Arizona moves to join lawsuit against federal Colorado River plan

The Grand Canyon State announced Friday that it intends to join Nevada’s lawsuit challenging the federal government’s most recent plan for the future of the Colorado River. 

The announcement comes after years of unsuccessful negotiations among the seven states that depend on Colorado River water to develop a plan to deal with decreasing water availability amid a 25-year mega-drought.

“Like Nevada, Arizona believes the federal government’s new operating framework ignores the basic elements of the law of the river,” Arizona Department of Water Resources Director Tom Buschatzke said during a Friday afternoon press conference. “It could result in cuts to the state apportionment that would devastate Arizona’s economy.”

Under the new federal framework that was revealed in August, Arizona and the other Lower Basin states will face significant cuts to their Colorado River water, but would work together on voluntary conservation efforts to at least temporarily avoid more extreme cuts proposed by the federal government. 

The framework crafted by the Trump administration prescribes that Lower Basin states — Arizona, California and Nevada — will collectively reduce their usage by 1.25 million acre-feet in both 2027 and 2028, more than twice the largest reductions required under the current guidelines that expire at the end of the year. Arizona will bear the brunt of those cuts at 760,000 acre-feet per year, with annual reductions of 440,000 and 50,000 acre-feet to California and Nevada, respectively. 

An acre-foot of water is enough to cover an acre of land to a depth of one foot, or about 325,851 gallons. That’s enough to provide three homes in Arizona a year of water, on average. 

The Upper Basin states of Colorado, New Mexico, Utah and Wyoming don’t currently face any government-mandated cuts, and the new federal plan doesn’t prescribe any — a point of contention for the Lower Basin states. 

Becky Mitchell, Colorado’s water commissioner, has been firm that her state already deals with mandatory cuts, but they are imposed by Mother Nature, not the U.S. government. The Colorado River is fed by melting snowpack in the Rocky Mountains, which is at a record low this year. 

The Lower Basin states have been equally as insistent, after decades of decreasing their water use, that the Upper Basin states must agree to government-mandated cuts of at least a small portion of its water in dry years. 

The Lower Basin states have also committed to conserving an additional 700,000 acre-feet of water through 2028, and are still finalizing an agreement that will have to be approved by each state’s legislature. 

But via the federal plan, the Lower Basin and Upper Basin states would have to negotiate new terms every two years for the next decade, after the expiration of the two-year plan that spans 2027 and 2028. Some of the options for cuts in that 10-year plan would be devastating to Arizona. 

“Those reductions could effectively dry up the Central Arizona Project, as well as many of our on-river communities, and would more than double the water cuts agreed to in the Lower Basin Agreement,” Buschatzke said. “Arizona believes that taking this action now provides the best stand forward for protecting Arizona water users.”

The Central Arizona Project delivers Colorado River water to cities, tribes and farms across Maricopa, Pinal and Pima counties — home to nearly 6 million people — and is the primary water source for some communities, including Tucson.

While Arizona initially praised the federal government’s decision to at least temporarily avoid more extreme cuts it proposed earlier this year, Nevada filed a lawsuit challenging the federal plan just days after it was announced. 

Nevada Gov. Joe Lombardo said challenging the federal plan was “a matter of survival” for Southern Nevada, the Nevada Current reported in August. 

The lawsuit requests an injunction to stop the federal plan from being implemented, alleging that it violates the Administrative Procedure Act, the National Environmental Policy Act and the Law of the River. 

In the complaint, Nevada officials said the federal government failed to consider a reasonable range of alternative plans, failed to adequately consider environmental and socioeconomic effects of the plan, and failed to respond to comments from Nevada.

“The challenged agency actions will have direct and potentially catastrophic effects on Arizona,” the state’s attorneys wrote Friday in Arizona’s motion to intervene in the Nevada lawsuit. “They will determine how much water Arizona receives over the next ten years, and they will affect the State’s rights and obligations with respect to the rest of the Colorado River Basin. As one of the seven States that are parties to the 1922 Compact — and as the Lower Basin State that will bear the brunt of supply cuts over the next two years — Arizona has a right to be heard in this case.”

Buschatzke told reporters that Arizona still hadn’t ruled out the possibility of filing its own lawsuit against the federal government if it breaches the terms of the 1922 Colorado River Compact. 

The Colorado River Compact allocated 7.5 million acre-feet for each basin, with an obligation from the federal government to deliver that amount of water to the Lower Basin. 

“We believe that, under the Law of the River, the federal government has an obligation to operate the Colorado River system to comply with the terms of the compact, including the volume of water that, under the law, is supposed to move from the Upper Basin to the Lower Basin,” Buschatzke said. 

Colorado disagrees, with its water officials arguing that the compact was based on a faulty model that assumed the river system could supply 15 million acre-feet annually, when it cannot. 

The cuts and conservation efforts in the Lower Basin are aimed at stabilizing water levels in Lake Powell and Lake Mead, the system’s two key reservoirs, whose water levels fell in July to their lowest point since 1957. 

In an Aug. 19 PBS special on the Colorado River, Brad Udall, a water and climate scientist at Colorado State University, described both reservoirs as being just above deadpool, the point at which water drops too low to flow past a dam by gravity. 

Reaching deadpool would turn those reservoirs into nothing more than concrete basins where water evaporates, he said. 

While the states have all said they would prefer to settle the water agreement outside of court, Buschatzke said it is vital that Arizona weighs in on the Nevada case as it moves forward. 

“We have to have a seat at that table to be able to give Arizona’s viewpoints,” he said.