Can Colorado River quench all thirsts?
Century-old rules, drought, intense demand raise question:
PINEDALE, Wyo. — Cowboy Michael Klaren heaved hay bales onto his wagon, climbed aboard and urged his two workhorses to drag it across a meadow, the ground spongy with the meltwater from a snowstorm.
Wet boots had raised his spirits on this March morning, as had two wet cow dogs he called Woodrow and Gus. The meadow was off to a more promising head start on spring than he had come to expect after years of drought.
If left to run off in rivulets or percolate through the pasture, the moisture from the Colorado River’s prodigious Wyoming headwaters would collect in the nearby New Fork, join the Green River, and ultimately surge across three state lines before swelling the Colorado in southeastern Utah and buoying the Southwest’s depleted reservoirs.
But first, Klaren would wring some of it out for his next hay crop.
“Personally, I think the water that falls in Wyoming is Wyoming’s until it gets to Utah,” he said. “When it falls here, it’s our water.”
If it were that simple, Klaren and his mountain town would have little to fear. But 100 years ago, Wyoming signed onto a deal to divide the water that flows through the Colorado River basin among seven states. It’s based on a formula — one likely based on mistaken beliefs about the river itself — that did not award extra credit for living in the mountains where the snow piles up.
Instead, the states signed a compact allocating the water where it would readily be put to work. It meant the more populated states of California, Colorado and Arizona would get the biggest shares. And it meant in lean years, water users in places like Pinedale might go without, watching as runoff from the jagged Wind River Range flowed past the mountain ranches to farmers and cities far downstream.
Over time, the government built massive dams near Las Vegas and Page to store the water for those big downstream users: a Yuma lettuce field, an Imperial Valley melon patch, the Phoenix suburbs, all stretching toward a desert horizon far from the river’s channel.
But more than two decades into a punishing drought that climate scientists say will likely intensify with more warming, the system can no longer supply everything that some 40 million people in a warming and drying region desire from it, or that grocers nationwide sell from its verdant fields. Since 2000, water demand and evaporation have exceeded the river’s flow, on average, by roughly 15%.
The federal and state governments that share the water are now urgently seeking conservation to save the river. Their negotiations could produce either a new system of sharing the pain of cutbacks or an impasse that ends in lawsuits as states and water users try to hang onto water promised them in a different time.
Farmers like Klaren are among the most at risk, in part because they use the most water. Agriculture, not big cities, consumes as much as 80% of the river’s flow in any given year. Shutting down the canal that feeds Phoenix and Tucson wouldn’t stabilize the reservoirs, Arizona’s water resources director said early in November. The government could cut off municipal deliveries across the basin and still face shortages if farms don’t adapt to the shrinking flows of a warming climate
Interstate negotiations have proceeded haltingly this year in an emergency effort to conserve billions of gallons needed to keep America’s biggest dammed reservoirs — lakes Mead and Powell — from emptying. The U.S. Interior Department has also begun a process for determining how to operate the dams and preserve the river beginning in four years, when current rules expire.
Despite his wish to use local water as he and his neighbors see fit, Klaren knows that a worsening shortage endangers the life he chose in 1989. That’s when, just three years removed from high school, he leased this place and started grazing cattle on it.
The compact: Based on wishful thinking?
The devastating combination of a warming climate and sustained overuse has long bent the Colorado River, but now stands ready to break it. If neither the demand nor the weather relents, it’s possible the river could finally stop flowing past Hoover Dam by the end of President Joe Biden’s term.
Farms with senior water rights on paper would not be able to claim their due from a dry riverbed. Phoenix, while backstopped with other in-state sources such as the Salt River, would have to stop pouring Colorado River water into its aquifer for future demands, and start pumping what is already there. Small ranch towns like Pinedale and even major farm service centers like Yuma would lose jobs and population as they are forced to reduce production.
A hundred years since seven states agreed to split up the Colorado River Basin’s bounty with a federally chartered compact, persistent drought and overuse have laid bare the flaws in the “Law of the River,” a set of laws, settlements and treaties that parcel out the water. The rules assumed a river flow that has only rarely existed since, and only in increasingly rare wet years. The states and Mexico now use more than the river supplies, and are drawing down their storage from years past.
Plunging reservoirs behind Hoover and Glen Canyon dams imposed austerity on central Arizona farmers this year and will spread still more pain in 2023. Without action to save massive amounts of water, a worst-case weather scenario could drop Lake Mead so low that it no longer releases any water toward the sprawling farm empires and cities of Arizona, Southern California and Mexico.
“We really are in a crisis,” Central Arizona Project General Manager Ted Cooke said. If everyone takes what they’re currently taking from the river over the next two years, he said, Lake Mead’s surface will sit just above the point where it can still flow through Hoover Dam. California and Arizona would be on the precipice of losing their massive supplies from the river.
The U.S. Department of the Interior and its water managers, the Bureau of Reclamation, established dam-operating guidelines in 2007 that were meant to prevent such a calamity. They hitched certain cutbacks to various water levels in Lake Mead, and led to Arizona’s first mandated cutbacks this year. Their updated guidelines for 2026 and beyond will likely prescribe deeper cuts.
The Interior Department declined to make officials available for interviews about if and how the new guidelines might address or alter allocations among the states. In public settings over the last year, Interior and Reclamation officials have said only that they intend to build on the existing compact, as they have done with various water-saving agreements over the years.
Many experts say the time has come for the federal government to shake up the system it created when it built the dams to grow the West. That scheme awarded half to an Upper Colorado Basin in the mountains and sagebrush plains, and half to the Lower Basin in the desert Southwest and coastal Southern California. Some, heeding climate scientists’ projections of still lower levels, say the government will have to limit the states to percentages of the Colorado’s year-to-year flow rather than the firm allocations they’ve always had on paper.
Having never used all the water that they were promised in the 1922 Colorado River Compact, the Upper Basin states now find there’s no more to go around. The only way Wyoming, Colorado, Utah and New Mexico could grow into their full allocation in the current climate would be to force Arizona, Nevada, California and Mexico to give back more of the water they’re already using.
Bruce Babbitt is among those who expect the U.S. will have to change the rules if drought continues to suppress river flows and reservoir levels over the next couple of years. The former Arizona governor and U.S. Interior secretary said the river will soon decline to the point where it’s impossible for the Upper Basin to meets its fixed yearly commitments to the Lower Basin without “progressively shutting down current Upper Basin uses. That is an ethical and political impossibility.
“At that point,” Babbit said, “the equitable solution will be to share reductions proportionately among all users in both Upper and Lower basins.”
The deal: Dividing the river seven ways
Klaren is one of the few remaining ranchers who still works his leased spread with workhorses instead of tractors and flatbed trucks. On a late-winter morning, some of his 230 cows awaiting their meals and others tending or even dropping newborn calves, he rolled his wagon through a marshy meadow, peeling and kicking off slabs of hay imported from other farms.
“We just borrowed more money,” he said. “My theory is one of these days cow prices are going to go up and we’ll get out of debt.”
In years past, he might have had enough homegrown alfalfa to get by. This March, a year after a paltry mountain snowpack had cut short his irrigation supply from the river, he had already burned through the half-crop of hay he had managed to sock away for winter, fenced off from the high country’s moose and antelope.
Unlike water users in Arizona, Nevada and California, he can’t draw water from giant government-financed reservoirs. When too little water melts into Wyoming streams, the state cuts off farmers and ranchers who don’t own the earliest-staked water claims. Last year in the upper Green River Valley, Wyoming cut off ranchers whose rights preceded statehood in 1890.
The 20th century river was expected to provide at least 17 million acre-feet of water in an average year.
An acre-foot is the arcane water measurement unit the government uses. It covers an acre (about a football field) to a 1-foot depth. It equals roughly 326,000 gallons and supplies two or three households a year in the Southwest. Its use simplifies calculations that on the Colorado would otherwise reach into incomprehensible trillions of gallons.
By the end of the last century, the average flow since 1906 would prove to have been just 15 million acre-feet, still enough to put away some water behind dams when mountain states like Wyoming weren’t using their full entitlements.
Since 2000 the flow has plunged still lower.
The compact and a subsequent suite of laws, settlements and treaties had been based on wishful thinking. They assigned 15 million acre-feet to the seven U.S. states that touch the river or the tributaries that refresh it, splitting that amount evenly between those above and below Lees Ferry in northern Arizona. That didn’t count 1.5 million owed to Mexico every year, or evaporation and seepage that would take about 1.5 million acre-feet a year.
The upstream states — Wyoming, Utah, Colorado and New Mexico — would join the sliver of Arizona that’s above Grand Canyon to form the Upper Basin. California, Nevada and most of Arizona would become the Lower Basin. Each basin could claim 7.5 million acrefeet, though to this day the Upper Basin has typically used only about 4 million.
Until last year the Lower Basin, with more irrigated acres than the Upper Basin and more than twice the population, used every drop of its allocation, and sometimes more. When the shortage in Lake Mead hit levels that 2007 river operating guidelines said would force cutbacks, the U.S. Bureau of Reclamation cut deliveries to junior rights holders, mostly in central Arizona and, to a lesser degree, in southern Nevada. Further declines forced deeper cuts for next year, bringing Arizona’s losses to more than a fifth of its former take from the river.
Arizona has borne the brunt of the shortage because, to win congressional approval for the Central Arizona Project’s canal, the state accepted a lower priority than California’s larger claims. California will likely have to cut its share to keep the river flowing out of Lake Mead in coming years, but has yet to do so.
The mechanism for ensuring equality of opportunity between the basins would prove simple in wet periods but disastrous in the current decades of megadrought, which scientists have determined to be the driest in 1,200 years. Instead of assigning each state a percentage of what flowed downriver each year, the Law of the River requires the less-developed Upper Basin to deliver, on average, at least the Lower Basin’s 7.5 million acre-feet plus Mexico’s share.
Whatever was left, in good times, was up for grabs. The federal government built Glen Canyon Dam to store years’ worth of flow just above Lees Ferry, simplifying the task of releasing at least the mandated flows to the Southwest even in occasional dry years.
Then the dry years started coming one after another.
The runoff: ‘Climate change is water change’
Kevin and Wade Payne revved their snowmobiles and clattered across frosty mud and lichen-crusted rocks, seeking a way uphill toward the Pocket Creek snow-gauging site. Exhaust fumes wafted through the premature springtime scent of mountain sagebrush in the Wind River Range foothills southeast of Pinedale.
The brothers grew up on a southeastern Idaho ranch, one valley removed from the Colorado River Basin, and now travel the Upper Green each winter to ground-truth automated sensors that help predict how much water the mountain snowpack is likely to send toward Wyoming ranchers and then to the Colorado. One works for the state engineer’s office; the other for the federal Natural Resources Conservation Service. In a cooler era, readings like theirs would paint a clear picture of the summer water supply to come. Rising temperatures now effectively wick moisture from the hills each spring and summer, complicating their forecasts.
Finding little snow to ride, Wade sped off alone, scouting for a route that could take them from 8,000 feet in elevation to their goal at 9,360, where they intended to sink an aluminum tube into the snow to measure its depth and to weigh it to calculate its water content. Minutes later he rode back, unsuccessful. There would likely be insufficient snow on which to reach Pocket Creek from then on, marking a March 25 close to a season that usually lasts until the thaw cranks up late in April.
Kevin, who supervises Green River water for the state, would have the unenviable job of shutting down diversions to some ranchers with old rights. There wouldn’t be enough to go around this year, not and still meet obligations to keep the river moving adequate water out of state.
“There’s years we’ve seen it just like this,” Kevin said. “We’re used to shortage around here.”
By late July he would cut off supplies to 117,000 acres irrigated by Wyoming’s Green River Basin ranchers, the vast majority of them with water rights that precede the 100-year-old Colorado River Compact. Without major storage reservoirs to draw from in these headwaters, continued diversions would drain the streams.
The Payne brothers rode their sleds back onto their truck trailers and hauled them west for an hour, to a well-packed public snowmobile trail that would take them through aspens and evergreens to the Rowdy Creek gauge site in the Wyoming Range. There, they stabbed the tube into the snow at several predetermined points, finding a maximum depth of 40.5 inches and an average water content equaling 12.4 inches.
Around the Upper Green, the snowpack at that time was about three-quarters of average for late March. With weeks of possible accumulation yet to come, the outlook would fluctuate before, as it has in so many years this century, the winter fell short of the old norms.
Months later, on June 14, a U.S. Geological Survey crew dangled a kickboard-shaped sonar gauge into the Green River from Warren Bridge northwest of Pinedale, where each summer U.S. 191 leads tourists toward the Tetons and Yellowstone National Park. The instrument measured both depth and velocity, and found the river running at 3,610 cubic feet per second. Peak flows can reach 5,900 cfs here, USGS hydrologist Cheryl Miller said, but peaks don’t always predict a season’s water supply. A slow and steady melt can deliver as much or more as a short-lived flood.
Northwestern Wyoming had just experienced a burst of rain on melting snow that had flooded Yellowstone’s northern gateway on the previous day, crashing a home into a different river descending the Continental Divide’s other side. Here, the Green was surging at a rate that would put it in the top quarter of yearly peak flows.
“It’s certainly high-ish,” Miller said, not ready to pass judgment on the water year. High peaks, such as those brought on by some unseasonable 80-degree days that preceded that one, can quickly give way to low flows. Her hesitation was warranted. Ultimately the water flowing under Warren Bridge throughout the thaw would reach 71% of average.
In all, the Bureau of Reclamation would go on to count this as a poor runoff year for southwestern Wyoming, despite the Green’s relatively high peak. At Flaming Gorge Reservoir, in the mountains where Wyoming meets Utah, the agency would calculate natural inflows gathered from upstream in Wyoming at 57% of normal for the spring-summer runoff season.
Low flows in one year can contribute to low flows in the next by drying out soils that then absorb part of a new season’s snowmelt. The Upper Basin’s snow piled up to 89% of normal in the winter of 2020-2021, but the water that Lake Powell gathered from all of it equaled just 36% of normal, trailing only 2002 for the low-flow record. One difference was the dry soil left behind by the previous year, according to river forecasters, sponging up the new moisture.
Another factor was and is rising heat. From 1916 through 2014, Colorado River flows declined by 16.5%, climate scientists Mu Xiao, Brad Udall and and Dennis Lettenmaier determined in a 2018 study published in the journal Water Resources Research.
More than half of the losses came as a result of warming temperatures, according to their calculations. A warmer environment squeezes more from the snow and rain that falls in it, by extending growing seasons for trees and plants, and by sending more back into the atmosphere as those plants transpire it.
It’s why Udall, a Colorado State University researcher who has long sounded the alarm on the river’s dwindling supply, shuns the term “drought” on the river. He calls it aridification, a word suggesting a long-term shift instead of a mere dry spell.
Since 1970, the region has warmed by 3 degrees Fahrenheit, or 1.7 degrees Celsius, a rate faster than the planet’s average. Numerous studies of the Colorado River’s climate have pegged a loss in flows of between 5% and 10% to every 1 degree Celsius of local warming, and temperatures are expected to keep rising with the concentration of greenhouse gases.
“Climate change is water change,” Udall said.
Udall collaborated with then-University of Arizona climate scientist Jonathan Overpeck on a 2017 study that projected the losses would grow to at least 35% later this century, and possibly by more than half, if greenhouse gas emissions continue on their current trajectory.
Already the river has averaged less than 12.5 million acre-feet of new flows each year since 2000, while the basin takes some 14 million acre-feet from it. It’s why Lake Powell and Lake Mead sit at barely one-quarter full.
The evidence of the West’s overuse of the Colorado was apparent beyond river scientist Jack Schmidt’s shoulder at Bullfrog Marina on a late-winter evening in southern Utah. He sat on a bench at the edge of a massive concrete boat ramp that for years provided house boaters and other recreationists access to Lake Powell. Now, the water was drained far out into the channel, and the ramp was closed to boats. The National Park Service had extended another ramp for temporary access and was considering moving the whole marina out of the increasingly shallow bay.
The seven states responsible for this drawdown would continue to overextend the river and its reservoirs until the federal government forced them to stop, said Schmidt, who previously headed the Grand Canyon Monitoring and Research Center and now directs Utah State University’s Center for Colorado River Studies.
“Nobody in Wyoming is going to say it’s better to grow broccoli in Yuma” than to use the water on headwaters ranches, he said. “And nobody in (California) is going to say, ‘Let’s fallow the alfalfa and grow it in Wyoming.’”
The result, he said, is that the Upper Basin is moving “ponderously slowly” toward meaningful water conservation, while the Lower Basin is cutting back quickly, especially in Arizona, but still uses more than the reservoirs can give for much longer. Changing the river’s trajectory will require someone to act according to the entire basin’s and nation’s interest, he said.
“Reclamation is going to have to assert its authority,” he said.
Schmidt co-authored a report this year that found a narrow pathway toward stabilizing Lake Mead and Lake Powell at their current, perilously low levels. He and colleagues, led by Oxford scientist Kevin Wheeler, found that if the Upper Basin holds the line at its current water use (just over half what it was promised a century ago), the Lower Basin could stop the bleeding with another 500,000 acre-feet of savings on top of commitments it has already made to slash about 1.5 million before Lake Mead hits dead pool.
To date, the Lower Basin and Mexico have cut deliveries by 613,000 acre-feet, mostly in Arizona, with deeper cuts for Arizona and Nevada scheduled to start next year.
The users: ‘Oh my God, there really is an end point’
Leslie Hagenstein knows her hometown has to change. That starts on the Pinedale homestead she and her sister inherited, just across the New Fork from Klaren and his cows.
“We use, excuse me for saying it, a s---load of water,” she said.
Hers is a small family farm leased to a friend, and in the grand scheme it only sips from the Colorado’s supply when compared to the Southwest’s hot, sprawling vegetable fields. But her farm’s method, like most farmers in the area, is to soak the fields. With short growing seasons and few crop options at an elevation above 7,000 feet, profits are too low to finance high-efficiency drip lines and sprinklers.
Hagenstein has good water rights. She just no longer has a sure supply.
“All you have to do is look at the mountains,” she said in March.
Visible from her yard, a dwindling snowpack hung in the Wind River Range. And in her yard, the snow was gone, something she couldn’t recall seeing so early before in her 68 years.
The warming and drying weather feed her concerns about her community. The farm had always managed to take its share until 2020, when the ditch got cut off in the middle of summer. Farms that share the ditch hayed early, and then lost out.
Then it happened again.
“Last year I really was sensitive to the fact that, ‘Oh my God, there really is an end point,’” she said.
The problem for Hagenstein — and even for the town of Pinedale’s municipal water supply — is that the big, 600foot-deep alpine lake above town is not primarily a local asset.
Pinedale helped build a little dam to raise the lake by 6 feet back in the 1930s. It added about 30,000 acre-feet, with half of the new capacity going to the town and half to area irrigators. In wetter eras, it was all anyone could ask.
As drought sapped the whole Colorado River Basin, a problem emerged. The dam is younger than the compact, and comes with younger and, in times of shortage, inferior rights. If the state has to curtail deliveries to meet downstream obligations, as it has warned the town to expect by 2025, that water won’t be available. The town would still have rights to water from the lake, but only in amounts that a mountain stream naturally dumps into it, and not from the storage pool it built.
Pinedale’s dilemma is a miniature version of all Wyoming’s. The state has not fully developed its would-be share of the Colorado River, but any new projects it builds would be last in line for scarce water.
To at least secure its continued access to its streamflow rights out of Fremont Lake, Pinedale is working on plans to pump water from the lake to its drinking water treatment system. That would keep faucets flowing if the lake is drawn down past its intake.
“We don’t want to call doomsday by any means,” said Abram Pearce, Pinedale’s public works director, “but we’re just trying to be prepared.”
Hagenstein, a retired nurse practitioner, follows her father’s example on water conservation. He dedicated some of his water rights to maintaining a minimum flow for the blue-ribbon trout stream that flows past her living room window. She’s busy applying for grants to upgrade efficiency on the ditches.
Her respect for the river extends beyond its ability to produce farm rents for retirement income. On her coffee table lay several books about the Colorado and its tributaries, including a Grand Canyon river guide with maps.
She would put those maps to use two months later, driving to Lees Ferry, the river’s Arizona dividing line between Upper and Lower Basins, to join a group of friends with Pinedale ties on the river trip of a lifetime.
She rose on May 25 and walked across the highway from the Marble Canyon Lodge to a little airstrip to welcome incoming women who would swell their party to 18. The all-women Grand Canyon float trip was about to begin from the same Colorado River beach where Hagenstein’s late mother had long ago thrilled with her own friends from Pinedale.
For Hagenstein, seeing desert waters that very well could have originated in the mountain stream by her home was its own thrill.
“We’ve witnessed the glaciers shrink and watched the water disappear,” she said. “I just want to kiss it because it’s made it this far. The water I walked in today could have been on the glaciers I walked on as a college kid.”