ARLINGTON – Construction is under way on the Edgecomb Creek Fish Passage state project just east of SR 531 (172nd Street NE) and 67th Avenue NE.

Mill Creek-based contractor McClure and Sons is clearing brush at the project site on the south side of 172nd where a new culvert will be installed to help restore the creek bed to a natural state, expand fish habitat and improve passage for local migratory fish.

The $3 million project will realign the creek and install a larger box culvert for better stream flow to replace the existing culvert, opening up about two miles of passage for steelhead and cutthroat trout, chum salmon and Coho salmon.

“Water flows are sometimes too shallow or too strong for younger and older fish to swim through,” said said. “Building a wider culvert will allow the creek to flow more naturally and improve fish habitat in the area.”

Washington state is under a federal court order issued in 2013 to fix hundreds of barriers built under state roads and highways that block access for migrating salmon and steelhead and thus interfere with Washington tribes’ treaty-backed right to catch fish.

In all, 21 northwest Washington tribes asked the U.S. District Court to find the state has a treaty-based duty to preserve fish runs, and the court ruled in their favor.

The Edgecomb project is one of about 1,000 culverts mandated to be replaced across the state by 2030.

The creek currently weaves underneath SR 531 using two culverts, WSDOT officials said. Both have become barriers to fish passage. By installing a larger box culvert away from the highway, stream flows will improve. One of the two existing culverts will be plugged and the second left open for storm water drainage and backwater refuge for fish.

There will be a signed detour in place during the closure.

Work is scheduled to be completed in October.