Click the link to read the article on the Big Pivots website (Allen Best):

November 3, 2026

Brad Udall remains hopeful a settlement will be negotiated but warns that huge changes will be needed in response to climate change. Might prior appropriation be one of them?

Colorado State University’s Brad Udall makes the case that the Colorado River Basin is the world’s first place where climate change is “forcing a complete redo of water management.”

The climate change component of that statement seems unassailable. Flows in the Colorado River have declined 21% this century. A river that averaged 15.2 million acre-feet in flows during the 20^thcentury has fallen to 12.2 million acre-feet in the 21^st. It has further tapered off to 10 million acre-feet in the last few years.

Temperature increases of 3.3 degrees Fahrenheit since 1970 explain much of that decline. A one- degree Fahrenheit rise in temperature results in 5% loss due to increased evaporation. “Hot drought,” the phrase Udall favors, will only worsen, he says, as the process he and others call aridification will continue to worsen. Temperatures, said Udall at a recent forum, can continue to rise.

“The latest science tells us that the rate of warming has almost doubled. And the fossil fuel industry is showing no signs of exit or no signs of transformation to some other business model that doesn’t involve polluting the Earth,” he said.

Existing greenhouse gas emissions will, he added, continue to incrementally heat the Earth into the 22^nd century even if humanity can reduce greenhouse gas emissions to zero.

As for the water management redo, it’s still early. Colorado River runoff has been in decline for the last quarter-century. California and Arizona, the two lower-basin states with great thirst, were able to live off water banked in the two giant reservoirs, Mead and Powell, for many of those years. Only as the storage has ratcheted down to dangerously low levels have meaningful reductions in use begun, some only temporary in nature but others permanent.

The two states plus Nevada last year used about 6.8 million acre-feet from the river, less than the 7.5 million apportioned them the Colorado River Compact of 1922 and far less than the 8.5 million acre-feet they had averaged for several decades.

Upper-basin states had also been allotted 7.5 million acre-feet by the 1922 compact, but they have never come close to using that much water. Lacking the certainty of large upstream reservoirs, they have used about 4.5 million acre-feet.

Big cuts ahead

But big changes necessarily lie ahead, certainly for the lower-basin states but also Colorado and the other upper-basin states, Udall said in in a recent 90-minute plus presentation called “Dancing with Deadpool: a 27-Year-Long Colorado River Crisis.” The forum in Jefferson County was sponsored by the Colorado Renewable Energy Society and New Energy Colorado.

“We gotta get rid of those old agreements,” said Udall, the senior water and climate research scientist/scholar at Colorado Water Center.

“We in the Upper Basin must share this risk and not increase our use. The Lower Basin needs to plan on bigger cuts, more than 3 million acre-feet,” he said, citing a paper he co-authored called “What will it take to stabilize the Colorado River?” that was published in 2022 in Science. In addition, he wrote a related paper along with New Mexico’s John Fleck that iin 2021 was published in Science.

“Ag has to bear the brunt of the cuts, because they’re 75% of the use, but M and I have to help,” he said, referring to agriculture, municipal and industrial.

Strong disagreements exist between the two basins, upper and lower, beyond a general agreement to cut 1.2 million acre-feet in use. “The lower Basin really wants the Upper Basin to share, maybe on the order of 200,000 acre-feet a year, maybe 5%. And the Upper Basin says no way, and until recently has said we’re going to even increase our use. “

Amidst all this, the claims of the 30 or so tribes in the basin need to be resolved. A 1907 Supreme Court ruling found that when the U.S. government ordered Native Americans onto reservations that it guaranteed them the water necessary to be farmers. They control about 25% of the water with some claims, importantly those of the Navajo Nation, still in question. “Tribal water is a really big deal,” said Udall.

And Arizona, he said, with two-thirds of tribes, has a disproportionate burden of figuring out how to satisfy rights of the tribes while making everything else work reasonably well, too.

Arizona, he emphasized, is “central to the problem and central to the solution.” The Central Arizona Project will necessarily get less water, but it will not be zero, he added.

As for the unprecedented low river flows — and unprecedented high temperatures — of the 2025-26 water year, he predicted “it won’t be the last time we see this. When it comes back, it’ll be worse.”

As Udall spoke those words, it was raining hard in Colorado’s San Juan Mountains, water that helped raise the water levels of Lake Powell by about 15 feet going into November compared to a mid-September low. Still, Powell was little more than 25% full. The Colorado River problems go far deeper than can be solved by even an extraordinary storm cycle.

“True,” said Kathryn Sorensen, director of research at Arizona State University’s Kyle Center for Water Research, responding to a New York Times story posted today,  “but they’ve helped pull us from the brink at Lake Powell, doubling or perhaps tripling the amount of realistically accessible storage there.”

Prior appropriation

Many analyists have concluded that the doctrine of prior appropriation, the legal structure for determining who gets how much water and when, must be modified. It is commonly called first in time, first in right.

The lower basin has roughly 100 diversions, nearly all very large and many of them administered through use of federal infrastructure. There, this principle is less important than in the upper basin, which has thousands and thousands of diversions, many small. Even so, it is the basic principle that allows California a bigger ladle for the Colorado River than Arizona. Arizona got in line as a result of federal legislation in 1968, the Colorado River Basin Project Act.

That law stipulated that water for the Central Arizona Project would be subordinate to California’s 4.4 million acre-foot annual allocation in case of  shortage.

Prior appropriation “doesn’t really fit with the 21^st century,” said Udall. He described it as a “winner take all” legal system developed in the 18^th century by the farmers and miners who were the first colonists of Colorado and other parts of the West.

“You know, first in time makes first in right,” he explained. “And I argue all the time that 4-year-olds around the globe discover this rule every day. ‘It’s mine. I was here first.’ And most parents step in and say, ‘No, no, you need to share that.’ That’s the system we have. And some people now own vastly expensive water rights because of this, and we’re not going to overturn it.”

The doctrine did, he conceded, make sense in the 20^th century. “If you were a junior water right holder, you could actually develop resilience and firm that water right by building storage, so that in really big years you’d capture some water. And then, in the low years, when you weren’t entitled to any water, you’d use your storage to make up that deficient. Well, in a climate change world, that strategy now becomes next to impossible to deal with. Because we don’t have these big years to fill up your reservoirs.”

The doctrine is “embedded in how the Colorado River works, including the Central Arizona Project and its junior status to California,” he continued. “Agricultural rights are generally senior to cities, and … this creates problems because you end up potentially with a situation where Denver could get called out by agricultural water rights on the West Slope” of Colorado, especially those ag rights with appropriation dates prior to the Colorado River Compact.

“I’ve been arguing that we can’t have 1,500 farmers depriving 20 million people in California and 7 million in Arizona and 2 million in Nevada and 2 million in Colorado with these senior rights,” he said.

In 2010, working with Jonathan Overpeck, a researcher then affiliated with the University of Arizona (and now Michigan), Udall had begun to warn of dry times ahead. In a paper published in 2017 by Water Resources Research called “The twenty-first century Colorado River hot drought and implications for the future,” they predicted 20% losses in river flows by mid-century and 35% by end of century. Those, they said, were conservative estimates.

The backstory is that for nearly a century the Colorado River Basin states — importantly abetted by the federal treasury — had created the infrastructure that assumed far more water even than what optimistically was assumed by the Colorado River Compact of 1922.

Deep family history

Udall brings to the Colorado River discussion perspectives informed by his unusual circumstances.

“I’m a great -great grandson of John D. Lee, the founder of Lee’s Ferry,” Brad at his presentation on Oct. 22. “You might think that’s kind of special. Turns out Lee had 21 wives, and there’s a chance he had 800,000 descendants, which might in fact be part of the problem right now.”

A long-time resident of Colorado, Brad grew up in Arizona, the son of Morris Udall, who represented Arizona in the U.S. House of Representatives from 1961 to 1991. His uncle Stewart Udall had represented the same district before becoming the secretary of Interior in the Kennedy and Johnson administrations from 1961 to 1969.

In other words, Udall’s relatives were involved in creating at least some of the agreement infrastructure that now looks ill-advised. That includes the Central Arizona Project, which delivers Colorado River water via a system of canals and pipes that pumps water up 3,000 feet in elevation and across 336 miles to Phoenix, Tucson and farms between. Even then, during the debate in the 1960s, Mo Udall and other supporters realized the Colorado River would not have sufficient water. They were betting that water could be imported, such as from the Snake River in Wyoming’s Jackson Hole. That never flew.

Alex Hager, formerly a reporter in Colorado for Greeley-based KUNC, probed the history in a story for KZJJ in Arizona title “Arizona’s lifeline to the Colorado River is drying up. Were warnings from history ignored?”

“I think Stewart and Mo sort of blew it on some of this,” Brad told Hager. But he also counseled some compassion. They had grown up on a farm in Arizona during the Great Depression. By the time they came to power after World War II, an era of booming national optimism may have colored their political thinking.

“The 1968 idea was we could build our way out of anything,” Brad said. “We could engineer our way out of every crisis. We’re smart. We’re rich. The world’s our oyster.”

Udall gives many slide shows, each building on the last one. The best of them need at least an hour to deliver, because the story is that complicated. This was the third presentation by Udall heard this year by this writer. Unlike some others, though, this audience consisted of people most attentive to the energy transition. To his credit, Udall was able to craft his presentation in a way that did not require vast knowledge of the arcane world of water. He did this without sacrificing details.

Udall sees himself as a truth-teller with an unpleasant message. “As a scientist, I kind of feel like it’s my job to tell people how it is. And if I can tell it with a little humor and a smile on my face, even if it’s a tough message, maybe they’ll hear that message,” he said.

The truth he sought to share was the need for great changes in how this declining source of water is shared by 40 million people — changes necessary very, very soon. Those changes will likely include Colorado and other headwaters states, probably an agreement to conservation measures that reduce use by 2% to 5%.

Important, he said, will be better accounting of volumes of use in the upper-basin states. Lacking hard numbers, it’s hard to judge equities. The counter argument has been that Colorado, in particular, has so many small users that this accounting poses an extremely difficult challenge.

What also must be noted is that Udall’s critique inevitably is easier to deliver than setting out a precise outline of what this new future must entail. That, of course, likely would have required another hour or more.

“I still think we’ll get a negotiated solution,” he said as he wrapped up his presentation. But then he added an asterisk, referencing the lawsuit filed by first Nevada in August, then joined by Arizona in October, challenging the federal government’s order for cuts in water use. “Although every day these lawsuits continue I get more depressed,” he added.

After Udall’s presentation, in the cafeteria where munchies were delivered, I heard one listener who suggested that Phil Weiser, when governor, might consider making Udall the representative of Colorado on the Upper Colorado River Commission. That is not a rap against Becky Mitchell, the current representative, who by all accounts has represented Colorado well in the difficult discussions. It is, though, an interesting idea.

Following are a few more highlights:

Fuzziness of 1922 compact

The 1922 compact has several fuzzy components, most troubling being what was meant in Article 3D, the non-depletion clause, which says the upper basin states “will not cause” the flows at Lee Ferry to drop below 75 million acre-feet across every rolling 10-year average.

“In the 20^th century, there was only one way for that number to fall below 75 million. acre-feet, and that was if the basin used the water. But in the 21^st century, we have a second way for those flows to fall below 75 million acre-feet, which is climate change, of course, and no one knows what this (delivery obligation) means,” said Udall.

Too, the compact “totally excluded tribal water rights, despite a critically important Supreme Court decree in 1908 (Winters Doctrine), saying that tribes were entitled to water.”

As for the abundance of annual flows in the river, “They actually thought in 1922 that they were going to come back in 1962 and allocate a whole bunch of water because they hadn’t allocated all of it.”

On deadpan

“There would be real harm if we hit deadpool. I mean, there would be a lot of people hurt. You hit Deadpool, you turn control of these reservoirs over to Mother Nature, away from us, and that’s a fundamental mistake.”

Getting into the mess

“We’ve made a whole bunch of mistakes through time,” he said. “We allocated water permanently. We assumed too much water. And there are a whole bunch of unrealistic policies. We now have a solution in sight for the next two years, but it will not be enough. And litigation (Nevada and now Arizona suing the federal government) just announced clouds what might really happen.”

Musical chairs

While the compact apportioned 7.5 million acre-feet to the upper basins states, they have never used more than 5.5 million acre-feet and mostly have stuck to around 4.5 million ace-feet.

“They feel like they’re still entitled to it, but it’s also a little bit of a game of musical chairs, right? I mean, the music stopped here, and because you never grew into that, it’s really hard to figure out how you possibly can use more given the facts on the ground., We’re sitting on a 2 million acre-feet per year imbalance.”

An acre-foot

An acre-foot is 325,000 gallons of water, enough for 10 people for a year. In the upper basin, a farmer might put one or two acre-feet of water on top of a field to get a crop of hay in the summer. In Arizona and California, where it’s hot, they might put 10 feet on top of their field to get 10 different cuttings of alfalfa.

The big reservoirs

In January 2000, Powell and Mead were about 95% full, with 47 million acre-feet. In August 2026, they were 24% full.

No analog

Our high-flow years on Colorado River are now half as frequent, and our low-flow years are about two and a half times as common. “The take-home here is that there’s no analog in the 20^th century to what we’re seeing now,” he said.

Colorado, the headwaters

Of the water that originates in Colorado, 90% flows out of the state.

Click the link to read the article on the Aspen Journalism website (Heather Sackett):

October 27, 2026

Colorado water managers say a state-run conservation program planned for 2027 is in jeopardy as they wait on an agreement with federal officials.

Before they open the application period for a new conservation program, state officials want assurance from the U.S. Bureau of Reclamation that conserved water they store in Lake Powell won’t just be released downstream for Lower Basin use.

In September, the state water board approved the application review process and criteria for what state officials are calling Colorado’s near-term contribution program for 2027. The program aims to use nearly $100 million in funding from Reclamation to pay water users in the Upper Basin states (Colorado, New Mexico, Utah and Wyoming) to voluntarily cut back.

But that approval depends upon whether Colorado can get credit for and have control over the stored water. State officials said repeatedly at an Oct. 21 meeting with the Colorado River Water Conservation District that they need assurance in writing from Reclamation that the pool of stored water must be “operationally neutral” — meaning it would not be factored into reservoir releases or used by the Lower Basin — before they move forward with a state-run program.

Amy Ostdiek, interstate section chief with the Colorado Water Conservation Board, state engineer Jason Ullmann and Becky Mitchell, the Upper Colorado River Commission’s Colorado representative, fielded questions from River District board members.

“Essentially, we don’t want to move forward with any of this process with opening the application window, going through all of this, unless and until we have that assurance from Reclamation that this water is not simply going to be released downstream,” Ostdiek told River District board members.

Federal officials say operational neutrality for a conservation pool in Lake Powell will require approval from the Lower Basin states (California, Arizona and Nevada). At a UCRC meeting Oct. 19, the Upper Basin states approved a grant implementation agreement, which allows Reclamation to administer the contribution program grant money to the states.

But according to a prepared statement by Wayne Pullan, Reclamation’s Upper Colorado Basin regional director, the grant agreement “does not establish any new terms for how conserved or contributed water will be credited to the system or subsequently released — that will require a separate process and agreement, as well as consensus among the seven basin states.”

The new two-year federal operating plan for the Colorado River, which was adopted in August, calls for 1.25 million acre-feet of mandatory cuts among the Lower Basin states and annual Lake Powell releases between 6 million and 7 million acre-feet. It also includes the possibility of up to 200,000 acre-feet of Upper Basin voluntary conservation. But beyond this basic framework, many details of operations and programs are left to be hashed out in separate agreements between the states and Reclamation.

Time is running out to get a conservation agreement in place before the 2027 irrigation season. According to the timeline given by state officials, the application window was supposed to be October and November, followed by an evaluation and approval process that would have contracts with participants in place by spring. The Upper Colorado River Commission sent a letter to Reclamation officials in September saying that operational neutrality was essential to the success of a program. Officials say they have not yet received a formal response.

“I’m optimistic that the Upper Division states and Reclamation will develop an appropriate agreement that meets everybody’s needs,” said Chuck Cullom, executive director of the UCRC. “What I am concerned about is how timely that agreement can be developed to support 2027 programs.”

River District General Manager Andy Mueller said the district backs state officials and supports the decision not to open the application process without a written agreement from Reclamation. The River District protects water interests across 15 Western Slope counties. Although the conservation program would be open to anyone in the state who uses water from the Colorado River Basin, it’s understood that most of the conserved water would come from Western Slope agriculture, as it has in previous pilot programs.

“Don’t run the program next year if you can’t run it well, if you can’t operate it in a way that protects the values and interests of our communities and agricultural industries,” Mueller told state officials. “Please don’t do it halfway. Don’t do it too late. Don’t let the federal government’s refusal to act in a timely way damage the communities that these folks represent.”

Delay could mean low participation rates

Last week’s discussion came as the federal government has taken over Colorado River operations and management of the nation’s biggest reservoirs after the seven states that share the river could not find agreement after years of failed negotiations.

Upper Basin water managers have long pointed fingers at their Lower Basin neighbors, saying their overuse was responsible for driving the system into crisis. They want to make sure that any water saved through conservation in the Upper Basin won’t simply be released downstream to be used by the Lower Basin. Precisely what the conserved water will be used for is still unclear and is one of the issues that remain to be figured out in an agreement between the Upper Colorado River Commission and Reclamation.

From 2019 to 2021, Colorado explored what officials called a demand management program, which would have allowed the Upper Basin states to conserve up to 500,000 acre-feet in a pool in Lake Powell. In that case, the water could have been used to help the Upper Basin states meet their water-delivery obligations to the Lower Basin under the terms of the 1922 Colorado River Compact.

But in recent years, officials have been talking about a conserved pool of water being used to boost Lake Powell levels to protect critical infrastructure and maintain the ability to produce hydropower at Glen Canyon Dam. Some experts say flexible, operationally neutral pools could protect Glen Canyon Dam infrastructure, minimize the need for large releases from upstream reservoirs and reduce the risk of litigation among the seven basin states that share the Colorado River.

“Reclamation’s priority remains balancing water-delivery obligations and protecting critical infrastructure at Lake Powell,” Pullan said at last week’s UCRC meeting. “And protecting critical infrastructure at Lake Powell means staying above elevation 3,510.”

Anne Castle, a Colorado River expert and former federal representative to the UCRC, explained why the Upper and Lower basin states might have different views on operational neutrality. Under the federal guidelines for reservoir operations the amount of water released from Lake Powell each year is based on how much water is in the reservoir. When levels dip below certain thresholds, it triggers a reduction in how much is released.

“The Lower Basin doesn’t want that to happen,” Castle said.

If a pool of water conserved by the Upper Basin is not operationally neutral, it could bump up Lake Powell above the trigger elevations and cause more water to be released to the Lower Basin.

“The Upper Basin states are saying we want that pool to be operationally neutral so that that increase in elevation doesn’t affect the releases from Powell,” Castle said. “Reclamation has always taken the position that they can’t do that on their own; the Lower Basin states would have to agree that some portion of the water in Powell doesn’t count against the release requirements.”

Because the amount of water released from Lake Powell each year is based on how much water is in the reservoir — not on the year’s snowpack or how much water flows into the reservoir — more water has been released over the past 25 years than has come in, drawing it down to critically low levels.

In 2023 and 2024, the Upper Basin states participated in a federally funded conservation program, known as the System Conservation Pilot Program. Officials received criticism from water users for its hasty rollout in the fall of 2023, and the first year didn’t see much participation because of the short timeline to apply and plan for the following irrigation season. This year’s delay could run the risk of a similar scenario.

“One of the painful lessons that we learned from 2023 projects is that the later you go into the fall and winter, the more difficult it is for water users to participate,” Cullom said. “The longer we go in time, I would anticipate the fewer participants we will get. … At what point have we run out of time? We’re already later in the year than I think anybody is happy with.”

Even if Colorado’s program can’t come together in time for the 2027 season, the Reclamation funding is good through 2031, Mitchell said, so a program could take place in a future year. She warned River District board members that if Colorado can’t run the program this year, she expects criticism from water users and managers.

“I want to be perfectly honest: If we can’t move forward with this program, there will be pressure from within our own state,” Mitchell said. “But as of right now, I don’t have the assurances that I need that this water will be protected, and I think that’s an important component.”

Click the link to read the article on the High Country News website (Stephanie Casanova):

October 20, 2026

The Arizona Department of Water Resources filed a motion Friday to intervene in Nevada’s earlier lawsuit, claiming the federal government’s plan for the shrinking river would “devastate Arizona’s economy,” the agency’s director said in a news release.

“The State’s towns, cities, tribes, farmers, factories, and businesses cannot survive without sufficient water from the Colorado River,” attorneys for the state claim in the motion.

Nevada filed a lawsuit in late August against several federal agencies, arguing that their plan places a heavier burden on the Lower Basin states. The amount of water in the  Colorado River is dwindling because of climate change, which is reducing the amount of snow and runoff that fills reservoirs like Lake Mead and Lake Powell, and mid-20th century agreements that promised water users more water than actually exists. Because the seven states that rely on the Colorado River couldn’t reach an agreement on how to manage the water, the federal issued a plan intended to better balance the amount of water in the river with the amount withdrawn.

Arizona and Nevada argue they have already taken steps to conserve water and are being unfairly targeted.

“The Lower Basin states have contributed millions of acre-feet of water toward stabilizing the river system. With more than 5.5 million acre-feet of Arizona water left in Lake Mead since 2014, no state has sacrificed more,” Arizona Department of Water Resources Director Tom Buschatzke said in an Oct. 16 statement. “The US decision puts the entire burden of sacrifice on the shoulders of three states. We are joining Nevada in challenging that framework.”

The Colorado River is divided between Upper Basin states — Colorado, New Mexico, Utah and Wyoming — and Lower Basin states: Arizona, Nevada and California. The 1922 Colorado River Compact allocates 7.5 million acre-feet of water annually to each of the two basins, as well as a smaller portion for parts of México. The U.S. states in each basin divide their shares.

An acre-foot is the equivalent of almost 326,000 gallons of water, enough water to cover a football field in roughly a foot of water. In Arizona, one acre-foot typically is enough to serve three single-family homes for a year, according to the Arizona Department of Water Resources.

California gets the largest share of Colorado River water: 4.4 million acre-feet per year, or about 27%. The state’s Lower Basin peers get smaller allocations. Arizona receives 2.8 million acre-feet, or about 17% annually. Nevada receives 300,000 acre-feet, or about 2% annually, according to Congressional reports and a California public policy analysis.

“We will not accept a forced federal plan that solves this crisis on the backs of our families, farmers, and businesses.”

The U.S. Bureau of Reclamation’s plan requires the Lower Basin states to shoulder potential cuts. For Arizona, the proposal means a reduction of 760,000 acre-feet per year — about a quarter of the state’s water allocation and the largest cut among the three Lower Basin states. California would be required to cut 440,000 acre-feet per year and Nevada 50,000 acre-feet. The cuts could amount to up to 3 million acre-feet.

The federal government is not requiring cuts for Upper Basin states. Instead, the government is asking the upstream states to voluntarily contribute 200,000 acre-feet each of the two years.

“Arizona has always been willing to do our part to protect the Colorado River, but we will not accept a forced federal plan that solves this crisis on the backs of our families, farmers, and businesses,” Arizona Gov. Katie Hobbs said in a statement Friday.

The Department of the Interior criticized Arizona’s legal action and said the Trump Administration is working with the Basin states, tribes and water users on an agreement.

“Governor Hobbs is wrong, and it’s unfortunate to see Arizona playing politics instead of working toward meaningful solutions,” a spokesperson for the Department of the Interior told Arizona Luminaria in an email statement. “Litigation won’t create a single additional drop of water or change the hydrologic realities facing the Colorado River Basin.” [ed. emphasis mine]

In a complaint Arizona filed with its motion to join Nevada’s lawsuit, the state claims there was a flaw in the federal government’s environmental review underpinning the decision. Every federal option considered “assumed that the Upper Basin States would make no meaningful reduction in their own use, no matter how little water the River produced.

“The alternatives placed the full burden of any resulting shortfall on the Lower Basin,” the complaint says.

Western water rights are prioritized according to a “first in time, first in right” doctrine, meaning those who claimed or purchased river water first are prioritized over water users who did so later. That means Arizona’s Colorado River rights are lower priority than California’s, which were acquired earlier.

“Such reductions could effectively dry up the Central Arizona Project canal system, as well as many of our on-river communities and would more than double the water cuts agreed to in the Lower Basin Agreement,” Buschatzke said.

Nevada’s August lawsuit came just three days after the U.S. Department of the Interior formally announced its Colorado River plan in August. In it, Nevada claims the cuts “will cause devastating environmental, socioeconomic, and health and human safety impacts to southern Nevada and its citizens.”

The lawsuit also claims that the federal government’s plan violates several requirements within the Law of the River, based on a series of records that include compacts, treaties, laws and court decisions that manage the Colorado River.

Nevada Gov. Joe Lombardo welcomed Arizona’s decision to join the lawsuit, saying in a Friday statement that it’s “an important step in challenging a federal plan that unfairly burdens the Lower Basin and fails to require the Upper Basin to make meaningful reductions.”

Arizona says joining Nevada’s lawsuit would allow it to avoid filing a separate but similar lawsuit, and allow the borderlands state to represent its own interests.

“Arizona believes that taking this action now provides the best path forward for protecting Arizona water users,” Buschatzke said.

This story was produced as part of the Western Environmental Reporting Collaborative, a partnership between Arizona Luminaria, High Country News, Report for America and local news organizations across the West.

We welcome reader letters. Email High Country News at editor@hcn.org or submit a letter to the editor. See our letters to the editor policy.

This story has been updated with comments from the U.S. Department of the Interior.

Click the link to read the article on the American Rivers website (Page Buono):

September 9, 2026

For more than the last century, the flows of the Colorado River have been managed and dictated by the demands of a rapidly growing and changing West. There are founding legal documents, and then agreements stacked on those, often known as the “Law of the River.” These agreements are between states, between sovereign nations, including Tribal Nations and Mexico; between districts and companies and branches of the US Government. It’s hard to find the appropriate metaphor for how all of these agreements work together (and at times against one another) to manage the Colorado River system. But even fraught metaphors are sometimes the only way to get through something so complicated.

Imagine the web of agreements and founding legal documents that guide the management of the Colorado River as a body. The 1922 Colorado River Compact would be the skeleton, the framework upon which all the other functions of the body are built. The limbs could be the communities, farms, Tribes, businesses, ecosystems, and economies that rely on the river’s blood (Colorado River water).  The agreements that build on the framework of the Compact, such as the 2007 Interim Guidelines or the 2019 Drought Contingency Plan (DCP), act as nerves that facilitate or trigger movement and action. Perhaps the brain is the network of decision makers – the Bureau of Reclamation, the states, the Tribes, Mexico and others whose decisions and cooperation keep the system functioning, underscoring why coordination and consensus are so important: a body whose different parts are working at cross-purposes cannot function effectively. The blood then, of course, is the Colorado River water allocated to parts of the body. 

Continuing the body metaphor for the contemporary management of the Colorado River system, additional agreements (or the nerves that trigger certain action) were added to the body.

On Friday, August 24, the Bureau of Reclamation released three documents outlining a 10-year framework for how the Colorado River will be managed for the next two years and how management decisions for the subsequent 8 years will be made. You can read the Bureau’s summary doc here.

1. The Final Environmental Impact Statement (FEIS): evaluates the many proposed plans Reclamation considered for how the river should be managed going forward, and identifies a preferred alternative, a 10-year framework built on operating plans developed in at least two-year increments;
2. The Record of Decision (ROD): adopts the 10-year operating framework and sets the principles and guardrails for future operations including how water can be stored, shortage sharing, critical infrastructure protection, consultation, and the movement of water between Lake Powell and Lake Mead; and
3. The 2027-2028 guidelines: establish the specific operating approach for the first two years under the new framework.

While the two-year guidelines put real numbers and real movement on the table, the ultimate test is whether the guidelines, alongside the side agreements, investments, and management tools needed to support them, are put in place and function as intended – and whether, together, they can keep the body upright.

Six months from now, the more consequential questions will be whether the new guidelines:

• provide more certainty and transparency, including clear pathways for addressing disputes and disagreements when they arise;
• support flexible and adaptive management tools that can respond to changing hydrology and conditions;
• meaningfully include Tribal Nations in both decision-making and implementation;
• reduce reliance on emergency operations and short-term crisis response; and
• create a workable path toward long-term resilience — one that can withstand disagreement, including litigation, without bringing implementation and collaboration to a halt.

Finally, and critically, these new guidelines must recognize healthy rivers and watersheds as a core element of the Basin’s resilience infrastructure, because in the middle of all the agreements – at the core of all the collaboration and controversy, the skeleton and nerves and muscles that move it, there is a river – there is a heart; the whole reason blood moves through the system at all.

Healthy rivers and forests, connected floodplains, and intact watersheds are essential to the body, to the Basin. They support the reliability of our water supplies, reduce the risks and impacts of wildfire; they sustain fish and wildlife, support recreation, and strengthen the Basin’s ability to withstand drought and changing conditions. They are invaluable.

Which is to say, at the center of all the agreements and negotiations and collaboration and controversy, is the river. Has always been the river. And if we succeed at all in our management, if we have any hope of keeping this body upright, there will always be the river.

Click the link to read the article on Ken’s Substack (Ken Neubecker):

September 16, 2026

Walter and I frequently walk along the Colorado River in Glenwood Springs’ Two Rivers Park, where the Roaring Fork joins in. The Colorado has been running reddish brown lately due to some intense rain and blowouts from small tributaries upstream, gullies that normally are dry. Not this summer. The Roaring Fork runs clear, creating a distinct division between the flows, a narrow ribbon of clear cold water that runs alongside the warmer and muddier stream for a long ways before they mix.

Both streams and most others are extremely low, even for late summer. Many of the USGS gauges have exclamation points next to them on the map, meaning “extremely below average”. There are rocks exposed to the air that I’ve never seen before. What little monsoon rain we had didn’t do anything, not even for the dry soils that will likely soak up much of the snow melt next spring before it can reach the rivers.

Years ago when I’d go to water meetings and conferences, back when people referred to our current situation as an unusually long drought, there was some talk about the Colorado River Compact’s requirement that the Upper Basin not cause the river flow to drop below 75 million acre feet (maf) over a ten year running average. Oh, we’ll see that train wreck coming with plenty of time to do something, they all said. That train wreck is now happening. The engine is sliding over the cliff as the States argue about the menu back in the dining car. All that really happened was serious can kicking along the tracks.

The first Upper Basin “tripwire” of 82.5 maf, the 75 maf plus 7.5 maf for Mexico could come as soon as next month. Now the can being kicked is full of lawyers.

So, what does the 1922 Compact actually say? The meat is in Article III:

This is what each basin could expect every year.

This is where the additional 1.5 maf per year, split as 750,000 acre feet due from each basin comes in. There was no agreement on Mexico’s share of the river in 1922, or in 1928 when the Compact was finally ratified. That came in 1944 with a formal treaty regarding Mexico’s share in both the Colorado and Rio Grande Rivers. The Compact negotiators anticipated such an agreement, hence paragraph (c). What they didn’t anticipate were decades of no “surplus”. That’s another story.

The more serious tripwire comes next:

October 1, 2026, may well see the flow at Lee Ferry cross the first line in the sand of a dry riverbed if the ten year running average drops below 82.5 maf for the first time since Lake Powell began filling. Back then water was held in the new reservoir to fill it. Everyone was OK with that. The Colorado River flows upstream were still quite robust on average and Lake Mead had plenty to satisfy the Compact requirements for the Lower Basin and Mexico as Powell filled.

Not anymore. Powell is shrinking rapidly. As of this writing the reservoir is at just under 22% full, and only about 27 feet from the elevation where the dam can no longer run water through the power plants penstocks. And the outflow is still about twice the inflow.

The monsoon rains turning the river reddish brown in Glenwood won’t help.

So what happens if that 82.5 maf tripwire is triggered and one or more states of the Lower Basin place a Compact Call?

It’s complicated.

It would mean a lawsuit between the states, which would go straight to the US Supreme Court. No lower courts would be involved, and it could take years to resolve. The last time there was a lawsuit about Colorado River apportionment it was between Arizona and California. The case was filed in 1952. The Court appointed a Special Master to work it out and recommend a solution. That took ten years. The case was finally argued in the Court in 1963, with a final decision handed down in 1964. That decision finalized the legal structure for allocations in the Lower Basin, based on the 1928 Boulder Canyon Act.

Twelve years for a resolution. We don’t have that much time for any new case on the Colorado River, especially with how the Upper Basin might comply with Article III, paragraph (d), and Mexico’s share thrown in.

In 2018 and 2019 the Colorado River Conservation District (River District) commissioned a risk study to look at how flows might augment storage in Lake Powell as well as what might happen should Lake Powell ever reach a level where Compact deliveries dropped to a point where the 82.5 maf over ten years wasn’t met, causing a Compact Call. It was, in light of today’s situation and the worsening hydrology, a tad optimistic. The first point in the Executive Summary’s Takeaway states:

The critical low level used for the analysis was 3525 feet, the Bureau of Reclamations critical low as well. Today, September 16, 2026, the elevation at Glen Canyon dam is just under 3517. It continues to drop every day, counting down to October 1.

If the Lower Basin states place a Compact Call it very well could be “catastrophic” for water users in the Upper Basin. But there are scenarios where it could be less so. At the very worst all diversions junior to November 24, 1922, or possibly June 25, 1929 when the Boulder Canyon Act was signed, would be curtailed, cut off, until the Compact deficiency is resolved. But that truly is a worst case scenario.

Curtailment would likely be based on what the flow deficit is at Lee Ferry when the call is placed and what increase through Upper Basin curtailment might make up the deficit. Diversions could be cut on a sliding scale, with the most junior taking the biggest hit, going back from today to that date in 1922 or 1929. We wouldn’t probably notice much at first as October 1, the start of the new water year, coincides pretty closely with the end of the irrigation season for most.

The River Districts study looked at various scenarios for Colorado, based on appropriation dates, river basins vs entire West Slope, and amounts of water that might be needed to satisfy the deficiency at Lee Ferry. The biggest hits would be in the Colorado River mainstem, especially with the large trans-mountain diversions taking water to Eastern Slope cities and farms. The Front Range cities, where most of Colorado’s population resides and who rely on as much as 50% or more of their water supply coming from the Colorado River, along with the significant agricultural areas along the South Platte and Arkansas Rivers, could see some pretty significant cuts regardless.

The State, through the Colorado Water Conservation Board (CWCB) and Attorney General’s office did a Compact compliance study some years ago but is keeping that confidential. I can’t blame them. It could become a basis for court arguments and negotiations should a compact call become a reality. The River District study could be as well. It’s worth a read if you are really interested in all this, and anyone who uses water in Colorado, East or West, to fill a tea pot from the faucet, flush a toilet or raise crops should be. They River District study can be found here or on their website.

Monsoonal moisture is still floating water laden clouds over us today, and some have dropped a good bit of rain. But that won’t help much. We are facing a “super El Nino” this winter, which may or may not provide a healthy snowpack. Anything would be better than last winter, except a repeat of that dry season. In any case it will take many years of “normal” snowfall to begin to refill the reservoirs. Given the trend of aridity and climate warming that is not something we should be counting on.

Perhaps, hopefully, the most important part of the compact written at the beginning will be called upon:

Of course the rub here will be in how “equitable division” is defined, and I imagine this could take much of the courts time in a Compact Call. In 1922 that meant an equal share of the rivers water for each basin. Now it could hinge on where the greater “value” is, and what that means. Back in 1922 “beneficial uses” were pretty straight forward. Now there are many more uses of the river deemed “beneficial”.

The needs and values today are quite different from what they were 104 years ago. The Tribes, the environment, recreation, local economies and traditions. All were either excluded in 1922 or covered by broad undefined ambiguity. Climate change wasn’t heard of, even though some scientists at the time had warned about it.

It’s a brave new world we are entering. Business as usual based on a 104 year old piece of paper and the other paper agreements founded on it won’t help us adapt to that world, nor will wishful thinking and other optimistic dreams based on hope. As Brad Udall noted during a recent PBS Newshour Tipping Point presentation, we need to re-think the whole thing. It won’t be easy, but as Udall pointed out it could be good. We need to rethink both what the river can provide and the reality of adapting to that. We also need to rethink the “values” we base our water needs on. It’s not just about endless economic growth anymore. Throwing lawyers at each other only enriches lawyers while it impoverishes us.

Meanwhile Walter and I will continue our ramblings with the river. We’ll also stop by the River District offices to say hi to the many friends there, to add some stress relief and try to keep their heads from graying any faster than they already are.