Flood District approves $400k for Willowmoor project on Lake Sammamish to reduce flooding, restore habitat

November 16, 2023

The King County Flood Control District on Tuesday approved $400,000 in funding to move forward on the Willowmoor Floodplain Restoration, a project intended to control flooding and restore salmon habitat in Lake Sammamish.

King County’s Water and Land Resources Division will use the approved funding – along with $332,000 that was previously allotted – to carry the project to 30% design. Hitting that key milestone will help planners and residents fully understand the range of benefits from the work.

"I am honored to have joined my Flood Control District colleagues in making an investment in the Willowmoor Floodplain Project that will move us forward in providing flood protection for Lake Sammamish residents and properties, as well as the added benefit of habitat protection," said Flood District Supervisor Sarah Perry. “Moving through this next phase and reaching 30% design will allow us to engage in a robust way with the community, tribal partners and stakeholders which will help inform our decision to move past 30% design or not. This is a critical next step in addressing flooding concerns for all in Lake Sammamish.”

First begun in 2013, the project has been long in the making, with many steps and outreach in the Lake Sammamish community going back even further. Tuesday’s decision follows multiple actions by the Flood Control District including annual maintenance and conducting a series of studies to fully understand the factors contributing to flooding on the lake and the effectiveness of different project alternatives. Flood concerns have only increased since the project began, with more frequent and significant flood events in the last decade.  Given this, the County is also implementing a pilot grant program to support a range of solutions for lakeshore property owners to decrease the impacts of future flooding.

If it advances beyond 30% design, the Willowmoor project has the potential to substantially decrease the frequency and level of flooding – and associated property damage – for Lake Sammamish residents. It will also improve chinook and kokanee salmon habitat by reducing summer river flow which creates a fish passage barrier, and providing canopy cover which offers shade and helps manage lake temperatures.

“This project will protect homeowners and property from flooding, while also enhancing the local environment and critical wildlife habitat,” said Flood District Supervisor Claudia Balducci. “I’m glad to include funding in our 2024 Flood Control District budget to move the project to the next stage of development. This step will advance design and develop important information to help us decide the best configuration for the final project to be built, to ensure it is as effective as possible to address flooding along the shores of Lake Sammamish.”

During this next phase of the work, Flood District Supervisors and staff will engage the community and partners to determine the next steps and timeline.

You can read more about the project and its background here.