The Colorado River Basin includes four of the eight fastest-growing states in the nation: Arizona, Colorado, Nevada, and Utah. All seven of the basin states project strong population growth over the next decade, placing pressure on a river system that is already overallocated. Water conservation, water sharing agreements, and the integration of water into land use planning will be key strategies for ensuring long-term, sustainable resource use.

View the PDF version of this map for more detail and a key.

Source: The Place Database. www.lincolninst.edu/research-data/data/place-database

Nineteen years after it began, a record-setting drought is still choking the Colorado River Basin. The so-called “Millennium Drought” is now recognized as the worst of the past century.

On the rocky walls that hem in Hoover Dam and Lake Mead behind it, the deepening drought can be plainly seen in scaly white “bathtub” rings left behind by the falling water levels. Amazingly, thanks to the river’s massive reservoir system, no one has been forced to go without water—yet. But officials throughout seven U.S. states and Mexico now obsessively monitor mountain snowpack estimates each winter in the hope that the coming year might bring relief.

The drought has haunted water managers not only because it has lasted so long, but also because “things turned really bad really fast—much faster than we thought,” says Jeff Kightlinger, head of the Metropolitan Water District of Southern California, which supplies water to 19 million people in Los Angeles, San Diego, and surrounding areas.

The drought has also brought a series of hard reckonings about the future, and spurred a tremendous amount of soul-searching among those who manage and rely on this river. The unprecedented conditions, along with increasingly available science about the looming impacts of climate change, have forced water managers to contemplate scenarios far outside what they’re comfortable with, and to radically rethink some of their most basic assumptions about the river—beginning with how much water it can actually provide.

Over the past decade and a half, water managers have been in near-perpetual negotiations with each other over how to deal with the drought. The tempo of that process has been relentless, and has, at times, had a distinctly Sisyphean air: Negotiators have been working overtime to stay ahead of the problem, yet the drought presses on.

But something remarkable is happening. The drought has helped bring people together on what has been a famously contentious river. And the so-called “Law of the River”—an accretion of agreements, treaties, acts of Congress, and court rulings often criticized as hopelessly inflexible—may be evolving to meet the hard realities of the twenty-first century.

Throughout much of last year, water managers in the upper and lower Colorado River basins pushed hard to finalize a pair of “drought contingency plans,” referred to collectively as the DCP. They are the biggest and most ambitious effort yet to come to terms with the problems on the river. And yet the DCP will ultimately be just a starting point.

“The DCP, in my mind, is like a tourniquet,” says Kightlinger—an emergency measure to stanch traumatic fluid loss and stave off shock. “We really need to start pulling together a summit of the states, and say, ‘OK, that’s bought us a decade or so—but now we need our 50-year plan. So let’s get to work.’”

Dealing with Drought

Like most of us, Colorado River water managers tend to keep a pretty close eye on their gauges. And the single most important indicator on the river is, for a variety of complicated reasons, the water level in Lake Mead, just outside of Las Vegas.

Although it’s not necessarily intuitive for laypeople, the water level’s elevation above sea level is a proxy for the amount of water in the reservoir. Lake Mead is full when the water level is at roughly 1,220 feet above sea level. “Empty”—or what managers ominously refer to as “dead pool”—lies somewhere around 895 feet.

In 2003, after the severity of the Millennium Drought started becoming apparent, representatives of the seven states that depend on the Colorado—Arizona, California, Colorado, Nevada, New Mexico, Utah, and Wyoming—began meeting to negotiate a plan for softening the blow. Their focus was on holding the water level in Lake Mead at 1,075 feet, or roughly 35 percent of capacity, a level that water managers simply refer to as “ten-seventy-five.” If the level dipped down even more, to about 1,025 feet, the U.S. Secretary of the Interior would likely declare a shortage. Avoiding that declaration is important to the states, because if a shortage is declared and the states can’t agree how to handle it, the federal government has the authority to take over management of the river.

At press time, Bureau of Reclamation Commissioner Brenda Burman announced a January 31, 2019 deadline for the states to complete their drought contingency plans. Speaking at the annual Colorado River Water Users Association convention, Burman spelled out the consequences of failing to meet this deadline: the federal government will step in to impose cuts in water deliveries. Five of the basin states have approved their plans; Arizona and California announced they are close and expect to finish before the deadline. “‘Close’ isn’t done,” Burman said. “Only ‘done’ will protect this basin.”

Together, they came up with the so-called 2007 interim shortage guidelines, the first major interstate agreement about how to respond to the drought. Were Lake Mead to fall below ten-seventy-five, Arizona and Nevada (but not, owing to some complicated legal history, California) would cut back their water allocations in three stages, each progressively more drastic.

Taking this step would force the two states to make do with less water in any given year. But it would also slow the decline in Lake Mead and reduce, or at least delay, reaching more severe drought levels.

The plan included several measures intended to keep Lake Mead above ten-seventy-five for as long as possible. That effort has worked—but just barely. Not once since the drought began has Lake Mead sunk below ten-seventy-five. This is in large part because the states and the U.S. Bureau of Reclamation have managed to add an extra 23 feet of water to the lake, primarily due to some irrigation districts and tribes agreeing to cut back on their own water use. But for the past four years, the reservoir has been hovering within feet of 1,075 feet. Meanwhile, scientists have released a succession of increasingly dire projections about the long-term impact that climate change will have on Colorado River water supplies.

To better prepare for worsening conditions, the states’ representatives began meeting again to negotiate a new set of drought contingency plans, one for the Upper Basin and one for the Lower Basin. In October, the states, together with the federal Bureau of Reclamation, finally released the draft agreements, which will essentially beef up and expand the 2007 shortage guidelines.

In the Lower Basin, Arizona, Nevada, and California committed to trying to keep Lake Mead above 1,020 feet through the year 2026. To do that, Arizona would progressively reduce its use of Colorado River water by up to 24 percent, a commitment 50 percent bigger than what the state had made under the 2007 guidelines. Nevada agreed to cuts its uses by up to 10 percent, also a 50 percent larger commitment than under the 2007 guidelines. Notably, California—whose Colorado River entitlement is effectively the most senior on the river, and therefore is exempt from reductions under the Law of the River and the 2007 guidelines—has agreed to reduce its use by up to eight percent in any given year by “banking” water in Lake Mead. In exchange, California, along with the two other Lower Basin states, will have new flexibility to recover and use this “banked” water for use within its borders when necessary; until it uses the banked water, any such supply will help keep the reservoir elevation higher. The idea is to delay and, with hope, reduce the severity of potential shortages.

In the Upper Basin, meanwhile, the drought contingency plan will set up a “drought operations agreement” to buttress water levels in Lake Powell—which lies to the north of Lake Mead and is now a little less than half full—by sending water down from reservoirs higher in the basin when necessary. Significantly, the Upper Basin DCP will also open the door to a “demand management program”—similar to an arrangement that has existed in the Lower Basin since the 2007 guidelines—that would allow state or municipal water agencies to pay farmers to temporarily cut back on water use in order to put more water in Lake Powell. The DCP also includes a program to augment river flows through cloud seeding—a technology that can increase precipitation levels and has proven popular in the West—and the eradication of water-thirsty plants like tamarisk.

In the course of these complex negotiations, Mexico pledged that if the seven U.S. states could agree on the DCP, it would reduce its use of Colorado River water by up to eight percent. All told, the twin DCPs will be a major step forward. Yet many observers—and water managers themselves—say they still won’t resolve the biggest problem that’s been haunting the river for decades.

As Doug Kenney, director of the University of Colorado’s Western Water Policy program, puts it: “We’re just using too much water.”

Facing Facts

It’s never been a secret that there wouldn’t be enough water in the river to meet the obligations hammered out among U.S. states, tribes, and Mexico during the twentieth century, and that there would eventually be some hard choices to make. The closest anyone ever got to tackling the issue head-on was in the 1960s, during congressional debates about whether to approve the Central Arizona Project—a massive, 336-mile canal system that diverts water into the southern and central parts of the state—when it became clear that in the future, there would not always be enough water to keep the project’s canals full. But Congress essentially punted, authorizing studies to evaluate ambitious plans to “augment” the flow of the Colorado River through a number of approaches. Those included cloud seeding, desalination of both ocean water and saline groundwater, and “importing” water from other rivers—including an early attempt to target the Columbia River, more than 800 miles away in the Pacific Northwest, an idea that was swiftly beaten back by the Washington congressional delegation.

For the next several decades, the issue went forgotten, for the simple reason that no one needed augmentation. But the conversation has begun to come full circle as demand has grown, the basin has been in a drought cycle, and climate change has diminished supplies. “Inventing augmentation,” says Eric Kuhn, who for decades led the Colorado River Water Conservancy District in western Colorado, “was a way of putting off the pain into the future, and the future is here.”

The first hints that the problem was no longer a purely theoretical possibility came in the mid-1990s, when California, Nevada, and Arizona began running up against the limits of their Colorado River entitlements. The Upper Basin states began worriedly asserting that there was not enough water left for them to ever receive their full entitlements under the Colorado River Compact.

Then came the drought, which transformed these pinch points into actual pain. On top of the drought and usage issues, there’s some basic math making things even more challenging: Each year, massive amounts of water—some 600,000 acre-feet, enough water for nearly half a million people—simply evaporate from Lake Mead. The traditional accounting system under the Law of the River failed to budget for the water lost to evaporation. In addition, Mexico’s share of the river water is simply “deducted” from the shared supply in Lake Mead, rather than being divvied up among the states. Together, evaporation and the Mexico delivery draw roughly 1.2 million acre-feet more water from Lake Mead each year than is released from Lake Powell, upstream—even without a drought.

Under the 2007 shortage guidelines, the Lower Basin states can receive extra water—so-called equalization releases—if river conditions are good enough. But “in most years, we’re still going to have a deficit at Mead of a million or more acre-feet,” says Terry Fulp, the federal Bureau of Reclamation’s Lower Colorado regional director.

That imbalance has come to be known as “the structural deficit,” and it lies at the heart of the Colorado River’s problems. “It’s a code word, in my mind, for overallocation,” says Fulp. “We’ve got an absolutely overallocated system.”

Untangling this problem will be key to long-term sustainability on the river. It will also be a tremendous challenge—and tremendously expensive. The 23 feet of water the states have managed to add to the water level in Lake Mead since the DCP negotiations began has cost at least $150 million.

That slug of extra water is “important when you’re right at the threshold,” says Kenney of the University of Colorado. But in the bigger picture, he says, “it’s a terribly small amount of water, and it’s a terribly big price tag.” Truly stabilizing the system will require much bolder action, and will cost far more.

Beyond DCP

So what might efforts beyond DCP actually look like?

“You’ve got to be focused on reducing the absolute load on the system,” says Peter Culp, an Arizona attorney who advises both the City of Phoenix and several environmental nongovernmental organizations. But because of wild swings in natural variability like the current drought, he says, “you also need to be prepared to deal with high levels of instability.”

As the states begin to look at longer-term solutions, several broad possible components seem likely to come to the fore:

Augmentation 

Today, the term has a far more modest connotation than it did in the 1960s, when vast water-importation plans and massive nuclear-powered desalination plants seemed within the realm of feasibility. Conventionally powered desalination of seawater is now the augmentation option cited most frequently, although the sole operating example is the Poseidon desalination plant that serves San Diego. It produces a relatively modest 56,000 acre-feet per year at a cost double that of water supplied from the Colorado River (Hiltzik 2017). Cloud seeding—artificially induced rainfall—has been carried out for decades, but has only limited effectiveness.

“Augmentation is part of the portfolio,” says Chuck Cullom, the Central Arizona Project’s Colorado River programs manager, “but there aren’t, and have never been, any silver bullet answers.” Augmentation projects, he says, “are all going to be hard-fought, challenging, modest-sized—and more expensive than we thought.”

Markets, Leasing, and Transfers

The ability to move water between water-rights holders will play a huge role in increasing the flexibility needed to weather the looming problems on the river. Although there are still gains to be made in urban water-use efficiency (think reduced water use for grass and landscaping), the water needs of the West’s 40 million, primarily urban, individual water users are relatively inelastic. A discussion is slowly taking shape about ways in which cities can make deals to acquire water from both native tribes and farms in a way that doesn’t threaten the survival of any of those three sectors.

Tribal Rights

Local tribes will likely play a bigger role in meeting future demands, particularly in Arizona, where their right to significant amounts of water has recently been affirmed. “The tribes are increasingly important political players, and they are increasingly important in this idea of leasing and flexibility within the existing rules,” says Dave White, who heads Arizona State University’s Decision Center for a Desert City, which is largely focused on finding ways to help policy makers make better decisions about uncertain futures. “That makes them an important lynchpin in moving from the current allocation system to the future one.” Tribes have rights to an estimated 2.4 million acre-feet of Colorado River water (Pitzer 2017).

Daryl Vigil is the water administrator for the Jicarilla Apache Nation in New Mexico and is head of the Ten Tribes Partnership, which has long pushed for the ability to lease its members’ water to other users. Vigil says that in an era of drought and climate change, tribal water can help cities and other users stabilize their water-supply portfolios while securing much-needed revenue. “Right now, there are tribes that, because of infrastructure issues or policy issues, aren’t able to develop their water rights, so it’s just going downstream” and being used by non-tribal entities without compensation, Vigil says. “To a large degree, we’re already the solution to a lot of these issues, but we’re not getting any kind of credit for it.”

Some tribes have already been able to parlay their water rights into revenue. The Jicarilla Apache tribe, for example, leases water to the federal Bureau of Reclamation to provide minimum river flows for endangered fish, and in 2017 the Gila River Indian Community in Arizona struck a deal with the Bureau, the City of Phoenix, and the Walton Family Foundation to lease its water in order to boost levels in Lake Mead.

Agriculture

Farms will also play a big role in a more comprehensive solution on the river. Agriculture accounts for around 75 percent of water use in the basin, the vast majority of which is used to grow forage and pasture, like alfalfa, for beef and dairy cattle. Farm water supplies could potentially be used for farm-to-city water transfers, or to help cushion the impact of temporary shortages on cities.

In fact, the framework for agricultural-to-urban water transfers on the Colorado River was first created in the late 1990s. The years since have seen a series of test runs and a slow expansion of the concept throughout the Lower Basin and even across the border to Mexico. The terms of the 2007 interim shortage guidelines allow irrigation districts in Arizona, California, and Nevada to “forbear”—that is, to forgo the use of a portion of their water allocation for a year, thereby freeing up water to be stored in Lake Mead for drought protection. The proposed Demand Management Program included in the Upper Basin drought contingency plan would open the door to a similar framework there.

Water for such programs can be generated in a variety of different ways: simply by fallowing farmland (i.e., taking it out of production), thereby freeing up the water that otherwise would have been used to grow crops there; by switching to crops that consume less water; or by improving irrigation efficiency and transferring the conserved water. Although transferring water away from farms is, in the public imagination, often equated with drying up farms and putting them out of business, there is a long history of innovative thinking about how farms can generate water for uses elsewhere while remaining financially viable. In California, for instance, the Palo Verde Irrigation District has been the focus of a long-running “rotational fallowing” program to generate water for the Metropolitan Water District, under which at most 29 percent of the irrigation district’s farmland is fallowed in any given year.

The transfer of water from farms to cities, either temporarily or permanently, is an extremely controversial issue. Any discussion of the topic—especially in Arizona, where farmers would be the first to have their water cut due to contractual agreements made well before the current negotiations began—quickly moves from technical talk of crop consumptive water-use coefficients to basic questions of social equity.

“That’s the crux of the problem: Do people perceive that the pain is distributed fairly?” says Cullom. The drought and the contingency-planning process, he says, are forcing people to come to terms with “the visceral understanding of what a future with less water looks like.”

Win, Lose, or Draw

Back in the early 1990s, a consortium of university researchers used computer models to simulate a “severe and sustained drought” on the river, in an effort to see how water users might respond. The simulated drought used in the exercise would ultimately prove to be eerily similar to the Millennium Drought that took hold less than a decade later. But at the time, notes Brad Udall, a senior water and climate research scientist at Colorado State University, barely any water managers bought into the drought-simulation effort. “The academics wanted to go push all this stuff, but they couldn’t get any decision makers to participate,” he says. “Nobody wanted to lay their cards out.”

If there’s one up side to a 19-year drought, it may be that it has opened up conversations that wouldn’t otherwise be happening. The players are increasingly willing to lay their cards on the table. And the past 19 years have shown that some problems on the Colorado can be addressed, for better or worse, not through radical change but through incrementalism, with the stakeholders gradually playing one hand after another.

But now the stakes are getting higher. Even as representatives of the seven states were in the midst of negotiating the drought contingency plans, climate scientists were delivering more bad news: The Colorado River Basin may be on the brink of a permanent shift into a much drier reality. In 2017, Udall and Jonathan Overpeck, now the dean of the University of Michigan’s School for Environment and Sustainability, found that increasing temperatures could cause the flow of the Colorado River to decline by more than 20 percent at mid-century and 35 percent at the end of the century.

“I don’t care what level of demand management you do,” says Arizona attorney Culp, “that’s a really big problem.”

The states’ negotiators will not get much reprieve before they have to tackle the next round of even tougher questions: The provisions of both the 2007 shortage guidelines and the arduously negotiated DCP will expire in 2026, and the states have agreed on the need to open negotiations for a follow-on agreement just a year from now, in 2020. That next phase will likely serve as the forum for tackling the bigger issues on the river.

“We have to find a way to permanently reduce our demands, and find a way to augment our supply,” says Kightlinger of California’s Metropolitan Water District. That effort, he says, won’t be fast or easy— and Dave White of the Decision Center for Desert City suggests it might require “recalibrating the entire system to what we think is the new availability of water.”

Are people willing to commit to a recalibration or radical overhaul of the way the river is managed, or will they simply adopt a more ambitious follow-on to the operational “updates” of the 2007 interim shortage criteria and the drought contingency plan? A wholesale revamp of the Law of the River—what Fulp calls “the start-over scenario”—is politically taboo for water managers.

Yet the DCP may be the first step in subtly steering everyone into that difficult conversation. The emphasis on tackling “drought”—rather than overuse—may have been a considered move on the part of negotiators. “Politically speaking, I think it’s a useful word for the states,” says Kenney. “To the extent that you talk about drought contingencies and shortage, you’re talking about what we’re going to have to do in an emergency.”

The message, he says, is that “the drought is getting really bad, and we have to make some adjustments. But”—at a time when the Colorado River states are running up against the limits of their allocations—“the reality is that it doesn’t take an emergency to get you to shortage. It doesn’t take an emergency to crash the systems. Just business as usual crashes the system” if the drought worsens.

In spite of calls for radical reform on the river, the key to a durable solution—which may ultimately be just as important as a comprehensive solution—could, paradoxically, be to go slow. “Incrementalism allows people to get comfortable with changes a little bit at a time,” says Kuhn of the Colorado River Water Conservancy District. “And I actually think the incremental change will happen as fast as necessary to adapt to the real-world conditions.”

That approach is obviously not without its risks. The primary result of all the negotiations that have occurred since 2003, which have all but consumed the lives of those involved in them, is that water managers have so far managed to push off a shortage declaration by the federal government by just three years. If negotiators continue to work incrementally, will they be able to keep pace with how quickly the system is changing?

No one knows, and the river isn’t telling. But for now, the DCP process has bought everyone a little time to catch their breath. “[DCP] will get the risk back down,” says Fulp. “It will give us that time to really open up the dialogue on much bigger, and much more difficult, issues.”

On the Colorado River, Change Is the Constant

After nearly 16 years of negotiations, water managers seem to have staved off disaster—for now. Will the next round of negotiations, which begins in 2020, be able to keep pace with how quickly the Colorado River system and conditions in the basin are changing? Dr. Jim Holway of the Babbitt Center for Land and Water Policy thinks it’s going to take significant change. “I believe we will need institutional, policy, and infrastructure changes to sustainably manage the river,” Holway says. Citing challenges including climate change, highly variable conditions, population growth, conflicts over the Law of the River, and increasing water costs, Holway explains that the Babbitt Center exists to recognize and address these challenges, with a particular focus on connecting land use decisions and sustainable water management at the local level. Looking beyond 2026, when both the interim shortage guidelines of 2007 and the proposed DCP modifications expire, Holway identifies a central question: “How do we best prepare for this future, and how do we ensure our policies and decision makers at every level are up for the challenge—and able to quickly adapt as conditions change?”

Matt Jenkins has been covering the Colorado River since 2001, primarily as a longtime contributor to High Country News. He has also written for The New York Times, Smithsonian, Men’s Journal, Grist, and numerous other publications.

Photograph: Fishing boat in the Colorado River Delta. Credit: Pete McBride

References

Hiltzik, Michael. 2017. “As Political Pressure for Approval Intensifies, the Case for a Big Desalination Plant Remains Cloudy.” Los Angeles Times, May 19, 2017. http://www.latimes.com/business/hiltzik/la-fi-hiltzik-desalination-20170521-story.html.

Pitzer, Gary. 2017. “The Colorado River: Living with Risk, Avoiding Curtailment.” Western Water, Fall 2017. https://www.watereducation.org/western-water-excerpt/colorado-river-living-risk-avoiding-curtailment.

Agriculture was the main driver of development along the Colorado River. According to a recent report from the U.S. Geological Survey, 85 percent of water withdrawals went toward irrigation between 1985 and 2010 (Maupin 2018). The fields around Yuma, Arizona, and the Imperial and Palo Verde valleys of California consume more than 4 million acre-feet of Colorado River water annually, nearly a third of the river’s annual flows. But with population growth, water use has shifted to urban needs.

In Colorado, for example, 95 percent of water imported from the Colorado River headwaters through the Colorado-Big Thompson (CBT) project was once used for agriculture; now, that number is closer to 50 percent. As another example of the complexity of systems in the Colorado River Basin, CBT water is divided into units which can be bought and sold. The amount of water in a unit varies year to year depending on the total amount of water available; when CBT is at full capacity, a unit is one acre-foot. Agricultural users owned 85 percent of the units when trading began in the late 1950s, but currently own less than one-third of available units. Municipalities own the balance, but often lease the water to farms until it’s needed. The current price for a CBT unit is close to $30,000.

Such water-sharing agreements are becoming more common in a system stretched too thin. Rotational fallowing, also known as lease-fallowing or alternative-transfer mechanisms, has played a role in shifting water from farms to cities. Farmers in the Palo Verde Valley struck a deal with the Metropolitan Water District of Southern California, which serves 19 million customers, to fallow between 7 and 35 percent of their land on a rotating basis. Metropolitan’s customers, in turn, get the water, which can be stored in Lake Mead. Similar deals, still underlined with tension but increasingly accepted, exist between Southern California municipalities and farmers in the Imperial Valley and between cities and farmers along Colorado’s Front Range urban corridor.

For their part, cities tend to tout conservation and development efforts they’ve made with water in mind. Many are encouraging density, reducing the water needed for landscaping; some have implemented turf-removal programs; and toilets, showers and other fixtures have become more efficient. Metropolitan Water District of Southern California chalked up a 36 percent per capita reduction in water use from 1985 to 2015, a time of several droughts, according to Planning magazine (Best 2018).

In Nevada, the population served by the Southern Nevada Water Authority has increased 41 percent since 2002, but the per capita consumption of Colorado River water fell 36 percent. The agency’s Colby Pellegrino, speaking at a September 2018 conference called “Risky Business on the Colorado River,” said conservation is the first, second, and third strategy for achieving reduced water consumption. “If you live in the Las Vegas Valley, where there is less than 4 inches of rainfall a year, and you have a median covered in turf, and the only person walking on that turf is the person pushing a lawn mower—that is a luxury our community cannot afford, if we want to continue to have the economy we have today,” she said.

Economy, culture, and values have been at the core of the basinwide debate about how to respond to the drought. No one sector or region can absorb the full burden of necessary reductions, and it’s clear that everyone must begin to think differently. Speaking at the “Risky Business” conference, Andy Mueller, general manager of the Colorado River Water Conservation District, put it this way: Instead of the intentional use of water, Colorado is now talking about the intentional non-use of water. As is everyone who lives and works in the Colorado River Basin.

This content is excerpted from the article “Hydraulic Empire” published December 14, 2018.

Allen Best writes about water, energy, and other topics from a base in metropolitan Denver, where 78 percent of his water comes from the Colorado River Basin.

Photograph: On a farm in Yuma, Arizona. Credit: Amy Martin, courtesy of American Rivers.

References

Arizona Daily Star. 1998. “Don’t Ignore Colorado Delta.” May 6, 1998.

Best, Allen. 2018. “Water Pressure: Smart Management Is Key to Making Sure Inland Cities Aren’t Left High and Dry in the Face of a Warming Climate.” Planning August/September: 40–45. https://www.planning.org/login/?next=/planning/2018/aug/waterpressure/.

Maupin, Molly A., Tamara Ivahnenko, and Breton Bruce. 2018. “Estimates of Water Use and Trends in the Colorado River Basin, Southwestern United States, 1985–2010.” Reston, Virginia: U.S. Geological Survey. https://pubs.er.usgs.gov/publication/sir20185049.

For six centuries, a people called the Hohokam inhabited central Arizona. Among their many accomplishments, they created a hydraulic empire of sorts, a spiderlike web of canals intended to deliver water from the Gila and Salt rivers—tributaries of the mighty Colorado—to their agricultural fields. Eventually, the Hohokam abandoned their fields and canals. To this day, the reason is uncertain, but historian Donald Worster once surmised that the productive but ill-fated tribe “suffered the political and environmental consequences of bigness” (Worster 1985).

Bigness. It’s the perfect word to describe not only the Colorado River Basin, but so much of the geography, history, culture, politics, and challenges associated with it.

In its sheer complexity, the Colorado stands out among the rivers of America, and probably the world. In this river basin of 244,000 square miles, one-twelfth the land mass of the continental United States, exist great diversities, places of oven-hot heat and icy vastness. All but 2,000 of those square miles lie in the United States. Just 10 percent of that land mass, mostly in an elevation band of 9,000 to 11,000 feet in the Rocky Mountains, produces 90 percent of the water in the system.

Hydraulic infrastructure abounds at almost every turn on the river’s 1,450-mile journey. The first diversions occur at its very headwaters in Rocky Mountain National Park, before the river can rightfully be called a creek. Fourteen dams have been erected on the Colorado River, and hundreds more on its tributaries. Hoover Dam, perhaps the best known, hulks a half-hour drive from Las Vegas. The U.S. Bureau of Reclamation (USBR) built it in the 1930s to hold back the river’s spring floods, creating a reservoir now known as Lake Mead. A second massive reservoir, Lake Powell, lies upstream 300 miles. It’s the result of Glen Canyon Dam, built in the 1960s with the goal of providing a means for the four Upper Basin states—Colorado, New Mexico, Utah, and Wyoming—to store the water they had agreed to deliver to the Lower Basin states of Arizona, California, and Nevada, and to Mexico.

At their fullest, the two reservoirs—which are the biggest in the country—can hold four years of flows of the Colorado River. A recent paper suggested that the two reservoirs could be considered one giant reservoir, bisected by a “glorious ditch” (CRRG 2018). That ditch is the Grand Canyon, which celebrates the one hundredth anniversary of its designation as a national park this year.

The dams, reservoirs, tunnels, and aqueducts of the Colorado deliver water to 40 million people in seven U.S. states—more than 1 in 10 Americans—and two Mexican states. The river’s water also nourishes more than 5.5 million acres of agricultural fields within and outside the river basin. Residents of Denver, Los Angeles, and other cities outside the basin rely on the river; crops in fields reaching almost to Nebraska benefit from transbasin exports and diversions.

The river provides a cultural and economic resource for 28 tribes within the basin. A $1.4 trillion economy hums along in and around the basin. This includes the snowmaking cannons at Vail and Aspen, the nightly water spectacle at the Bellagio in Las Vegas, and the aeronautics industry of Southern California. Up and down the river, more than 225 federal recreation sites draw visitors eager to try their luck at fishing, rafting, hiking, or just taking in the sights. This river and the lands around it loom large in the public imagination.

It’s a big, complicated, and now vulnerable hydraulic web. Entering the twenty-first century, the river was already a sponge fully squeezed, its water rarely making it to the Gulf of California.

Rapid population growth, rising temperatures, and declining river flows are putting pressure on the system, forcing river managers and users to devise creative, forward-looking plans that consider both water and land. The Lincoln Institute’s Babbitt Center for Land and Water Policy strongly encourages this approach. “We are trying to think more holistically by considering the management and planning of land and water resources together,” says Babbitt Center Program Manager Faith Sternlieb. “These are the foundations upon which water policy in the Colorado River Basin has been considered and crafted, and these are the roots we must nurture for a sustainable water future.” 

Taming the Colorado

The need to nurture roots has driven the development of the Colorado River Basin since the first people began farming there. The Hohokam, Mojave, and other tribes built canal systems of varying complexity to irrigate their fields. In the late 1800s, federal interest in tapping the river to boost agricultural production surged. By 1902, the U.S. Department of the Interior (DOI) had created what is now the Bureau of Reclamation. During the twentieth century, the Bureau became the prime builder, and funder, of agricultural water projects throughout the basin.

Work on the Laguna Diversion Dam, the first dam on the Colorado River, began in 1904, yielding water a few years later for fields near Yuma, Arizona. Yuma sits in the Mojave Desert, where Arizona, California, and Mexico come together. There, long, nearly frost-free growing seasons coupled with fertile soils and Colorado River water enable extraordinary productivity. Today, farmers in the Yuma area of Arizona and Imperial Valley of California proclaim that during winter they grow 80 to 90 percent of the greens and other vegetables in the United States and Canada. This area, declares Arizona’s Yuma County Agriculture Water Coalition, is to U.S. agriculture what Silicon Valley is to electronics and what Detroit was to automobiles (YCAWC 2015).

All told, irrigation accounted for 85 percent of total water withdrawals in the basin between 1985–2010 (Maupin 2018). Today, agriculture still accounts for 75 to 80 percent of total water withdrawals. This supports row crops such as corn and the perennial crop of alfalfa, which is grown from Wyoming to Mexico. Much of the crops go to livestock: The Pacific Institute, in a 2013 report, estimated that 60 percent of agricultural production in the basin feeds beef cattle, dairy cattle, and horses (Cohen 2013). Agriculture has always been, and will remain, a key piece of the Colorado River puzzle.

But almost as quickly as the Bureau of Reclamation began diverting water for agriculture, other needs arose, from producing electricity to slaking the thirst of booming Los Angeles. By the early 1920s, the seven states of the arid West realized they had to find a way to share a river that would become—as the river’s preeminent historian, the late Norris Hundley, would later write—“the most disputed body of water in the country and probably in the world” (Hundley 1996). Years later, Hundley famously referred to the area as a “basin of contention” (Hundley 2009).

Today, dozens of laws, treaties, and other agreements and rulings collectively called the Law of the River govern the use of Colorado River Basin water. They include federal environmental laws, a treaty over salinity, amendments to treaties, a U.S. Supreme Court case, and interstate compacts. None is more fundamental than the Colorado River Compact of 1922, which still guides the annual share of water each state gets. Representatives of the seven basin states hammered out its provisions in grueling meetings held near Santa Fe. They were driven by both ambition and fear.

Ambitious California needed federal muscle to tame the Colorado River if it was to realize its agricultural potential. Los Angeles had aspirations, too. In the century’s first two decades, it had grown more than 500 percent and wanted the electricity that a large dam on the river could deliver. A few years later, it also decided it wanted the water itself. To pay for this giant dam, California needed federal help. Congress would approve that aid only if California had secured support from the other southwestern states.

Fear drove the other basin states. If the first-in-time, first-in-right legal system of prior appropriation used by Western states was to be applied to the Colorado River, California and perhaps Arizona would reap the benefits. The headwaters states, including Colorado, were developing too slowly to benefit from their own long and snowy winters. Delph Carpenter, a Colorado farm boy turned water lawyer, forged the consensus. Both basins, upper and lower, got 7.5 million acre-feet, for a total of 15 million acre-feet. Mexico needed water, too, which the compact assumed would come from surplus waters. A later treaty between the two nations specified 1.5 million acre-feet for Mexico.

The 1922 Colorado River Compact also nodded, but no more, at what later writers called a sword of Damocles hanging over these allocations: water for the basin’s Indian reservations. The U.S. Supreme Court, in a 1908 case called Winters v. United States, had declared that when Congress reserved land for a reservation, it implicitly reserved water sufficient to fulfill the purpose of that reservation, including agriculture. That ruling did not determine the amounts that were needed. Tribal water rights within the basin now constitute 2.4 million acre-feet, in many cases senior in priority to all other users within the allocations of the individual states. That’s a fifth of the river’s total flows. Importantly, specific water allocations for some of the largest tribes still have not been resolved.

The framers of the 1922 compact made a big, fatally flawed assumption: That enough water existed to meet everyone’s needs. Average annual flows from 1906 to 1921 had averaged 18 million acre-feet. But even by 1925, just three years after the Compact came into being and three years short of its Congressional approval, a U.S. Geological Survey scientist named Eugene Clyde La Rue had delivered a report indicating the river probably would deliver too little water to meet these hopes and expectations. Other studies about the same time delivered the same conclusions.

They were right. Over a longer period, from 1906 to 2018, the river has averaged 14.8 million acre-feet per year. Averages have dropped during the twenty-first century, in the midst of a 19-year drought, to 12.3 million acre-feet. In the last water year, ending in September 2018, the river carried only 4.6 million acre-feet. That’s just 200,000 more acre-feet than California’s annual entitlement.

The Shift from Farms to Cities

Agriculture was the main driver of development along the Colorado River. According to a recent report from the U.S. Geological Survey, 85 percent of water withdrawals went toward irrigation between 1985 and 2010 (Maupin 2018). The fields around Yuma, Arizona, and the Imperial and Palo Verde valleys of California consume more than 4 million acre-feet of Colorado River water annually, nearly a third of the river’s annual flows. But with population growth, water use has shifted to urban needs.

In Colorado, for example, 95 percent of water imported from the Colorado River headwaters through the Colorado-Big Thompson (CBT) project was once used for agriculture; now, that number is closer to 50 percent. As another example of the complexity of systems in the Colorado River Basin, CBT water is divided into units which can be bought and sold. The amount of water in a unit varies year to year depending on the total amount of water available; when CBT is at full capacity, a unit is one acre-foot. Agricultural users owned 85 percent of the units when trading began in the late 1950s, but currently own less than one-third of available units. Municipalities own the balance, but often lease the water to farms until it’s needed. The current price for a CBT unit is close to $30,000.

Such water-sharing agreements are becoming more common in a system stretched too thin. Rotational fallowing, also known as lease-fallowing or alternative-transfer mechanisms, has played a role in shifting water from farms to cities. Farmers in the Palo Verde Valley struck a deal with the Metropolitan Water District of Southern California, which serves 19 million customers, to fallow between 7 and 35 percent of their land on a rotating basis. Metropolitan’s customers, in turn, get the water, which can be stored in Lake Mead. Similar deals, still underlined with tension but increasingly accepted, exist between Southern California municipalities and farmers in the Imperial Valley and between cities and farmers along Colorado’s Front Range urban corridor.

For their part, cities tend to tout conservation and development efforts they’ve made with water in mind. Many are encouraging density, reducing the water needed for landscaping; some have implemented turf-removal programs; and toilets, showers and other fixtures have become more efficient. Metropolitan Water District of Southern California chalked up a 36 percent per capita reduction in water use from 1985 to 2015, a time of several droughts, according to Planning magazine (Best 2018).

In Nevada, the population served by the Southern Nevada Water Authority has increased 41 percent since 2002, but the per capita consumption of Colorado River water fell 36 percent. The agency’s Colby Pellegrino, speaking at a September 2018 conference called “Risky Business on the Colorado River,” said conservation is the first, second, and third strategy for achieving reduced water consumption. “If you live in the Las Vegas Valley, where there is less than 4 inches of rainfall a year, and you have a median covered in turf, and the only person walking on that turf is the person pushing a lawn mower—that is a luxury our community cannot afford, if we want to continue to have the economy we have today,” she said.

Economy, culture, and values have been at the core of the basinwide debate about how to respond to the drought. No one sector or region can absorb the full burden of necessary reductions, and it’s clear that everyone must begin to think differently. Speaking at the “Risky Business” conference, Andy Mueller, general manager of the Colorado River Water Conservation District, put it this way: Instead of the intentional use of water, Colorado is now talking about the intentional non-use of water. As is everyone who lives and works in the Colorado River Basin.

A River Shared

In late 1928, Congress approved the Boulder Canyon Project Act. This legislation accomplished three significant things: It authorized construction of a dam in Boulder Canyon, near Las Vegas, which was later named Hoover Dam. The law also authorized construction of the All American Canal, crucial for developing the productive farmland of California’s Imperial Valley, an area that’s now the single largest user of Colorado River water. And the Boulder Canyon Project Act divided waters among the Lower Basin states: 4.4 million acre-feet each year to California, 2.8 million acre-feet to Arizona, and 300,000 acre-feet for Nevada. Las Vegas then had a population of fewer than 3,000 people.

As the twentieth century rolled on, headwaters states also got dams, tunnels, and other hydraulic infrastructure. In 1937, Congress agreed to bankroll the Colorado-Big Thompson Project, what historian David Lavender called a “massive violation of geography” intended to divert Colorado River waters to farms in northeastern Colorado, outside of the hydrological basin. In 1956, Congress approved the Colorado River Storage Project Act, authorizing a handful of dams, including Glen Canyon.

Only Arizona remained left out. It had vigorously opposed the 1922 compact, then remained defiant. Its Congressional representatives opposed Hoover Dam and, in 1934, then-Governor Benjamin Moeur even dispatched the state’s National Guard in a showy opposition to construction of another dam being built downstream to deliver water to Los Angeles. “Put simply, Arizonans feared there would be little water remaining for them after the Upper Basin, California, and Mexico got what they wanted,” Hundley explains (Hundley 1996). Finally, in 1944—the same year the U.S. and Mexico reached an agreement about the amount of water due to the latter—Arizona legislators succumbed to political realities. Cooperation, not confrontation, would be needed for the state to get federal help to develop its share of the river. At last, the compact had the signatures of all seven states.

Arizona finally got its big slice of Colorado River pie in the 1960s. A U.S. Supreme Court decision in 1963—one in a series of Arizona vs. California cases over many decades—confirmed Arizona had the right to 2.8 million acre-feet, as Congress had specified in 1928, along with all the water in its own tributaries. This is what Arizona had wanted all along. In 1968, Congress approved funding for the massive Central Arizona Project, ultimately resulting in the construction of 307 miles of concrete canal to deliver water from Lake Havasu to Phoenix and Tucson and farmers between. California supported the authorization, with a hitch: In times of shortage, it would still have rights to its 4.4 million acre-feet first. This led Arizona to later create a water banking authority to store Colorado River in underground aquifers, providing at least partial security against future shortages.

Upper Basin states had reached accord about how to apportion their 7.5 million acre-feet without notable friction: Colorado 51.75 percent, Utah 23 percent, Wyoming 14 percent, and New Mexico 11.25 percent. They used percentages, as Hundley explained, because of “uncertainty over how much water would remain after the upper basin had fulfilled its obligation to the lower-basin states” and Mexico. Fluctuations in the river’s flow, they reasoned, might mean that some years they had an amount smaller than 7.5 million acre-feet to divide between themselves. It was, in retrospect, an eminently wise decision.

Conservation Concerns

The same year the basin states framed the original Colorado River Compact, the great naturalist Aldo Leopold canoed through the Colorado River Delta in Mexico. In an essay later published in A Sand County Almanac, he described the delta as “a milk and honey wilderness.” The river itself was “nowhere and everywhere,” he wrote, and was camouflaged by a “hundred green lagoons” in its leisurely journey to the ocean. Six decades later, visiting the delta after a half-century of feverish engineering, construction, and management had emerged to put the river’s waters to good use, the journalist Philip Fradkin had a different take. He called his book A River No More.

As the 20th century closed, the environmental impacts of essentially regarding a river as plumbing drew new attention, especially in the now dewatered delta. The lagoons that had so enchanted Leopold were gone, because the stopped-up river no longer reached its southern outlet. Drainage from vast agricultural enterprises had made the river so saline that, among other things, Mexico protested that the water it was receiving was unfit to use. The many dams and diversions that came after Leopold’s visit had also put 102 river-dependent rare birds, fish, and mammals on the brink of extinction, reported the Arizona Daily Star. The newspaper lauded the work of stakeholders in a new transborder conservation effort: “The fundamental principle of ecology calls for land managers to look to the good of the whole system, not just its parts.”

Environmental groups might have used the Endangered Species Act to force the argument about solutions, but the delta was not within the United States. So they looked to find collaborative solutions. In the closing days of the tenure of Bruce Babbitt, secretary of the Interior in the Clinton administration and namesake of the Babbitt Center, the two countries adopted Minute 306. It created the framework for a dialogue that produced, under Babbitt’s successors in the Bush administration, an agreement called Minute 319 and a one-time pulse flow of more than 100,000 acre-feet in the river in 2014.

Children gleefully splashed in the rare waters of the river in Mexico during that pulse flow, but adults on both sides of the border were equally happy. Among those grinning was Jennifer Pitt, then of the Environmental Defense Fund. Litigation had been a possible route, she said, but an inclusive and transparent process with stakeholders was more productive.

“The institutional legal and physical framework we have on the Colorado River is the basis for great competition and the potential for litigation between parties,” says Pitt, who is now with Audubon. “But it is exactly that same framework that has given those parties the opportunity to collaborate as an alternative to having solutions handed to them by a court.”

Collaboration Is Critical

Reservoirs were full as the next century arrived, thanks to robust snowfall in the Rockies during the 1990s. Still, there was tension. California for decades had exceeded its apportionment of 4.4 million acre-feet, consuming a high of 5.4 million acre-feet in 1974. Upper Basin states never have fully developed their 7.5 million acre-feet, averaging 3.7 to 4 million since the 1980s, plus 500,000 acre-feet from reservoir evaporation.

Then came drought, deep and extended. The river carried just 69 percent in 2000. The winter of 2001 to 2002 was even more stingy, the river delivering just 5.9 million acre-feet, or 39 percent of average, at Lake Powell. From 2000 to 2004 was the lowest 5-year cumulative flow in the observed record. Since then, more years have been dry than wet. The reservoir levels are at near-record lows.

The 1922 compact had not contemplated this kind of long-term drought. A structural deficit came into sharp relief. Tom McCann, assistant general manager of the Central Arizona Project, coined the phrase. Very simply, the Lower Basin states were using more water than was delivered from Lake Powell each year. This was so even when the Bureau of Reclamation authorized the release of extra “equalization” flows from Powell.

“Equalization releases are like hitting the jackpot on the slot machine,” McCann says. “Back then, we were hitting the jackpot every three or four or five years, and we thought we had nothing to worry about.” Even with the jackpots, Lake Mead continued to decline, the reservoir’s widening bathtub ring charting the losses.

Climate change overlays the structural deficit. Scientists argue that warming temperatures swing a big bat in the Colorado River Basin. They term the early-twenty-first-century declines a “hot drought” as distinguished from a “dry drought.”

The prospect of this new, human-induced “hot” drought on top of a conventional drought worries many. Tree-ring studies show that the region has suffered longer, deeper droughts in the past, before measurements began. “A number of folks claim that the current 19-year period of 2000 to 2018 is the driest 19-year period on the Colorado River,” says Eric Kuhn, former general manager of the Colorado River Water Conservation District. “Nonsense. It’s not even close. If these past droughts were to happen with today’s temperatures, things could be much worse.”

The first two decades of the new millennium have seen a series of efforts to confront this new reality. In 2007, the Department of the Interior issued interim shortage guidelines, the first formal response to the drought. The Bureau of Reclamation released a Basin Supply and Demand Study in 2012, an exhaustive effort to provide a platform for future decisions. The many reports stacked tall enough to fill a box that could ship a football. They discussed population growth, rising temperatures, and the impact of increasing rain on snowpack. Demand, the study concluded, would exceed supply by 3.2 million acre-feet by 2060 (USBR 2012).

“You can argue about the numbers, you can argue about the forecast, but it was something that got everybody’s attention,” says Colorado’s Anne Castle, who was then assistant secretary of Interior for water and science. “It served as a catalyst to focus the discussion about Colorado River management more directly in dealing with future scarcity.”

Castle sees the basin now struggling to find collaborative solutions. “In a complex water system, there are so many moving parts, it’s not about one answer,” she says. “You have to manage a complex system, and you can only do that through negotiated agreements.”

Those negotiations are happening now, in the form of drought contingency planning. Even as scarcity has become more prominent, collaboration has also grown. But the measuring stick for success may well be the white mineralized walls of Lake Mead, a big reservoir in a big basin facing big challenges. Now the seven states, the tribes, and the governments of the U.S. and Mexico, with input from environmental and other nongovernmental organizations, must figure out how to keep those water levels from sagging even more. They must concoct a plan that ensures a sustainable future, while heeding the twists and turns of the past.

Allen Best writes about water, energy, and other topics from a base in metropolitan Denver, where 78 percent of his water comes from the Colorado River Basin.

Photograph: Lake Powell at Glen Canyon Dam. Credit: Pete McBride.

References

Arizona Daily Star. 1998. “Don’t Ignore Colorado Delta.” May 6, 1998.

Best, Allen. 2018. “Water Pressure: Smart Management Is Key to Making Sure Inland Cities Aren’t Left High and Dry in the Face of a Warming Climate.” Planning August/September: 40–45. https://www.planning.org/login/?next=/planning/2018/aug/waterpressure/.

Cohen, Michael, Juliet Christian-Smith, and John Berggren. 2013. Water to Supply the Land: Irrigated Agriculture in the Colorado River Basin. Oakland, CA: Pacific Institute. (May). http://pacinst.org/publication/water-to-supply-the-land-irrigated-agriculture-in-the-colorado-river-basin/.

CRRG (Colorado River Research Group). 2018. “It’s Hard to Fill a Bathtub When the Drain is Wide Open: The Case of Lake Powell.” Boulder, CO: Colorado River Research Group. (August). https://www.coloradoriverresearchgroup.org/uploads/4/2/3/6/42362959/crrg_the_case_of_lake_powell.pdf.

Fradkin, Philip. 1996. A River No More: The Colorado River and the West. Oakland, CA: University of California Press.

Hundley, Norris Jr. 1996. “The West Against Itself: The Colorado River—An Institutional History.” In New Courses for the Colorado River: Major Issues for the Next Century, ed. Gary D. Weatherford and F. Lee Brown. Albuquerque, NM: University of New Mexico Press. http://web.sahra.arizona.edu/education2/hwr213/docs/Unit1Wk4/Hundley_CRWUA.pdf.

———. 2009. Water in the West: The Colorado River Compact and the Politics of Water in the American West. Oakland, CA: University of California Press.

Leopold, Aldo. 1949. A Sand County Almanac: And Sketches Here and There. New York, NY: Oxford University Press.

Maupin, Molly A., Tamara Ivahnenko, and Breton Bruce. 2018. “Estimates of Water Use and Trends in the Colorado River Basin, Southwestern United States, 1985–2010.” Reston, Virginia: U.S. Geological Survey. https://pubs.er.usgs.gov/publication/sir20185049.

USBR (U.S Bureau of Reclamation). 2012. “Colorado River Basin Supply and Demand Study.” Washington, D.C.: U.S. Department of Interior. https://www.usbr.gov/lc/region/programs/crbstudy/finalreport/Study%20Report/CRBS_Study_Report_FINAL.pdf.

Worster, Donald. 1985. Rivers of Empire: Water, Aridity, and the Growth of the American West. New York, NY: Pantheon Books.

YCAWC (Yuma County Agriculture Water Coalition). 2015. “A Case Study in Efficiency: Agriculture and Water Use in the Yuma, Arizona Area.” Yuma, AZ: Yuma County Agriculture Water Coalition. (February). https://www.agwateryuma.com/wp-content/uploads/2018/02/ACaseStudyInEfficiency.pdf.