The seven U.S. states (including California) that get their water from the Colorado River could be looking at severe water supply cuts, as the Colorado River is shrinking prodigiously, potentially setting up both a water crisis and an electricity crisis.

On a state of California level, this year’s practically biblical storms have meant the end of drought conditions in much of the state. But in the larger western U.S., the rains that hit the west coast were nowhere near enough to make up for what is now more than a 20-year drought.

That’s where the Colorado River comes in. The Colorado River is not just in Colorado, it stretches nearly 1,500 miles through the U.S. and part of Mexico,  and it’s a significant source for the water supply in California, as well as Arizona, Colorado, New Mexico, Nevada, Utah, and Wyoming. The river also provides agricultural water to some five million acres of farmland. Additionally, the electricity generated by dams at Lake Mead (Hoover Dam) and Lake Powell (Glen Canyon Dam) relies on the flow of the Colorado River, and keeping the power on for millions of Americans relies on that river flowing. Right now, despite the winter's rains, the river's flow is down by a third, and turbines are at risk of being unable to generate electricity.

That’s why it’s major news that the U.S. Department of the Interior is proposing unilateral restrictions on how much water California, Arizona, and Nevada can take from the Colorado River, as the New York Times reports. All seven states could be rationed much less water than they’re used to getting, but the Times reports that California, Arizona, and Nevada could see their Colorado River water supply cut "by as much as one-quarter,” and that “The size of those reductions and the prospect of the federal government unilaterally imposing them on states have never occurred in American history.”

The Interior Department is "showing that they will tell the states what to do," University of Arizona Water Resources Research Center director Sharon Megdal tells the Times. "It will now be up to the states to say, well, we have a better idea — and here it is."

CNN adds that “major Western cities – including Los Angeles, Las Vegas and Phoenix – would take the vast majority of the water cuts,” under one proposal being considered.

These are not final decisions, but instead a draft analysis that lays out different scenarios, and possible ways to effectively divvy up the reductions, water cuts, and general pain. According to CNN, “The Interior Department is expected to make a final decision on the cuts – and how and when they would be implemented – later this summer.”

In terms of established water rights, California has the most seniority among those states, and Nevada and Arizona has less seniority and fewer water rights. But the Interior Department argues, in the words of the Times, that “the shocks of climate change couldn’t have been predicted when those rights were agreed to decades ago.”

And there are political implications. Of the three states facing the most severe cutbacks (California, Arizona, and Nevada) California is completely in the bag for Democrats in every presidential election, while Nevada and Arizona are swing states. So that’s likely to come into the Biden administration’s calculus. Though the Times also points out that Arizona has a possible ace in the hole, because many of the Native American tribes there have water rights guaranteed by treaty. (And there may be some overdue scrutiny applied to the practice of selling water to Saudi Arabia.)  

California has the most senior rights to the river's water, and, arguably, Arizona has been allowing growth to happen in its cities without regard for future availability of water. (One local Arizona battle was afoot in January and made national news, as the town of Rio Verde Foothills was completely cut off from its water supply by the city of Scottsdale.) As the Times reported in January, the conflicts between the two states that rely most heavily on the river's water, Arizona and California, seem destined to land in the courts — and legally, California is on stronger footing, because of those water rights agreements from a century ago. Also, California is home to farms that produce a huge chunk of the nation's food supply, and they need the water.

The seven states could all ultimately come to some sort of an agreement, and the Interior Department may be floating drastic scenarios hoping to encourage that. Though it would not be surprising if this all does get hashed out acrimoniously in lawsuits.

And the federal government has been trying to facilitate that compromise, but two sentences in the Times report gives good insight into battle lines being drawn there.

As that paper notes, “Last fall, the [Interior] department again asked the states to come up with a plan. In January, six of the states — all but California — reached an agreement: They proposed that the bulk of the cuts come from California.”

Related: Newsom Declares Drought Emergency In Sonoma and Mendocino Counties [SFist]

Image: Charles Wang via Wikimedia Commons