Yakima Project “Flip-Flop” Operations Underway

Media Contact: Annette Ross, (208) 378-5322, aross@usbr.gov

For Release: August 20, 2018

YAKIMA, Wash. – To aid in successful spawning and incubation of the Chinook salmon eggs in the Yakima basin, the Bureau of Reclamation has begun its annual “flip-flop” operation. Flows out of Keechelus and Cle Elum reservoirs in the upper Yakima River basin will be gradually reduced while increasing flows from Kachess and Rimrock reservoirs. This operation will affect flows in the Tieton and Naches rivers, and Kachess Reservoir flows into Lake Easton in the upper basin.

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 the spring Chinook salmon spawn. These lower flows are closer to natural flow conditions. Additionally, impacts on irrigation water supply are reduced 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. 4, Reclamation will begin diverting water down the Kittitas Reclamation District’s Spillway 1146 into the Yakima River near Thorp. Buoys will be in place from Sept. 4 or 5 until soon after the flow from Spillway 1146 stops in mid-October. For safety reasons, recreationists are strongly advised to portage around the buoys and stay out of the dangerously turbulent flows.

“Those who are enjoying the river should avoid 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 July 26 from a high of 3,772 cubic feet per second (cfs) and will continue to decline to a low of about 200 cfs around Sept. 10. Flows from Rimrock Reservoir are expected to be between 1,000 and 1,500 cfs by Sept. 1 and increase to between 1,800 and 2,400 cfs by mid-September, depending on irrigation demands and weather conditions. Rimrock outflows will begin to decrease in late September and will be at the minimum winter flow by Oct. 22.

Streamflow changes will occur gradually during the Labor Day holiday weekend. Streamflow information can be obtained from Reclamation’s website at https://www.usbr.gov/pn/hydromet/yakima/index.html.

# # #

Reclamation is the largest wholesale water supplier in the United States, and the nation's second largest producer of hydroelectric power. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at https://www.usbr.gov and follow us on Twitter @USBR.

Relevant Link: