Water Rights on the Colorado River in a Drought-Prone World
The Colorado River is the beating heart of the West, pumping life into the region’s cities, farms, and deserts. Its water is used for reasons as diverse as growing alfalfa that is shipped to Saudi Arabia to providing hydroelectric power to over 40 million people in the southwestern U.S. and northwestern Mexico. The Colorado River is the principal source of water for seven states (Colorado, New Mexico, Utah, Wyoming, Arizona, Nevada, and California); it also provides water for Mexico.
Water rights on the Colorado River are governed by a complicated network of laws, court decisions, contracts, and regulations known as the Law of the River.
The Colorado River Compact
The Colorado River Compact is a 1922 agreement between the seven states that share the river. It was the first interstate water agreement in the U.S. The compact divides the river’s water between the Upper Basin (Colorado, New Mexico, Utah, and Wyoming) and the Lower Basin (Arizona, Nevada, and California). The compact also sets a limit on how much water each state can use.
The idea for the Colorado River Compact began in part from a concern by individuals in the Western states that the federal government would take charge of Western water rights distribution to the detriment of the states. Delegates from each of the seven compact states met together to negotiate an acceptable solution. As discussions progressed, it became clear that the greatest disputes were between the Upper Basin states and the Lower Basin states rather than between the states within each basin.
The delegates ultimately apportioned 7.5 million acre-feet of water yearly per basin (averaged over 10 years). However, this allotment was based on an assessment of the river’s flow that was greater than average. Because of this, the compact ultimately built water scarcity into the agreement. This has led to near crisis in the present.
Arizona initially rejected the Colorado River Compact because it feared California would consume the bulk of the Lower Basin allotment. The conflict eventually reached the Supreme Court for a decision, wherein Arizona was granted 2.8 million acre-feet and California 4.4 million acre-feet per year. The dispute over water allotment between California and Arizona, however, remains tense.
United States and Mexico water treaty
In 1944, the U.S. and Mexico negotiated a treaty for the utilization of water from the Colorado River, Tijuana River, and Rio Grande. Mexico was guaranteed 1.5 million acre-feet of the Colorado River per year (averaged over five years). Additionally, the U.S. is allotted 350,000 acre-feet of water from the Mexican tributaries of the Rio Grande.
In dry years, the treaty can cause strife between the two countries. The U.S. delivers Mexico its water from the Colorado River before U.S. allocations are made for the year. However, Mexico has often been late in providing the U.S. its water allocations, at times waiting until big storms replenish water stores. Small farmers within Mexico have often expressed fury over water rights issues as droughts in areas such as Chihuahua leave small farms in Mexico without water. At the same time, farmers in the U.S., Texas in particular, protest delays in Mexico’s delivery of water in times of shortages.
Central Arizona Project
Concerns about drought and about California’s usage of Lower Basin water from the Colorado River have always plagued Arizona. As the Phoenix and Tucson areas grew, it was important for Arizona to have a way to transport and store water from the Colorado River to those areas of Arizona that are most populous but also far away from the Colorado River.
The Central Arizona Project (CAP) was developed as a series of aqueducts, pumping stations, and reservoirs used to move more than 1.4 million acre-feet of water yearly from the Colorado River across 336 miles of Arizona. It was authorized in 1968, and construction took place from 1973 to 1993.
In negotiating for authorization of CAP, Arizona agreed to allow California priority rights to water from the Colorado River and accepted junior rights for Arizona. This could mean that if water shortages became severe, Arizona would be cut off from Colorado River water to allow California its full usage.
CAP has always faced controversy. In its early days, California blocked attempts to authorize CAP in opposition to Arizona claiming water from the Gila River, which California argued was a tributary of the Colorado. More intense controversy followed when opponents argued that planned dams would cause grievous environmental damage, including to Grand Canyon National Park and to the habitat of endangered desert tortoises and bald eagles. Additionally, the cost and funding of various CAP projects has been a continual controversy.
Tribal water rights
The 1922 Colorado River Compact included a single line about water rights of the Native American tribes of the river basin: “Nothing in this compact shall be construed as affecting the obligation of the United States of America to Indian tribes.” However, the amount of water due to the tribes and the means to transport such water have always been vague at best and difficult for tribes to utilize or enforce. While it is clear the tribes have rights to Colorado River water, many of the tribes lack the infrastructure to exercise those rights or any way to sell that water to those downstream. Additionally, the exact amount of water due to the tribes has never been clearly defined. And to deepen the wound, the Native American tribes have routinely been excluded from water rights negotiations in the region.
In June 2023 the U.S. Supreme Court issued a decision regarding tribal water rights in the case of Arizona v. Navajo Nation. The case arose out of a dispute between the Navajo Nation and the states of Arizona, Nevada, and Colorado over the allocation of water from the Colorado River. The Navajo Nation argued that the U.S. had a fiduciary duty to secure water for the Navajo Nation under a treaty dating back to 1868 and that this duty included the obligation to take affirmative steps to quantify their water rights and to devise a plan to meet the Nation’s water needs. However, the Supreme Court rejected the Navajo Nation’s argument, holding that the treaty did not impose any specific obligations on the U.S. with respect to water. The Court found that the treaty only reserved a right to water for the Navajo Nation but did not require the U.S. to take any specific actions to secure that water.
Drought contingency plan
The Colorado River continues to face countless challenges, including drought, climate change, and population growth. These challenges put a strain on the river’s resources and make it increasingly difficult to meet the water needs of the seven states and Mexico.
In 2007, representatives from the Colorado River basin states and the Bureau of Reclamation negotiated and adopted a water conservation plan — the Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Lake Mead (“Interim Guidelines”) — that remains in effect until the end of 2025. The Interim Guidelines, in part, are intended to prevent Lake Mead from exceptional drops in water elevation, as loss of elevation would not only affect water usage but would also threaten the vast amount of hydroelectric power supplied by Hoover Dam. The Interim Guidelines cut water apportionments when Lake Mead drops to certain levels and also require Lake Powell to release water into Lake Mead in certain cases. An addendum to the Interim Guidelines also requires certain water conservation measures by both the U.S. and Mexico.
As the Interim Guidelines are only temporary, the seven states and Mexico are working together to develop a long-term plan to conserve water and ensure the river’s resources are used sustainably. This plan, known as the Drought Contingency Plan, is hoped to be finalized in 2023. The federal government has called on the states to reduce their consumption of Colorado River water by 2-4 million acre-feet of water per year. In 2019 Arizona, California, and Nevada agreed to water consumption cuts, but those reductions have not been enough, as reservoir levels continue to drop. The federal government is offering the three states at least $1 billion in drought relief funding if they are able to come to an agreement with the Department of the Interior for additional voluntary water cuts.
Conclusion
Water rights on the Colorado River have a complicated history and will continue to have a complex future. It will take a great deal of knowledge and compromise to come to solutions that are sustainable, effective, and just. However, as complicated as the solutions may be, they are absolutely necessary for the future of the American Southwest.