© Joshua Lott/The Washington Post
Water flows through Navajo Canyon.

The Biden administration on Tuesday moved closer to imposing unprecedented cuts in how much water Arizona, California and Nevada could pull from the Colorado River, while raising the possibility that these reductions could be distributed in ways that contradict long-standing water rights that favor powerful farming regions.

In releasing a new environmental review of how to operate the Colorado River’s major reservoirs, the Interior Department detailed the painful dilemma facing the American West after a two-decade drought and chronic overuse.

Interior officials also defended Secretary Deb Haaland’s right to make cuts in a proportional way in times of emergency even if that goes against water rights held by farming communities from more than a century ago.

Over the past year, the seven states of the Colorado River basin have been unable to reach an agreement among themselves to make major cuts to protect the reservoirs. The federal government expects to make a decision on how reductions could be distributed by August.

Amid the tables of numbers and technical jargon in the draft environmental review, the three options the Interior Department proposes for consideration expose the stark decision in the coming months. One option would strictly follow water rights and give priority to farming regions in California, such as the Imperial Valley, that stock supermarkets across the country with winter vegetables — while letting a large part of the water supply of Phoenix and Los Angeles “get taken virtually to zero,” as Interior Department Deputy Secretary Tommy Beaudreau put it in an interview.

Another option would distribute up to 2 million acre-feet of cuts in water usage — more than 15 percent of the river’s average flow over the past two decades — in the same percentage across all users in Arizona, California and Nevada. That would be different from how cuts have been distributed in the past.

Both federal and state officials have warned that the third option, changing nothing, would be the worst of all. That’s because climate change and the drying of the West have put the reservoirs of Lake Powell and Lake Mead — the water supply for tens of millions of people — on a path toward falling so far that the dams could no longer produce hydropower, or even hit “dead pool,” when water would effectively be blocked from flowing to the southern states.

If no action is taken, “we can expect water levels to continue to decline, threatening the operations of the system, and the water supply of 40 million people,” U.S. Bureau of Reclamation Commissioner Camille Calimlim Touton said Tuesday from a conference room at the Hoover Dam.

Through the windows behind her, the bleached “bathtub ring” on the hillside above Lake Mead was clearly visible — a reminder of how far the reservoir, now about a quarter full, has fallen over the past two decades of drought.

“Some may believe that this winter’s snow and rain has saved the river, but that is not the case,” said Tom Buschatzke, director of the Arizona Department of Water Resources. “We have a lot of hard work and difficult decisions ahead of us in this basin.”

State officials expressed the desire for all seven Colorado River basin states to reach an agreement over the next few months and avoid the need for the federal government to impose cuts unilaterally. Federal officials described the two alternatives they laid out — strictly following water rights, or making cuts of the same percentage across California, Arizona and Nevada — as “bookends” on a spectrum, giving state officials direction to seek compromise in between.

“It gives us the framework … on which we can build and perhaps find something that is partway between those two bookends,” said Estevan Lopez, New Mexico’s representative on the Upper Colorado River Commission. “I think that’s our challenge right now.”

The goal of the document is to assess potential rule changes for how water is released from Lake Powell and Lake Mead to protect these reservoirs from falling below what is known as “minimum power pool.” That’s the point at which the Glen Canyon and Hoover dams can no longer produce hydropower because there is not enough water to flow through the turbines safely. These reservoir elevations — about 3,500 feet above sea level at Lake Powell and 950 feet at Lake Mead — will be the thresholds that the federal government is working to avoid. Lake Powell stands just 20 feet above that level and is less than a quarter full.

“Our fundamental assumption is we’re protecting the system and we’re not going to allow shortages to bring the system below those elevations,” Beaudreau said.

The unusually wet and snowy winter in the West has eased some of the most dire predictions for immediate cuts. The 2.083 million acre-feet ceiling on cuts that the environmental review establishes is at the low end of the 2 million-to-4 million acre-feet range that Touton, the Bureau of Reclamation commissioner, called for last summer.

Beaudreau said that he was “comfortable with that number” and that it would be the “outer bounds” of what the federal government would consider cutting heading into next year. It also gives the seven states of the Colorado River basin something to shoot for, he said, as they develop programs to conserve water by paying farmers not to plant crops and making other improvements to improve the efficiency of irrigation.

An acre-foot is about 326,000 gallons, what it would take to cover an acre of land with a foot of water.

The Biden administration has set aside billions of dollars from new legislation to fund payments for drought resilience and to encourage such water savings. The more cuts to water usage that can be made voluntarily within the states would reduce the amount the federal government might impose unilaterally.

In some ways, the options presented in the environmental review mirror the proposals that the seven basin states have been wrestling with this year.

In January, six of the states — Arizona, Nevada, New Mexico, Colorado, Utah and Wyoming — agreed on an approach that would make major cuts in a proportional way among states. That would hit California farmers in places such as the Imperial Valley — who suck up a lot of the river and have rights to it that predate some cities — particularly hard.

California, the largest user of Colorado River water, rejected that approach, and called for cuts that adhered to water rights priority. The plan would be devastating to Arizona, state officials there say.

© Matt McClain/The Washington Post
The Central Arizona Project that diverts water from the Colorado River is seen on Tuesday August 31, 2021 in Maricopa County, AZ. Water restrictions for some Arizona users have gone into effect.

The states have so far failed to reach an agreement on voluntary cuts.

But Tuesday’s environmental review also establishes a different way to justify the reductions. The six-state plan rationalized departing from a strict adherence to water rights by attributing some 1.5 million acre-feet of cuts to evaporation and other losses as water travels down the canals from the major reservoirs.

But the federal government’s second alternative — the one for proportional cuts — is based not on evaporation but on Haaland’s legal authority to protect the river.

“In our mind, the appropriate presentation is grounded in the secretary’s authorities to provide for human health and safety, manage the system under emergency conditions, and provide for beneficial use,” Beaudreau said. “It is the secretary’s responsibility, and she has the authority, to protect the system.”

Haaland’s authority could be at issue if states decide to bring lawsuits challenging the federal government’s decision. The threat of litigation has hung over this process from the beginning, and many worry that a prolonged legal battle would delay taking action and let the reservoirs continue to fall.

“We have to avoid that outcome,” said Buschatzke, with the Arizona Department of Water Resources. “Litigation that might take 10 or 15 or 20 years is going to be occurring while the system and the lake behind us is going to crash.”

Colorado River Board of California Chairman J.B. Hamby, who is also a board member of the Imperial Irrigation District, said California is “looking to develop a true seven-state consensus” over the next two months.

While the Interior Department did not say which option it preferred, Beaudreau acknowledged that “nobody’s advocating” for the path that strictly follows water rights seniority and would cut off major cities such as Phoenix and Los Angeles from big portions of their water supply.

“Even California would say that’s not what we want,” he said. “But we think analytically it’s important to show if you just follow strict priority and you had to cut 2 million acre-feet out of the system, this is what would happen.”

Now that the environmental review has been published, a public comment period will last for 45 days. Haaland is expected to choose an option this summer. By August, Lake Powell and Lake Mead will have new rules for how much water comes out of the dams and flows to the Southwest.

“We’re on a little bit of a merry-go-round. We got to get off the merry-go-round. We need to have an outcome,” Buschatzke said. “I think we lose confidence of the public if they don’t see us taking major steps, creating an outcome in which we are stabilizing the system for a long time out into the future.”