The seven states that share the Colorado River are floating a new concept for how water could be shared in the future, marking forward progress after a long standoff between the Upper Basin and Lower Basin states. 

Officials from Colorado laid out the proposal, which they are calling a supply-driven approach, at a meeting of the Interbasin Compact Committee (IBCC) in Grand Junction on Wednesday. 

The amount of water released from Lake Powell would be based on a percentage of a three-year rolling average of the “natural flow” at Lee Ferry, the dividing line between the Upper Basin (Colorado, New Mexico, Utah and Wyoming) and the Lower Basin (Arizona, California and Nevada). The natural flow is what would flow past Lee Ferry if there weren’t any Upper Basin dams or diversions. 

A supply-driven approach adds a measure of annual variability, meaning that in dry years there would be less water released from Lake Powell and therefore less available for Lower Basin use. Exactly how much of the natural flow would be released to the Lower Basin is one of the big unanswered questions of the concept, still to be fleshed out.

The proposal allows the two basins to set aside (without resolving) long-standing and contentious legal arguments stemming from the 1922 Colorado River Compact. Officials have called it a divorce between the Upper and Lower basin, or as Colorado officials called it, a “conscious uncoupling” that allows the two basins to manage their own water supplies separately. 

“If the Powell release is based on actual conditions, in theory, this should force the Lower Basin to live within a budget, something they have not been doing throughout the course of the ’07 guidelines,” said Amy Ostdiek, section chief of the Interstate, Federal and Water Information Section of the Colorado Water Conservation Board. “And in the Upper Basin, we would manage our available supplies, as we have been doing successfully for a very long time with strict administration of water rights.”

IBCC Chair and lead negotiator for Colorado Becky Mitchell said at Wednesday’s meeting that the supply-driven approach sets a water budget for the Lower Basin based on how much water is available, not on hopes and dreams. Figuring out how cuts would be implemented among the three Lower Basin states is where the real work lies, Mitchell said. 

“This (Powell release curve) is a small part of what the future looks like,” Mitchell said at a Thursday meeting of the Upper Colorado River Commission. “I hope the real discussion in the Lower Basin is about how they distribute the cuts that are coming to them in one way or another in 18 months.”

Since the turn of the century, the Colorado River basin has been locked in the grip of a mega-drought. Exacerbated by climate change and unrelenting water demands, the nation’s two largest reservoirs Lake Powell and Lake Mead have fallen to record-low levels in recent years and pushed river management into crisis mode. 

The current negotiations between the seven states are aimed at replacing the 2007 Interim Guidelines, which lay out how the reservoirs will be operated and shortages shared, and which expire at the end of 2026. The 2007 guidelines set annual Powell releases based on reservoir levels and did not go far enough to prevent it from being drawn down during consecutive dry years.

At Thursday’s UCRC meeting, the U.S. Bureau of Reclamation’s Acting Assistant Secretary for Water and Science Scott Cameron noted two deadlines that the states would need to hit in order to have new guidelines in place by 2027. He said federal officials need to know the broad outlines of a plan by Nov. 11 and details of a plan by Feb. 14, 2026. New guidelines would need to be implemented by Oct. 1, 2026, and Congress would need to enshrine the new guidelines into law, Cameron said. 

“Clearly, they would prefer to have more than a couple of weeks’ notice to get a bill passed to Congress and on the president’s desk,” Cameron said. “So to the extent we can let them know in the early winter what a seven-state deal looks like, if it’s at all complex, they can start writing bill language.”

Federal officials have repeatedly said that if the seven states fail to come up with an agreement, Reclamation will exercise its authority to protect critical reservoir levels. 

Colorado officials said any new agreements must do better than the ’07 guidelines to protect the system and rebuild storage in Lake Powell. The reservoir is currently about 33% full and total seasonal runoff into Powell is forecast to be just 45% of normal.

“There are some real challenges with going into a brand-new operational framework with very depleted storage and very bad hydrologic conditions,” Ostdiek said. “We cannot have operational goals that continue to deplete our reservoirs and continue to have us teetering on the brink of crisis.”

Don’t call it a delivery obligation

Under the new supply-driven concept, the Upper Basin would still be responsible for making sure the agreed-upon percentage of water to be released from Powell makes it there — but Upper Basin officials aren’t calling it a delivery obligation. 

“This is not a delivery obligation,” Mitchell said. “I want to make sure everyone hears that in the room. We didn’t agree to that in 1922 and there is nothing that I will sign that does that. There is also nothing that I will sign that commits the Upper Basin states to mandatory cuts.”

At a June 17 meeting of the Arizona Reconsultation Committee, officials said the Lower Basin will not dictate how the Upper Basin gets the agreed-upon percentage of water to Lee Ferry, but that the Lower Basin will rely on the Upper Basin to perform.

“If this concept comes to fruition, the Upper Basin is going to agree to provide us a certain percentage of the water that Mother Nature provides, and they’re going to have to figure out how to do it,” said Tom Buschatzke, director of the Arizona Department of Water Resources. “Whether that means they’re going to have to reduce their uses; whether that means they’re going to have to move water from Flaming Gorge into Lake Powell — whatever that is — they’re going to have to make that happen.”

For years the Upper Basin states have studied and experimented with various voluntary, temporary and compensated water conservation programs, and the future of Colorado River management will almost certainly include some type of conservation program for the Upper Basin. In an earlier proposal, the Upper Basin states offered up to 200,000 acre-feet per year of conservation in designated savings accounts in Lake Powell. 

There remain two outstanding questions about the supply-driven approach, said Colorado River expert and author Eric Kuhn: What will be the exact percentage of natural flow at Lee Ferry that the Lower Basin is entitled to and what happens if the Upper Basin can’t hit that number. Reclamation staff is currently running the numbers on the new concept.

“There’s a lot of modeling details left to be worked out,” Kuhn said. “I think the sweet spot is when there’s going to be a little bit of pain for the Upper Basin and a whole lot of pain for the Lower Basin.”

Driven by climate change, the amount of water the river provides has been steadily shrinking over the past quarter century, and some climate experts predict just 10 million acre-feet of flows by 2100. The supply-driven concept represents a shift in river management tailored for a hotter and drier 21st century. 

“The bottom line is it’s very positive because they are agreeing to try and divide the water that’s available,” Kuhn said. “It’s not focused on what they had or what was promised to them 50 or 100 years ago.”

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