The King County Flood Control District invests in regional programs and projects that reduce the risk to people and property from river flooding and channel migration in King County. King County is home to several river watersheds that carry water flows from the Cascade Mountains to Puget Sound. These rivers pass through forested, agricultural and highly urbanized areas. Flooding is a significant threat.
Historically, rivers in King County have flooded in every month with the exception of August. River flooding has led to 13 presidentially declared disasters in King County since 1990 with the most recent being declared in 2020.
The conceptual map below shows the major rivers served by the District: Cedar, Green, Raging, Sammamish, Snoqulamie, South Fork Skykomish, Tolt, and White. These rivers are grouped into the river basins outlined below.
About the Seattle Basin
The King County Flood Control District invests resources in Seattle to protect public safety, the regional economy and critical infrastructure.
About the White River Basin
The King County Flood Control District invests resources in the White River Basin to protect public safety, the regional economy and critical infrastructure.
About the Green River Basin
The King County Flood Control District invests resources in the Green River Basin to protect public safety, the regional economy and critical infrastructure.
About the Cedar/Sammamish/Issaquah River Basin
The King County Flood Control District invests resources in the Cedar/Sammamish/Issaquah River Basin to protect public safety, the regional economy and critical infrastructure.
About the Snoqualmie/South Fork Skykomish River Basin
The King County Flood Control District invests resources in the Snoqualmie/South Fork/Skykomish River Basin to protect public safety, the regional economy and critical infrastructure.
Investments & Projects by River Basin
Cedar River Basin
The Cedar River Basin runs northeast within the boundaries of King County and includes the Cedar and Sammamish rivers and Issaquah Creek. Read more about Cedar River Basin.
Green River Basin
The Green River Basin is located in the south quadrant of King County and stretches from the County’s western to its eastern boundaries. The major tributaries to the Green River include Soos, Newaukum, and Mill creeks, and the Black River. Read more about Green River Basin.
The District is developing the Lower Green River Corridor Flood Hazard Management Plan (Plan)—a comprehensive strategy to provide a long-term approach to reduce flood risk and improve fish habitat and other multi-benefits, where feasible, while supporting the economic prosperity of the region. The plan will build on the recently completed Final Programmatic Environmental Impact Statement (PEIS) and will include input from Tribes, local jurisdictions, interested parties, and the community. Learn more about the Lower Green River Plan.
Snoqualmie/South Fork Skykomish River Basin
The Snoqualmie River/South Fork Skykomish River Basin is located in northeast King County and includes the Lower Snoqualmie, Raging , South Fork Skykomish, Tolt, and Upper Snoqulamie rivers. Read more about Snoqualmie/South Fork Skykomish River Basin.
White River Basin
The White River Basin is located in the southern most portion of King County, and includes the boundary line between King and Pierce counties. Read More about White River Basin.
The King County Flood Control District’s work plan is guided by the 2006 King County Flood Hazard Management Plan which serves as the comprehensive map of development for flood control and floodplain management and identifies up to $335 million in critical flood protection repairs to aging flood risk reduction infrastructure throughout King County. Read more about the District’s plans, strategies, and guiding documents.
Project Partners
In addition to working with our 40 local and regional government entities, the King County Flood Control District partners with a wide range of organizations – from local tribes and watershed planning groups to state and federal agencies – to carry out our projects and programs.
Here is a list of our project partners:
- American Red Cross
- Federal Emergency Management Agency
- King County Agriculture Program
- King Conservation District
- King County Fire Chiefs Association
- Local homeowners associations
- Local governments
- Local non-profits
- Puget Sound Partnership
- Snoqualmie Watershed Forum
- Sound Cities Association
- U.S. Army Corps of Engineers
- Washington State Department of Ecology
- Washington Emergency Management Division
- Washington State Association of Fire Chiefs
- WRIA 7, 8, 9 and 10 watershed salmon conservation partnerships