Colorado River Basin Focus Area Study

Science Center Objects

As one of several Focus Area Studies within the USGS National Water Census (NWC), the USGS has completed a 3-year study of water availability and use in the Colorado River Basin.

National Water Census  •  Colorado River Basin  •  Evapotranspiration  •  Snowpack  •  Water Use  •   Groundwater Discharge 


Colorado Basin Focus Area Study Map

The Colorado River is about 1,450 miles long, with headwaters in Colorado and Wyoming, and eventually flows across the international border into Mexico.  The drainage basin area of about 246,000 square miles includes all of Arizona, and parts of California, Colorado, New Mexico, Nevada, Utah, and Wyoming. The Colorado River is an important water resource for areas outside of the basin, including Denver, Salt Lake City, Albuquerque, Los Angeles, and San Diego for public (municipal) supply, and the Imperial Valley in California for agricultural water supplies. The river and its tributaries provide water to nearly 40 million people, both within and outside of the basin, and irrigates nearly 5.5 million acres of agricultural lands (Colorado River Basin Water Supply and Demand Study (, 2012)).

Water management is governed by a complex system of international treaties, interstate compacts, and Supreme Court decrees. The Bureau of Reclamation (Reclamation) plays a major role in the control and distribution of surface water within the Colorado River Basin through management of large Federal water projects like Glen Canyon Dam (Lake Power) and Hoover Dam (Lake Mead).

In discussions with Reclamation and its partners, the Focus Area Study identified several components of the water budget in the Colorado River Basin for in-depth focused study.  



National Water Census  •  Colorado River Basin  •  Evapotranspiration  •  Snowpack  •  Water Use  •   Groundwater Discharge