Kachess Dam, Kachess River, 1.5 miles north of Interstate 90, Easton, Kittitas County, WA

Significance: The dam and reservoir provide nearly a quarter of the water stored for the Yakima Project, which irrigates the Yakima Valley in central Washington. The valley, while blessed with a greater natural water supply than most arid regions, required an integrated, valley-wide system dependent on stored water in order to realize its agricultural potential. Private irrigation companies lacked the capitol and the engineering expertise to make such an investment in the valley, but the 1902 Newlands Act enabled the U.S. Reclamation Service to do so. Kachess, along with the other dams and reservoirs that compose the Storage Unit of the Yakima Project, represents the complete transition of private to federal irrigation in the region.
Survey number: HAER WA-79
Building/structure dates: 1910-1912 Initial Construction
Building/structure dates: 1936 Subsequent Work
Building/structure dates: 1996 Subsequent Work
Building/structure dates: 1952 Subsequent Work