Update August 21st, 2023: The U.S. Army Corps of Engineers-led project has been delayed by a few weeks – the new start date for repair work is set for Sept. 11, and repairs are expected to be completed by Sept. 30.
The Mason Thorson Ells Levee is located on the western bank of the Middle Fork Snoqualmie River near the City of North Bend.
A portion of the downstream end of the Mason Thorson Ells Levee was damaged during a flood in February 2020, creating a flood and erosion risk that threatens the safety of the nearby community, properties, and roads.
King County, as the primary service provider to the King County Flood Control District, is partnering with the U.S. Army Corps of Engineers (Corps of Engineers) to repair the levee and reduce flood risks to people and property. Repairs are planned for 2023, using 80% federal and 20% local funds.
Construction will include regrading and adding rock to the eroded bank and plants to help further stabilize the slope and area behind the levee.
King County sought input from tribes, local recreational groups, the City of North Bend, and other stakeholders on the project design and outreach plans. This input informed County comments to the Corps of Engineers and the County’s public notification plans. The project is expected to be completed by October 2023.
Access to the levee’s downstream end and the Blue Hole beach will be closed during construction. Passing boaters should stay to the right.
What is a levee?
A levee is a human-made structure designed to contain, control, or divert water to reduce the risk of flooding and erosion in the surrounding area.
Project goal
- Repair and stabilize active erosion at the downstream end of Mason Thorson Ells Levee.
Project schedule
Activity Date Corps of Engineers Design and National Environmental Policy Act (NEPA) Process 2020-2023 Construction A two-week period between August 14 and September 8, 2023 Site monitoring Ongoing
Construction impacts
King County is working to limit the impacts of construction.
Access to the levee’s downstream end and the Blue Hole beach will be closed during construction. Passing boaters should stay to the right.
A memorial bench will be temporarily moved during construction and replaced in the same location when the project is done. A large sequoia tree and two smaller trees are too close to the damaged area and must be removed to repair the levee safely. In their place, nine new trees will be planted behind the levee on public land. The trees will enhance habitat for fish and wildlife.
King County will update the construction webpage with further impacts to the area’s roads, sidewalks, trails, or parks as the project progresses through design and permitting. They will also post signs and flyers near the project site and notify local businesses and residents before and during construction. To receive updates, please sign up for project announcements.
[Information provided by King County]
