From email from ADWR:
October 16, 2026
Today the State of Arizona filed a motion to intervene in the Nevada lawsuit challenging the recent federal decision governing the operation of the Colorado River.
Like Nevada, Arizona believes the federal government’s new operating framework ignores basic elements of the Law of the River and could result in cuts to the state’s apportionment that would devastate Arizona’s economy.
These elements go far beyond and fall outside the Lower Basin Agreement to which we are strongly committed and continue to work with Nevada and California to implement.
Our problems with the federal government’s Record of Decision are twofold.
One: the federal government’s plan fails to deliver the water that Arizona and our fellow Lower Basin states are owed according to the Law of the River.
Two: the federal government’s Year 3-10 plan includes a range of “sideboards” that, if triggered, could require reductions to the Lower Basin of up to 3 million acre-feet per year in priority. Such reductions could effectively dry up the Central Arizona Project canal system, as well as many of our on-river communities and would more than double the water cuts agreed to in the Lower Basin Agreement.
Arizona believes that taking this action now provides the best path forward for protecting Arizona water users. We are confident that our negotiations with California, Nevada and the U.S. will move forward. In fact, by taking this step we are protecting the integrity of our Agreement. By joining this litigation we can protect Arizona’s interests, whether that’s before a judge or in any settlement discussions that may ensue.
Arizona’s priority remains the completion of a Lower Basin Agreement with California, Nevada, and the U.S. to share in water reductions over the next two years and to memorialize the Intentionally Created Surplus tool. Through our participation in this litigation we will seek to assure that the agreement is implemented.
The Lower Basin states have contributed millions of acre-feet of water toward stabilizing the river system. With more than 5.5 million acre-feet of Arizona water left in Lake Mead since 2014, no state has sacrificed more. In collaboration with our Lower Basin state partners, the Lower Basin Agreement demonstrates that we are doing more. But the US decision puts the entire burden of sacrifice on the shoulders of three states. We are joining Nevada in challenging that framework.
