The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico (the other being the Rio Grande). The 1450mi river drains an expansive, arid watershed that encompasses parts of seven U.S. and two Mexican states. Starting in the central Rocky Mountains in the U.S., the river flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona–Nevada border, where it turns south toward the international border. After entering Mexico, the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora.Known for its dramatic canyons, whitewater rapids, and eleven U.S. National Parks, the Colorado River system is a vital source of water for 40 million people in southwestern North America. The river and its tributaries are controlled by an extensive system of dams, reservoirs, and aqueducts, which in most years divert its entire flow for agricultural irrigation and domestic water supply. Its large flow and steep gradient are used for generating hydroelectric power, and its major dams regulate peaking power demands in much of the Intermountain West. Intensive water consumption has dried up the lower 100mi of the river, which has rarely reached the sea since the 1960s.
