Climate Change Threatens to Dry Up the Southwest’s Future

Cover Story

photo of the top of Hoover Dam at dawnColorado River photos by Karen Halverson from her book Downstream.

The high ceilings of the Miracle Mile shopping mall in Las Vegas’s Planet Hollywood Hotel and Casino are painted to resemble a perfect-day sky – the soft blues and downy white clouds of an idealized spring. About every hour, the scene is interrupted by “the rainstorm.” The sky darkens, a thunder soundtrack rumbles as strobes mimic lightning, and a one-minute sprinkle comes down from the ceiling. The water falls into a shallow pool set between an Aldo Shoes and a Ben & Jerry’s. As smoke machine fog rises off the pool’s surface, onlookers snap photographs.

The wet weather show at Planet Hollywood is a large leap from the reality outside, where tourists wither beneath the pounding heat that, on a June evening, remains in the triple digits past 6 p.m. In Las Vegas, rain is rare: a scant four inches a year, about half of what Tucson, AZ receives. A rainstorm in the Mojave Desert, whether man-made or natural, is an unusual event worth photographing.

One could easily forget that, though, on a tour around the booming city. At Lake Las Vegas, a multi-resort and casino about 30 miles from the city center, grass lines the roads and a faux waterfall tumbles down boulders at the resort entrance. Across town, on the city’s affluent west side, sod decorates the front of auto dealerships. Homeowners at a gated community called “Beach View Estates” enjoy private docks on their local fake lake. Driving Las Vegas’s broad boulevards, the green tops of palm and pine trees often obscure the bare, red mountains that ring the city.

This amazing oasis is made possible by Lake Mead, located a 45-minute drive from the Strip. The lake – which stretches for 110 miles when full — is a marvel of modern engineering. Capable of holding nearly nine trillion gallons of water, the lake stands out like a vast sapphire amid the rust-colored cliffs and sharp peaks.

Lake Mead is so huge that for generations it was difficult to conceive that it would ever be at risk of being drained. Now, something is amiss. From the shore, even a casual glance reveals that the lake is shrinking. A bright white stripe encircles the lake edge, marking the more than 100-foot-drop from the “normal” water level. Ancient desert spires, once submerged, have reappeared, now as islands. Lake Mead is only half full.

The bleached white rock surrounding the lake marks a sharp dividing line between a now-evaporating era when the Southwest exploded in population and an uncertain future that is forcing the region’s leaders to ask whether they can keep the water flowing.

The Mojave and Sonora Deserts, home to millions of people, are formidably hot and dry places. Modern life in the region is possible only because of a system of reservoirs that collects the precipitation from hundreds of thousands of square miles and stores it. According to climate models, the region is set to become even hotter and drier – and, for water managers, more formidable. Some desert communities may find relief by transferring water from other areas. But as climate change forces water levels down, efforts to cut CO2 emissions will push energy prices upward, making some large-scale water transfers uneconomical. The abundant water and cheap energy that have fueled the Southwest’s transformation are starting to dry up.

“By 2025 or so we are headed for a train wreck in the West,” says Tim Barnett, a researcher at the Scripps Institution of Oceanography, who co-published a study that concluded Lake Mead would be empty by 2021 at current consumption rates. “The truth of the matter is that the Bureau of Reclamation will not let the reservoir go dry. They will just cut off deliveries. And that will send shivers down your spine, because someone will not get the water they are expecting.

“There is no extra water,” Barnett adds. “So when new people come into Phoenix or Tucson, tell them to bring their own water with them.”

photo of a dry riverbed, concrete overpass aboveKaren HalversonIf what currently passes for a low water level becomes the new norm, freshwater
will be in short supply. Already, the Colorado River is dry before it
reaches the Sea of Cortez.

The prospect of water scarcities is ratcheting up tensions in the region, pitting states against each other and causing jealousy between cities and farmers. The likelihood of shortages is forcing conversations about the fundamental sustainability of the Southwest. People are starting to ask: How many humans can live in an arid land?

“With constant growth comes a constant search for water,” says Jim Deacon, a former environmental studies professor at University of Nevada, Las Vegas (UNLV). “At this point, unless we can more efficiently use the water that is here, sustainability means population stability. Fundamentally we are already way too big.”

The Bureau of Reclamation’s headquarters for the Lower Colorado Basin is located in a whitewashed Art Deco-style building in Boulder City, NV, a town that didn’t exist until workers swarmed into the area during the construction of Hoover Dam. The government offices are rather modest, a two-story building surrounded by a broad sweep of lawn. The responsibilities of the employees who work inside, however, are immense.

The Bureau’s most important task is to manage the water stored in Lake Mead as well as in the chain of reservoirs behind the Davis, Parker, and Imperial Dams farther down the Colorado River. Some 25 million people rely on the water in the Lower Colorado Basin, including residents in Las Vegas, Phoenix, Tucson, Los Angeles, and San Diego. The water held behind the dams irrigates an estimated 1.5 million acres of farmland, sustaining a multi-billion-dollar agriculture industry in California and Arizona.

Since a drought hit the region in 1999, the government staff’s work has been as difficult as ever. “There is no additional water in the system,” says Lori Gray, the regional director for the Lower Colorado. “Whether there will be cutbacks, I don’t know. It depends on the precipitation.”

The distribution of the region’s water is governed by the Colorado River Compact. Signed in 1922, the agreement sets out the terms by which Colorado, Utah, New Mexico, and Wyoming (the upper basin), and Arizona, Nevada, and California (the lower basin) divvy up the precious resource. Eighty-five years later, it appears there is a major problem with the agreement: The compact overestimated the total amount of water in the river system.

According to weather records, the compact was developed during an especially wet period in the West. In the 1920s, an average of 18 million acre-feet of water flowed past the monitoring station at Lee’s Ferry, near the Arizona-Utah border. In the first decade of the 21st century, an average of 13.5 million acre-feet has flowed past the same spot. (An acre-foot is the volume of water required to fill one acre one foot deep.)

“That means that all of your uncertainty estimates are skewed,” Barnett says. “You don’t know how much water will flow down the Colorado every year. The last 100 years are not representative of the last 1,000 years, so your predictions are going to be biased, and biased toward wet events.”

Simply put, the assumptions underlying the expansion of the Southwest are flawed. For 30 years, Las Vegas and Phoenix have consistently topped the ranks of the fastest-growing cities in the US. With water becoming scarcer, these cities may be outgrowing the ability of local resources to sustain them.

The Bureau of Reclamation’s reservoir system relies on especially wet years to fill up the lakes and guarantee a steady supply of water. But according to recent studies, the Southwest is susceptible to mega-droughts – decades-long dry periods in which there would be no chance to refill the reservoirs.

David Meko, a researcher at the University of Arizona, has used tree ring records to trace the long-term precipitation patterns in the Colorado Basin. Meko has been able to reconstruct desert weather patterns back to 762 AD. He estimates that a decade-long drought in the Colorado region occurs roughly once a century. During the worst drought he identified, which occurred in the 1100s, six decades passed without a really wet year.

“You go back in time and you’ll see multiple-decade droughts scattered throughout the record,” Meko says. “Since these things have happened in the past, we’ll have that type of variability in the future. … If you had a drought that lasted 10 or 12 years, yeah, there would be some big problems on the river.”

Meko’s findings are compounded by the predictions of climate change forecasters. According to the climate models, water flow in the region is expected to decrease anywhere from two to 40 percent in this century. If what currently passes for a “low” water level becomes the new norm, freshwater will be in short supply.

The concentration of CO2 in the atmosphere is expected to raise temperatures in the Southwest and decrease precipitation. Less rain will mean reduced ability to recharge the reservoirs. Higher springtime temperatures will evaporate mountain snowpack before it has a chance to run off into the rivers. Hotter temperatures will also increase the amount of water that evaporates off the giant lakes; each year, Lakes Mead and Powell lose 1.3 million acre-feet of water to the sun, or about 10 percent of the river’s annual flow.

“We know there are likely to be shortages, but we don’t know how deep,” says Steve Rossi, Phoenix’s water resources manager. “We’ll still have supplies for City of Phoenix customers in 2015. That’s the point when shortages will affect us. We can plan pretty well for the next five to 10 years, but not so well for the 10 years after that.”

Compared with other desert metropolises, Phoenix is blessed. In addition to its share of the Colorado River, the city gets water from underground aquifers and a string of reservoirs in Arizona’s forested northeastern mountains. Las Vegas isn’t so lucky.

“Ninety percent of our water comes from the Colorado. You can’t conserve 90 percent – the fire hydrants wouldn’t work,” says Pat Mulroy, general manager of the Southern Nevada Water Authority (SNWA). Fiercely intelligent and eagerly combative, she is a kind of latter-day William Mulholland, determined to supply enough water to maintain Las Vegas’s breakneck growth. Mulroy – polished and sound-bite ready – is a towering figure when it comes to the water politics of the Southwest; it is nearly impossible to have a conversation about the region’s future without her name coming up.

For Mulroy, nothing is a greater threat to that future than climate change. “Water is in the bull’s-eye of climate change,” she says. “From my vantage point, I won’t spend time arguing about the possibilities [of climate change.] We will lose our upper intake [at Lake Mead] some day. Once the shortages get declared, Las Vegas will lose some of its supply.”

Asked if, in the case of shortages, Las Vegas might use its political clout to force the federal government to keep the water flowing to a major city, Mulroy practically jumps out of her chair.

“What, the Bureau of Reclamation is going to do a rain dance? That’s the problem: People can’t wrap their minds around the idea of an empty Lake Mead.”

To say that Las Vegas or Phoenix is running out of water is to misunderstand a crucial element of how the Colorado River water is divided. There is plenty of water in the system to maintain the strip malls, backyard lawns, swimming pools, and even golf courses that make life bearable in an area where afternoon summer temperatures routinely top 110ºF. But only if water managers were to reallocate some of the water currently used by the desert’s farmers.

About three quarters of the Lower Colorado River water goes to agriculture. Growers in Southern California’s Imperial Valley alone receive about 20 percent of the total allocation. All of this water, it should be noted, comes at sharply subsidized rates.

With cities desperately looking for new sources of freshwater, the farmers’ hefty allotment has become an obvious target of desire.

“Does it make any more sense to have a swimming pool in the desert than it does to grow rice in the desert,” asks Scott Huntley, an official at the SNWA, “or to grow watermelons in the desert, as is done? When it comes to the use of water in agriculture, there is very little talk of conservation.”

photo of irrigating crops in a dry landscapeRobert DawsonAbout three quarters of the Lower Colorado River water goes to desert farmers.

The Southwest’s farmers say that such complaints miss a vital point. While acknowledging that the market value of their crops is dwarfed by the revenues of Las Vegas casinos or the semiconductor factories in Phoenix, they say food carries a value beyond its dollar price. Yes, farmers are using a lot of water, but they are doing so to grow food – some of which ends up on the buffet lines at Excalibur and the Luxor.

“They use the same water that we do, but they use it indirectly,” says Larry Gilbert, a farmer in the Imperial Valley, speaking of Las Vegas. “When they sit down at the dinner table, they use three quarters of an acre-foot a year, indirectly, in the food that they eat. They are using water on my farm so they can have something to eat.”

The trade-off between rural and urban water use can be seen most clearly in the valley where Gilbert has grown sugar beets, wheat, and alfalfa for the past 40 years. In 2003, Imperial Valley farmers agreed to a deal under which they would sell about 200,000 of their annual 3 million acre-feet water allotment to San Diego by cutting back on the acreage they cultivate.

Another way to shift some water away from farmers may be by switching the kinds of crops that are grown. If water becomes more scarce and expensive, farmers might have to abandon water-intensive crops such as rice, cotton, and alfalfa.

“I would predict it’s a matter of time, and not a lot of time, before those types of crops can no longer be grown,” says Scott Stine, a professor of geography at Cal State East Bay. “They are going to have to start shifting some crops, going to crops that don’t involve flood irrigation, for example.”

To farmers, that argument betrays a misunderstanding about the fundamentals of the agricultural economy.

“The question is: Why should we not grow them?” says Ron Rayner, who along with his two brothers and two nephews farms 5,000 acres west of Phoenix. “Alfalfa is our most profitable crop right now. We sell it to Arizona dairies, and it’s our biggest crop.”

In theory, the broccoli grown along the banks of the Colorado River or the alfalfa raised near Phoenix could be cultivated someplace else. But then, say Rayner and Gilbert, other questions of sustainability intrude. Does it really make any more sense to grow food farther away and then truck it – using increasingly expensive petroleum – into the desert? The millions of people living in Las Vegas and Phoenix need to get their milk and produce from somewhere. After all, even craps dealers need to eat.

“If you want to eat, it takes water to produce food,” Gilbert says. “You can do it here, you can do it in Mexico or South America or wherever. It’s a matter of ‘Do you want to import your food from someplace else?’”

Rayner’s flood-irrigated alfalfa fields may give the impression there is water to share. But water experts warn that just because water is available does not mean it is accessible. As climate change threatens to reduce the overall amount of water in the Lower Colorado Basin, it is also contributing to higher energy prices, making it more costly to move water around.

“You can make more water available by retiring farmland,” Phoenix water manager Rossi says. “But how you get the water around logistically and economically is a different question. Every new supply you bring on will be more expensive than the last.”

Modern water delivery systems are extremely energy intensive. In California, the State Water Project, which moves freshwater from the San Francisco Bay Delta to Southern California, is the largest single user of electricity in the state. Similarly, in Nevada, Mulroy’s SNWA uses more electricity than the Las Vegas casinos.

The reason is simple: Water is heavy. A gallon of water weighs about eight pounds. According to Bob Wilkinson, a professor at UC Santa Barbara, it requires about 2,000 kilowatt-hours to move an acre-foot of water from the Colorado River to the cities of Southern California. The transfer of water from Northern California to Southern California is even more energy intensive, gobbling up anywhere from 2,500 kWh to more than 5,000 kWh per acre-foot. (Wilkinson is a founding member of the board of directors of Earth Island Institute.)

missing image fileKaren HalversonThe Southwest’s identity is based on the idea of
constant growth.

“There is lot of concern around energy demand,” says Kathy Jacobs, executive director of the Arizona Water Institute. “A lot of the [water transfer] projections that have been done are probably wrong, because they haven’t taken into account these higher energy costs.”

Energy prices are still relatively cheap enough that it’s feasible to transfer water long distances. But when the US eventually adopts some kind of carbon pricing regime, electricity costs will rise, and some plans may have to be rethought. For example, the river water that currently flows to the fields of the Imperial Valley is mostly gravity fed. Redirecting that water to the coastal cities would require energy intensive pumping.

“We’ve got two conflicting trends here,” Cal State Professor Stine says. “One is the upward spiral of energy, and the other is the rapidly dropping groundwater tables. This is a clash, and the energy prices are going to win out. All of a sudden, the economics are different, if not prohibitive.”

The dynamics of this double whammy may already be at work. As less water runs off into the reservoirs, it decreases what hydroelectric engineers call the “head” – the weight of the water pushing through the turbines. A lake at lower volume means less force through the floodgates, which results in less energy created by the dam’s turbines. Less water = less electricity. And less hydroelectricity means less energy to move the water to thirsty customers.

Environmentalists caution that even if some large-scale water transfers remain economical, that is not the same as saying they are advisable. A century’s worth of damming and re-routing rivers and pumping underground aquifers has already resulted in massive environmental injury. The creation of Lake Powell submerged the unique beauty of Glen Canyon and has contributed to erosion in the Grand Canyon. In California, the damage to Mono Lake and Owens Lake are only the most high-profile examples of how native areas have succumbed to the cities’ thirst. As desert communities grasp for new sources of water, environmental groups worry that sensitive areas will be sacrificed again.

“It’s a tough one, trying to balance out the equities between the urban uses and agriculture, and unfortunately the environment seems to come out on the short end pretty consistently,” Wilkinson says. “It’s not about sustaining where we are at now, because the situation is already pretty bad. It’s about restoration. We have to meet our needs while putting more water back into natural systems.”

In Arizona, worries about the environmental impacts of increased water diversion are playing out in the northern part of the state. As the towns of Prescott and Sedona look for more water, they are developing plans to drill into an important aquifer. Environmentalists say this could reduce flows in the Verde River, the only wild and scenic river remaining in the state.

“We’ve already dried up a lot of our rivers through pumping and damming,” says Sandy Bahr, the executive director of the Arizona Sierra Club. “Those kinds of places are special in an arid land, so we want to keep them.”

A similar, if more high-profile, fight is underway in Nevada, where Mulroy’s SNWA is planning to pump water from Spring Valley, an agricultural district 300 miles from Las Vegas. The water authority already has the permits in place to pump 60,000 acre-feet of water a year from the valley and is pursuing permission to transfer an additional 120,000 acre-feet annually from the adjacent Snake Valley. Ranchers in the area are vehemently opposed to the proposed $3.5 billion pipeline. They say the water transfer will destroy the aquifer they use for growing alfalfa and dry up local springs that endemic species rely on.

“The water project poses a massive threat to the biodiversity of the region,” says retired UNLV Professor Deacon, who has published a study on the environmental costs of the pipeline. “The whole southern part of the Great Basin would be impacted twice as much by the proposed water project as what has happened over the past 12,000 years.”

Launce Rake, a spokesperson for the Progressive Leadership Alliance of Nevada, a coalition of labor and environmental groups that has battled with Mulroy’s agency over the planned water transfers, is more emphatic: “It is really hard to overstate the opposition in rural areas to the idea that Las Vegas should defoliate the rest of the state for more slot machines and tract houses. … We are looking at the very real destruction of the Great Basin. When we send dust storms across the US, what’s Pat Mulroy going to say? ‘My bad?’”

Mulroy has little patience with such rhetoric. She says the water authority will be very careful in the way it extracts water from the area. If signs of environmental damage begin to appear, the water authority will move the wells to other areas of the valley or slow the pumping. And, Mulroy adds, Las Vegas has few other options: Either the city goes to other parts of the state to find water, or else it will begin to decline.

“I don’t want to destroy the world for my kids – those are incredibly beautiful areas,” Mulroy says. “But we have to have a balance. We have to bring water in from somewhere outside the Colorado River Basin because right now we’re being the eight ball.”

At the center of the freshwater fights rests a larger question of ecological sustainability that the region’s policy makers have been reluctant to address: How many people can live in these desert environments?

That question has long preoccupied Grady Gammage, Jr., an attorney who has represented some of the state’s biggest developers. A former president of the Central Arizona Project (the canal that brings Colorado River water to Phoenix and Tucson) and a lecturer at Arizona State University, Gammage has thought deeply about the challenges of maintaining the quality of life that attracts some 40,000 new residents to Phoenix every year.

“If you want, you can cram another 10 to 12 million people into the Sun Corridor [between Phoenix and Tucson], but you won’t be able to live with the landscape we have now,” Gammage says. “They’ll be living in crushed granite and dust. I’m unwilling to consign myself to the idea that it will get so bad.”

For Gammage, the fundamental challenge for Phoenix lies in developing an identity that is not grounded in growth. The difficulty of that task can be glimpsed on the city’s metastasizing west side, where the frames of fresh apartment buildings rise from among the cacti. The city’s ethos is based on the idea that nothing is as valuable as being new – new homes, new streets, new neighborhoods, new schools.

“Right now, everything we do in Phoenix, everything, is based on the assumption that growth is the goal,” Gammage says. “People can’t grasp the idea of becoming a stable and mature city. That’s inconceivable to people. It’s all about growth. We don’t have another way of thinking about this place.”

Las Vegas has a similar state of mind. The defining element of the city’s skyline is the construction cranes that are always a-swivel. In June, at least 10 high-rise buildings were under construction, and for every new casino that is built, new homes are needed for the employees to live in. The housing boom ever expands the city’s edge, as dun-colored McMansions march relentlessly toward the desert cliffs.

According to Pat Mulroy, there is no way to stem the inflow of new people. Her responsibility, as she sees it, is to ensure that the water is there for the immigrants. “People are going to go to where they find jobs,” she says. “You have to put those people somewhere, and no matter where you put them, you’ll have water challenges. For us, the key isn’t whether we grow – it’s inevitable. It’s how we grow.”

Jim Deacon isn’t so sure. “It’s really stupid, I think, to maintain the very aggressive pro-growth policies that the Las Vegas city fathers have been promoting since Hoover Dam was completed,” he says. “There was this expectation that the water is so abundant that we will never be able to use it all. And now we’re looking for more water because we keep growing.”

Well aware of the need to reduce water use, both Phoenix and Las Vegas have worked to promote household water conservation. During the last decade, Phoenix has kept its water consumption to 340,000 acre-feet a year even as its population has grown. Las Vegas has launched a widely praised “cash-for-grass” program that offers homeowners a rebate for ripping out their lawns.

But the effectiveness of conservation programs is undermined by the perception that the water is just being saved to make room for more newcomers – not to restore river systems or recharge groundwater aquifers. With tens of thousands of people pouring into the desert every year in search of sun and swimming pools, long-time residents often greet the conservation campaigns with cynicism.

“The mindset in the public policy arena is always, ‘How can we shift water around?’ but not, ‘We should conserve and change,’” says Bahr of the Arizona Sierra Club. “But a problem with getting people to conserve is that they think they are just being asked to conserve to jam more houses in here.”

Phoenix City Water Manager Rossi acknowledges that as long as the metropolitan area continues to grow, any water savings are merely being banked for future use. “Our work is about delaying that redline,” he says. “If we were in a static population, conservation would maintain the status quo. But especially in a growth situation, conservation just prolongs the day of reckoning.”

Located one block from the city’s busy Papago Freeway and right underneath the landing path of jets headed for Sky Harbor Airport, Phoenix’s Pueblo Grande Museum and Archaeological Park is a haunting reminder of the difficulty of surviving in a desert environment. Inside the museum’s walls stand the remains of an adobe castle that was once at the center of a thriving civilization. For more than 1,000 years, the lodge was home to a society of advanced engineers. Then, the people abandoned the place.

Before Columbus arrived, a highly organized, urban culture flourished along the banks of the Salt River, which used to flow year-round but is now dammed and dry. From roughly 300 to 1380, the Hohokam (or Tohono O’odham) built and maintained an elaborate network of irrigation canals snaking across the valley. Using only digging sticks and stones, the Hohokam carved some 1,000 miles of canal to irrigate about 10,000 acres of corn, beans, squash, and cotton. The canals – some of which stretched seven miles long – were so well designed that when 20th century engineers began laying out Phoenix’s water system, they simply reused the prehistoric channels.

For centuries, the Hohokam carefully improved and perfected the canal system despite cyclical floods and droughts, and the civilization’s numbers steadily grew to as many as 50,000 people. But as the population increased, the human settlement started to overexploit key resources. After a particularly devastating flood in the 14th century, the people decided not to rebuild the canals, and the civilization collapsed.

“There was a breakdown in the system, and that, of course, was due in large part to an increase in their population and an inability to have their agricultural productivity meet their population,” says Todd Bostwick, Phoenix’s head archaeologist. “The challenges of maintaining sustainable water levels to match the population is a story that goes back 2,000 years. Every culture that comes here has to confront that challenge.”

Of course, it’s dangerous to draw too many lessons from the prehistoric past. Comparisons can run afoul, especially when measuring an agrarian, stone-technology society against a giant, industrial economy. Nevertheless, the fundamentals remain the same. Even an information society relies on natural resources, and few resources are as essential as water, without which it’s impossible to grow the food we need for our basic survival. The difficulties confronted by the Hohokam – maintaining a comfortable quality of life in the middle of the desert – are the same as ones that southwestern cities face now.

“The system broke down as the average Hohokam decided not to participate,” Bostwick says. “They are a model to study for the problems we have today. Here is a sustainable society that fails. And it has to do with the management of water and population. Sound familiar?”

Jason Mark is the editor of Earth Island Journal. A Phoenix native, he co-wrote Building the Green Economy: Success Stories from the Grassroots.

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