News Release Archive

Yakima Project “Flip-Flop” Operations Underway

Public should exercise increased caution around Yakima basin rivers.

Media Contact: Christine Schuldheisz, 208-378-5212,

For Release: August 27, 2020

YAKIMA, Wash. – The Bureau of Reclamation will begin its annual “flip-flop” operation in early September to aid in successful spawning and incubation of Chinook salmon eggs and to improve winter reservoir storage in the Yakima basin. This means flows out of Keechelus and Cle Elum reservoirs in the upper Yakima River basin will be gradually reduced, while flows from Kachess and Rimrock reservoirs will be increased. This operation will affect flows in the Tieton and Naches rivers, and the Kachess River flows into Lake Easton in the upper Yakima basin.

“Reclamation urges those recreating or working along Yakima basin rivers, particularly in the Yakima River near Thorp, to exercise increased caution, stay away from the areas where spillway water flows into the river, portage around buoys, and stay out of dangerously turbulent flows," said Chuck Garner, Yakima Project River Operations supervisor.

Reclamation will begin diverting water down the Kittitas Reclamation District’s Spillway 1146 into the Yakima River near Thorp during the week after Labor Day weekend. Buoys and warning signs will be in place in the Yakima River from Sept. 8 or 9 until soon after the flow from Spillway 1146 ends in mid-October. Flows below Cle Elum Reservoir will continue to decrease from a July 28 high of 4,000 cubic feet per second to a low of about 200 to 250 cfs around Sept. 15. Conversely, flows from Rimrock Reservoir will increase from the current flow of below 1000 cfs to between 1,700 and 2,400 cfs by mid-September, depending on irrigation demands and weather conditions. Rimrock flows should be between 1,200 and 1,800 cfs by Labor Day weekend depending on prevailing conditions. Rimrock outflows will begin to decrease in the latter half of September and will be reduced to between 50 and 130 cfs by the end of the irrigation season, Oct. 20, to maintain required downstream minimum flows.

This annual flip-flop operation maintains relatively low, more natural flows, which are important for Chinook salmon spawning in the upper Yakima, Cle Elum, and Bumping rivers. It also allows Reclamation to reduce impacts on irrigation water supplies because lower reservoir releases improve storage for the coming season. Real-time streamflow information can be found on Reclamation’s website at

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