Droughtbusters
Anita Hamilton, Time Magazine
Record droughts have parched the earth’s crust from Somalia to Texas this year. The effects on the world’s drinking-water supply have been enormous. The level of China’s Yangtze River, the third largest in the world, sank so low this spring that about 400,000 people along its shores were stuck without a local drinking-water source until the government opened the gates of its massive Three Gorges dam to help counteract the crisis. In East Africa, some 10 million people have been punished by the region’s worst drought in 60 years. And in Texas, where wildfires scorched 4 million acres (1.6 million hectares) this summer, the financial losses from starving cattle and blighted crops have reached $5 billion.
Things will likely get worse. According to a new report from McKinsey, by 2030, global water supplies will meet just 60% of the total demand. Meanwhile, we’ll spend an estimated $50 billion to $60 billion per year trying to bridge that gap. But while water scarcity is real, it’s not happening because we have any less than we did a century ago. “We have the same amount of water,” says James Famiglietti, a professor of earth-system science and civil engineering at the University of California at Irvine. But we have 250% more people drinking it. What’s more, climate change means that water is “moving around to different places, even as populations are growing,” notes Famiglietti. The result is not only a shortage but also a mismatch between where water is and where it’s needed.
In the past, we beat water shortages by drilling for groundwater, building dams and erecting massive pipelines. But the enormousness of the problem today demands radical solutions that promote conservation as well as boost supply. “One of the reasons we have been so wasteful in the past is because it has been so easy to find another source of water,” says Peter Gleick of the Pacific Institute. “But those days are over.”
Novel ideas abound. In the Punjab region of India, for example, 6,500 rice and wheat farmers are testing out a $7 device called a tensiometer that analyzes ground moisture in order to prevent overwatering crops. In 2010, farmers using the tensiometer cut their water use by 22%. The trial, sponsored by PepsiCo and Columbia Water Center, will expand to some 50,000 farmers by 2012. Since agriculture accounts for 70% of global water consumption, a large-scale rollout of such devices could create massive savings.
While no single solution makes sense everywhere because of differences in climate, geography and local politics, a few are gaining traction. The best strategy often involves combining several tactics. Here are five smart ways that communities around the globe are fighting back against water scarcity:
1 Tackling the toilet-to-tap taboo Windhoek, Namibia
The idea of drinking water that was once in your toilet bowl may seem like a bad joke, but it’s not. Stripped of its impurities and rigorously tested to ensure its safety, reclaimed water is one of the most inexpensive and reliable supplies of water on earth. “This is where we have to use our rational brains to overcome our natural aversion,” says Alex Prud’homme, author of The Ripple Effect. In Namibia, the driest country south of the Sahara, such recycled water accounts for 35% of the drinking supply in the country’s capital city of Windhoek.
Located some 5,000 ft. (1,500 m) above sea level and surrounded by mountains, Windhoek receives a paltry amount of precipitation–just 14 in. (36 cm) a year on average–which quickly evaporates in the region’s hot, windy clime. Although Namibia sits on the western Atlantic, Windhoek is too high for desalination to be feasible and too far from big rivers to the north and south to build expensive pipelines to them. So this fast-growing city first turned to wastewater processing in 1968 when local reservoirs began running dry. Upgraded in 2002, the New Goreangab Water Reclamation Plant, which cost about $16 million to build, now delivers 2 billion gal. (7.6 billion L) of water a year to the city’s more than 300,000 residents, who use it for everything from drinking to bathing.
Forced through a series of sand and carbon filters as well as ultrafine membranes–some with pores less than one-hundredth the width of a human hair–before being chlorinated and tested for impurities, the treated water is then blended with freshwater piped in from a network of three different reservoirs in a 35%-to-65% ratio. The process is 37% cheaper than pumping in water from distant reservoirs, and the recycled wastewater costs the city less than two-tenths of a penny a gallon to treat.
The economics are persuading many to put aside their prejudices. In 2008, Orange County, California, began treating about 70 million gal. (265 million L) of sewage water that it then pours into its underground aquifers. Meanwhile, Zimbabwe’s capital city of Harare will begin recycling some 21 million gal. (79 million L) of wastewater a day by 2014 for use as drinking water.
2 Success with seawater desalination Perth, Australia
Most of our planet’s surface is covered by oceans, so finding a way to turn our salty seas into something palatable is an obvious solution. Desalination, which typically involves using high pressure to force water through membranes that keep the brine behind, has become increasingly popular, with more than 15,000 desalination plants churning out about 17 billion gal. (64 billion L) of freshwater a day.
One place where desal makes sense is Perth (pop. 1.7 million), the largest city in Western Australia. With daytime watering bans firmly in place and most homeowners already collecting rainwater in backyard barrels to hydrate their gardens, Western Australia’s capital city turned to desal in 2007 as a drought-proof insurance policy when water levels in dams dipped to less than a quarter of their maximum capacity.
Today, a third of Perth’s 96 billion-gal. (363 billion L) annual water supply comes from government-owned desalination plants in nearby Kwinana and Binningup. By the end of 2012, half the city’s freshwater will come from the two plants, which will be powered by renewable-energy credits from wind and solar farms. Households will pay an extra $50 on top of their average annual bill of $700 to cover building and maintenance costs for the additional supply.
Desal is no cure-all. Even as the technology has taken off in much of Australia, Israel and the Persian Gulf, residents in some coastal communities in California, for example, are balking at the costs, which can be up to five times more than for wastewater recycling.
But new measures to reduce desalination’s ecological impact, combined with smart thinking on how to lower the costs of powering the plants, are making desalination much easier to swallow. In July, Siemens announced that it had successfully tested a new desalination technique called electrodialysis that mimics the human kidney’s electrochemical filtering process and uses less than half the power of traditional desalination methods.
3 Mandating rainwater harvesting Bangalore, India
Water scarcity is a problem not just in desert climates. Even Bangalore, in southern India, which gets more than 38 in. (97 cm) of rain a year and is nicknamed the Garden City for its lush, hilly terrain, has been rationing tap water for its 9.5 million residents in recent years. The population has increased nearly 50% since 2001, thanks to an influx of workers to the city, the heart of India’s Silicon Valley. Now half of Bangalore’s 2,000 wells–which account for some 40% of the city’s water supply–have gone dry, and running water is available only two to three hours a day. Shortages have become so bad that some people use bottled water for bathing or buy tanks of it from privately run trucks that drive around town when the city taps shut down.
In 2009, when Bangalore’s water supply fell 25% below the estimated 112 billion gal. (424 billion L) needed each year, the city finally resorted to mandatory rainwater collection on both commercial and residential plots larger than 2,400 sq. ft. (223 sq m). In less than two years, half of the 60,000 households covered by the order began harvesting rainwater on their properties.
Those who have complied have done so without a government subsidy of any sort, even though a typical setup costs about $500. That rate of compliance can be attributed to government threats to cut off the water supply, a rather draconian stick. To ease the transition, the state has set up educational fairs, trained 1,300 plumbers and developed low-cost, compact filters to replace the larger, less effective sandpits used in other areas of the country. In addition, the city plans to offer a 2% property-tax rebate for those who comply by the end of the year. With the program expanding to smaller plots as well as all commercial and government buildings, A.R. Shivakumar, one of the program’s architects, hopes that 40% of the city’s water supply will come from rainwater harvesting within the next few years.
4 Incentivizing conservation Albuquerque, New Mexico
Graced with an abundance of freshwater resources, Americans have long been the poster children for water gluttony, consuming an estimated 147 gal. (556 L) of water per person per day–several times more per person than their counterparts across the pond in England. But even water hogs can change their ways: Albuquerque (pop. 550,000), once one of the most wasteful cities in the U.S., has decreased its per capita water use 38%–from 251 gal. (950 L) to 175 gal. (662 L) per person per day–since 1995, in large part by handing out more than $14 million in rebates for everything from low-flow toilets to more climate-friendly landscaping.
With just 9 in. (23 cm) of rain per year on average, Albuquerque, the largest city in New Mexico, had long gulped down massive amounts of water for outdoor landscaping. As recently as the 1980s, lawns were actually required for residential plots, despite that fact that the city is located on the northern edge of the Chihuahuan Desert.
But since 1996, Albuquerque’s water authority has been paying residents 75¢ per square foot (7¢/sq m) to rip out their thirsty lawns and replace them with native plants that need little water to thrive. To date, some 6 million sq. ft. (557,000 sq m) of turf has been replaced with agave plants, Joshua trees, hyacinths and other desert-appropriate vegetation in a style known as xeriscaping, which has taken off everywhere from Las Vegas to San Antonio.
To get consumers to cut back indoors, Albuquerque has instituted another set of rebates, including $200 off the price of low-flow toilets, $75 for waterless urinals, and $100 off high-efficiency washing machines. The city even pays residents $20 each to attend classes on conservation. “The most effective thing we do is educate our customers,” says Albuquerque’s water-conservation manager, Katherine Yuhas.
Fines and rate hikes play a key role in that education. Since 1995 the city has brought in $1 million in fines, which are levied on homeowners who let water run off their property or turn on sprinklers between 11 a.m. and 7 p.m. from April to October. A new rate hike set to kick in next year will increase residential customers’ bills by about $3 a month, for a total price increase of 154% since 1995. That may sound extreme, but some think the price of water should be even higher. “If you compare the price of water with the price of gasoline, it is grossly underpriced,” notes Upmanu Lall, director of Columbia Water Center.
The city’s mostly gentle nudging has paid off. Since 1994, Albuquerque has saved more than 100 billion gal. (380 billion L) of water. That’s a three-year supply.
5 Closing the water loop, Singapore
The world leader in water conservation is arguably the tiny island nation of Singapore. Smaller than New York City and packed with some 6 million residents, this economic powerhouse located just north of the equator gets plenty of rain but has little room to store it. Its densely populated terrain and sandy soil don’t hold groundwater. As a result, Singapore has had to import up to 40% of the 380 million gal. (1.4 billion L) of water it uses each day from neighboring Malaysia, from which it gained political independence in 1965.
To achieve its goal of water independence before 2061, when its contract with Malaysia expires, Singapore has moved fast to exploit new technologies, promote conservation and ensure that every drop of water used is also recycled.
The Singapore solution has four main “faucets.” First, 17 reservoirs, many of which were created by damming rivers, collect the nation’s 100 in. (254 cm) of annual rainfall. Second, all rain that flows into the city sewers gets recycled as drinking water. Third, the county desalinates water from the surrounding seas to supply another 10% of its drinking water. Most impressive, however, is Singapore’s $3 billion wastewater-recycling system, which channels all water from toilets and other household uses into a 30-mile (48 km) underground tunnel, then sends it out to four water-recycling plants that use reverse osmosis and ultraviolet light for purification. This water is not reused for drinking but instead gets piped to the island’s silicon-wafer plants for use in their water-intensive manufacturing process. The recycled water is also used to cool commercial air-conditioning systems in the country’s many high-rise buildings.
The government’s tiered pricing structure penalizes those who use too much water. Use of dual-flush toilets (which vary the amount of water per flush for liquid or solid waste) and other efficient appliances is strongly encouraged.
“They’ve become the world’s ultimate water conservationists,” notes Cynthia Barnett, author of Blue Revolution, a new book on water scarcity. In 2010, Singaporeans used just 41 gal. (155 L) of water per person per day–a fraction of that consumed by Americans–all while enjoying one of the highest standards of living on earth. Even the city’s many reservoirs double as water parks, where boating and other aquatic sports can be enjoyed by all. It’s real-world proof that conservation doesn’t have to mean deprivation.
