With no progress to speak of in the Colorado River negotiations, some water experts are looking to a conservation program — featuring pools of invisible water and some accounting magic — as a possible path forward.
The seven Colorado River states, including Colorado, remain deeply divided over how to manage the nation’s largest reservoirs, lakes Mead and Powell, after the current management rules expire this fall. But other water users have put forward a plethora of innovative ideas for how to manage the water supply for 40 million people after 2026 as the basin’s two-decade drought continues.
One type of conservation program, called a conservation pool, is generating a lot of conversation. Some water experts say it’s the wave of the future. A path toward, finally, some agreement among basin states.
Others say it’s a flawed concept that could hurt economies, especially in rural, agricultural areas.
“They hold great promise. They do incentivize conservation. They do create tremendous operational flexibility,” said Kathryn Sorensen, director of research at Arizona State University’s Kyl Center for Water Policy. “I think people want to see them go forward. They just also know that there’s some things that need to be fixed.”
Under a conservation pool program, water users in Colorado River states would cut back on water use, track the saved water, store it in Lake Powell on the Utah-Arizona border and/or Lake Mead on the Arizona-Nevada border, and use it to help create a more secure water supply in the river basin.
Colorado River officials are worried about the state of the basin. The river’s average flow has declined, and scientists have attributed 10 trillion gallons in water loss to higher temperatures and climate change. Lakes Mead and Powell, which together make up about 92% of the reservoir storage capacity for the entire basin, are each around one-third full.
A pool of conserved water in Lake Mead and Lake Powell could help maintain higher water levels in the reservoirs and defer drastic cuts, Stephen Roe Lewis, governor of the Gila River Indian Community in Arizona, said during an early February meeting.
It could help bring the two subbasins — the Upper Basin and the Lower Basin — closer together in their negotiations, he said.
“In our view, it offers really the only path forward that we can see that addresses the core challenge of risk each basin is facing, and provides a shared tool to manage uncertainty … in the years ahead,” Lewis said.
So how would it work?
So far, the conservation pool concept is half-baked.
There are lingering questions around who can participate in such a program, who would control the pool, how (and whether) people would be paid to conserve, and how the water would be used.
In Colorado, the conservation pool idea would likely start with a water user, say a farmer who grows hay near Kremmling on the Western Slope.
Colorado River water users, like farmers and ranchers, have legal rights to use water for specific purposes, at certain times and from certain places. The legal water-sharing system, called prior appropriation, gives older, more senior, rights priority. In dry years, these senior rights get water first, while more recent, or junior, rights holders might get cut off earlier than usual.
This system, however, doesn’t incentivize conservation, Sorensen said. But conservation pools would change that.
The Kremmling farmer might normally divert 5 acre-feet of water each summer, sending it through rotating sprinklers to saturate soils and grow crops.
One acre-foot is enough to cover an acre of cropland a foot deep, or roughly the annual water use of two to three urban households.
When that farmer joins a conservation program, he or she might decide to cut their use down to 3 acre-feet one summer by not growing crops on certain fields.
The difference, 2 acre-feet, would be “conserved” water, but where does it go? Under the current water-sharing system, it would simply flow downstream, and any downstream farmer could use it on their fields.
This was one of the inherent problems in the Upper Basin’s recent pilot conservation program. In 2023, Colorado farmers and ranchers received almost $1 million to cut their use by about 2,000 acre-feet. In 2024, the estimated cuts totaled about 14,200 acre-feet and the cost was about $7 million.
Under a conservation pool program, Colorado farmers could rest assured that their conserved water would actually end up in Lake Powell.
The problem is that Upper Basin states don’t actually have ways to track that water — yet.
To reach Lake Powell, Colorado and its sister states would need to be able to shepherd conserved water past headgate after headgate, through different water districts and divisions — each with their own systems for managing water — and across state lines before it would reach Lake Powell.
“There are challenges for sure,” said John Berggren, regional policy manager for the healthy rivers department at Western Resource Advocates. “But you can overcome those challenges, and there’s a broader need to, which is to actually stay out of the courts and have an agreement.”
Once water reaches Powell, different groups want it to be used for different purposes. The Colorado River District, for example, says they will only support the idea if the water protects Upper Basin states from forced water cuts that could happen under water law if the basin’s supply falls to extreme lows.
“We do think a conservation program in the Upper Basin could be part of the solution and part of our future, but these programs should be designed and implemented in a thoughtful manner that minimizes and mitigates negative impacts,” said Raquel Flinker, the district’s director of interstate and regional water resources.
Berggren and other environmental groups are pushing for conservation pool water to be used to help Colorado River ecosystems in the Grand Canyon. The dam impacts sediment flow and water temperatures downstream from Lake Powell, which helps non-native fish species thrive and outcompete native fish.
The Bureau of Reclamation could take to their computers and “move” conserved water between Lake Mead and Lake Powell in the accounting books to make more of those releases, he said.
The art of invisible water
Many of the conservation pool ideas aim to keep the water “invisible” when the Bureau of Reclamation decides how much water to release from each massive reservoir.
The conserved water would physically be in a reservoir to keep the water levels from falling too low. At certain elevations, the dams can’t generate electricity or release water for millions of people across the West.
But when Reclamation officials look at the water accounting records, they would ignore the conserved water when calculating how much water to release and what kind of water shortages the basin states could face in dry years.
This approach would address one of the critical flaws in a similar program that has been happening in the Lower Basin since 2007, experts said.
That Intentionally Created Surplus program allows water users in Arizona, California and Nevada to cut their use and keep the water in Lake Mead to be used at a later date. In some cases, they can even divert water from other watersheds and import it into the reservoir, Sorensen said.
One of the biggest flaws of the Lower Basin program was that it artificially kept the physical water levels at Lake Mead higher than they would have otherwise been. Water levels have dictated Lower Basin shortages for the past 20 years, and the higher levels insulated the states from deeper water cutbacks, which delayed steps to adapt to the overstressed water supply in the basin.
The new conservation pools would try to correct this and expand the effort. Upper Basin, Lower Basin and tribal water users could also conserve water and use that water to help flows in rivers, protect infrastructure and many other uses, Berggren said.
“That’s new. We didn’t have that ability before. That’s why it’s innovative,” he said.
The wave of the future?
The Department of the Interior in January laid out five options for managing the river. Three included some form of a conservation pool.
“Conservation pools are the way of the future for the Colorado River Basin,” Berggren said. “They allow for so much more flexibility in managing our reservoirs, managing our water. You’re able to respond to changing conditions quicker.”
Not everyone agrees. The Colorado River District said conserving up to 500,000 acre-feet of water in Colorado and other Upper Basin states, which is proposed in the federal options, would shrink agricultural land use and require water cuts in cities and towns.
“Conservation at this scale would have significant and potentially permanent adverse consequences, including economic impacts to communities,” Flinker of the Colorado River District said.
But — and this is a big caveat — the conservation pool concept cannot move forward without support from all of the basin states.
To set up a conservation pool program, states would need to launch new water-tracking systems. Someone would have to compensate the people conserving water. The way federal officials track, store and release water in the immense reservoirs would change.
And under its current legal authority, the federal government cannot move forward with conservation pools without risking expensive lawsuits that would tie up water management for years. But with a seven-state agreement, the feds could take action.
Arizona and Colorado, which often find themselves on opposite sides of Colorado River discussions, are open to the conservation pool idea.
The concept has merit, Tom Buschatzke, Arizona’s top water negotiator, said during an Arizona Reconsultation Committee meeting Feb. 2.
It is “something we should continue to pursue because I do believe that just formulaic attempts to deal with how you split up the water have been failing us so far,” he said.
Colorado and its sister states in the Upper Basin — New Mexico, Utah and Wyoming — have been consistently willing to do a conservation program that involves saving water in a pool within Lake Powell and potentially other upstream reservoirs, Becky Mitchell, Colorado’s top negotiator said.
“The particulars of the program and potential pool would depend upon the operational framework and/or other components of a seven-state consensus,” she said.