Fish barrier removal work to slow traffic on U.S. 101 near Thurston-Mason county line for weeks

A fish barrier removal project will slow traffic on U.S. 101 near the Thurston-Mason county line starting at the end of this week.

Crews plan to close the median between U.S. 101 at Old Olympic Highway near Oyster Bay starting Friday, July 19, according to a Wednesday news release from the Washington State Department of Transportation.

As a result, travelers on Old Olympic Highway will only be able to turn right onto southbound U.S. 101. The agency warns travelers to anticipate weeknight single-lane closures and shoulder closures during the work period as well.

Come mid-August, work crews are expected to reduce U.S. 101 to one lane in each direction and the speed limit will decrease from 60 to 45 miles per hour. Crews also plan to close the intersection of U.S. 101 and Old Olympic Highway to all traffic.

These limitations will remain in effect until the fall when crews are scheduled to complete work on new bridges that will carry U.S. 101 over Griggs Creek.

All this work is part of a $51.8 million WSDOT project to remove multiple fish barriers under U.S. 101 as well as State Route 108 near Kamilche in Mason County. In addition to building new bridges, the release says crews will restore creek beds to improve fish habitat.

Work on SR 108 will involve a series of closures at two locations. The first closure began on Monday between West Hurley Waldrip Road and Eich Road. That closure will end by 8 a.m. July 22.

The second closure on SR 108 will occur from July 26 to Aug. 9 between milepost 7.6 and 8.8, which is west of Eich Road. Lastly, another closure will occur between West Hurley Waldrip Road and Eich Road from Aug. 14-28.

The closures mean travelers will have to detour via U.S. 101 and State Route 8 in Thurston and Gray Harbor counties, according to the project website.

WSDOT says this work can only be done during a summer “fish window,” a time period when working in the water is least disruptive to aquatic life.

As part of this project, WSDOT says crews removed fish barriers at two locations on SR 108 near McCleary after closing the highway for two weeks in 2023.

WSDOT must complete this work because it’s under a 2013 federal court injunction that requires it to “significantly increase efforts” to remove fish barriers, the project website says.

The state has been actively working to improve fish migration to help salmon and steelhead populations recover, according to the Washington Department of Fish and Wildlife .

For recovery efforts to succeed, WDFW says fish need to swim upstream to their traditional spawning grounds. The agency notes that well designed culverts and bridges also can reduce flood risks and emergency repair costs.