The federal government has finalized new Colorado River operating rules that will require Arizona, California and Nevada to cut their combined water use by 1.25 million acre-feet annually for the next two years amid record-low reservoir levels.
The Department of the Interior (DOI) on Aug. 21 issued its 2027-28 Operating Guidelines along with a Record of Decision for post-2026 Colorado River operations. The decision establishes a 10-year framework for managing Lake Powell and Lake Mead while leaving room for the seven basin states, Tribes and other water users to continue negotiating a longer-term agreement.
“Forty million people, millions of acres of farmland and ranchland, industries that power the American West, and some of our nation’s fastest growing metropolitan areas depend on the Colorado River,” said Interior Secretary Doug Burgum.
Under a proposed Lower Basin sharing agreement, Arizona would take the largest reduction at 760,000 acre-feet (an acre-foot is 325,851 gallons) annually, followed by California at 440,000 acre-feet and Nevada at 50,000 acre-feet. The three states would also voluntarily conserve and store at least another 700,000 acre-feet over the two years.
The reductions come as river conditions have deteriorated sharply. DOI said the combined contents of Lake Powell and Lake Mead are lower than at any point since Lake Powell began filling after Glen Canyon Dam was completed in the 1960s. The agency shows Lake Powell is currently at 21% of storage capacity (3,518 feet) and Lake Mead at 27% (1,099 feet).
The Bureau of Reclamation expects Lake Powell to begin the Oct. 1 water year between 3,510 and 3,540 feet, with releases of 6-7 million acre-feet to protect Glen Canyon Dam operations. The final 2027 release will be set in April based on hydrology.
While the Lower Basin states face immediate reductions, the plan does not mandate comparable cuts from the Upper Basin states of Colorado, New Mexico, Utah and Wyoming. Instead, it allows those states to develop an agreement involving operations at Aspinall, Flaming Gorge and Navajo reservoirs to help protect Glen Canyon Dam.
Lower Basin states react
The difference remains contentious, with Lower Basin states calling for reductions for all basin states and Nevada filing a lawsuit to set aside the Record of Decision.
JB Hamby, chairman of the Colorado River Board of California and California’s Colorado River commissioner, told NPR the Lower Basin reductions are consistent with proposals California and its partners have advanced to address the river’s “structural deficit,” where use has exceeded available supplies. Hamby said that all seven states ultimately need to participate in reducing demand as supplies decline.
“We’re open to providing relief and having some flexibility provided to the Upper Basin states,” Hamby said. “But certainly, there’s not going to be a situation moving forward where we have the three of seven states do all the lifting for all seven while four sit it out.”
Arizona officials offered qualified support for the two-year agreement while stressing that a broader solution remains necessary.
Arizona Department of Water Resources Director Tom Buschatzke said the decision provides stability after more than three years of difficult negotiations and allows discussions to continue without surrendering Arizona’s legal rights.
“With the Record of Decision, the 2027-2028 Operating Guidelines and the supporting agreements in place, we can focus on a longer-term, equitable, basin-wide outcome that includes shared sacrifices along with our Upper Basin partners in an effort to avoid protracted litigation,” Buschatzke said.
Nevada, however, moved from criticism to litigation, filing a federal lawsuit challenging the longer-term framework. The state, the Colorado River Commission of Nevada and the Southern Nevada Water Authority contend the rules could eventually require Nevada to absorb a 213,556-acre-foot reduction, equivalent to about 71% of the state’s Colorado River entitlement.
Nevada argues that it would disproportionately burden a state that has already reduced Colorado River consumption by more than 40% since 2002, while the Las Vegas Valley has added roughly 875,000 residents.
Nevada Gov. Joe Lombardo (R) had warned after the guidelines were released that the federal framework provides “little certainty” for Nevada and could place too much responsibility on Lower Basin users.
Southern Nevada Water Authority General Manager John Entsminger called Interior’s proposed reductions “entirely unrealistic,” noting southern Nevada has cut Colorado River use about 40% over the past 25 years. “Conservation has its limits,” he said, arguing the proposed water supply would not meet the community’s basic needs.
The dispute leaves the Colorado River states with another two years to try to bridge their differences. — Charles Wallace, WLJ contributing editor
