Fish Passage Enhancement Program

The Pacific Northwest is home to hundreds of salmon bearing streams. However, old culverts used to divert streams under roads have impacted the iconic fish, blocking them from vital upstream habitat. In 2016, the Thurston County Board of Commissioners directed Public Works to create a program to help improve fish passage by identifying culverts that block fish under county roads, and replacing them with new fish-passable structures. Replacement of outdated culverts opens passable stream habitat that allows fish to spawn and rear their young in areas not available for decades. So far, the program has resulted in the opening of more than 7.5 miles of upstream fish habitat.

  •  Hunter Point Rd. Bridge
  •  Troy Dr. Bridge
  •  Flumerfelt Rd. Bridge
  •  Waddell Creek Rd. Culvert
  •  26th Ave. Culvert

Selection Process

process chart

The foundation of the program is the development of a holistic process for prioritizing culvert replacement. Of the more than 3,000 culverts in use under Thurston County roadways, engineers and environmental specialists identified roughly 150 potential fish blocking culverts. As part of the process, county culverts were inventoried, cataloged and scored based upon fish access, potential habitat gain, barrier status, culvert condition and maintenance history. Priority culverts are then identified, field tested, and recommended for construction based upon the highest collective return of fish habitat for the budget cycle.


A total of $4.5 million was budgeted from the Thurston County Real Estate Excise Tax (REET) to pay for the initial start of the program and the first project cycle (2017-2018). An additional $4 million has been budgeted for the 2019-2020 budget cycle, with $500,00 more in Federal grants secured by program managers to support the program.