Beneath the twin I-5 bridges recently completed just north of the Snohomish-Skagit county line, crews are preparing to remove a culvert that has restricted the flow of Fisher Creek since about 1970.
The hope is to restore a 346-foot section of the creek — currently flowing through the 8-foot-diameter culvert — to a natural creek bed.
That stretch of creek is about the length of 4½ semitrailers.
“When we’re finished it will really look like a creek,” state Department of Transportation engineer Shane Spahr said while looking out at the culvert.
Transforming the site into a natural stream bed will help fish swim to 17 miles of habitat upstream, benefiting salmon and trout that are protected under the federal Endangered Species Act.
“It will through here be a much more natural stream gradient for the fish that would normally be going through here,” Spahr said.
Downstream of the site, Fisher Creek meets up with the south fork of the Skagit River.
This is the second fish passage project to be done in Skagit County following a 2013 U.S. District Court ruling that directed the Department of Transportation to improve the passage fish under state-managed roads.
The court ruling was in response to a request from 21 northwest Washington tribes that said some of the state’s culverts impede salmon migration, thereby threatening treaty-backed fishing rights.
Culverts can hinder fish passage when they become clogged with debris, if the water moves through them too quickly or if they are not level with the stream.
“Improving these fish passages is the right thing to do,” Petrich said.
Statewide, the Department of Transportation has completed 44 of about 800 fish passage projects required by the ruling. That’s well below the 40 projects per year the state estimated it needs to complete in order to comply with the 2030 deadline set in the ruling.
Petrich said the Department of Transportation is limited to about 14 of the projects every two years due to state funding.
Interwest Construction of Burlington and subcontractors working on the Fisher Creek project have until Oct. 15 to complete the work, Spahr said. They may finish earlier than that.
Since starting the project in April 2016, crews built a traffic bypass, then built two 110-foot bridges over the creek — one for northbound traffic and one for southbound traffic — and removed the bypass lane before recently beginning work on the culvert.
Crews recently dug out mud that buried the culvert, brought in rocky material that will make a better stream bed, removed fish from the project site and put up nets to prevent fish from entering the culvert.
Before tearing the culvert apart, Spahr said next week crews will reroute the creek through a series of smaller pipes to avoid creating more mud at the project site.