New Colorado River plan locks in big water cuts for Arizona

A new plan for managing the shrinking Colorado River has been announced, and it will mean significant cuts to Arizona's water supply.

The federal government released details of its strategy to rein in demand for the river's water through 2027 and 2028. Arizona, California, and Nevada will be forced to take less, with the most significant reductions landing on cities in the Phoenix and Tucson areas.

Arizona takes the largest cuts

The federal government is reducing water deliveries to the three states by 1.25 million acre-feet each year. Arizona's supply will be reduced by 760,000 acre-feet per year. California's will be cut by 440,000 acre-feet, and Nevada's by 50,000.

The states are also volunteering to cut back more water — at least 700,000 acre-feet total across the two years.

For context, one acre-foot is roughly a year's supply of water for three homes in the Phoenix area, according to the Arizona Department of Water Resources.

Despite the sharp cuts, the state is avoiding even larger ones. In July, the Bureau of Reclamation — the federal agency that manages reservoirs and dams across the West — outlined a plan that gave it the ability to cut water for the three states by up to 40% each year. The cuts announced this week will reduce their annual supply by about 20%.

Most residents won't notice

Utility leaders around Central Arizona have seen these cuts coming for years and have taken costly steps to secure backup supplies. They will turn to stored groundwater, supplies from the nearby Salt River, and a complex web of transfers and exchange agreements to keep even the most vulnerable cities from going dry.

The cutbacks come after state negotiators failed to agree on a plan for managing the river. Representatives from each of the seven states that use the Colorado River had been meeting behind closed doors for years, hoping to find consensus. They were unable to do so, leaving the federal government in an uneasy and unprecedented position.

The plan announced this week is the result of negotiations between the lower-basin states and Reclamation. Andrea Travnicek, Reclamation's assistant secretary for water and science, said the federal government "accepted almost everything" from the lower basin's proposal.

The federal plan does not include mandatory cutbacks from the river's Upper Basin states of Colorado, New Mexico, Utah, and Wyoming, which argue they are already taking de facto cuts in dry, low-snow winters.

Reservoirs at record lows

The new plan is needed because the massive reservoirs that store the river's water have shrunk to record lows. Lake Mead, which straddles the Arizona-Nevada border near Las Vegas, recently fell to its lowest level since it was filled about 90 years ago.

The new plan aims to keep Lake Powell — which straddles the Utah-Arizona border — above 3,510 feet, a margin Reclamation officials say provides more decision space during the prolonged drought.

The previous rules for managing the river expire at the beginning of October. The guidelines announced this week represent the first two years of a 10-year strategy that will replace the expiring one, requiring the states to return to the table and tweak the plan every two years.

Reclamation officials said the agency will spend this fall evaluating water-saving projects that states suggested earlier this year.