The Washington State Department of Transportation recently wrapped up a roughly $13 million fish barrier correction project – resulting in a new 440-foot bridge that spans Kilisut Harbor along State Route 116. The new bridge not only improves safety for human travelers but also is, in the words WSDOT Project Engineer Dan McKernan, a “huge win” for local salmon and other fish species in the area.

[Photo courtesy of Washington State Department of Transportation.]

“The work involved replacing two small culverts that were installed in the 1950s. The channel here now with the bridge was not here previously,” he said, adding that the new channel aids in the annual migration of salmon in the area.

This work is part of WSDOT’s Fish Barrier Removal Program, which identifies and removes barriers to fish caused by culverts under state highways. The agency noted in a statement that it worked with the North Olympic Salmon Coalition or NOSC to complete this specific bridge project while also continuing to work with the Washington State Department of Fish and Wildlife to identify locations where culvert replacement will increase fish habitat.

“The area between Indian and Marrowstone Islands was historically comprised of tidal channels and salt marsh,” NOSC noted in separate statement. “Tidal waters exchanged freely between Oak Bay and Kilisut Harbor, flushing cold water, moving sediment, and allowing juvenile salmon to migrate northward from Oak Bay into the shallow, productive waters of Kilisut Harbor. The installation of the causeway in between Kilisut Harbor and Oak Bay eased transportation between the Islands, but choked the flow of water and sediment, eventually creating an artificial beach berm, a filled channel, and increased water temperatures in Kilisut Harbor.”

The construction of the new bridge also resulted in the removal that land barrier, reconnecting the large numbers of Hood Canal and Puget Sound out-migrating juvenile salmon that converge at Oak Bay with immense foraging opportunities available within Kilisut Harbor while also restoring and enhance important staging and foraging habitat for multiple coastal dependent and migratory birds. “Clean, cold water is now flowing north into Kilisut Harbor/Scow Bay,” the organization noted. “This mixing on each tide cycle is expected to improve water quality in Kilisut Harbor over time.”