Drivers will soon need to plan for partial and full closures along a short segment of State Route 106 at Twanoh State Park once a project to remove and replace an outdated culvert begins Monday, June 19. Contractor crews working for the Washington State Department of Transportation will begin a summer-long project to replace a barrier to fish at Twanoh Creek. The work is part of WSDOT’s ongoing effort to remove barriers to fish under state highways.

 Construction timeline
The project is limited to a short segment of road at Twanoh State Park.

  • From Monday, June 19, to Sunday, July 9—and again from Monday, July 31, to Friday, Sept. 1—travelers will encounter intermittent, one-way alternating traffic during construction, along with occasional traffic stops of up to 15 minutes. 
  • Between Monday, July 10, and Sunday, July 30, WSDOT will close SR 106 around the clock to all traffic at Twanoh State Park. A signed detour will direct traffic around the closure onto US 101 and State Route 3 through Shelton. County roads will be available for detour with access at E Trails Rd and E McReavy Rd. (See North Mason Regional Fire Authority Recommended Detour Map)

WSDOT travel toolsTravelers can receive email updates about this project and other major roadworks on state highways in Mason County. Real-time information is available via the WSDOT app and WSDOT Travel Center Map.