A new major airport on the Plateau? Commission briefed on potential site near Enumclaw

There are many reasons why “King County Southeast” would be challenging to develop, but that doesn’t mean it’s an impossible scenario.

Editor’s note, updated August 5: We made a couple of errors in this article, which also appeared in the print edition, that have now been corrected. First: An earlier version of this article said that the new airport would have to be an international airport. This is not necessarily true — the legislation did not define whether the new major airport would have to handle international travel, and a consultant’s analysis showed it would likely focus on domestic travel. Second: The CACC was not created as part of WSDOT, according to WSDOT spokesperson Christina Crea. Instead, CACC was created by the legislature and tasked WSDOT’s Aviation branch to provide staff support in carrying out the commission’s needs. The Courier-Herald regrets these errors and will work to prevent mistakes like them from happening again.

A new airport right in the heart of the Enumclaw Plateau? It’s a possibility, albeit one with practical and legal roadblocks.

A state evaluation of potential sites for Washington’s next airport, presented in a June 23 meeting to the Commercial Aviation Coordination Commission (CACC), included one option called “King County Southeast,” located just east of the Muckleshoot Reservation in the Wabash area.

The legality and practicality of actually putting the airport on the Plateau remains unclear. Enumclaw city officials, strongly against the idea, are still researching how exactly it would work, were state and federal officials to pursue it.

“Enumclaw is strongly opposed to locating this airport in prime farmland and salmon-bearing streams,” Enumclaw Mayor Jan Molinaro said in an interview. “The council, their reaction was pretty adamant against it.”

The news raised alarm bells for many Plateau residents used to the grazing cows, rolling fields and rural charm that seem essential to this region’s way of life. Even the smallest size template considered by the commission, 2,400 acres, is just 100 acres shy of the size of Sea-Tac International itself.

“I don’t know how you would construct a major regional airport without having the surrounding land and infrastructure all be modified to support and enhance that,” city administrator Chris Searcy said. “Just the infrastructure for transportation alone; whether by light rail or bus or car, it’s hard enough to get two lanes just to get to the (White River) Amphitheatre.”

At this point, Molinaro said, Enumclaw is reaching out to nearby cities, county leaders and the Muckleshoot Tribe to loop them in on the process and assess their options.

“Our interest right now is to try to steer this vehicle back into the lane that we think it’s supposed to be in,” Molinaro said.

But the location, rated the highest among ten potential “greenfield” sites, could fulfill the broader region’s growing need for a new airport. To the rest of the state, a Plateau airport might look like a big step in an inevitable march toward urbanization in a part of the country that has seen explosive growth over the last two decades.

Either way, the CACC has until October to narrow their options down to the top two, and until June 2023 to make a recommendation to the legislature.

In the meantime, several roadblocks stand in the way of a King County Southeast airport.

First: The law that created CACC also specified that the commission can’t recommend a location within King County, although the ultimate decision lies with the state legislature, an airport sponsor and the FAA, who could ignore the CACC’s recommendation.

Second: Most of the Enumclaw Plateau, including land directly within “King County Southeast,” is under a voter-approved four-decade old farmland preservation project, under which King County bought the development rights to more than 20,000 acres of rural Plateau farmland to keep it designated for agricultural use.

Third: The land to build the airport would have to be obtained — such as through property purchases or eminent domain — from the residents who currently live there.

So how did we get here?

It started in 2019, when the state legislature created the CACC seeking a location for the region’s next major airport. CACC was tasked with finding six options for a new or expanded airport and then providing one final recommendation to lawmakers. The Washington State Department of Transportation (WSDOT) is responsible for helping it do so.

The greater Seattle area continues to grow in population, and Sea-Tac International Airport, already physically small for the number of passengers it serves, has little space left to grow.

An update from WSDOT consultants showed forecasted 2031 as the year, roughly, when demand will exceed the planned capacity of Sea-Tac and Paine Field in Snohomish. By 2050, according to that presentation, the number could grow to as many as 40 million passengers over capacity.

It’s not unusual for major urban centers to have multiple major airports. Think New York City’s JFK and LaGuardia airports, or Chicago’s O’Hare and Midway airports.

But the big factors for any potential site are: Is there enough space? Is it close enough to a lot of people who would use it (i.e., close to the greater Seattle area)? And what would people in the area think of building an airport there?

The commission is required by the legislation that created it to not recommend anywhere in King County. So in 2021, CACC came back with six existing airports in Arlington, Snohomish County, Bremerton, Tacoma, Shelton and Lewis County.

Of each, Paine Field in Snohomish County seemed to be the most viable option to have its passenger and cargo operations increased, according to WSDOT aviation spokesperson Christina Crea.

In the meantime, WSDOT hired a consultant, Kimley-Horn, to work on their Washington Aviation System Plan (WASP) update, an FAA-required process that covers similar topics as the CACC but which is separate from the CACC process and its limitations.

That consultant was tasked with looking at potential “greenfield” sites — i.e. new sites unconstrained by existing infrastructure — and to present those to the CACC.

In the CACC’s most recent June meeting, the consultants presented the findings of the WASP process and the 10 new sites from Skagit County to Lewis County, based on a technical analysis. In their presentation, the consultants noted that Sea-Tac would likely remain the primary airport for passengers with connecting flights or international trips, especially long-haul flights.

The site that, so far, rated the most highly of their criteria for a new airport is “King County Southeast.” It’s the sole location considered in King County.

The area is attractive to airport design, largely due to its flat terrain and proximity to Seattle. But the presence of large floodplains would complicate the airport layout, researchers said.

The WASP update from the consultants laid out three general sizes that could be considered: The smallest, a short-term airport solution, would have one runway and take about 2,400 acres (just 100 acres smaller than Sea-Tac itself). It would serve around 21 to 25 million annual passengers.

The largest, meanwhile, would be an extended-term airport with three runways. It would take up 4,670 acres (similar in size to the Anchorage, AK or Atlanta, GA airports) and serve anywhere from 50 to 71 million annual passengers.

CACC must recommend a single site by June next year, and all 16 sites — both the greenfields and the existing airports — are technically in the running, Crea said. The CACC will make a recommendation, but the ultimate decision would be made by the state legislature, the FAA and a future airport sponsor, she said.

In the meantime, the CACC will continue to solicit input from the public as the options for the new airport are narrowed down. There are several opportunities to do so coming up, including an online open house from August 15 through September 9, and virtual public meetings on August 23 and 31.

Links and information about the events have not yet been posted, but the Courier-Herald will share them with the community as soon as they are made available.