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King County sets March 14 for Lake Sammamish Willowmoor project update

Summary

King County hosts a public meeting on Saturday, March 14 in Redmond to share updated information about a project to reconfigure the transition zone between the Sammamish River and Lake Sammamish through Marymoor Park.

Story

King County hosts a public meeting on Saturday, March 14 in Redmond to share updated information about a project to reconfigure the transition zoneFlood Control Zone District Logo between the Sammamish River and Lake Sammamish through Marymoor Park.

The meeting is scheduled for 10 a.m. to noon at the Redmond Senior Center, 8703 160th Ave. NE in Redmond.

Presentations by King County Department of Natural Resources and Parks employees will focus on three project design alternatives to address existing flood control and habitat issues on the Sammamish River at its outlet in King County’s Marymoor Park.

The design alternatives are an outcome of an ongoing Stakeholder Advisory Committee process that began in 2013 and represents a variety of interests and backgrounds.

Project planning and preliminary design is funded by the King County Flood Control District and the City of Redmond, and will be completed in coordination with King County Parks, the Muckleshoot Indian Tribe, and lakeside property owners.

Funding for final design and construction will be pursued following completion of this first phase, and will likely include Flood Control District funds combined with federal and state grants.

The outlet from Lake Sammamish into the Sammamish River is marked by a shallow concrete weir and a straight, rock-lined channel, 200 feet wide and extending 1,500 feet downstream from the weir. This area is known as “Willowmoor” and is also referred to as the “transition zone” where the lake becomes the river.

These transition zone features are specifically designed to pass flood flows quickly downstream, and to help maintain summer lake levels for recreational use, while still allowing for upstream fish passage, including salmon returning to the Issaquah Hatchery from their time in saltwater.

The transition zone is not sustainable in its current condition and configuration. In order to ensure the transition zone’s capability to pass flood flows, County crews must perform intensive and costly maintenance including mowing, removing sediment and riverside plants.

These maintenance practices degrade habitat and water quality and conflict with the Endangered Species Act, as well as federal, state and local requirements to protect ecological functions and species.

The existing weir or a similar replacement and the reconstructed channel will continue to maintain summer lake levels and control lake outflow. Other features may be included to enhance habitat and public access.

Project and Stakeholder Advisory Committee information is available on the Willowmoor Floodplain Restoration Project web page at www.kingcounty.gov/rivers or by contacting contact Craig Garric at 206-477-4694 or craig.garric@kingcounty.gov.

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The King County Flood Control District is a special purpose government created to provide funding and policy oversight for flood protection projects and programs in King County.  The Flood Control District’s Board is composed of the members of the King County Council. The Water and Land Resources Division of the King County Department of Natural Resources and Parks develops and implements the approved flood protection projects and programs. Information is available at www.kingcountyfloodcontrol.org.