By Steven Schauer, Deputy Executive Director, and King County Staff
The King County Flood Control District (KCFCD) has been working diligently since its creation in 2007 to safeguard our communities from flooding. The KCFCD, in collaboration with King County as service provider, has spearheaded over 370 capital projects aimed at mitigating the risk of levee and revetment failures. These projects, along with the operation and maintenance of over 500 flood protection facilities, cover 118 linear miles and approximately 800 acres of land crucial for flood mitigation.
While the KCFCD’s weekly blog typically shares information about new and ongoing projects, each month, we will shine a spotlight on a completed project that is quietly doing its job to safeguard our community against the threat of flooding. The project we’re covering this month is the Rainbow Bend Levee Removal and Floodplain Reconnection Project along the Cedar River on part of the Larry Phillips Natural Area.
For this project, the KCFCD was not the lead agency, but rather a funding partner collaborating with a large array of Tribal, federal, state, and local agencies, all working toward an important common goal. As we near the end of May, a month set aside to celebrate wetlands, we’re honoring a project that both restores and reconnects critical floodplain habitat while also demonstrating the power of collaboration.
Restoring a River and Reducing Flood Risk: The Rainbow Bend Levee Removal and Floodplain Restoration Project (2013)
For over a decade, King County, in partnership with the City of Seattle and multiple funding partners, including the KCFCD, worked to transform a flood-prone stretch of the Cedar River into a thriving, resilient ecosystem. The Rainbow Bend Levee Removal and Floodplain Reconnection Project is a powerful example of how long-term planning, strategic investment, and environmental stewardship can come together to benefit both people and nature.
The project began with a challenge: a degraded 900-foot levee at Rainbow Bend had long cut off the Cedar River from its natural floodplain. While levees can offer protection from floods, this one had a steep environmental cost. It disrupted natural river processes, limited salmon access to critical habitat, and failed to protect a mobile home park and nine single-family homes that were repeatedly flooded during high-water events.
Recognizing the dual need to reduce flood risk and restore salmon habitat, a bold plan was created. Over several years, at risk properties were acquired and more than 50 families were relocated out of the 100-year floodplain. The stage was then set for ecological restoration.
Reconnecting 40 Acres of Floodplain
With the homes removed, construction crews got to work removing the levee and excavating new channels across the floodplain. Large logs and rootwads were strategically placed to slow water flow and create shelter for fish. Native trees and plants were installed to restore riparian vegetation and stabilize the area.
The result? Roughly 40 acres of floodplain and backwater habitat were reconnected to the Cedar River. This restored area now provides complex, dynamic habitat for young Chinook salmon and other species, including crucial off-channel and backwater zones where juvenile fish can feed and escape predators.
A Safer, More Resilient River System
Beyond ecological benefits, the project delivers major gains in public safety and infrastructure protection. By allowing the Cedar River to move more naturally across its floodplain, the project reduces pressure on the river’s left bank—home to the Cedar River Trail, State Route 169, and a regional fiber optic cable line. It also provides valuable space for floodwaters to spread out during storms, reducing risk for downstream communities.
Early post-construction monitoring showed promising results. In just two years, the number of young Chinook salmon able to use the site nearly doubled, and habitat diversity continues to increase as the river adapts to its new freedom.
Collaboration That Made It Possible
The Rainbow Bend project wouldn’t have been possible without extensive collaboration and funding support. Partners include:
- City of Seattle Cedar River Watershed Habitat Conservation Plan
- King County Flood Control District
- Federal Emergency Management Agency
- National Oceanic and Atmospheric Administration’s Pacific Coastal Salmon Recovery Fund
- King County Conservation Futures
- King Conservation District
- Puget Sound Acquisition and Restoration Fund
- Salmon Recovery Funding Board
A Model for the Future
Building on the success at Rainbow Bend, in 2023, the King County Mitigation Reserves Program created and enhanced approximately 6 acres of floodplain wetlands and 5 acres of uplands within the Rainbow Bend project. These complimentary actions increase floodplain connection with an area of Rainbow Bend that had remained disconnected from its historic floodplain following completion of the original project.
The Rainbow Bend project is a high-priority success story under both the WRIA 8 Chinook Salmon Conservation Plan and the King County Flood Hazard Management Plan. It demonstrates what’s possible when we take bold steps to restore natural systems, support communities, and invest in long-term resilience.
As our climate continues to change, projects like these two provide blueprints for the future—where healthy rivers, thriving salmon populations, and safer neighborhoods can coexist.