The Corps of Engineers’ Seattle District has sent out flood fight teams to the Yakima, White/Puyallup, Green, Snohomish, Skagit and Chehalis River basins, and the Corps’ Emergency Operations Center and Reservoir Control Center are in 24-hour operation as warm heavy rainfall continues in western Washington.
Teams deployed to the White and Green river basins are monitoring conditions in the basin and communicating what they see back to the Seattle District’s reservoir control center and emergency operations center. Flows are above or near levels–6,000 cubic feet per second along the White River and 9,000 cfs along the Green River – that trigger the Corps to monitor levees 24 hours a day to make on-the-spot visual assessments of river conditions and levee-system integrity.
The Army Corps of Engineers does not expect the amount of precipitation in the basins of the Green and White rivers to create operational challenges for its dams. The Corps keeps the reservoirs empty at Mud Mountain Dam along the White River, as well as Howard Hanson Dam along the Green River until storage is required for flood risk management, and both had empty reservoirs on Jan. 14. The Corps is storing water behind both dams.
The Corps manages outflow from Howard Hanson Dam to keep flows at Auburn below 12,000 cubic feet per second, the level of concern for levees from Auburn downstream. Inflows to Howard Hanson Dam have been above 16,000 cfs, while outflows have been below 7,000 cfs. The Corps expects to hold water behind the dam that would raise the reservoir level above an elevation (1,147 feet above sea level) that triggers increased on-site monitoring to ensure dam safety.
There is a risk of flooding for property owners along the non-leveed middle Green basin, the rural portion of the river upstream from Auburn to Howard Hanson Dam. Potential flows above 9,000 cubic feet per second as measured at the Auburn gage are predicted. Such flows currently trigger a flood warning from the National Weather Service due to flooding concerns in the Middle Green River. These flows do not present flooding concerns for the more highly populated areas downstream, including Auburn, Kent, Tukwila or Renton.
The Corps’ Seattle District maintains and controls Mud Mountain and Howard Hanson Dams and is in constant communication with local jurisdictions regarding its operations at those projects. Current flow information for any of the river basins in Western Washington may be found here: http://www.nwd-wc.usace.army.mil/nws/hh/index-j.html
Talk to us
Please share your story tips by emailing editor@kentreporter.com.
To share your opinion for publication, submit a letter through our website https://www.kentreporter.com/submit-letter/. Include your name, address and daytime phone number. (We’ll only publish your name and hometown.) Please keep letters to 300 words or less.
