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Navajo Dam & Reservoir Operations Draft Enviornmental Impact Statement

The Colorado River Storage Project (CRSP) includes many storage facilities constructed on the mainstem of the Colorado River and various tributaries including the Aspinall Unit on the Gunnison River, Flaming Gorge Dam on the Green River, and Navajo Dam on the San Juan River. The Navajo Unit of the CRSP consists of a dam and reservoir that is owned, operated, and maintained by the Bureau of Reclamation (Reclamation). The facility is located on the San Juan River in New Mexico and Colorado and operates as a storage unit of the CRSP, subject to the terms of the Upper Colorado River Basin Compact, the Colorado River Storage Project Act of April 11, 1956 (70 Stat.105), and the act of June 13, 1962, authorizing the San Juan-Chama and Navajo Indian Irrigation Projects. The CRSP provides an irrigation and municipal and industrial water supply, flood control, recreation, hydropower, and fish and wildlife benefits.

Construction of the CRSP water storage facilities was critical to the development of the Upper Basin's (Utah, Colorado, Wyoming, and New Mexico) water resources, however, natural riverine habitats were altered due to the variation of natural flow regimes, water quality, and water temperatures. In addition, other urban-development related impacts resulted in a reduction of native fish populations and eventual listing of the Colorado pikeminnow (formerly Colorado squawfish) and razorback sucker as endangered.

A reevaluation of Navajo Dam operations began when Reclamation requested formal consultation with the U.S. Fish and Wildlife Service (Service) under Section 7, of the Endangered Species Act (ESA)1973, in 1991. The catalyst for operational changes and Section 7 consultation (which ensures federal agency actions are not likely to jeopardize the continued existence of listed species) on Navajo Dam was the proposed construction of the Animas-La Plata (ALP) Project. A draft biological opinion on ALP (May, 7, 1990) concluded that construction of the project would jeopardize the continued existence of the pikeminnow. During this time, new hydrological investigations suggested that additional flexibility which existed in the operation of Navajo Dam could help offset the negative impacts of ALP's construction. A reduction in late fall and winter releases would allow for water availability to increase spring peaks and return the San Juan River to a more natural hydrograph that would mimic pre-dam historic flow conditions. This flexibility in flow patterns would assist in the development of a reasonable and prudent alternative to the jeopardy biological opinion and allow initial ALP construction efforts to move forward. The reasonable and prudent alternative (RPA) that was developed required Navajo Dam operations to mimic a natural hydrograph for the life of the dam. Since no natural hydrograph was defined or developed for the San Juan River, the RPA also included a commitment to fund approximately seven years of research to determine the flow requirements for the pikeminnow and razorback sucker. This seven-year study was completed in 1997 under the San Juan River Basin Recovery Implementation Program (Program).

Flow Recommendations

In May 1999, the Program's Biology Committee provided year-round flow recommendations for the San Juan River necessary for the recovery of the two endangered fishes. It is anticipated that implementation of the flow recommendations, or reasonable alternative to it, will allow for a non-jeopardy biological opinion to be issued by the Service for the operations of Navajo Dam.

Reclamation proposes to implement recommended flows from Navajo Dam, or reasonable alternative to it, resulting from the consultation under the ESA. The proposed action would be implemented by modifying the operations decision criteria of Navajo Dam to provide sufficient releases of water at times, quantities, and durations necessary to protect the endangered fish and their designated critical habitat while maintaining the other authorized purposes of the Navajo Unit.

Draft Environmental Impact Statement

The criteria for reservoir operation decisions, that include the needs of the endangered fishes in the San Juan River, are new to the operations decision process for the Navajo Unit. Operations that result from implementing flow recommendations for endangered fishes will be different than historic operations. Reclamation considers it prudent to voluntarily complete an environmental impact statement (EIS) covering the incorporation of recommended flows into the decision criteria for Navajo Dam and Reservoir. Reclamation filed a notice of intent on October 1, 1999, in the Federal Register to initiate the preparation of the draft EIS. As part of this process several public meetings were held to provide information and obtain input from the public. The list of meetings is contained in the October 4, 1999 press release.

The San Juan River Basin Recovery Implementation Program

The purpose of the San Juan River Basin Recovery Implementation Program is to protect and recover endangered fishes in the San Juan River basin while water allowing water development to proceed in compliance with all applicable federal and state laws. The San Juan River Basin Recovery Implementation Program was developed as a cooperative effort among agencies of the Department of the Interior, tribes, states, and water development interests including the following: US bureau of Reclamation, US Bureau of Indian Affairs, US Fish and Wildlife Service, US Bureau of Land Management, Ute Mountain Ute Indian Tribe, Southern Ute Indian Tribe, Jicarilla Apache Indian Tribe, Navajo Nation, Water Development Interests, and the states of New Mexico, Colorado, and Utah.

Associated Documents

 

Last updated: November 25, 2008