Water users across the American Southwest are confronting the significant likelihood of mandatory reductions in Colorado River usage, potentially amounting to hundreds of billions of gallons, following the release of a new federal management plan for the coming decade. The U.S. Bureau of Reclamation unveiled a 10-year operational framework designed to adapt to fluctuating hydrological conditions impacting the river’s flow, with provisions for operational adjustments every two years. This proposed strategy includes scaling back water allotments for the Lower Basin states of Arizona, California, and Nevada, while the Upper Basin states – Colorado, New Mexico, Utah, and Wyoming – may implement voluntary conservation measures.

This new federal plan arrives as existing interim guidelines and drought contingency measures, established in 2007 and 2019, are slated to expire in 2027. Negotiations among the basin states for a successor agreement have faltered, with repeated deadlines for consensus passing without resolution. However, the Bureau of Reclamation, which manages critical infrastructure like the Hoover and Glen Canyon Dams—forming the vast Lake Mead and Lake Powell reservoirs—holds significant authority over the river’s operations. The Bureau’s release of a final environmental impact statement on Friday precedes a record of decision that will finalize the river’s operational plan for the next two years.

Andrea Travnicek, the Interior Department’s Assistant Secretary for Water and Science, emphasized that the plan aims to balance flexibility with predictability for the vital Colorado River system, which supports an estimated 40 million people. She noted that the plan responds to unprecedented hydrologic conditions and acknowledges the potential for considerable impacts on water users, while also allowing for adaptive responses to changing circumstances and the pursuit of consensus.

Under consideration by the Bureau are releases from Lake Powell, the reservoir demarcating the upper and lower basins, ranging from 5 million to 12 million acre-feet to downstream states. An acre-foot of water can typically sustain two to four households for a year. The Lower Basin, including Mexico, could face substantial cuts to their water allocations, potentially losing 1.5 million acre-feet in both 2027 and 2028, according to a proposal submitted by the Lower Basin states. Specifically, Arizona’s allotment could be reduced by 760,000 acre-feet, California by 440,000 acre-feet, and Nevada by 50,000 acre-feet. Beyond 2028, these Lower Basin reductions could escalate to as much as 3 million acre-feet annually.

The Arizona Department of Water Resources deemed such extensive reductions "unacceptable," warning in a published statement that these cuts would "devastate Arizona’s water users and its economy."

The Bureau of Reclamation is also exploring voluntary reductions of up to 200,000 acre-feet from the Upper Basin, alongside discussions about potentially relocating water from federally managed dams in that region downstream, contingent on hydrological conditions.

JB Hamby, California’s Colorado River Commissioner, underscored the fundamental challenge: "The proposal responds to a fundamental reality: the Colorado River no longer reliably produces enough water to support all the uses and expectations built around it." He added that this shared challenge necessitates "specific, measurable reductions in water use by every state."

A spokesperson for the Colorado Department of Natural Resources indicated the state is currently "analyzing" the federal document. Governors from the Upper Basin states expressed encouragement that the new operating guidelines "will better reflect existing water supply, which must underpin any practicable plan going forward."

The Colorado River, a lifeline for an arid region, is arguably the most climate-stressed waterway in the United States. It supplies water to an estimated 35 to 40 million people across seven Western states, serves 30 Native American tribes, and extends its reach into two Mexican states. The river’s watershed encompasses some of the nation’s most arid landscapes, making its water resources critical for agriculture, urban populations, and ecosystems. Furthermore, millions of Western residents depend on the electricity generated by hydroelectric dams along the river, such as the Hoover and Glen Canyon Dams.

The foundational 1922 Colorado River Compact, which allocated water rights, presumed an annual availability of approximately 17.5 million acre-feet for the two basins and Mexico. However, the historical average natural flow of the river has only been around 14.7 million acre-feet. Compounding this deficit, provisional data from the Bureau of Reclamation reveals that the average flow plummeted to a mere 11.2 million acre-feet between 2020 and 2024. During this same period, the agency calculated that average usage and evaporative losses across the basin exceeded 13 million acre-feet, highlighting a significant and persistent imbalance between supply and demand.

John Berggren, regional policy manager at Western Resource Advocates, views the operational ranges proposed by Reclamation as "the right things that we need to be doing in order to fix the supply and demand imbalance." However, he stressed that these are merely ranges, and the actual operational decisions made in the coming years will be critical in determining whether the system can be brought back into balance. Berggren expressed hope that the short-term certainty provided by this plan might help break the deadlock in negotiations among the states. He urged basin commissioners to abandon past unproductive approaches and "try something new and hopefully get to a seven-state agreement."

The Bureau of Reclamation’s final environmental impact statement was initially intended to formalize a management plan agreed upon by the basin states. Despite the missed deadlines for state-level negotiations, Reclamation maintains an open door for a collaborative agreement, which is widely considered the most sustainable path toward a durable, long-term operating framework for the river.

The ongoing negotiations are primarily stalled over the fundamental question of whether water use reductions should be mandatory and uniformly applied across the entire basin. Decades of over-allocation and increased demand have led to a situation where, according to federal accounting, the Lower Basin now uses less water than its legally apportioned share. Consequently, Lower Basin states advocate for shared responsibility in future cuts. Conversely, the Upper Basin states, which have historically utilized less than their allocated water rights, have strongly resisted mandatory reductions, proposing voluntary conservation instead. They argue that variable environmental conditions, such as record-low snowpack, naturally limit their water usage.

The absence of a comprehensive seven-state agreement, even with federal management options now on the table, significantly heightens the prospect of protracted legal battles. States heavily reliant on the Colorado River could resort to suing one another, with disputes likely to be adjudicated by the U.S. Supreme Court.

Celene Hawkins, Colorado River program director at The Nature Conservancy, described the proposal to manage the river adaptively to hydrological conditions as "the kind of agreement that we are going to need to really think about long-term how do we live in this basin with much less water moving forward." She expressed optimism that this federal action might spur the much-needed seven-state agreement, enabling "really good work for communities and for the river itself."