Geography of Arizona of which the one most vital to Arizona is the Central Arizona Project. The Central Arizona Project, which is 336 miles (541 km) long, diverts of water from Lake Havasu City into central and southern Arizona. The river is also utilized for hydroelectric power through various dams along the river. The dams on the Colorado River, going downstream, are the Glen Canyon Dam, Hoover Dam, Davis Dam, Parker Dam, Imperial Dam, Laguna Dam, and the Morelos Dam. The Gila River is long, and extends from southwestern New Mexico to its confluence with the Colorado River near Yuma. While the upper
Colorado River beyond Yuma, Arizona, and the confluence with the intermittent Gila River – which carries runoff from western New Mexico and most of Arizona – before defining about of the Mexico–United States border. At Morelos Dam, the entire remaining flow of the Colorado is diverted to irrigate the Mexicali Valley, among Mexico's most fertile agricultural lands. Below San Luis Río Colorado, the Colorado passes entirely into Mexico, defining the Baja California–Sonora border; in most years, the stretch of the Colorado between here and the Gulf of California is dry or a trickle formed by irrigation return flows. The Hardy River provides