Tjossem Ditch -- Improving Salmonid Survival

Trout Unlimited (TU) proposes a restoration project to improve salmonid survival in the Yakima River near Ellensburg, WA. TU will work with local partners and landowners (water users) to eliminate surface water withdrawal and juvenile salmonid mortality associated with the Tjossem Ditch by replacing the Yakima River point of diversion with on-demand water delivery systems for up to 7 water users. The Ditchs configuration requires irrigators to divert water rights and convey them ~2 miles to the furthest places of use. The Ditch causes entrainment and mortality of ESA-listed steelhead and unlisted fish (Chinook, Coho, Pacific Lamprey, Sockeye) because the aging fish screen lacks an evident fish-bypass and is about 1 mile down-ditch from the head gate. Conditions and fish mortality likely worsen when the Ditch loses connection with the Yakima River and the fish become stranded in the Ditch. Also, the current system requires significant work in the Yakima River to maintain continuous water diversion as streamflows fluctuate during the irrigation season. Ditch users recognize the fish issues and the need to divert significant water amounts to meet their agricultural needs. As such, TU proposes to change the point of diversion for remaining irrigators from the Ditch to on-demand water delivery systems. The completion of this project will retire surface water diversions through the Tjossem Ditch, which will close the headgate and the Ditch.

The goal of this project is to eliminate surface water withdrawal and juvenile salmonid mortality associated with the Tjossem Ditch by replacing the Yakima River point of diversion with on-demand water delivery systems for up to 7 water users.