion focused on three near-term priorities: encouraging the Federal Aviation Administration to finish its Part 150 noise review and related modeling (including reconsideration of the 65‑DNL contour), compiling simple, easily understood local metrics (such as flight growth versus population growth), and designing community outreach that documents residents’ concerns and demonstrates civic backing when the committee engages state and federal officials.

Members noted technical and policy limits. The group discussed that the FAA uses the Day‑Night Average Sound Level (DNL) metric — commonly referenced as the “65 DNL” contour — to determine eligibility for mitigation such as home insulation; members said that an abrupt contour threshold can leave homes just outside the line without mitigation despite audible and health‑relevant noise impacts. Committee members also discussed the FAA’s ongoing review of noise metrics (referred to in the meeting as “Part 150” and the newer modeled noise‑impact boundaries) and the need to press legislators to fund and complete that work.

Electrification of aircraft and quieter night‑time operations were raised as longer‑term and shorter‑term policy levers, respectively. One participant noted that electric aircraft could reduce noise by as much as 50% on landing as a theoretical long‑term outcome, while other participants urged continued pressure on the port and airlines to encourage quieter aircraft, particularly for night flights.

On data and community engagement, members discussed using an existing city survey process and running targeted neighborhood meetings (several venues were suggested) to collect local testimony and metrics. The committee suggested a small set of easily understood indicators — for example, number of complaints tied to households, changes in flight counts versus population growth, and property‑value analyses that compare local trends to national airport studies — to present to legislators and the port.

Members also reviewed past studies: the group discussed an earlier, larger 1997 study and contrasted its scope and funding to more recent work. Meeting remarks referenced a recent state-funded effort that had approximately $600,000 in funding and noted the 1997 effort was larger (participants mentioned figures including $750,000 in original dollars and an inflation‑adjusted estimate cited in the discussion). Committee members said those prior studies and case studies from other airports (Miami, Phoenix, Boston and others mentioned in an appendix) could help the committee make a focused case locally.

As an example of local advocacy, members cited the Burien Airport Committee and a letter that Burien’s council sent to the Port Commission seeking updates to sound‑insulation programs; Brian Davis, who the committee said is part of that Burien effort, was referenced as having read that material at a prior meeting. The Des Moines committee discussed whether similar letters, city council engagement, or coordinated intercity legal approaches would be appropriate.

Next steps the committee identified included drafting a short work plan and priorities to bring back at the next meeting, scheduling neighbor meetings (members floated holding community events in November as a possibility), developing a city survey after the heavier citywide surveys conclude, and having staff share the noise and membership reports they already receive. Rebecca Deming said staff will bring more information once the interlocal legal team is identified.

The meeting concluded after the committee approved the prior meeting minutes by head nods and agreed to continue the planning and outreach work at the next meeting.