A decades-long drought and population growth has left the Colorado River over-leveraged and in dire need of a new management plan before the water runs out for millions of Americans.
Negotiations between seven states to reapportion the river’s water have been deadlocked for months, and the federal government is threatening to break the deadlock with its own management plan — whether the states like it or not.
The Department of the Interior has given Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming a deadline to reach an agreement twice, and each time the states blew past it without reaching consensus.
The federal government’s request is unprecedented in U.S. history. The Colorado River supplies water for roughly 40 million Americans. The Bureau of Reclamation has asked the Basin states to cut water usage by about one-third.
The latest deadline passed on Wednesday with six of the seven states agreeing on a plan to cut water usage, with only California dissenting. The Golden State put forward its own plan emphasizing its priority rights over the Colorado River that have been a part of the legal framework governing the basin for a century.
The lack of consensus increases the chance that the Bureau of Reclamation will devise its own plan and force the basin states to follow it whether they like it or not. The bureau needs a plan soon in order to model the water level of the river and its reservoirs and complete an Environmental Impact Statement (EIS) on the basin. The EIS will inform the Department of the Interior’s long-term water management strategy.
The Colorado River has been governed under the same rough legal framework of water apportionment for the past 100 years, though it has been updated as new infrastructure has been added and court cases have been settled. The body of law that governs the basin is collectively known as “The Law of the River.”
The cornerstone of that legal framework was set in 1922 in an agreement called the Colorado River Compact. The agreement divided the basin into upper and lower halves and guaranteed each 7.5 million acre-feet of water from the river. The Mexican Water Treaty of 1944 allotted 1.5 million acre-feet of the Colorado River to Mexico. One acre-foot is about the amount of water two or three households use in a year.
The upper basin, where the Colorado River originates, consists of parts of Colorado, New Mexico, Utah, and Wyoming and is above the river’s two reservoirs: Lake Powell, behind Glen Canyon Dam, and Lake Mead, behind Hoover Dam. The lower basin states – Arizona, California, and Nevada – are located roughly below the reservoirs and can pull from them, whereas the upper basin must rely on the river’s natural flow.
The 1922 agreement that set out the apportionment for the upper and lower basins may always have been too optimistic. The compact estimated the Colorado River’s annual flows at 17 million acre-feet. In the century since, the river has averaged about 12 million acre-feet annually. The compact, we now know, was drawn up during the river’s wettest season in the past 500 years, according to Shawn Regan, vice president of research at the Property and Environment Research Center.
In addition to poor planning and population growth, the river is under stress from an extended drought that has beat down on the American West for over two decades. A study published last year suggests that the West is the driest it’s been in 1,200 years.
“In the Colorado River Basin, the period from 2000 through 2021 has been the driest 22-year period recorded in more than 100 years of record-keeping,” Tanya Trujillo, an experienced water lawyer and Interior’s assistant secretary for Water and Science, told Congress in 2021. “The reservoir system was 95 percent full in 2000, but as of September 28th, Colorado River system reservoirs sit at just 39 percent, the lowest levels since they began to fill.”
The water level has continued to drop since Trujillo’s testimony. The strain is evident in the Colorado River basin’s two major reservoirs. Lakes Powell and Mead are both at all-time lows. Lake Mead, in particular, has made a number of ghastly headlines over the past year as its water level has dropped, revealing sunken ships and bodies weighted and sunk to its lake bed.
Officials across the seven states fear what could happen as each reservoir approaches two low-water benchmarks, each of which would have severe consequences.
The first and highest benchmark is known as the minimum power pool elevation: the level at which the lakes need to sit in order for their dams to produce hydropower.
The Glen Canyon and Hoover dams produce power for millions of Americans. Should that power be cut off, the worst effects could be mitigated by siphoning power from other parts of the U.S. electrical grid.
The scenario officials are seeking to avoid at all costs, which would likely have catastrophic effects, takes place at the lower benchmark, a condition known as “dead pool.” If the reservoirs reach dead pool status, no more water can flow downriver from the lakes. The effects would be disastrous for cities such as Los Angeles, which gets half its water from the Colorado River, and Las Vegas, which gets 90% of its water from the Colorado.
Despite the urgency, officials across the seven states have not been able to agree on a way to collectively cut down water usage from the Colorado by two to four million acre-feet as the Interior Department has requested. The brunt of the responsibility to cut has fallen on the lower basin states. The upper basin states are only pulling about half their legal allotment of water because the drought has crippled the river upstream.
The lower basin states cannot agree on how to implement the cuts. The two sides on Wednesday clashed to a large extent on California’s insistence that priority water rights, a feature of the current legal framework that give priority to claims to the Colorado River’s water made earlier, still apply.
“[D]espite big disagreements about how to approach this, we have unanimity among all seven states that very deep cuts in Lower Basin water use are needed,” University of New Mexico professor and Colorado River expert John Fleck wrote Wednesday. The two sides both presented plans based on cuts that scale up as the water level in Lake Mead falls.
“The difference is in timing,” Fleck wrote. “California’s cuts don’t kick in until later – essentially a gamble on good hydrology once again helping us avoid conflict by letting us use more water in the short term.”
Officials in Arizona, which has the second-largest water usage in the lower basin behind California, recognized California’s legal claim, but said the approach simply is not realistic.
“If you want to model cutting off most or all of the water supply of 27 million Americans, you can go through the exercise but implementing that on the ground would have the direst consequence for almost 10% of the country,” Southern Nevada Water Authority general manager John Enstminger told CNN.