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How Does a State Use 40 Percent Less Water?

A recent study found that if the Colorado River drought continues, Arizona, California, and Nevada may have to cut their water usage by nearly half. Acceptance is the first step.

Low water levels are seen at Lake Mead, indicated by bleached rock where water once was.
Justin Sullivan/Getty Images
A tall bleached “bathtub ring” can be seen on the rock around Lake Mead in 2015, where water levels have sunk lower and lower.

Arizona, California, and Nevada will need to cut their use of Colorado River water by nearly 40 percent by 2050. A study by researchers at Utah State University, which the Arizona Daily Star reported this past Sunday, noted that Colorado, New Mexico, Utah, and Wyoming—the Upper Basin states—will have to reduce their usage, as well, though not by as much as those pulling water from the Lower Basin.

While Arizona water officials declined to engage with these findings when asked by the Star, Kathryn Sorensen, the research director of Arizona State University’s Kyl Center for Water Policy, told the paper that she agreed with “everything” in the study.  “We are going to have to take a much harder look at how water is used in the basin,” Sorensen said.

To fully understand Southwest water use would require untangling a century of multistate, multination water laws and compacts, in addition to unraveling the ongoing causes of the current drought. But, viewed from 10,000 feet, the challenges and stakes of this notice are clear: In five years, the states and tribal nations in the Upper and Lower Basin regions are set to reconvene to draft a new set of guidelines that dictate how these entities will roll out water cuts in the event that the current water shortage crisis continues. But if the research produced by Utah State’s Colorado River Studies program is to be heeded, none of the stakeholders have that long to begin negotiations. 

Negotiations scheduled for 2026 will need to pay attention to every part of the research being produced on long-term over-usage and climate change, while also considering and correcting the lasting impact of the past century’s anti-Indigenous water deals. It’s a hairy spot for 40 million people to be in, to say the least. As of last fall, Lake Powell and Lake Mead, which serve as the river’s largest reservoirs, sat at 48 percent and 40 percent of their respective capacity levels—teetering close to the emergency level that triggers automatic reductions across the Lower and Upper Basins. 

To grasp what a 40 percent reduction in water use would look like, it’s important to understand the agreements already in place to limit water use. In 2007, the federal Bureau of Reclamation released Interim Guidelines that, among many things, set the markers for Lake Powell and Lake Mead that determine when and how the Lower Basin states and tribal nations make cuts to their water usage levels. 

But as the drought, which began in 2000, extended into the following decade, both the Lower and Upper Basin states and tribal nations realized they needed more detailed guidance in place to begin methodically rolling back how water was being pulled from their reservoirs. The result was the Lower Basin’s Colorado River Drought Contingency Plan, or DCP, which was designed to answer a question: How do the states and tribal nations equitably cut their water usage if (or when) the water levels at Lake Mead drop to 1,075 feet above sea level?

A major component of the DCP, unlike past water agreements, was the participation of one group of major stakeholders that has been routinely overlooked as U.S. officials dictated how water would be distributed: tribal nations. A quarter of all water that flows through the Central Arizona Project aqueduct—the 336-mile canal that runs through the state—belongs to the Gila River Indian Community, a tribal nation situated just southwest of Tempe. The deal was nearly derailed by a last-minute display of political theater caused by a bill introduced by Arizona’s Republican House Speaker Rusty Bowers, who sought to grant farm owners in Pinal County the ability to hold onto to their water shares for an indefinite period of time. (Under current Arizona Water Law, landowners must show they are using their water rights at least every five years or risk forfeiture.)

Ultimately, Gila River committed to a deal to give up 500,000 acre-feet of water to the Central Arizona Groundwater Replenishment District in exchange for $60 million. (An acre-foot of water is roughly the amount that two families would use in a full year.) Similarly, the Colorado River Indian Tribes agreed to leave 10,000 acres of their farmland fallow for three years and keep the water in Lake Mead, in exchange for $38 million in payments. With the grievances settled and the CAGRD deal in place, the Lower Basin DCP was officially approved by state, federal, and tribal leadership in May 2019. The Upper Basin states signed their DCP in December 2018. As part of the 2019 Lower Basin DCP, Arizona agreed to leave 720,000 acre-feet in Lake Mead in the event that water levels in Lake Mead dip to 1,025 feet above sea level. However, that amount is mitigated by the offsets granted by the Gila River Indian Community and the Colorado River Indian Tribes. The remainder would mostly come from the Pinal County farm owners. 

As a not-so-brief aside, it is worth noting here that tribal nations have frequently been asked or coerced to relinquish their water rights for the supposed greater good of American cities and agriculture industry. A recently published paper by University of Arizona professor and Diné citizen Andrew Curley looked at the exploitation of the Navajo Nation’s resources by way of water deals in the 1920s, 1960s, and early 2000s, observing that because “infrastructures are almost always colonial,” it has been nearly impossible for tribal nations to gain a political foothold in water planning conversations. In that light, the fact that the 2019 deal hinged on the two tribal nations, and that they were able to leverage their water shares into preventing harmful legislation, could be taken hesitantly as a sign of progress.

Despite the immense political maneuvering that went into securing the DCP, it is hard to think of it now as anything more than an emergency plan that was drafted after the actual emergency started. The Gila River agreement—and the DCP more broadly—only extends to 2025. After that, the tribal nation, like the rest of the major stakeholders, will have the ability to renegotiate its water usage levels based on its available shares. 

Thinking ahead to those dealings is precisely what every stakeholder should be doing now—and researchers are well ahead of them. The Utah State study was the sixth installment in a series of white papers produced by the university’s Future of the Colorado River Project. In the third paper in the series, authors called for a greater amount of flexibility to be built into the post-2025 plans, arguing that “hydrology, water demand, and river ecosystem conditions are likely to look quite different” in 10 years than they do now.

One of the things they propose is measurement models that account for greater volatility. So far, the authors wrote, Colorado River managers have analyzed the Lake Powell and Lake Mead levels with the assumption that future water flow will look a lot like current water flow. But climate scientists widely agree that future water flows will be “lower, more variable, and more uncertain.”

Better models can’t solve everything, though. Right now, tribal water and resource rights are being used to buoy cities in Southern California, as well as Phoenix and Tucson. That’s not a sustainable long-term plan. There is also the immense quandary of how to tackle agricultural water use; the industry is allotted over 70 percent of the river’s available water. The initial cutbacks in the 2019 DCP focused on Central Arizona farmers, whose sales rank among the most profitable in the nation, due to their ability to grow and produce year-round, per CivilEats. But according to the U.S. Department of Agriculture, the industry accounts “for approximately 80 percent of the Nation’s consumptive water use and over 90 percent in many Western States.” This past year, farmers had their water allotments cut by roughly 15 percent; come 2022, the Lower Basin DCP will officially boot Central Arizona farmers off the CAP canal, forcing them to rely on limited amounts of groundwater. 

Climate change is now an inevitability, not a possibility. But it’s yet to be treated with the seriousness it deserves. After the 2019 DCP, Colorado State’s Brad Udall, University of Colorado’s Douglas Kenney, and University of New Mexico’s John Fleck co-authored a piece for The Conversation that argued researchers and policymakers needed tostep back, look at the big picture and design a water management system that works for all stakeholders in the basin for the next several decades.” Two years later, it’s not clear any such big-picture plan yet exists. The study finding that three states will have to nearly halve their water use in the next 30 years didn’t even make national headlines. The time has come and gone for “what if” conversations about this drought. Lake Mead’s bathtub ring is growing: We can’t wait until our next scheduled appointment in 2026 to think about it.