YAKIMA, Washington - The Bureau of Reclamation announced that it will begin the annual "flip-flop" operation in the Yakima Basin by gradually reducing flows out of Cle Elum Reservoir in the upper Yakima River basin and increasing flows from Rimrock Reservoir affecting flows in the Tieton and Naches Rivers.
The purpose of the "flip-flop" operation is to achieve and maintain relatively low flows in the upper Yakima, Cle Elum, and Bumping rivers where spring Chinook salmon spawn. These lower flows are closer to natural flow conditions and are therefore more helpful to successful spawning and incubation of salmon eggs. This operation also reduces impacts on irrigation water supply by allowing for lower flow releases throughout the winter to improve reservoir storage for the coming season.
As part of the process, on or about Sept. 8, Reclamation will begin diverting water down the Kittitas Reclamation District's Spillway 1146 into the Yakima River near Thorp. Reclamation will install buoys that will be in place from Sept. 8 until about Oct. 21. Recreationists are strongly advised, for their safety and well-being, to portage around the buoys and stay out of the dangerously turbulent flows.
"Those who are enjoying the river should definitely avoid the dangerously turbulent water in the area where the spillway water pours into the river," said Chuck Garner, Yakima Project River Operations supervisor.
Flows out of Cle Elum Reservoir have been gradually decreasing since Aug. 1 from a high of about 2,700 cfs and will continue to decline to a low of about 180 cfs in early September. Flows from Rimrock Reservoir are expected to be in the 900 to 1,200 cfs range by Sept. 1 and increase to about 1,800 cfs by mid-September depending on irrigation demands and weather conditions.
Streamflow changes will occur gradually during the Labor Day holiday weekend. Streamflow information can be obtained by calling (509) 575-5854 or on Reclamation's website at:
http://www.usbr.gov/pn/hydromet/yakima/index.html.
Source: Bureau of Reclamation
