The Secretary of the Interior - Washington - CO River Interim Guidelines for Lower Basin Shortages and the Coordinated Operations for Lake Powell and Lake Mead

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Interim Guidelines for the Operation of Lake Powell and Lake Mead appropriate balance between the storage of water for future deliveries and the lack of disruption of near-term water deliveries. Reclamation selected from among the four key operational elements disclosed in the Draft EIS to formulate the Preferred Alternative. Reclamation has determined that the four operational elements selected under this alternative best meet all aspects of the purpose and need of the proposed federal action. A. No Action Alternative The No Action Alternative represents a projection of future conditions that could occur during the life of the proposed federal action without an action alternative being implemented. It provides a baseline for comparison of each of the action alternatives. Pursuant to LROC, the Secretary makes a number of determinations at the beginning of each operating year through the development and execution of the AOP, including the water supply available to users in the Lower Basin and the annual release from Lake Powell. However, the LROC currently does not include specific guidelines for such determinations. Furthermore, there is no actual operating experience under low reservoir conditions, i.e., there has never been a shortage determination in the Lower Basin. Therefore, in the absence of specific guidelines, the outcome of the annual determination in any particular year in the future cannot be precisely known. However, a reasonable representation of future conditions under the No Action Alternative is needed for comparison to each action alternative. The modeling assumptions used for this representation are consistent with the assumptions used in previous environmental compliance documents for the ISG, the Colorado River `Dater Delivery Agreement, and the Louver Colorado River Multi-Species Conservation Program (LCR MSCP). However, the assumptions used in the No Action Alternative are not intended to limit or predetermine these decisions in any future AOP determination. B. Basin States Alternative The Basin States Alternative was developed by the Basin States and proposes a coordinated operation of Lake Powell and Lake Mead that would minimize shortages in the Lower Basin and avoid risk of curtailments of Colorado River water use in the Upper Basin. This alternative includes shortages to conserve reservoir storage; coordinated operations of Lake Powell and Lake Mead determined by specified reservoir conditions; a mechanism for the creation, accounting, and delivery of conserved system and non-system water (ICS); and a modification and extension of the ISG through 2026. ROD -Colorado River Interim Guidelines for December 2007 Lower Basin Shortages and Coordinated 9 Operations for Lake Powell and Lake Mead