To provide water for the Upper Basin and ensure delivery to the Lower Basin, the Bureau of Reclamation proposed the Colorado River Storage Project, which would consist of a dam on the Colorado River at Glen Canyon, several dams on the Gunnison River and San Juan River, and a pair of dams to be built on the Green River, the Colorado's major upper tributary, at Echo Park and Split Mountain. The 1956 Colorado River Storage Project Act authorized the purposes of "regulating the flow of the Colorado River, storing water for beneficial consumptive use, providing for reclamation of arid and semi-arid lands, providing flood control, and generating hydropower."