<P> This is a list of dams on the Colorado River system of the southwestern United States and northwestern Mexico . The Colorado runs 1,450 mi ( 2,330 km ) from the Rocky Mountains to the Gulf of California , draining parts of seven U.S. states and two Mexican states . The river system is one of the most heavily developed in the world , with fifteen dams on the main stem of the Colorado and hundreds more on tributaries . Collectively , dams in the Colorado River basin can hold four to five times the river 's annual flow , generating hydroelectricity and supplying irrigation and municipal water for over 35 million people . </P>
how many dams are in the colorado river
fifteen dams on the main stem of the Colorado hundreds more on tributaries