PHOENIX — Arizona is taking its fight over the future of the Colorado River to court. The Arizona Department of Water Resources announced on Friday that they are joining Nevada's lawsuit against the Federal Government over the new Colorado River cuts.
The legal action comes after years of failed negotiations among seven Western states over how to divide the Colorado River's dwindling water supply.
In August, the federal government finalized a new operating plan for the river that requires Arizona, California and Nevada to reduce their water use, while imposing no mandatory reductions on the four Upper Basin states: Colorado, Utah, Wyoming and New Mexico.
See previous coverage of Arizona's river battle in the video player above
If the states finalize their proposed sharing agreement, Arizona would absorb 760,000 acre-feet of those annual reductions, representing roughly 27% of its full Colorado River allocation.
Arizona officials have argued that the Upper Basin should be required to contribute to mandatory conservation efforts, rather than leaving the Lower Basin to absorb the reductions.
The Upper Basin states maintain that they already use less water when river flows decline and that their legal obligations differ from those of downstream states.
Arizona has been preparing for a court battle
The possibility of litigation is not new.
Arizona lawmakers previously set aside millions of dollars for potential legal action, while the Arizona Department of Water Resources retained outside legal counsel to defend the state's Colorado River interests.
In August, the City of Phoenix lawyered up for a potential lawsuit. In September, the governing board of the Central Arizona Project also authorized its attorneys to pursue legal action under certain circumstances.
Meanwhile, Nevada filed its own lawsuit against the federal government in August, challenging the process used to develop the new operating guidelines.
What does this mean for Arizona?
The outcome will have significant consequences for millions of Arizonans who rely on Colorado River water.
The Central Arizona Project delivers water through a 336-mile canal system to communities, farms and tribal water users across central and southern Arizona, including the Phoenix and Tucson metropolitan areas.
While the federal government's new operating framework took effect October 1, reductions to Arizona's water deliveries are scheduled to begin January 1, 2027.
Even deeper cuts remain possible in subsequent years under the federal government's ten-year framework. The legal dispute adds another layer of uncertainty as Arizona and its neighboring states work to secure a long-term agreement governing one of the West's most important water sources.
