Busy flood levee construction season gets under way along King County rivers

Ambitious work schedule follows emergency repairs from winter storms

While the region is enjoying summertime weather, King County is working to protect residents and businesses from potential flooding that could come during this fall and winter’s heavy rainstorms.

The King County Flood Control District, in partnership with the U.S. Army Corps of Engineers and local governments, will begin work on 25 capital improvement and repair projects in flood-prone areas throughout the county.

“Completing this ambitious work plan will go a long way to prepare us for the next flood season,” said Flood District Board Chair Julia Patterson. “These efforts will enhance flood protection for people, property and commerce in our region.”

Last year, during its first construction season, the Flood District finished 24 projects that were deemed high-priority out of a total of 55. The projects would have taken about 17 years to complete if it were not for the additional funding from the Flood District and federal partners such as the U.S. Army Corps of Engineers. The remaining 31 projects are large-scale, multi-year efforts.

“The Flood District was created to provide a much-needed funding source to accelerate repairs on our aging flood-protection infrastructure,” said King County Executive Kurt Triplett. “The Flood District determines which projects to undertake, while the Water and Land Resources Division of the King County Department of Natural Resources and Parks implements approved flood protection projects and programs.”
 
In response to damages caused by last January’s flooding, the Flood District Board of Supervisors revisited the 2009 capital budget and the six-year capital improvement plan to prioritize damaged facilities. The Flood District and King County have completed emergency repairs at six sites, including two breached levees on the Tolt River that protect residential areas and four other levees where critical public infrastructure and residential areas were at imminent risk.

“Now that the targeted repairs are done, we can focus on large-scale projects that will offer wide-ranging protection to our communities and businesses throughout the county,” said King County Flood Control District Executive Committee Chair Reagan Dunn.

One significant area of focus for repair work continues to be on the Green River, below the Corps’ Howard Hanson Dam, which held back a record amount of water and was itself damaged during January’s record storm.  The Corps announced in February that storage capacity at the dam would be restricted until engineers could evaluate damage and complete repairs to the right flank of the flood-storage facility.

While the Corps points out there is no immediate danger to people and property in the Green River Valley, there is an increased risk of flooding within the valley in the event of a major rainstorm or significant snowmelt because of the dam’s limited storage capacity.

Of this season’s 25 projects, 10 will be taking place at the Cedar River Basin and nine at the Snoqualmie and South Fork Skykomish Basin. Six projects will occur at the Green River Basin. Four will be in partnership with the Corps of Engineers.

Some of the highlights for this season include:

• Horseshoe Bend, Green River: Partnering with the Corps of Engineers, the Flood Control District will repair 2,200 feet of the levee. This work has elevated importance given the limited capacity at the Howard Hanson Dam. The Corps will provide 100 percent of the construction funds necessary to complete this project.

• Si View and Reif Road levees, Snoqualmie River: Workers will continue early action repairs that are part of a multi-year $7 million project initiated in 2008 to rehabilitate the five mile-long South Fork Snoqualmie levee system. This levee system protects commercial and residential areas of North Bend as well as roads and other public infrastructure.

• Cedar River Trail: After last January’s storm, the Cedar River eroded the river bank, moving within a few feet of State Route 169 and the Cedar River trail. Under the trail is a major fiber optic cable that transmits financial transactions throughout the Northwest. During the recent emergency repairs, workers stabilized the bank. Now, they will focus on two revetments to further shore up the trail and its neighboring infrastructure.

• Stoneway Lower, Green River: Workers will repair a slumped riverbank and cracked road under which a pipe carries landfill runoff to a wastewater treatment facility. The repair will prevent additional slumping and ensure that the pipe is not damaged.

The Flood District leveraged $5 million in federal dollars for the projects, with $4 million directed to the Horseshoe Bend on the Green River. The City of Kent also received $10 million from the state to acquire the right-of-way necessary to rehabilitate the Horseshoe Bend levee.

Workers have a narrow timeframe to complete their tasks. The construction season is limited by a “fish window.”  The window varies by river, but is roughly between July 1 and Sept. 1, when in-water construction activities will not disturb the migration or spawning of federally-protected salmon species.

Information about King County’s flood management activities is available at http://www.kingcounty.gov/environment/waterandland/flooding.aspx.

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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.

Related information

Cedar River/Lake Washington Watershed
Green River Watershed
Snoqualmie/Skykomish Watershed
Water and Land Resources Division