Colorado River

La Sal Mountain Loop on the Colorado River

The Colorado River is perhaps the most prominent of all interstate streams because it serves more than 40 million people in seven states and Mexico. The Colorado River is highly esteemed for both its iconic beauty and as a vital natural resource. It is often described as the most regulated river in the world with a complex and extensive history surrounding its development. The collection of agreements, federal laws, and court decisions that define how the river is managed is commonly referred to as “The Law of the River.”

Balancing river resources between states and other interests is an ever-evolving process, and this chronology of policy has expanded since the inception of the 1922 Colorado River Compact. 

Colorado River Compact 1922: Negotiated by the seven basin states and the federal government, it defines the relationship between the Upper Basin states (Colorado, New Mexico, Utah and Wyoming) and the Lower Basin states (Arizona, California and Nevada) and protects each state’s right to develop its allocation on its own timeframe. Each basin has the right to develop and use 7.5 million acre-feet of river water annually.

Upper Colorado River Basin Compact 1948: Created the Upper Colorado River Commission and apportioned the Upper Basin’s 7.5 million acre-feet among Colorado (51.75%), New Mexico (11.25%), Utah (23%) and Wyoming (14%). The portion of Arizona that lies within the Upper Colorado River Basin was also apportioned 50,000 acre-feet annually.

Interim Guidelines (2007): The interim operational guidelines can be used to address the operations of Lake Powell and Lake Mead during drought and low reservoir conditions, and remain in effect through 2025. Reclamation is currently conducting a formal review to evaluate the effectiveness of the guidelines.

Drought Contingency Plan (2019): The Upper and Lower Colorado River Basin states have developed contingency plans both independently and collaboratively. The product of these discussions is five documents that comprise the Drought Contingency Plan (DCP) for the Colorado River. They are:

  1. Companion Agreement
  2. Upper Basin Drought Response Operations Agreement
  3. Upper Basin Demand Management Storage Agreement
  4. Lower Basin Drought Contingency Plan Agreement
  5. Lower Basin Drought Contingency Operations