State highways cross streams and rivers in thousands of places in Washington. Crossings can impede fish migration. Many culverts were built decades before the needs for fish were fully known.
WSDOT now builds much improved structures. They provide for fish passage. WSDOT often replaces outdated culverts with a new bridge or other fish passable structures. Both help increase the likelihood of migration. Fish are able to pass through creeks more easily as water is slower. Crews also restore creeks to create a more natural environment.
Fish passage is an important part of the state's efforts to protect and restore fish runs. WSDOT has worked to remove barriers to fish since 1991. A 2013 federal court injunction required the state to significantly increase efforts to remove barriers to fish.