Feds finalize Colorado River plan. Here's how much Arizona will lose

The U.S. Interior Department announced guidelines Friday for dealing with the river’s shortage for the next two years by trimming 1.25 million acre-feet out of the usual allocation of 7.5 million that Arizona, California and Nevada share.

That’s essentially what those states had already offered to surrender over two years, though they have continued to press the four upstream states to commit to their own cutbacks in the following years if dry conditions in the Rocky Mountains continue to deplete the river.

The two-year operating plan closes the first chapter in a 10-year “framework” that the department released earlier this summer — one that could take substantially more water from the three states that pull water from Lake Mead on the Arizona-Nevada state line if reservoir elevations continue to drop.

“These decisions provide a water management strategy for Basin stakeholders to respond to the prolonged drought by incorporating flexible tools and voluntary actions while leaving room for consensus agreements,” Andrea Travnicek, assistant Interior secretary for water and science, said in a statement. “The Department and (U.S. Bureau of) Reclamation will continue to work with all Basin stakeholders to identify areas to maximize efforts throughout the Basin to modernize infrastructure, develop conservation programs, and identify innovative approaches to deliver water under changing conditions.”

Arizona will take the largest cut, 760,000 acre-feet, due to the lower legal priority of its Central Arizona Project supply as compared with California and Nevada. California will lose 440,000 acre-feet a year, and Nevada, with the river’s smallest allocation, will lose 50,000. An acre-foot is about enough water to supply three households for a year.

State 'stands prepared' to protect water rights

Arizona officials have said this outcome would be a short-term win, though they continue to insist that Colorado, Wyoming, Utah and New Mexico must commit to their own mandatory cuts if things worsen. Those states make up the river’s Upper Basin, and they collectively use less from the river than the Lower Basin does.

Without more help from the Upper Basin, though, Arizona has set aside funds for a potential Supreme Court battle to enforce the Colorado River Compact’s 7.5 million acre-foot allocation to the Lower Basin.

Arizona Gov. Katie Hobbs released a statement celebrating the federal government's acceptance of the two-year cuts that the state had offered but projecting a fight if officials come for more in future years without first tapping the Rocky Mountain states.

“I’m glad the federal government has chosen to implement the Lower Basin’s water allocation plan for 2027 and 2028," Hobbs said. "With this plan, we saved Arizona from forced federal cuts that would have crippled our economy and America’s national security."

But the governor said other states' failure to commit to mandatory cuts puts Lake Mead at risk and threatens users downstream of it with greater and unacceptable cuts in future years.

"Arizona stands prepared to protect our water by any legal means necessary and won’t back down in defense of our rights," she said.

Arizona water experts and representatives of cities in the Phoenix area and Tucson have said residents are not at risk of losing tap water under the two-year plan, though the reductions will force cities and other providers to begin dipping into groundwater banks where they have stored previous deliveries of river water.

Feds will adjust flows after winter runoff

Interior's plan specifies that it will seek to protect the minimum water elevation in Lake Powell to allow continued electrical generation at Glen Canyon Dam. Doing so will require paring releases from Powell to somewhere between 6 million and 7 million acre-feet in the coming water year, which begins in October.

Dam managers with the U.S. Bureau of Reclamation will review conditions between now and next spring and adjust flows within that range to keep a buffer at the dam. It means the agency will delay its final annual release determination from the normal decision point in August until next April, after it becomes clear how much water this winter's snowpack can replenish.

Such low releases from Powell, which normally spills more than 8 million acre-feet in a year, will cause Lake Mead to dip closer to its own minimum power pool. But a two-year forecast of water levels that the government released alongside its new guidelines projects that flows as low as 6 million acre-feet would not cause Mead to lose its ability to generate power.

Central Arizona Project General Manager Brenda Burman said the federal plan is flawed because it shifts too much risk from Lake Powell onto Lake Mead.

“Both lakes are in Arizona, and we want them both healthy for our communities," Burman said. "But the framework presented is flawed. Lake Mead should not be sacrificed to protect Lake Powell or other Upper Basin reservoirs, and every state that relies on the river should be part of the solution. The Colorado River needs to be treated as the system it is.”

In a webinar discussing their plans for the next decade, U.S. Bureau of Reclamation officials said the prospect of still-deeper cuts for the Lower Basin after 2028 would only happen with further consultation and only if declining reservoir levels threaten hydropower production and infrastructure at Glen Canyon and Hoover dams.

In a worst-case scenario, the Lower Basin could face 3 million acre-feet of reductions. Officials with the state and the Central Arizona Project have called that amount of reductions "devastating" for its potential to completely drain the CAP canal and even harm Yuma-area farmers with older water rights on the river.

Still, the two-year plan provides some stability and allows time for further negotiations among the states, Arizona Water Resources director Tom Buschatzke said in a statement.

"While the framework for years 3-10 continues to be of concern, we applaud the Department of the Interior for clarifying the decision-making process for operations beyond 2028," Buschatzke said. "That outcome allows for continued negotiations for years 3-10 while preserving our ability to protect Arizona’s legal rights to Colorado River water."

California’s lead river negotiator praised the government’s plan for the first two years, but signaled continued conflict unless the states reach an agreement for later years within the framework.

"This is a bridge, not a permanent solution," J.B. Hamby, California’s Colorado River commissioner, said in a statement. "California, Arizona, and Nevada have shown that states can compromise, make difficult decisions, and reduce water use when the river demands it. But three states cannot carry the responsibility of all seven.”