Colorado River storage project, a multipurpose plan, undertaken by the U.S. Bureau of Reclamation in 1956, to control the flow of the upper Colorado and its tributaries and to aid in the development of the rugged, remote upper Colorado River basin; includes parts of Wyo., Utah, Colo., Ariz., and N.Mex. The Colorado River Compact of 1922 established the division between the upper and lower basins and stipulated that the upper basin's water consumption be contingent on the delivery of a set amount of water to the lower basin. Since the flow of the Colorado is erratic, a storage project was needed to maintain an even flow of water to the lower basin in dry years (the estimate of the average flow of the river, however, was based on what historically was a relatively wet period, and was 10% to 25% more than long-term estimates now indicate). A series of dams regulates stream flow, provides storage reservoirs, creates hydroelectric power, and irrigates both new and previously developed acreage. The four major units of the project are Glen Canyon Dam, on the Colorado River in Arizona; Flaming Gorge Dam, on the Green River in Utah; Navajo Dam, on the San Juan River in New Mexico; and the Curecanti dams on the Gunnison River in Colorado. The three reservoirs of the Curecanti unit are included in the Curecanti National Recreation Area (see National Parks and Monuments, table). There are 11 authorized participating projects, including the Central Utah project.