SR 203 - Langlois Creek - Fish Passage - Complete September 2018


WSDOT replaced the old narrow round culvert channeling Langlois Creek with a large box culvert. Langlois Creek crosses under State Route 203 between Northeast 32nd Street and Langlois Lake Road in Carnation. The old 30-inch diameter culvert was too narrow and created water flows that were occasionally too low or strong for fish to navigate upstream. Installing the 18-foot wide box culvert allows the creek to flow more naturally under the highway and improve fish habitat in the area for migratory steelhead, cutthroat and coho. The completion of this project opened up almost 5.5 miles of additional fish habitat.

The old culvert was one of about 1,000 culverts across the state that are mandated to be replaced. In 2013, the U.S. District Court for Western Washington ruled that the state must remove culverts that block fish passage under state highways.

Needs & benefits

  • Environment: Replacing the culvert and rebuilding the streambed:
    • Improved fish passage.
    • Created a more inviting habitat for wildlife.
    • Opened up an additional 5.5 miles of habitat for steelhead, cutthroat and coho in Langlois Creek.
    • Helped restore historical fish migration patterns and tribal fishing rights.
  • Compliance: The project helps WSDOT comply with the U.S. District Court ruling regarding fish passage.


  • The total estimated cost for this project was $1.5 million.
  • ​The project was funded through the 2015 Connecting Washington transportation package and pre-existing funds.


Northwest Region Communications
15700 Dayton Ave. N.
Seattle, WA 98133

WSDOT will replace a culvert near SR 203 just south of Carnation.

WSDOT contractor crews will replace the concrete culvert that channels Langlois Creek under SR 203.
Langlois Creek flows through a narrow round concrete culvert adjacent to SR 203 in Carnation.

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