Project overview
As part of WSDOT's efforts to remove barriers to fish, this project addressed two blocking culverts where State Route 161 crosses over an Unnamed Tributary to South Creek at milepost 14.85 just north of 280th Street East in Pierce County.
What to expect
This project is complete.
This project replaced two blocking culverts beneath SR 161 between milepost 14.76 and 14.95.
Crews built a temporary one-lane bypass road near the creek in spring 2025. This kept people moving while the roadway was excavated. It allowed crews to remove the existing culverts.
The culverts were replaced with a larger box culvert in September 2025. WSDOT also made improvements to the creek. Major construction was finished in October 2025. Workers finished up stream channel restoration and minor construction activities during winter and spring 2026.
The new bridge and stream enhancements will make it easier for fish to pass through the creek. Both will slow the water and create a more natural environment.
The stream has a seasonal flow. While seasonal streams do dry out, they are still important to fish. For example, streams can sustain young or juvenile coho salmon because there are often residual pools scattered through watersheds where they can wait out the dry periods. In these situations, young fish can benefit from using seasonal streams that dry up in summer. In the Pacific Northwest, it has been documented that juvenile coho salmon using intermittent streams are larger and have a greater chance of survival than streams with year-round flow. Researchers think this may be due to reduced competition for food resources compared to year-round streams.
Our construction project will allow more potential fish habitat to be opened, and it is required to comply with the federal injunction. The injunction required a significant increase in state efforts to remove culverts under state highways that block habitat.