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November 16, 2022  |  Written by Daniel J. Condren

Colorado River Update: Department of Interior Announces Intent to (Potentially) Revise Reservoir Operating Guidelines and Impose Additional Cuts in 2023-24 Water Year

On October 28, 2022, the U.S. Bureau of Reclamation issued a release stating it is initiating efforts to modify the existing operating guidelines for Glen Canyon and Hoover Dams in in the 2023 and 2024 water year, potentially paving the way for even more drastic water cuts next year to the Lower Basin states of Arizona, Nevada, and California than those spelled out in existing agreements. While it is too early to speculate about what actions (if any) may result from this process, water managers and right-holders should be aware of the potential for significant changes in river management and take advantage of opportunities for public input.

Currently, releases from Glen Canyon and Hoover Dams are tied to reservoir water elevation benchmarks set forth in the 2007 Interim Guidelines and agreements adopted pursuant to the 2019 Drought Contingency Plan (DCP). Reclamation’s October release states the agency will publish a Notice of Intent (NOI) in the Federal Register to prepare a Supplemental Environmental Impact Statement (SEIS) exploring proposed alternatives for revision of the 2007 Interim Guidelines. The 2007 Interim Guidelines are set to run through 2026, but as stated in the NOI, “Reclamation has concluded that the potential impacts to flow runoff conditions in the coming winter (2022-23) pose unacceptable risks to routine operations of Glen Canyon and Hoover Dams during the interim period (prior to Jan. 1, 2027) and, accordingly, modified operating guidelines need to be expeditiously developed.”

Reclamation’s October release states the agency may need to further reduce releases from Glen Canyon and Hoover Dams, and the NOI provides a “preliminary overview” of three alternatives to be explored:

  • No Action Alternative: Reclamation would continue implementation of existing agreements that control operation of the two dams, most notably the 2007 Interim Guidelines and agreements adopted pursuant to the 2019 Drought Contingency Plan (DCP).
  • Framework Agreement Alternative: An additional set of consensus-based actions that would “likely build” on commitments and obligations developed by the Basin States, Basin Tribes, and non-governmental organizations that were included in the 2019 DCP.
  • Reservoir Operations Modification Alternative: A set of “actions and measures” developed by Reclamation and “adopted pursuant to Secretarial authority under applicable federal law.” In other words, this alternative is referring to unilateral action by the federal government.

The NOI anticipates that a draft SEIS will be completed in Spring 2023, followed by a 45-day public comment period, with a final SEIS and Record of Decision adopted in late summer 2023, which would allow decisions to become effective for 2023-24 operations. The October 28 release states the NOI will be published in the Federal Register “in the coming days,” and members of the public may provide input on it through December 20, 2022. However, as of this article’s publication date (November 15), the NOI has not yet been published. Interested parties can monitor the Federal Register for the publication here.

Separate but Related:  Evaporation and System Loss Accounting

The last page of the NOI states, almost in passing, that “separate from the development of the SEIS, Reclamation anticipates publishing an informational report in 2023 addressing potential methodologies to support assessments for evaporation, seepage, and other system losses in the Colorado River Basin in future years.” Far from an afterthought, however, the issue of evaporation and transit loss accounting has come to the forefront in recent months. This has significant ramifications for users in the Lower Basin, who, unlike the Upper Basin, are not charged for such losses under current accounting methods.

As explained in an October 2022 memo written by the general manager of the Colorado River District, “[t]he Upper Basin and the River District have been calling upon the USBR to remedy the fact that evaporation from federal Lower Basin system reservoirs and transit losses related to Lower Basin deliveries are not charged to the Lower Basin contractors and, therefore, there is approximately 1.2 [million acre-feet] of depletions that are not charged to the Lower Basin. Most recently, Southern Nevada Water Authority and the Arizona Department of Water Resources joined in this effort.” During a September Colorado River symposium held in Santa Fe, both Interior Department Secretary Deb Haaland and Bureau of Reclamation Commissioner Camille Calimlim Touton told attendees that the issue of evaporation and transit loss in the Lower Colorado River Basin were short-term priorities for their respective agencies. More than 10% of the river’s water is lost to evaporation from reservoirs, seepage, and other losses, according to Haaland’s prepared remarks. “In these serious times, we need to take the overdue step of assessing how to account for those losses throughout the Basin,” the statement goes on. “This is another tough reality that we must work together to address.”

For more information, please contact Dan Condren at

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