Fish passage project reaches milestone with completion of first passable culvert

STANWOOD - The Interstate 5/Secret Creek Fish Passage project near Stanwood will reach a milestone Friday, Feb. 20, as northbound I-5 shifts back into its usual three-lane configuration.

Both directions of I-5 have been using temporary two-lane bypass roads south of the State Route 532 interchange (milepost 212) while contractor crews working for the Washington State Department of Transportation removed barriers to fish passage and installed new 70-foot-diameter steel arch culverts along Secret Creek.

Traffic shifts

Starting at 9 p.m. Thursday, Feb. 19, crews will begin shifting northbound traffic from the bypass road back onto the mainline. People traveling through the area should expect rolling slowdowns as traffic is shifted. Two lanes of northbound I-5 will open on the mainline by 6 a.m. Friday, Feb. 20, and all three lanes will open by noon if the weather cooperates.

Southbound I-5 will continue to use its bypass road through March.

Removing barriers

The Secret Creek project restores fish passage by building two new culverts under I-5 and a third under Pacific Highway near Stanwood. For the new culvert under northbound I-5, crews excavated more than 30,000 cubic yards of material and installed a culvert that is 65 feet long and 70 feet in diameter. They also built an 11,000 square foot reinforced wall.

Crews are close to finishing a similar culvert beneath southbound I-5. After the I-5 culverts are complete, crews will begin work replacing the culvert beneath Pacific Highway immediately west of I-5. They'll also rehabilitate about 2,000 feet of the Secret Creek stream bed throughout the project area.

The new crossings in Secret Creek provide a potential habitat gain of nearly 5 miles for salmon and steelhead. In addition to WSDOT's ongoing work to correct barriers statewide, a 2013 federal court injunction requires the state to correct barrier culverts to salmon and steelhead within the injunction area in western Washington.

The $57.5 million Secret Creek fish passage project is scheduled for completion by December 2026.

Plan ahead

To stay informed, travelers are encouraged to check WSDOT's resources, including real-time travel map and the mobile app or by checking real-time travel data.