Los Angeles traffic is worse than usual as hordes of parched citizens evacuate a concrete tomb that once supported millions of lives. Savvy entrepreneurs are selling bottled water from wheeled coolers for $40 a piece. Windshields are caked with desert dust and cars are overheating. The city is nearly engulfed by wildfires. People swarm slowly moving cars after they abandon their own on the road, because the gas stations have gone dry from overuse. Children eat canned food; it's all they have left.
America is unlikely to let a city slip into that sort of dystopic future. But some of our Western cities are on a dangerous path to losing access to water. And the results could be devastating to the future of those communities if they don't fundamentally alter how they manage their resources.
No one expected Los Angeles, Phoenix, Las Vegas, or the cities of West Texas to sustain the kind of population they do now when the cities were founded. The towns made sense at the time: rivers, lakes, and natural springs provided enough water to support a small population. As the towns grew, they learned to cast their nets out to further water supplies. In the early 1900s, residents of the Owens Valley area of California bombed the brand new Los Angeles Aqueduct with dynamite in protest of the city taking water from their farmland. Today, governed by a complex legal agreement between seven states, the Colorado River alone brings water to Los Angeles, Las Vegas, Phoenix, Tucson, San Diego, and many others. We've grown used to dry cities finding water where they can—for now.
With some scientists saying California could be in the midst of a 35-year megadrought, and other parts of the southwest feeling the same strain, desert cities in America will have to cope with more water scarcity, projected climate-change-induced temperature increases of up to 10 degrees Fahrenheit and a continuing growth in population. Some estimates put the population of the Greater Phoenix area at around 28 million by the year 2050, from its current population of about 4 million. That's a lot of extra water. There are several ways to combat these problems and change the ways desert cities exist.
WATER HARVESTING AND RECYCLING
There are many ways to capture water, including new concepts like billboards that harvest humidity and funnels it to collect rainwater, but these methods can only go so far. As the drought continues and population grows, more drastic water capturing must be used.
Desalination of seawater, where seawater is collected and salts and other solids are removed, is an expensive but advancing option. Currently, a large-scale desalination plant can range from $400 million to $1 billion. The technology is become more efficient and cost-effective, though, and it will likely become a valuable resource for coastal cities. Even at its current price, cities will do what they have to to survive. "Cities are wealthy, and if it's possible to attain water by spending money, then cities can and will do that," Michael Hanemann, a chancellor's professor and professor of environmental and resource economics at the University of California, Berkeley, told Co.Exist. He believes desalination will be a major player in the next few decades, but he says other methods of water harvesting and recycling will take hold first and eventually complement desalination. Perth, Australia, has already found success with such techniques and produces half of its water with seawater desalination.
Desalination doesn't only apply to seawater. Hanemann explains that for non-coastal cities and coastal cities alike, desalinating brackish groundwater is a great option. While seawater contains over 35,000 milligrams per liter (mg/l) of total dissolved solids (TDS) like salt, brackish groundwater only contains around 1,000 to 10,000 mg/l. It's the groundwater we previously thought was too dirty to use, but it's actually much easier and cheaper to clean than seawater. Texas estimates it has 880 trillion gallons of the stuff, which could conceivably support the state for over a century. The city of El Paso, Texas, is already desalinating brackish groundwater and currently gets 25% of its water from it.
It's not that pleasant to think about, but water can also be recycled from, well, used water. Wastewater that is cleaned and processed already provides Los Angeles County with 65 million gallons of water per day. "Los Angeles and many cities in California are making large investments in water recycling, and in this case it's turning out to be potable water recycling. So, they're taking sewage effluent from the city and they're doing advance treatment on it and putting it back into the drinking water supply," says David Sedlak, a professor in mineral engineering at UC Berkeley and co-director of the Berkeley Water Center. "Even in the middle of a drought, there's still wastewater coming from wastewater treatment plants." It's very likely more wastewater recycling programs will be required in the future for desert cities.
A NEW KIND OF CITY
Beyond obtaining and recycling water, desert cities of the future will have to restructure in order to become more water efficient and more hospitable to rising temperatures and growing population. City planning, rethinking the water industry and new lifestyles can attain a sustainable desert city. In Making Desert Cities, by Arizona State University architecture professor John Meunier, he explains the needs of a desert city.
In an effort to maintain shade to protect us from scorching temperatures, we often plant trees, but trees often take up valuable water resources. Future desert cities in America will have to become more like cities of the Middle East. As opposed to walking along vehicle roads that will become hot from the asphalt reflecting the sun, "pedestrian dominated parts of the desert city should be served, not by streets predominantly conceived of as vehicular roadways with pedestrian sidewalks, but as relatively narrow shaded pedestrian ways, with limited access for service and emergency vehicles as well as purely local traffic," Meunier writes.
American desert cities of the future will benefit from pedestrian alleyways and streets that receive shade from overhangs and other manmade shading. Alleys that lead to social courtyards will be the destination of future city dwellers, and such alleys and pathways can be designed to harness consistent airflow to maintain lower temperatures. "As we get smarter about outdoor water use and stop growing trees and lawns in desert cities, we're probably going to have to spend more of our time indoors and crank up the air conditioners," David Sedlak says.
Future plant life of desert cities will have to mimic the plants that naturally live in the desert. Xeriscaping, where desert plants replace grass and other fixtures that wouldn't naturally survive a desert climate, will help conserve water and create an environment more logical for desert living.
We'll also have to build up, instead of out. Residential areas in desert cities will have to be taller and contain more people, as to be more efficient with water and energy. "Higher density residential developments would use substantially less water on a per capita basis because outdoor landscapes and water are leveraged over more people," Patricia Gober, co-Director of the National Science Foundation’s Decision Center for a Desert City, writes in "Water, Climate and the Future of Phoenix." "Smaller lot sizes and a shift from single to multi-family living units and from low to high rise development would allows significantly more people to reside in the region, even at existing use rates for particular kinds of housing units."
GIVING WAY TO CHANGE
"The idea that [desert cities] could function as a long-term water supply for any [business] sector that has to have reliable water supply I think is going away and going away quickly," says Laura Huffman, state director of the Nature Conservancy of Texas. She said that the fracking industry in Texas, which many worry contaminates water anyway, will have difficulty continuing to use the large amounts of water it needs to collect natural gas in desert areas. Other industries that rely on a heavy and consistent water supply may be eradicated as well.
It's unlikely these industries will cease to exist, but they will likely have to move away from the desert. One can imagine they will stick it out as long as possible, putting the business needs of water at odds with the people in our desert cities. Who will win a conflict between the demands of industry and the resources to sustain life for the booming populations?
In California, 80% of the water is used in agriculture and "there's nothing that says we couldn't increase the urban water supply by 50% just by reducing the agricultural water supply from 80% to 70%," says David Sedlak. A portion of California's agriculture may also be on its way out further down the line, but farmers can get smarter about water use as well.
Legislation that supports these changes and helps fix the water problem in America has been slow but somewhat steady. It is clear that states will start taking more drastic action as living needs become more dire. There are many solutions to the major problems desert cities can face, but situations like Phoenix where there are dozens of water suppliers and competing interests means that people will have to work together. Water will need to move toward real regulation, cities will have to transform, and desert inhabitants will have to get used to a different way of living.