Fish passage problem-solving

Learn about fish passage barrier problems and solutions, and find videos about how we are working with our partners to help restore salmon runs and the considerations that go into the design and construction of fish passage projects.

Fish passage barriers

A fish passage barrier is anything that hinders any life stage of fish from moving through a waterway. Culverts, which are generally large pipes beneath roadways, may allow water to flow but not provide conditions that fish can swim through. The water that flows through culverts may block fish migration because the flow is too swift, too shallow or has a waterfall into or out of the culvert.

Exploring solutions

In the 2021-23 biennium, approximately $726 million will be spent on the design and construction of stand-alone fish passage barrier corrections. In addition to these projects, other larger highway projects will correct barriers that are within the boundaries of those projects.

Making culverts fish-passable involves much more than simple replacement. The recent federal court injunction is not about replacement per se. Rather, it requires that fish passage be achieved (in order of preference) by:

  1. Avoiding the necessity for the roadway to cross the stream.
  2. Using a full span bridge.
  3. Using a “stream simulation” methodology.

Whenever possible, WSDOT will work with owners of adjacent barriers to coordinate barrier corrections. Partnerships such as this are key to the success of WSDOT's Fish Passage program.


  • An up-close look at Minter Creek 2020 – Learn more from this video about the many considerations that go into design and construction of fish passage projects that often lead to project-specific approaches and efficiencies. This video highlights a barrier correction project currently underway, correcting three culverts on Minter Creek and Little Minter Creek, located along State Route (SR) 302 in Pierce County near Purdy, WA.
  • SR 116 Kilisut Harbor bridge construction – Learn about a WSDOT partnership that restored historic tidal channels between Kilisut Harbor and Oak Bay in Jefferson County along SR 116. This project was spearheaded by the North Olympic Salmon Coalition, funded by WSDOT and several other partners to improve fish migration between these two channels.
  • GBI Loutsis Creek Fish Passage – Time-lapse video created by WSDOT contractor Goodfellow Bros., Inc. of the Loutsis Creek Fish Passage project they constructed on SR 203 in Duvall, WA. This bridge project was the first of its kind on the west coast, using fiberglass arch tubes that were placed and filled with concrete.
  • Designing Fish Passage Projects – Learn more about the process WSDOT fish passage projects go through during the design phase before construction begins.
  • Fish Passage Restoration at WSDOT – Learn how we are working with our partners to help restore salmon runs and see results from recent fish passage projects.
  • WSDOT Fish Passage Information Meeting and Forum Recording Feb. 24, 2021 – Learn about the 2021-23 fish passage delivery plan from this recording of WSDOT’s Feb. 24, 2021 industry-wide Fish Passage Program update meeting. WSDOT Fish Passage Delivery Manager Kim Mueller, WSDOT Director of Development Steve Roark, WSDOT Construction Director Chris Christopher, along with Assistant Regional Administrators from both Olympic and Northwest Regions and others, walk through the 2021-23 delivery plan and provide preliminary information on the various projects/bundles anticipated for the next biennium. The last portion of the meeting includes panel members answering questions from the audience.

14 fish passage projects were completed in 2020

improving access to 54.2 miles of upstream habitat.

11,959 incidents responded to

by WSDOT’s incident Response teams during second quarter of 2021, 15% more than same quarter in 2020.

41 Pre-existing Funds Projects Advertised

during the eighth quarter of the 2019-2021 biennium.