Benefiting fish, families and flood protection, Tolt River floodplain project gets under way

One of the most important salmon-habitat restoration projects in the region is under way at the confluence of the Tolt and Snoqualmie rivers.

When completed, the Lower Tolt River Floodplain Restoration Project will offer improved spawning and rearing habitat for chinook salmon and other fish, continued flood protection for the nearby Carnation community, improved public river access and enhanced amenities for visitors to King County’s Tolt-MacDonald Park. 

The $6.4 million project is a collaborative effort between the City of Seattle and King County. The project is of regional significance to ongoing salmon-recovery efforts because of the opportunity to increase spawning and rearing habitat in an area that has historically been highly productive for chinook salmon.

“Each year, nearly 20 percent of the Snoqualmie watershed’s threatened chinook salmon spawns in the Tolt River,” said Clint Loper of King County’s Water and Land Resources Division.

“Seattle Public Utilities has a critical interest in this project not just because we count on the freshwater supply upstream on the Tolt River, but also because we take a strong interest in regional salmon recovery throughout Puget Sound,” said Brent Lackey, who chairs the partnership group that includes King County and Seattle agencies.

“This project will help improve habitat for adult chinook and other salmon at a critical point in their upstream migration, and will increase the amount of spawning area available to those fish,” Lackey said, noting that restoring natural river processes will also benefit young salmon as they migrate downstream by providing increased areas to shelter and feed.

The project restores natural habitat-forming processes in the lower Tolt River by opening up the historic floodplain of the Tolt so side channels can form. Installing large wood features will create better fish and wildlife habitat, and help stabilize the river during higher flows.

Additionally, a new “setback” levee will be built to modern construction standards, and will continue to provide Carnation with flood protection from the Tolt. The existing, degraded levee will be removed after the setback levee is built, and new public trails will be constructed throughout the project area to improve public access between the river and new parking areas and to other local trail systems.

The new levee will give the river more space to meander within its historic floodplain, allowing it to return to a more natural, condition.

“Our goal all along has been to improve habitat and to ensure flood protection for the City of Carnation, while providing improved recreational and family amenities at Tolt-MacDonald Park,” said Theresa Jennings, Director of the King County Department of Natural Resources and Parks.

Work in July and August of this year includes constructing a wood revetment to protect the park’s campground from river erosion. Wood piles will be driven into the floodplain soils to create a structure that will protect the campground from erosion.

Pilings and other large wood are also being stockpiled on site. Pile driving is expected to begin in mid-July and finish in September. Final construction this year includes replanting the construction area with native vegetation. Additional work will occur in 2009.

While some portions of Tolt-MacDonald Park will be closed to public access while project materials are staged and work is under way, most of the park will remain open and available for public use throughout the duration of this project during 2008, including:

• Access to the Tolt River and the Snoqualmie River.
• Access to the Boy Scout Bridge and all portions of the park on the western shore of the Snoqualmie River, including King County’s six new yurts.
• All ballfields will remain open for the duration of the construction project.
• Seventeen tent camping sites and seven RV camping sites, including large group campsites for 40 and 60 people, will remain available for use during the project.

Park information is available by calling 206-205-5434 or by visiting http://www.metrokc.gov/parks/parks/toltmacdonald.html.

The restoration project has been shaped with the help of extensive public input. King County and Seattle have had several public meetings, presented information on the project at Carnation City Council and other venues, and have invited public comment at various stages during the project’s development.

“Public input has been invaluable throughout this process,” Jennings said. “We believe that upon completion of this project, the lower Tolt River will be a better place for people, fish and wildlife.”

The project is expected to be completed by December 2009.

Information is available on the Lower Tolt River Floodplain Restoration Project Web site at http://www.kingcounty.gov/environment/animalsAndPlants/restoration-projects/tolt-restoration.aspx. Information is also available by contacting Loper at 206-296-8378, or Lackey at 206-684-7890.

Related Information

Snoqualmie-Skykomish Watershed

Flooding Services and Information

Parks and Recreation