US 12 - Unnamed Tributary to Wynoochee River - Remove Fish Barrier

Project news

  • For a 15-minute period between 8 p.m. and 11 p.m. on Monday, Aug. 20, drivers will encounter a total closure of US 12 near Montesano to allow crews to reposition a crane used to move pieces of the culvert.
  • View our construction progress.
  • The highway at this location has been reduced from two lanes in each direction to one lane in each direction. The speed limit will also be lowered from 60 mph to 25 mph through fall.
  • This work is the final phase of a 7-mile paving project that has been underway on US 12 since May.

Why is WSDOT replacing the culvert under US 12 near Montesano
The existing culvert that sends this stream under both directions of US 12 west of Montesano is a barrier to fish passage and identified needing correction. The small culvert will be replaced with a larger box culvert to improve stream flows for migratory fish. 

This work is part of WSDOT's Fish Passage Barrier Removal Program, which identifies and removes barriers to fish passage caused by culverts under state highways. Improving fish passage at this location provides adults and juvenile fish the opportunity to navigate valley-bottom agricultural lands and up into the foested headwaters where there is a great potential for spawning habitat. WSDOT works in parternship with the Washington State Department of Fish and Wildlife to identify fish species on our state-owned culvert sites. Coho salmon and cutthroat traout are expected to utilize this upstream habitat. 

In 2013, a federal court injunction required the state to significantly increase the state’s efforts in removing state-owned culverts that block habitat for fish. 

Because of a narrow work zone and traveler lanes, pedestrians and bicyclists will be detoured through Devonshire Road and Alder Grove Road through fall. 

The End Result
The existing culvert will be replaced with a 220-foot-long concrete box structure that will open up two miles of potential fish habitat. This fish passage project will help restore the stream bed to a more natural state and improve fish passage for local migratory fish.

Needs & benefits

  • This project will improve fish passage and open potential fish habitat for approximately two miles.
  • The work will help WSDOT comply with the U.S. District Court ruling regarding fish passage.


  • Winter 2017: Project advertised for competitive bidding.
  • Spring 2018: Contract was awarded to Lakeside Industries
  • Mid-Summer 2018: Estimated construction start.
  • Fall 2018: Most work is completed.


Financial Data for PIN 301268A
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $4,830
CWA $0
Total $4,830


Tina Werner
WSDOT Communications

John Romero
WSDOT Project Engineer

US 12 - Unnamed Tributary to Wynoochee River - Remove Fish Barrier - Project vicinity map

View new traffic configuration through fall.

Existing US 12 culvert

Existing culvert has been identified as a barrier to fish passage.