King County Road Services - The road to salmon recovery

N.E. 124th Street Road Widening Project

Originally, there were several streams in the valley that flowed into the Sammamish River. One small tributary flowed from east of Woodinville-Redmond Road N.E. and under N.E. 124th Street into a straight ditch along N.E. 124th Street. The stream then flowed through a 48-inch diameter culvert for 350 feet before discharging into the Sammamish River. The culvert outlet was perched five feet over the river. This perched culvert made it inaccessible for fish.

As a part of the road widening, a new stream channel was created on a 12.5-acre site to mitigate for disturbance to local wetlands and streams. The mitigation effort created a meandering stream channel through the adjacent field to improve the stream configuration and to provide habitat for fish and other aquatic animals. The new stream in located within a 200-foot wide corridor complete with native plants and in-water structures such as boulders and woody debris. These structures provide support for the banks of the stream but also help to create stream complexity that provides better habitat than a straight-flowing ditch. Properly sized stream gravel was placed for fish spawning habitat and pools were created to provide areas for fish to rest. The new stream channel was connected to the Sammamish River last summer making the stream accessible to fish once again.

Further upstream where the stream flows under Woodinville-Redmond Road N.E. and N.E. 124th Street, two new box culverts were installed to provide better access for migrating fish.

The new stream provides for over 3,000 feet and over 10 acres of habitat for birds, amphibians, insects and fish!

For more information about this project please contact:

Howard Haemmerle
Senior Engineer
King County Department of Transportation
Road Services Division
Engineering Services Section
206-296-8767