In an effort to improve native fish habitat and reduce flooding risks, the City of Kirkland helped replace an aging culvert where Cedar Creek flows under one of the city’s busiest arterial roads.

The new culvert on 100th Avenue Northeast and improvements to Cedar Creek were designed by Stantec, a global engineering, architecture, and consulting firm.

As a high priority with the City, this project removes the most significant fish barrier on Cedar Creek,” said Tim Nightengale, one of Stantec’s Bellevue-based project biologists. “The improvements open up significant habitat to migratory anadromous fish upstream of this location and will improve the overall health of Cedar Creek.”

The project aims to restore native fish access to more than a mile of upstream habitat by removing the 40-year-old barrier. The improvements rebuilt 1,200 feet of the severely degraded creek channel, recreating a sinuous alignment with 23 log structures, bank stabilizing plantings, and deep pools.

A new side channel also allows larger flows to spread across the adjacent wetland and minimize downstream flooding.

The $2.5 million project replaced the original 36-inch concrete box culvert, which was structurally deficient and too small, with a culvert that is 14 feet wide, 10 feet tall and 120 feet long. To accomplish the work, crews bypassed the existing creek, excavated 100th Avenue Northeast down to the creek bed, and rebuilt the arterial to meet the needs for a future roadway widening project.

Critical to the project’s success was its 23-day road closure. Stantec, Interwest Construction, and the City of Kirkland collaborated to limit traffic disruption.

“Twenty-three days is a long time to shut down one of your city’s busiest arterials,” said Laura Drake, the City of Kirkland project engineer, who co-managed the project. “But tight coordination between Stantec, Interwest, and the City of Kirkland helped us keep the community informed of the closure and the need for it.”