Why Are There Two Colorado Rivers?

The Colorado River Compact restricts the amount of water that can be diverted from the Upper and Lower Colorado Rivers, which affects states along both waterways.

The Compact is an agreement between seven Western states and Mexico that was signed in 1922. In 2011, a proposal to allow for increased water diversion on the part of Arizona led to protests from other member states; however, it was ultimately rejected by Congress.

The situation has been further complicated by record-breaking drought conditions in some areas of the basin, which have lowered river levels significantly.

Why Are There Two Colorado Rivers?

The Colorado River Compact is an agreement between the U.S. states along the Upper and Lower Colorado Rivers that ensures a balanced flow of water in each river system.

The compact was signed in 1922 and has been revised several times since then to reflect changes in population, agriculture and infrastructure along the rivers. Under current conditions, it is anticipated that there will be less water available for both systems by 2026 than there was in 2008-2009, which could have serious implications for farmers and other users of the waterways.

States on either side of the Rockies are working together to revise the compact so that all stakeholders can agree to its provisions without conflict or litigation.
Learn more about how states are adapting to changing conditions along these critical American waterways by reading our blog post: “States Adapt To Changing Conditions Along The Colorado River”.

Colorado River Compact

The Colorado River is one of the longest rivers in the United States and it flows through seven states: Arizona, California, Nevada, New Mexico, Utah, Colorado and Wyoming.

The river’s source is located in the Rocky Mountains and its mouth is located at the Gulf of California. In 1922, representatives from several states met to discuss how to share this valuable resource between them and create what became known as the Colorado River Compact.

This treaty set up rules that said certain amounts of water would be released from Lake Mead each year for use by all users downstream (Arizona, California and Nevada). Since then there have been a number of changes to how much water can flow down the river basin each year based on population growth rates and other factors.

Upper and Lower Colorado Rivers

The two Colorado rivers are actually the result of a series of events that occurred over centuries. The Upper Colorado River originates in the Rocky Mountains and flows south before turning west and eventually flowing into Mexico.

The Lower Colorado River originates in western Wyoming and flows east before turning north and joining with the Upper Colorado River near Grand Junction, CO. Over time, different things have happened along the riverbanks which has resulted in these two separate waterways occupying their current locations.

There is still some dispute about where exactly one river begins and ends, but at least now we know how they got their unique names.

States Along The Upper and Lower Colorado Rivers

The two Colorado Rivers are the result of a long-standing disagreement between the United States and Mexico. The US wanted to claim all of the river, while Mexico argued that it belonged to them jointly.

In 1848, a Treaty was signed which established that both countries would have access to the entire river system – but only up to where they met. This created what is now known as the Upper Colorado River Basin and the Lower Colorado River Basin, respectively.

Each basin has different resources and benefits that are important for their economies and citizens.

To Recap

The Colorado River originates in the Rocky Mountains and flows south through Utah, Arizona, and California before reaching the Pacific Ocean. The Colorado River Delta is a large area of land in Southern California that’s made up of sandbars, channels, islands, and reefs.