Historic Colorado River deal not enough to stave off long-term crisis, experts say

A hard-fought agreement between California, Arizona and Nevada to slash the states’ use of the shrinking Colorado River is only a temporary salve to a long-term water crisis that continues to threaten the foundations of life in the American west, experts have warned.

The deal, announced on Monday, between the three states that make up the lower portion of the sprawling Colorado basin will pare back 13% of water consumption from the beleaguered river over the next three years if adopted, averting the prospect of more stringent cuts imposed by the federal government. Backed by $1.2bn in federal funds, the bulk of the reductions are structured to encourage voluntary cuts taken by rights holders, in exchange for grant money.

Now under federal environmental review, the agreement is being hailed as a breakthrough after months of stalled negotiations and missed deadlines. But the emergency intervention will not itself be enough to head off the existential crisis faced by the Colorado River, a result of decades of over-allocation to slake the thirst of a rapidly expanding US west, and it is now caught firmly in the teeth of global heating.

The flow of the river has declined by about 20% since the turn of the century, a period defined by a “megadrought” that is the most severe the west has seen in 1,200 years. The future of a river that supports 40 million people, underpinning the existence of cities from Los Angeles to Denver, and millions of acres of cropland remains precarious.

“This deal is clearly a Band-Aid solution for a short-term fix,” said Katharine Jacobs, an expert in water and climate adaptation at the University of Arizona.

“It’s better than nothing, but we are just putting off a much more dramatic change needed to resolve this problem. The problem we’re trying to solve is just far greater than this. We have a significant shortfall between the river’s supply and demand.”

Jacobs said it is “almost unfortunate” that the US west was deluged by a glut of snow and rainfall over the winter that eased some of the pressure on parched farmland and puddle-like reservoirs, taking some of the onus off negotiators from the seven states – which also include Wyoming, Colorado, New Mexico and Utah – that rely upon the river to agree on more ambitious cuts to confront its long-term decline.

The cuts looked like they would be much tougher last summer, when the federal government said one-third of the river’s annual average flow needed to be saved or it would step in to impose reductions itself.

The warning came as Lake Mead, the US’s largest reservoir, which collects water behind the hulking art deco edifice of the Hoover dam, slumped to a record low level of 1,040ft, revealing dead bodies and sunken boats in its now-desiccated underbelly.

If the lake drops much further, it will not be able to generate the hydroelectric power that millions of people rely on. At an even lower point – 895ft – no water would be able to pass through the dam at all, a disastrous situation called “dead pool” which would essentially cut the water flow to California, Arizona and Nevada.

Scientists have warned that the flow of the river will come under increasing strain due to warming temperatures caused by the burning of fossil fuels, with more water evaporating in the heat and a shrinking of the Rocky Mountain snowpack that nourishes the river at its origins.

The whole basin, which stretches from Wyoming to northern Mexico, is going through a process of “aridification”, in which a hotter, drier state prevails, rather than simply a drought, researchers have warned.

Even without the climate crisis, the Colorado River would probably be stressed. Its allocation is based upon a compact struck in 1922, an unusually wet year, which guaranteed highly optimistic levels of water to states based on a system of seniority (California has always been at the head of the queue).

The apportionment of 17.5m acre-feet of water (an acre-foot is the amount of water that would cover an acre, about the size of a football field, in foot-deep water) a year hasn’t been met, on average, at all over the past century, and during the last two decades of severe drought the shortfall has been stark – less than 10m acre-feet, on average, has flowed through the river each year.

The lower-basin proposal shaves 3m acre-feet off the states’ consumption but the mismatch in supply and demand remains glaring. “This deal does not address the long-term water sustainability challenges in the region,” Dave White, who specialises in water sustainability at Arizona State University, said.

The seven states and the federal government now face the unenviable task of forging a longer-term deal, to last beyond 2026, to bring some sort of stability to the system. Deeper questions may have to be asked about profitable but thirsty crops – like alfalfa – grown in the desert, or the booming levels of housing development happening in water-stressed states like Arizona.

Tempering the growth of the US west in an increasingly punishing climate will probably require fraught compromises, a slew of lawsuits and buckets of compensation – the latest deal will funnel more than $1bn to states, water districts and tribes to offset their lost water. Upper-basin states’ desire to develop their water resource like lower-basin states will somehow have to be managed on a rapidly dwindling resource.

Farmers may be required to fallow land, or shift to different forms of irrigation or even switch crops, but this will require time and money, according to Sharon Megdal, a water policy expert at the University of Arizona.

“Our system requires compensation for taking of property or property rights. You can’t just start with a blank piece of paper and redesign the system – we have to be mindful of that,” she said.

“We need to get to an equilibrium where we use the amount of water nature is providing us. Three million acre-feet probably isn’t enough of a cut but we just can’t let the system crash. This deal at least buys us some time.”

Originally published in The Guardian on May 23, 2023. Gabrielle Canon contributed reporting.