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Colorado River Interim Guidelines for
Lower Basin Shortages and Coordinated Operations
for Lake Powell and Lake Mead

About the Project

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In May 2005, the Secretary of the Interior (Secretary) directed Reclamation to develop additional strategies for improving coordinated management of the reservoirs of the Colorado River system. It was anticipated that, among other elements, these strategies, or operational guidelines, would identify those circumstances under which the Secretary would reduce the annual amount of water available for consumptive use from Lake Mead to the Lower Division states (Arizona, California, and Nevada) below the apportioned 7.5 million acre-feet -- (a "Shortage") pursuant to Article II of the Decree in Arizona v. California.

Reclamation issued a Federal Register notice on June 15, 2005 which gave public notice of the proposed Federal Action and solicited public input on the content, format, mechanism, and analyses to be considered during the development of the proposed shortage guidelines and reservoir management strategies. A series of public meetings were held and the level of public interest and comment was high. The outcome of this process was a decision by the Secretary to begin a formal National Environmental Policy Act (NEPA) process and preparation of an Environmental Impact Statement (EIS).

Environmental Review Process

On September 30, 2005, Reclamation published a Notice of Intent to prepare an EIS and described the proposed Federal Action as having two elements: 1) adoption of specific (interim) Lower Basin Shortage Guidelines, and 2) coordinated reservoir management strategies to address operations of Mead and Powell under low reservoir conditions. In November 2005, Reclamation held four public scoping meetings in the Colorado River Basin (Salt Lake City, Utah; Denver, Colorado; Phoenix, Arizona; and Henderson, Nevada) to introduce the project and solicit public comments on the scope. Reclamation also consulted with representatives from the Basin States, Indian tribes, non-governmental organizations (NGOs), and other interested parties. Comments received during the scoping process identified a broad range of concerns regarding the availability and reliability of Colorado River water supplies. While many of the concerns related to operations during drought and under low reservoir conditions, there were other comments that expressed a need to consider other water supply, water management, and operational strategies or programs that could improve the availability and reliability of Colorado River water supplies. After thorough consideration of these issues and comments, the Interior Department determined that the Proposed Federal Action will address this broader range of issues and comments.

The Proposed Federal Action has four operational elements and they are:

  • Shortage guidelines for Lake Mead and the Lower Division states
  • Coordinated reservoir operations for Lake Powell and Lake Mead
  • Mechanism for the storage and delivery of conserved system and non-system water in Lake Mead
  • Modification/extension of the Interim Surplus Guidelines established in 2001

Reclamation conducted public scoping meetings in November 2005 in support of the preparation of the EIS. A Scoping Summary Report that summarizes the issues raised during scoping and describes the Interior Department's assessment of the scope of the environmental analysis that will be included in the draft EIS was published in March 2006. A total of 1,153 written comment letters were received during the scoping process. The comment letters were submitted by a wide range of interested parties that included federal, state, and local agencies; Indian tribes; businesses; special interest groups; and individuals.

The next step in the EIS process was to develop a range of alternatives that will permit the evaluation of the full range of operational elements being considered under the Proposed Federal Action. This enabled Reclamation to identify the water supply management and operational strategies that provide the greatest benefit and that best meet the purpose and need of the Proposed Federal Action. A Draft Alternatives Summary (and associated tables - Table 1: Matrix of Draft Alternatives, Table 2: Lake Mead Operational Diagram, and Table 3: Lake Powell Operational Diagram) was completed and made available to the public in July 2006.

In February 2007 a Draft EIS was released for public review through April 30, 2007. As part of its efforts to seek public input, Reclamation scheduled three public hearings in April 2007 in Salt Lake City, Utah; Phoenix, Arizona; and Henderson, Nevada to receive comments on this document. The Draft EIS presented four action alternatives for implementation, plus a “No Action Alternative,” but did not identify a preferred alternative. Additionally, a Modeling Workshop was held on March 6, 2007 in Henderson, Nevada to provide the public with information on the modeling performed and used in the Draft EIS to analyze the potential impacts of hydrologic resources and water deliveries. A total of 78 written comments were received and two individuals provided oral comments during the public hearings.

In June 2007, a fifth action alternative -- the preferred alternative (and associated tables - Table 1: Matrix of Alternatives, Table 2: Lake Powell Operational Diagram, and Table 3: Lake Mead Operational Diagram) -- was developed after consideration of the public comments on the Draft EIS and further analysis.

The Preferred Alternative is analyzed in the Final EIS that was published in November 2007 and proposes that: 1) specific water levels in Lake Mead be used to determine when a shortage condition (the availability of less than 7.5 million acre-feet of water) would be declared in the lower Colorado River Basin, and how that shortage would be shared by the three Lower Division states – Arizona, California and Nevada;  2) specific reservoir conditions at Lakes Powell and Mead be used to determine the annual operation of these reservoirs, in a manner that would minimize shortages in the Lower Basin and avoid the risk of water delivery curtailments in the Upper Basin; 3) a mechanism be implemented to encourage and account for augmentation and conservation of water supplies in Lake Mead to minimize the likelihood and severity of potential future shortages and to provide additional flexibility to meet water use needs, particularly under low reservoir conditions;  and 4) the Interim Surplus Guidelines established in 2001 be modified and extended through 2026.

A Record of Decision was signed in December 2007.

Webmaster: sha-lcr-webcomments@usbr.gov
Updated: December 2007