Colorado River Information for Utah

Revised: January 2, 2007

Utah is signatory to the Colorado River Compact and the Upper Colorado River Compact. These compacts basically divide the river so the upper basin states (New Mexico, Colorado, Utah, and Wyoming) have an obligation to deliver to the lower basin (Nevada, Arizona, and California) 7.5 million acre feet per year measured at Lee Ferry (just below Glen Canyon Dam). The Upper Basin is then entitled to deplete up to the next 7.5 million acre feet from the Colorado River Basin which is divided among the states by percentage (Utah's share is 23 percent). After accounting for reservoir evaporation losses and treaty obligations to Mexico Utah's share is about 1.4 million acre-feet. The many agreements, laws, and Court Decisions which constitute the rules for operation on the Colorado River are referred to as the Law of the River.

Water depletion accounting is an important component of the Colorado River operation. The United States Bureau of Reclamation (USBR) operates as a technical resource to the Secretary of Interior who has oversite over river project operations. The USBR also maintains federal project water records which are helpful to understand operation of the river.

Flaming Gorge and Lake Powell are federal storage projects on the Colorado System in Utah which were constructed to generate power and to serve both in state project needs and provide a buffer so the lower basin obligation can be met. Click the links at the left to review historical storage trends in the two reservoirs.

Utah is a participant in the Upper Colorado River Endangered Fish Recovery Program. This partnership works to recover the endangered species while allowing continued and future water development.

Evaluation of the long term water supply on the Colorado is a topic of particular interest since the division of the river is based upon assumed hydrology. Correlation with tree rings is being used to estimate the long term trends. Information is available on Lees Ferry streamflow reconstruction.