Tribe becomes key water player As Arizona faces mandatory cuts next year in its Colorado River supply, the tribes see themselves as major players in the future of water Author: Lake Mead is the largest reservoir on the 1.450-mile Colorado River, which serves millions of people in the Southwest. (Photo by Jordan Evans/Cronkite News) As Arizona faces mandatory cuts next year in its Colorado River supply, the tribes see themselves as major players in the future of water Felicia Fonseca Associated Press FLAGSTAFF, Ariz. — For thousands of years, an Arizona tribe relied on the Colorado River's natural flooding patterns to farm. Later, it hand-dug ditches and canals to route water to fields.