Colorado River

The Colorado River flows through seven U.S. states: Colorado, Wyoming, Utah, New Mexico, Arizona, Nevada, and California, before crossing into Mexico. Its drainage basin covers approximately 246,000 square miles across these states and extends into northern Mexico.

The Colorado River Compact divided the river's water between an Upper Basin (Colorado, Wyoming, Utah, and New Mexico) and a Lower Basin (Arizona, Nevada, and California), with each basin allocated 7.5 million acre-feet per year. Herbert Hoover, then U.S. Secretary of Commerce, chaired the negotiations among the seven basin states.

The two most significant dams are Hoover Dam (completed 1936), which created Lake Mead, and Glen Canyon Dam (completed 1966), which created Lake Powell. Together these two reservoirs can store tens of millions of acre-feet of water, representing the vast majority of the river system's storage capacity.

Decades of over-allocation and heavy water use for agriculture and municipalities have reduced the river's flow so severely that it rarely reaches its delta at the Gulf of California. The river's water serves over 40 million people across the American Southwest, and prolonged drought conditions exacerbated by climate change have pushed the system toward crisis.