King County, Washington earns Salmon-Safe certification for wastewater infrastructure project

King County, Washington, announced on April 9, 2025 that its major sewer upgrade in Bellevue is the first infrastructure project of its kind to earn a Salmon-Safe certification.

The 5-year Coal Creek sewer upgrade project, scheduled to begin spring 2025, will build on improvements the city of Bellevue has made along its Red Cedar Trailhead to make the hiking area more accessible. The project will also upgrade a regional sewer line that serves Bellevue and Newcastle. The existing pipeline is nearing its maximum capacity and needs to be upgraded to carry more wastewater to meet growing demands.

The current pipeline was built between 1966 and 1991, and crosses under Coal Creek in multiple locations, generally following the creek through the Coal Creek Natural Area with multiple maintenance holes. The new pipeline will largely bypass the natural area, while much of the existing pipeline will be safely decommissioned and left in place to minimize disruption.

The $96.5 million project will also restore and expand existing wetlands, add fencing and tree canopy to keep creek water cool and clean for salmon. Work performed on the creek will be limited to three-month windows during summer months to minimize the impact on salmon and neighbors.

“Modernizing critical infrastructure, improving salmon habitat, and enhancing popular trails is a lasting legacy of Executive Constantine’s approach to public investments,” said King County Executive Shannon Braddock in a King County news article. “We will build on that solid foundation to continue producing benefits for people, fish, and wildlife.”