Colorado River Fact Sheet

About the Colorado River

  • The Colorado River:
    • supplies water to 40 million people in the S. and Mexico;
    • irrigates nearly 5 million acres of land; and
    • is a water source for 30 federally recognized tribes. 1
  • Nearly 70% of Colorado River water use is for agriculture
  • The Colorado River basin (“basin”) is divided into an Upper and Lower Basin at Lee Ferry,
  • The Upper Division States of Utah, Colorado, New Mexico and Wyoming receive Colorado River water, as do the Lower Division States of Arizona, California and Nevada (collectively, the “Basin States”).
  • Nearly 90% of Colorado River water originates in the Upper Basin.
  • The Colorado River is approximately 1,400 miles long and the basin is approximately 250,000 square miles.
  • The “Law of the River” refers to the body of laws, regulation, and policy that governs Colorado River operations.
  • The 1922 Colorado River Compact (“1922 Compact”) is the cornerstone of the Law of the River.

The River’s Track Record

  • The Colorado River system has experienced frequent cycles of drought and recovery throughout its history.
  • Although Colorado River hydrology has been impacted by drought and climate change since 2000, over the past century the river, together with storage, has provided sufficient water in both wet and dry cycles to meet established uses and compact requirements.
  • The Upper Division States have historically supplied and received credit for Colorado River flows to the Lower Basin in excess of their 1922 Compact obligations.2

Allocations and Obligations

Basin States

  • The primary purpose of the 1922 Compact is “to provide for the equitable division and apportionment of the use of the waters of the Colorado River System.”3
  • The compact allocates the exclusive beneficial consumptive use of 5 million acre-feet of water annually to each basin.4
  • 1928 Boulder Canyon Project Act allocated to each Lower Division State a fixed portion of the Lower Basin’s apportionment.5

1 Colorado River Basin Water Supply and Demand Study, Executive Summary, December 2012

2 Under the 1922 Compact, the states of the Upper Division will not cause the flow of the river at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any period of ten consecutive years.

3 Colorado River Compact, Art. I.

4 Colorado River Compact, Art. III(a).

5 Boulder Canyon Project Act, Sec. 4(a).

  • 1948 Upper Colorado River Basin Compact (“1948 Compact”) apportions to each Upper Division state a fixed percentage of the supply available to the Upper Basin in any given year and 50,000 to the state of Arizona.6
  • The 1922 Compact provides that the “States of the Upper Division will not cause the flow of the river at Lee Ferry to be depleted below an aggregate of 75,000,000 acre-feet for any period of ten consecutive years (the “non-depletion obligation”).7
  • The 1922 Compact also provides that “present perfected rights to the beneficial use of waters of the Colorado River system are unimpaired by this compact.”8
  • In the event the Upper Basin cannot meet its non-depletion obligation under the 1922 Compact and curtailment of Upper Basin uses becomes necessary, the extent of curtailment by each Upper Division state shall be in the quantities and at the times determined by the Upper Colorado River Commission in accordance with the 1948 Compact.
  • Each state will then determine how water users subject to its jurisdiction will be required to help meet the state’s curtailment obligation.
  • Utah will administer curtailment within the state in accordance with Utah law and under the regulation of the State Engineer.


  • The United States committed 5 million acre-feet of the river’s annual flow to Mexico under the 1944 Mexican Water Treaty.9
  • The 1922 Compact also requires satisfaction of Mexico’s Treaty 10

Tribal Water Rights11

  • Tribal water rights are assessed against the Colorado River apportionment of the state in which the Tribe’s lands are situated.

Developing River Water

  • The Lower Division States have the right to develop and beneficially use their respective allocations of the 5 million acre-feet of Colorado River water apportioned to the Lower Basin.
  • The Upper Division States have the right to develop and beneficially use their allocated percentages of the supply available to the Upper Basin after deducting Arizona’s 50,000 acre-feet allocation.
  • The compacts were expressly developed to ensure that faster-growing states would not be able to claim all available Colorado River water.

Utah’s Colorado River Allocation, Current and Future Use

  • The 1948 Compact allocates Utah 23% of the Upper Basin available 12

6 Upper Colorado River Basin Compact, Art. III(a)(2).

7 Colorado River Compact, Art. III(d).

8Id., Art. VIII.

9 Treaty Between the United States and Mexico, Art. 10

10 Colorado River Compact, Art. III(c).

11 Review of the Colorado River Interim Guidelines for Lower Basin Shortages and Coordinated Operates for Lake Powell and Lake Mead, U.S. Department of the Interior, October 2020

12 Upper Colorado River Basin Compact, Art.III(a)(2).

  • 27% of all water used in Utah comes from the Colorado 13
  • Utah’s future water plans incorporate the impacts of climate change, extended drought and reduced natural flows in the Colorado River.
  • Potential future/proposed development
  • Tribal water right settlements in the Upper Basin
    • Navajo Nation: 81,500 acre-feet (2015 Agreement and 2020 Settlement ratified by Congress)
    • Ute Indian Tribe: 144,000 acre-feet (Court Decree) and potential for an additional 115,000 AF (1990 Compact ratified by Congress in the 1992 Central Utah Project Completion Act legislation and Utah. Tribe has yet to ratify)
  • Municipal and Agricultural Uses

Additional municipal and industrial uses are contemplated within Utah’s compact allocation.

Colorado River Operations

2007 Interim Guidelines14

  • Current Colorado River operations are governed by the 2007 Interim Guidelines, which provide for:
  • The coordinated operations of the basin’s primary water storage facilities – Lake Powell in the Upper Basin and Lake Mead in the Lower Basin
  • Releases from Lake Powell to Lake Mead
  • Lower Basin shortages in certain volumes at various Lake Mead elevations
  • A mechanism for augmentation and conservation of water supply in the Lower Basin in the form of Intentionally Created Surplus (ICS)
  • The Lower Basin is in a shortage condition in 2022 for the first time since the implementation of the 2007 Guidelines.
  • The 2007 Interim Guidelines will expire in
  • Utah will play an active role, together with the other Basin States and the federal government, in negotiating the Post-2026 Operational Criteria.

Drought Contingency Plans

  • Drought contingency plans (DCP) executed on May 20, 2019, supplement the 2007 Interim Guidelines by providing a greater likelihood of sustainable operation of the Colorado River system until new operational criteria are implemented in 2026.
  • The Upper Basin DCP is designed to protect Lake Powell from falling below critical elevations to help protect hydropower generation and ensure continued compliance with the 1922
  • The two agreements that comprise the Upper Basin DCP are the Drought Response Operations Agreement (“DROA”) and the Demand Management Storage Weather modification is a third element of the Upper Basin DCP and is governed by ongoing activities and existing agreements.
  • The negotiation of Post 2026 Operational Criteria likely will include negotiations related to the renewal of the Upper and Lower Basin (DCPs).

13 Utah Division of Water Resources, as cited on

14 2007 Colorado River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Mead.

  • Under the Lower Basin DCP, the Lower Division States leave additional water in Lake Mead at predetermined elevations and incentivize additional voluntary conservation of water to be stored at Lake Mead.
  • In 2021 and 2022, the Lower Division States of Arizona and Nevada take less water from Lake Mead in accordance with the Lower Basin DCP.

Minute 323

  • In 2017, the United States and Mexico entered into Minute 323, an implementing agreement to the 1944 Mexican Water Treaty.
  • Minute 323 includes conditional storage of the Mexican Treaty entitlement in the United States and requires Mexico to take reductions in Treaty deliveries based upon low elevations at Lake
  • Minute 323 also includes measures for Binational Water Scarcity Contingency Planning, similar to those required under the Lower Basin DCP.

Under Minute 323, Mexico has made Binational Water Scarcity Contingency Plan contributions in 2021 and 2022, in addition to taking reductions.