- Arizona says the federal plan could allow severe Colorado River cuts to the Lower Basin.
- The state argues the plan does not adequately address the Colorado River Compact.
- Arizona objects to a 10-year federal framework and favors a two-year approach.
- The state challenges how possible reductions are divided between the Upper and Lower basins.
- Arizona has reserved the right to take its Colorado River claims to court.
Friday, August 14, 2026 — Arizona has put the federal government on notice that it strongly objects to key parts of the proposed rules for operating the Colorado River after 2026.
In an August 10 letter to the U.S. Department of the Interior
, Arizona Department of Water Resources Director Tom Buschatzke laid out seven objections to the federal government’s preferred plan for operating Lake Powell and Lake Mead.
The objections range from how much water could be released from Lake Powell to how deeply Arizona, California and Nevada could be required to cut their Colorado River use.
But running through much of the four-page letter is a larger legal question: What happens when the seven Colorado River Basin states cannot agree on new rules, and the federal government steps in?
Arizona argues that federal authority still has limits.
Arizona Says the Colorado River Compact Still Matters.
Arizona’s first objection goes to the legal foundation of Colorado River management.
The state argues that the federal government’s preferred alternative is inconsistent with the Colorado River Compact and what is commonly called the “Law of the River,” the collection of laws, court decisions, agreements and other legal authorities governing the river.
The Colorado River Compact was signed in 1922 and divided the Colorado River Basin into an Upper Basin and Lower Basin.
Arizona’s August 10 letter points out that the Final Environmental Impact Statement does not mention the Compact. It also disputes the federal government’s approach to interpreting its obligations under the larger body of Colorado River law.
Arizona acknowledges that the federal government has broad authority to establish operating guidelines for Colorado River infrastructure. But the state argues that this authority does not replace obligations imposed by the Compact.
The state also says the lack of a clear federal interpretation makes future planning difficult.
“The Department gives Arizona neither transparency about how the River will be managed nor any basis on which to plan for its water future,” Buschatzke wrote.
Arizona then makes an important legal reservation. The state says it retains the right to seek resolution of its Compact rights “in an appropriate judicial forum.”
In other words, Arizona is not agreeing that the federal government’s interpretation of its authority settles the issue.
Arizona Wants a Shorter Plan.
The length of the proposed federal framework is another major disagreement.
Arizona supports a two-year approach rather than the 10-year decision framework described in the preferred alternative.
Under the federal framework, operating guidelines would be issued in anticipated two-year intervals, but the overall principles and boundaries would remain in place through 2036.
Arizona argues that two years would provide more flexibility. The shorter period, according to the state, would allow officials to consider climate conditions and continue negotiating a more comprehensive, long-term solution.
The state says the federal government has not provided adequate technical or legal justification for keeping the framework in place for 10 years.
Arizona also objects to giving the federal government discretion to choose from a broad range of operating options every two years within that longer framework.
A Dispute Over Water Released From Lake Powell.
Another objection involves the amount of water that could be released from Lake Powell.
Arizona points to federal Long-Range Operating Criteria that provide for a minimum annual release of 8.23 million acre-feet from Lake Powell.
An acre-foot is roughly the amount of water needed to cover one acre of land with one foot of water.
According to Arizona’s letter, the federal preferred alternative contemplates Lake Powell releases below 8.23 million acre-feet. Its operating boundaries would allow annual releases as low as 5 million acre-feet.
Arizona argues that the Long-Range Operating Criteria cannot simply be changed through the environmental review process.
That disagreement matters because water released from Lake Powell moves downstream toward the Lower Basin.
Arizona Questions Upper Basin Contributions.
The state also objects to how the plan handles potential contributions from reservoirs in the Upper Basin.
Arizona says those contributions are left largely undefined.
Under the preferred alternative described in the state’s letter, contributions from certain Upper Basin reservoirs would be voluntary and capped at 200,000 acre-feet per year, depending on water conditions.
Arizona contrasts that with the much larger potential reductions facing the Lower Basin.
The state argues that contributions from those Upper Basin reservoirs should have been addressed directly in the preferred alternative rather than left for future decisions.
This is part of a broader disagreement over how responsibility for shortages should be divided between the two halves of the Colorado River Basin.
The Upper Basin includes Colorado, New Mexico, Utah and Wyoming. The Lower Basin includes Arizona, California and Nevada.
Cuts Could Reach 3 Million Acre-Feet.
Perhaps the strongest language in Arizona’s letter concerns potential Lower Basin reductions.
Arizona says it does not consent to annual reductions of up to 3 million acre-feet that could be authorized under the federal plan’s operating boundaries.
When assumed reductions to Mexico are included, the Final Environmental Impact Statement models reductions of up to 3.6 million acre-feet, according to Arizona’s letter.
The Lower Basin states had instead voluntarily proposed reductions totaling 1.25 million acre-feet per year for a two-year period.
Arizona argues that the larger reductions contemplated by the federal government could be devastating.
Buschatzke wrote that reductions of that magnitude, if implemented, would “inflict catastrophic harm on Arizona’s citizens” without a corresponding mandatory contribution from the Upper Basin states.
The federal framework also contemplates the possibility of additional Lower Basin reductions if Lake Mead is projected to fall below an elevation of 1,000 feet, according to the Arizona letter.
Arizona argues that shortages should not be imposed on the Lower Basin to cover a deficiency that the state believes could instead involve Upper Basin delivery obligations or releases from Upper Basin reservoirs.
Arizona Says Some Federal Rules Are Too Vague.
Arizona’s sixth objection is more straightforward: The state says it cannot adequately plan for rules that have not been clearly defined.
For example, the preferred alternative could allow temporary actions to protect critical federal infrastructure under extraordinary circumstances.
Arizona says the federal document does not adequately explain what those temporary actions might be, how long “temporary” would last or what circumstances would trigger them.
The state raises similar concerns about provisions allowing the Secretary of the Interior to take necessary management actions consistent with federal law.
Arizona argues that the federal government has not clearly explained what it believes that law requires or what actions it might take.
That uncertainty, according to the state, leaves Arizona and its water users without enough information to plan for future Colorado River supplies.
State Also Challenges the Federal Review.
Arizona’s final objection involves the federal environmental and administrative review itself.
The state argues that the Final Environmental Impact Statement does not adequately address several issues Arizona raised earlier in the process.
Those include possible engineering measures at Glen Canyon Dam that could provide access to water stored below the 3,500-foot protection elevation.
Arizona also objects to what it describes as outdated projections of Upper Basin water demand and assumptions about future water depletion.
Finally, the state says the federal analysis did not adequately evaluate possible economic and national security consequences of the proposed reductions for Arizona agriculture, manufacturing and municipal water users.
These are Arizona’s allegations concerning the federal review. The August 10 letter does not resolve the underlying legal disputes.
Is a Colorado River Court Battle Getting Closer?
The possibility of litigation is becoming increasingly difficult to ignore.
Public radio KJZZ reported on August 14 that the arguments contained in Buschatzke’s letter could form the basis of a future Colorado River lawsuit. KJZZ also reported that Arizona lawmakers increased the state’s Colorado River litigation fund to $9 million earlier in the summer.
A court fight is not certain.
Arizona closes its August 10 letter by saying the state remains committed to working constructively with the Department of the Interior toward a path forward.
At the same time, the letter expressly preserves Arizona’s ability to seek judicial resolution of its rights under the Colorado River Compact.
The federal government is expected to release specific operating plans for 2027 and 2028. KJZZ reported August 14 that those rules appear likely to include elements of a counterproposal supported by Arizona.
For now, Arizona’s letter provides a detailed record of where the state believes the federal approach falls short.
What happens next will depend not only on how much water is available in the Colorado River, but also on how the federal government and seven Basin states interpret the rules governing how that water is shared.
