The U.S. Bureau of Reclamation on Jan. 9 released a draft review of the management of the Colorado River’s two largest reservoirs after 2026, which will affect dam operations, hydropower reliability and infrastructure risk management in the West.
The Draft Environmental Impact Statement (EIS) evaluates post-2026 operational alternatives for Lake Powell and Lake Mead beginning in 2027, when the 2007 interim guidelines governing coordinated operations at Glen Canyon Dam and Hoover Dam expire. The recall did not designate a preferred alternative, preserving flexibility as negotiations continue among the seven states in the Colorado River Basin.
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These negotiations involve the seven states that make up the Colorado River Compact (Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming), which are divided between the upper basin and the lower basin according to the original 1922 agreement governing the use of the river.
“The Department of the Interior is moving forward with this process to ensure environmental compliance so that operations can continue without disruption when the current guidelines expire,” said Andrea Travnicek, assistant secretary for water and science at the U.S. Department of the Interior. “The river and the 40 million people who depend on it cannot wait. Faced with a severe ongoing drought, inaction is not an option,” he added.
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A New Reality
The draft EIS reflects the operational stress created by approximately 25 years of prolonged drought in the Colorado River Basin and forecasts that continue to point toward drier conditions.
A Bureau of Reclamation diagram shows the Glen Canyon Dam intake structures, highlighting the minimum power pool at 3,490 feet and the dead pool at 3,370 feet, central thresholds for post-2026 operations planning.
Image courtesy of the Claims Office
These pressures have reduced reservoir levels to points that limit hydropower production and hamper dam operations, so federal administrators are focusing on safeguarding the infrastructure itself, in addition to the water supply.
The recovery looked at five operational alternatives. The alternatives differ in how releases are coordinated between Lake Powell and Lake Mead, how shortages are triggered and distributed, and how stored water is stored and released under changing hydrologic conditions.
It is hoped that any eventual agreement between Covenant states will incorporate elements or variations of these approaches rather than adopting a single option wholesale.
“Given the importance of a consensus-based approach to operations for system stability, Reclamation has not yet identified a preferred alternative,” Scott Cameron, acting commissioner of the Bureau of Reclamation, said in a statement.
“Reclamation anticipates that, when an agreement is reached, it will incorporate elements or variations of these five alternatives,” added Cameron, who noted the breadth of alternatives in the EIS for “sustainable and effective management of the Colorado River.”
The Draft EIS directly addresses how close federal facilities are operating to critical thresholds. At Lake Powell, the analysis models conditions approaching the minimum power pool, where turbine generation is limited, and evaluates operations below this level using alternative outlet works.
Federally operated Colorado River hydroelectric facilities
The Colorado River system includes nine hydroelectric facilities managed by the Bureau of Reclamation, located on the main river and key tributaries.
Lower basin and main trunk
- Hoover Dam
- Davis Dam
- Parker dam
Upper Basin and Colorado River Storage Project
- Glen Canyon Dam
- Flaming Gorge Dam
- Navajo Dam
- Blue Mesa Dam
- Morrow Point Dam
- Crystal dam
Historically, these facilities have generated about 12 billion kWh annually, although production has declined during prolonged drought as reservoir elevations have declined.
The recovery also assessed buffer elevations intended to reduce the likelihood of Powell or Mead falling into ranges that would endanger hydroelectric power generation and system operations.
To compare alternatives, the Draft EIS uses decision-making under “significant uncertainty,” evaluating how often reservoir levels remain above specified performance thresholds under hundreds of possible future hydrological scenarios, rather than based on a single forecast.
The comprehensive approach highlights which operational strategies are most resilient to prolonged drought and points to scenarios that could push the system into undesirable operating conditions.
The Colorado River supplies water to more than 40 million people in seven states and supports hydroelectric power generation at nine federally operated facilities throughout the system, while serving 30 tribal nations, two Mexican states, and about 5.5 million acres of irrigated farmland.
Reclamation said the draft EIS only addresses domestic river operations. A separate bi-national process addressing deliveries to Mexico under the 1944 Water Treaty is also underway through the International Boundary and Water Commission.
Reclamation said the Draft EIS will be published in the Federal Register on Jan. 16, starting a 45-day public comment period that runs through March 2. A decision on post-2026 operations is expected by October 1, the start of the 2027 water year.
