By Steven Schauer, Deputy Executive Director and King County staff
Today, we’re diving into an exciting project aimed at enhancing both flood protection and habitat restoration, among other multibenefits, along the Tolt River: the Lower Frew Levee Setback Project.
Project Background and Context
The Tolt River’s lower two miles have long been confined by levees on both banks, built before the 1960s to protect farmland. These aging levees offer limited and unequal flood protection, some overtopping between the 2- and the 5-year flood event, putting nearby areas, including SR 203, at risk of erosion, breaching, and channel avulsion.
Recognizing these issues, the King County Flood Control District (KCFCD), together with King County as service provider, completed the Tolt River Capital Investment Strategy (Tolt River CIS) in 2017. This comprehensive plan prioritizes projects to mitigate flood and erosion risks. One key project identified was the Lower Frew Levee Setback Project, designed to address these risks while enhancing the river’s ecological health.
Why This Project Matters
In 2009, the Tolt River experienced severe flooding, damaging homes, closing roads, and necessitating costly repairs. This highlighted the inadequacies of the existing levees, many of which were built over 60 years ago. The Lower Frew Levee Setback Project aims to reduce flood risk to nearby communities and improve habitat for fish, including the Chinook salmon, which are listed under the U.S. Endangered Species Act.
By relocating the existing levee farther from the river and replacing a frequently flooded culvert under SR 203 with a raised bridge, the project can provide climate-resilient flood protection and safer recreational access. This new levee will reconnect the river to 34 acres of floodplain, restoring critical habitat for fish while reducing flood and erosion risks to people, property, roads, and bridges.
“The Lower Frew Levee Setback Project is a pivotal step in safeguarding our community while restoring the natural ecosystem of the Tolt River,” said Sarah Perry, King County Councilmember for District 3 and Vice Chair of the King County Flood Control District. “By improving flood protection and reconnecting the river to its historic floodplain, we are creating a resilient environment for both residents and wildlife. This project embodies our commitment to innovative solutions that balance safety, recreation, and conservation for the enjoyment of all for decades to come.”
Project Benefits
The KCFCD is committed to integrated floodplain management and implementing multibenefit projects aimed at reducing flood risks, ensuring public safety, and restoring river ecosystems equitably and justly. Utilizing this multibenefit principle, there are several benefits to the Lower Frew Levee Setback Project including:
- Improved Flood Protection: The new levee and raised SR 203 bridge will accommodate projected future 100-year flood flows, ensuring safer access in and out of the City of Carnation and along this important transportation corridor.
- Enhanced Habitat: Reconnecting the river to its historical floodplain will create a more natural river shoreline, providing critical habitat for Chinook salmon, bull trout, and steelhead trout. These species, listed as threatened under the Endangered Species Act, will benefit from improved spawning and rearing conditions.
- Recreational Opportunities: The Tolt River Trail, a popular year-round destination, will be rebuilt on the new setback levee. This will reduce the frequency of trail closures and damages due to flooding, offering safer and more enjoyable access for recreational users.
What to Expect
Construction is planned to be initiated in 2027. During construction, King County will provide a traffic bypass or detour on SR 203 to minimize disruptions. The Tolt River Trail will also be temporarily closed between SR 203 and the Snoqualmie Valley Trail for safety, with clear signage and detours provided for trail users.
Next Steps
The KCFCD and King County are committed to engaging with the community throughout this project. We will collect site-specific data to inform the preliminary design and seek input from residents, tribes, the City of Carnation, and other interested parties through various platforms:
- Website updates
- Meetings & presentations
- Online engagement hub
- On-site signage
- Community events
Your feedback will be crucial in shaping the project to best meet the needs of our community while achieving our goals of flood risk reduction, habitat improvement, and recreational access. Click here to provide feedback in the Lower Frew Levee Setback Project Virtual Open House.
Get Involved
We encourage you to stay informed and participate in upcoming community engagement opportunities. For more information, visit the project website, and don’t hesitate to reach out with any questions or comments – Sarah McCarthy, the Project Manager, is available at sarah.mccarthy@nullkingcounty.gov or 206-477-4766.
The KCFCD and King County are committed to protecting life and property along the Tolt River and creating a better future for our community and its natural habitats! Together, we can make the Lower Frew Levee Setback Project a success, ensuring a safer and more vibrant Tolt River for all.