WSDOT to share SR 169 fish culvert replacement details | UPDATE

Published 11:45 am Thursday, June 11, 2026

Update: WSDOT provided additional information after this article was published. This information includes construction timelines and how traffic will be affected.

If you thought Black Diamond construction on SR 169 would soon be over – think again.

As the two roundabouts near completion, the Washington State Department of Transportation is planning to start replacing five fish culverts under the highway, extending construction on SR 169 to 2029.

Details are still up in the air, but WSDOT is hosting a community meeting this Tuesday, June 16, to share more information about the multi-million dollar project will bring traffic woes to locals and commuters.

Casey Conley with WSDOT communications described the meeting as a “30,000 foot view of the project” to share some details and tentative timelines. It will be a hybrid presentation, with WSDOT officials being remote.

The meeting is scheduled for noon, and can be attended virtually at https://shorturl.at/tkkzD (or go to the Black Diamond City Council’s agenda page for a link). Information shared at the meeting will be made available to those who could not attend the meeting.

Here’s what information is already available.

There are five total culverts under SR 169, and the state is required by a 2013 court injunction to remove barriers to these culverts and hundreds of others around the state.

Two culverts for Ginder Creek and another unnamed tributary are under SR 169 near Roberts Drivel; Rock Creek and two other unnamed tributaries flow under the highway east of Jones Lake.

According to Conley, construction on the culverts near Jones Lake is expected to begin next month and happen in phases; work will pause in the fall and resume the sprint of 2027.

At that time, WSDOT will start working on the culverts near Roberts Drive, and again will pause that fall.

“[C]rews will return in spring 2028 to complete any remaining work at both sites,” Conley said. “We expect the project will take about two years total, pending favorable weather and other variables beyond WSDOT control.”

There will be single-lane closures on SR 169 for up to 60 days when Jones Lake construction begins as soon as late July.

“We will share a firm schedule once it is finalized,” Conley said. “Signed detours will be available to guide passenger vehicles, cyclists, pedestrians and freight traffic around the work zone.”

There will be additional road closures in 2027, but the timing and location of the closures are still being determined based on project progress.

“That said, we are planning for up to 60 days of both directions of SR 169 to close near Black Diamond-Ravensdale Road in summer 2027,”Conley added.

According to WSDOT, replacing these failing culverts will improve the habitat for chum, coho, resident trout, steelhead, and se-run cutthroat that use these creeks and culverts.

“Opening habitat allows more salmon and steelhead at all life stages, including juveniles that aren’t yet strong swimmers like adults, to access important spawning and rearing habitat, including areas that haven’t been accessed in years,” the department’s project page reads. “Opening habitat allows more salmon and steelhead at all life stages, including juveniles that aren’t yet strong swimmers like adults, to access important spawning and rearing habitat, including areas that haven’t been accessed in years.”

Replacing the culverts provides a potential habitat gain of more than four and a half miles.

The total cost of the project comes out to about $73 million.