YAKIMA, Wash. - The Bureau of Reclamation has started the annual flip-flop operation in the Yakima Basin. The operation gradually reduces flows out of Cle Elum Reservoir in the upper Yakima River basin and increases flows out of Rimrock Reservoir affecting flows in the Tieton and Naches Rivers.
The purpose of the 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. This operation also reduces impacts on irrigation water supply by keeping reservoirs as full as possible for the next season.