Last month, the Port of Seattle approved funds to add five portable noise monitors to its system for measuring the sound of air traffic in communities bordering the Seattle-Tacoma International Airport.

One of those monitors will be designated for Vashon, a result of pressure from islanders who compelled Port commissioners to make a device available, sending letters and giving testimony in recent months as part of a year’s long campaign to obtain it.

While the outcome is less than what many hoped for — the nonprofit Vashon Island Fair Skies pushed for two permanent monitors to be added to the Port’s system — founder David Goebel said the Port’s motion to install more monitors is a welcome turning point.

“This has been a long time coming,” he said, noting that the Port was not planning to install additional monitors in new locations as stated on the Questions and Answers web page for the Air Noise Program. “It’s been a big triumph getting it here.”

The Port’s 24 existing monitors are in communities within five miles of the airport. Vashon’s monitor — at a cost of around $20,000, provided by airport contingency funds, according to spokesman Perry Cooper — will temporarily capture overflight noise outside of the boundary of the current system for one year, and the data it collects will be available to the public online within a month of its installation.

Much of the effort to reach this point began at the 2018 Vashon Strawberry Festival, where Goebel introduced a petition to deliver to commissioners urging them to add the monitors. It was signed by nearly 700 islanders by the time it was delivered to the Port in December.

Vashon Island Fair Skies has pressed the Port to install two monitors on the island since then — one at a location with the highest day/night noise level (DNL) for all air traffic traveling south, and one at the highest DNL for flights traveling north — at spots in the north and south of Vashon respectively.

Most of the traffic arriving at SeaTac comes from the south — flights catch the wind coming from that direction on approach in order to reduce their ground speed, cruising north of the airport before turning back to land on what is called a “downwind leg.”

Up to 250 flights a day cross over Vashon on arrival to Sea-Tac on that trajectory, accounting for about 70% of the airport’s traffic. They follow a hyper-focused path from the sky to the runway implemented by a controversial Federal Aviation Administration program guiding air traffic called NextGen, a series of initiatives designed to upgrade old technology while increasing flight safety and efficiency at airports across the country.

Its implementation has been challenged by the courts in numerous communities, most recently in Burien, where last month the Ninth Circuit Court of Appeals ruled in favor of advocates suing the FAA. That decision forces the federal agency to redraw its razor-sharp flight path over the city and could set a precedent in other cases, according to The Seattle Times.

Cooper said the Port expected more than a million passengers traveled through SeaTac between Nov. 25 to Dec. 2 for the Thanksgiving holiday, adding that the noise level is owed in great part to the amount of traffic moving through the airport annually.

On Vashon, the Port has yet to finalize where the portable monitors will be located, although it is required that they are placed on public property such as a school building or community center and secured against theft and vandalism. Goebel stressed that the monitor cannot go somewhere with a high ambient noise level that is not representative of the characteristic peace and quiet of the island, such as close to town or a busy roadway. But that leaves few locations where a monitor could feasibly be installed while remaining effective as a tool, jeopardizing the chance of recording dramatic swings in volume posed by air traffic that the group has been fighting to prove is menacing residences on the island.

One potentially suitable home for a monitor is Wingehaven Park, on the island’s north end. Commissioners of the Vashon Park District discussed the subject as part of their regular board meeting on Tuesday, after press time.

Port Commissioner Fred Felleman said he was sympathetic to those voicing concerns about noise stemming from air traffic, including that of islanders. The general perspective provided by the monitors, he said, is an important one for helping to understand the impacts of air traffic in the region.

“My obligation as a public official is to represent the diversity of the communities that I’ve got to the best of my ability,” he said, noting that the Port does not dictate flight routes. He said he hopes the added monitors provide new insights the Port had not thought of or reveals benefits associated with noise monitoring that were not foreseen, trusting that Goebel and Vashon Island Fair Skies will be able to find the information useful.

Felleman’s background is in marine conservation and maritime safety, and he earned a graduate degree studying the feeding ecology of the Southern Resident orcas. Now he has a home in the San Juan Islands so he can be in close proximity to the animals he loves, where he said he enjoys the same quiet tranquility and deep reverence for nature that brought so many to Vashon.

“I know you don’t live on Vashon for the convenience,” he said.

This version of the article corrects the funding source for the Port of Seattle’s portable noise monitors.