AMP Background

photo: Colorado River through Grand Canyon

The construction and operation of Glen Canyon Dam fundamentally altered the Colorado River ecosystem. Given the importance of Colorado River water to the states and economies of the Southwest, it is not surprising that there has been and remains considerable controversy over how to share this major river. As we begin the 21st century, challenges abound over how best to manage this resource for the benefit of agricultural, municipal, industrial, tribal, environmental and recreational interests alike.

The Grand Canyon Protection Act of 1992 directed the Secretary of the Interior to manage Glen Canyon Dam in such a way as to “protect, mitigate adverse impacts to and improve the values for which Grand Canyon National Park and Glen Canyon National Recreation Area were established.” The act provided direction for the Glen Canyon Dam Environmental Impact Statement, in that all dam operations would need to be analyzed with those goals in mind.

After nearly five years of study - and more than 40 different projects undertaken by more than 15 different agencies - the Record of Decision (ROD) for the Glen Canyon Dam EIS was signed in 1996. The ROD specified operating parameters for Glen Canyon Dam and mandated that adaptive management of the resources in Grand Canyon be undertaken. The act stipulated that a close watch be maintained on the effects of Glen Canyon Dam operations and ordered that future modifications of those operations and management actions be considered to protect and enhance the Colorado River ecosystems.

As part of this process, Interior Secretary Babbitt created a federal advisory committee composed of the numerous interests who share in the management of the river. These interests sit at what is called the Adaptive Management Work Group (AMWG). This group recommends dam operations and management actions to the Secretary of the Interior based on a wide variety of public and technical resources.

Law of the River

The following is a profile of some of the various federal and state laws, compacts, treaties and administrative actions that are generally referred to as the “Law of the River” and control river operations and the rights to the use of the Colorado River.

Colorado River Compact of 1922 - The foundational agreement governing the Colorado River. Apportions Colorado River water in "perpetuity" between the Upper and Lower Basins.
Boulder Canyon Project Act of 1928 - This act provided for the necessary Congressional approval of the Colorado River Compact of 1922. Authorized the construction of Hoover Dam and other water storage and delivery facilities in the Lower Basin. Created a comprehensive apportionment among California (4.4 maf), Arizona (2.8 maf), and Nevada (0.3 maf) of the Lower Basin's share of the mainstream waters of the Colorado River.
California Seven Party Agreement of 1931 - This agreement helped settle the long-standing conflict between California agricultural and municipal interests over Colorado River water priorities. The seven principal claimants reached consensus in the amounts of water to be allocated on an annual basis to each entity.
Mexican Water Treaty of 1944 - Allots to Mexico, a guaranteed annual quantity of 1.5 million acre feet of the waters of the Colorado River. It also provides for additional or lesser deliveries in identified circumstances.
Upper Colorado River Basin Compact of 1948 - Apportions the Upper Basin's allocation of Colorado River water among Colorado, New Mexico, Utah, Wyoming, and the portion of Arizona that lies within the Upper Colorado River Basin.
Colorado River Storage Project Act of 1956 - Provides a comprehensive water resource development plan for the Upper Basin and authorized the construction of Glen Canyon, Flaming Gorge, Navajo and Curecanti dams as well as other participating projects, for multiple purposes.
Arizona v. California 1964 - Supreme Court's original decree issued in Arizona v. California. This decree addresses allocation of Colorado River water and establishes limits on the United States operation of certain Colorado River reservoirs. The decree has been updated and amended on numerous occasions since 1964. The Supreme Court entered a Consolidated Decree in 2006 which incorporates all applicable provisions of the earlier issued decrees.
Colorado River Basin Project Act of 1968 - This act authorized construction of a number of water development projects in both the upper and lower Colorado River basins, including the Central Arizona Project (CAP). It also made the priority of the CAP water supply subordinate to California's apportionment in times of shortage, and directed the Secretary to prepare, among other things, long-range operating criteria for the Colorado River reservoir system in consultation with the Colorado River Basin states.
The Criteria for Coordinated Long-Range Operation of Colorado River Reservoirs of 1970 (amended March 21, 2005) - Addresses the coordinated long-range operation of Colorado River reservoirs in the upper and lower basins pursuant to the Colorado River Basin Project Act of 1968.
Minute 242 of the U.S. - Mexico International Boundary and Water Commission of 1973 - Addresses actions to reduce the salinity of water being delivered to Mexico at Morelos Dam.
Colorado River Basin Salinity Control Act of 1974 - Authorized desalting and salinity control projects, including the Yuma Desalting Plant, to improving Colorado River quality.
Grand Canyon Protection Act of 1992 - Addresses the protection of resources in Grand Canyon National Park and in Glen Canyon National Recreation Area, consistent with and subject to applicable provisions of federal law.