Improving fish passage along state roads

Number of fish passage barrier corrections increasing

The Washington State Department of Transportation is working to correct barriers to fish passage along state facilities.

Fish passage barriers occur when culverts or other drainage structures underneath roadways cross fish-bearing rivers or streams and keep fish from being able to pass through.

WSDOT began its Fish Passage Barrier Correction Program in 1991. Prior to that, there had been only one state-owned fish passage barrier correction in the central Puget Sound region.

Since 1990, 124 out of 737 state-owned fish passage barriers in the central Puget Sound region have been corrected. The percentage of fish passage barriers that have been corrected has grown from 3% in 2000 to nearly 17% in 2018.



WSDOT has been increasing its rate of fish passage barrier corrections in the central Puget Sound region over the last three decades. Between 1990 and 1999, an annual average of two fish passage barriers were corrected. This number increased to 4.9 between 2000 and 2009 and to 6.4 between 2010 and 2018.



For each fish passage barrier that is corrected, a certain amount of upstream fish habitat is restored. The amount of habitat restored varies significantly depending on the location of the barrier and various other factors.

WSDOT has aimed to strategically prioritize the correction of barriers that restore the most habitat access. Since 1990, state-owned fish passage barrier corrections in the central Puget Sound region have resulted in a total of roughly 354 miles of fish habitat gain.

For more information on fish passage corrections, including a map of existing barriers and corrections, see our latest Puget Sound Trend.