Yakima Project “Flip-Flop” Operation Underway
The Bureau of Reclamation announced that it has started the annual “flip-flop” operation in the Yakima Basin.
They do this by gradually reducing flows out of Cle Elum Reservoir in the upper Yakima River basin and increasing flows out of Rimrock Reservoir affecting flows in the Tieton and Naches Rivers.
The purpose of the "flip-flop" operation is to maintain relatively low flows in the spring Chinook salmon spawning areas in the upper Yakima, Cle Elum and Bumping rivers.
These lower river flows can then be maintained during the winter and successfully keep the egg nests under water.
The operation also reduces impacts on irrigation water supply by keeping reservoirs as full as possible for the next season.
“We started the flip-flop operation earlier this year to make it a more gradual transition than normal easing the impact of the changing flows on the river ecosystem,” said Chuck Garner. “The transition will get the river flows to the same mid-September levels as in the past, but we are taking a slower approach this year which will be more beneficial for fish.”
As part of the process, on or about Sept. 3, Reclamation will begin to divert water down the Kittitas Reclamation District's Spillway 1146 into the Yakima River near Thorp, Wash.
Reclamation will install buoys that will be in place from Sept. 3 until about Oct. 21. Recreationists are advised, for their safety, to portage around the buoys and to stay out of the turbulent flows.
Flows out of Cle Elum Reservoir have been gradually decreasing in August from a high of about 4000 cfs July 25 to a low of about 220 cfs by about Sept. 10 to 15.
Flows from Rimrock Reservoir are expected to increase to near 2,000 cfs by mid-September and could possibly reach 2,200 to 2,400 cfs, depending on irrigation demands and weather conditions.
Flows could exceed 1,500 cfs by Sept. 1, depending on irrigation demands and weather.
Stream flow changes will occur gradually during the Labor Day holiday weekend.
Stream flow information can be obtained by calling (509) 575-5854 or on the Internet at: http://www.usbr.gov/pn/hydromet/yakima/index.html