Water, Water Everywhere...: But Will There Be Enough?
Sep 28, 2011 10:19AM
● By Sandra Postel
For at least three decades, Americans have talked about our uncertain energy future, but we’ve mostly ignored another worrisome crisis—water.
Cheap and seemingly abundant, water is so common that it’s hard to believe we could ever run out of it. Ever since the Apollo 8 astronauts photographed Earth from space in 1968, we’ve had the image of our home as a strikingly blue planet, a place of great water wealth. But of all the water on Earth, only about 2.5 percent is fresh—and two-thirds of that is locked up in glaciers and ice caps. Less than one hundredth of 1 percent of Earth’s water is fresh and available.
Across the United States and around the world, we’re already reaching or overshooting the limits of Earth’s natural replenishment of fresh water through the hydrologic cycle. The Colorado and Rio Grande rivers are now so over-tapped that they discharge little or no water into the sea for months at a time. According to the U.S. Geological Survey (USGS), the massive Ogallala Aquifer, which spans parts of eight states, from southern South Dakota to northwest Texas, and provides 30 percent of the groundwater used for irrigation in the country, is steadily being depleted. In much of the world, we’re growing food and supplying water to communities by over-pumping groundwater. This creates a potential crisis in the food economy: We are meeting some of today’s food needs with tomorrow’s water.
The Changing Climate Equation
Due to climate change, we may no longer be able to count on familiar patterns of rain and snow and river flow to refill our urban reservoirs, irrigate our farms and power our dams. While farmers in the Midwest were recovering from the spring flood of 2008 (in some areas, the second “100-year flood” in 15 years), farmers in California and Texas allowed cropland to lie fallow and sent cattle to early slaughter to cope with the drought of 2009.
In the Southeast, after 20 months of dryness, then-Georgia Governor Sonny Perdue stood outside the state capitol in November 2007 and led a prayer for rain. Two years later, he was pleading instead for federal aid, after intense rainfall near Atlanta caused massive flooding that claimed eight lives. This year again saw record regional precipitation, this time producing epic flooding in the Mississippi and Missouri river basins.
The United States withdraws more fresh water per capita than any other country, much of which we could save. The vast majority of demand does not require drinkable water.
Source: Pacific Institute
Climate scientists warn of more extreme droughts and floods and changing precipitation patterns that will continue to make weather, storms and natural disasters more severe and less predictable. As a policy forum in the journal Science notes, the historical data and statistical tools used to plan billions of dollars worth of annual global investment in dams, flood control structures, diversion projects and other big pieces of water infrastructure are no longer reliable. Yet today’s decision about using, allocating and managing water will determine the survival of most of the planet’s species, including our own.
For most of modern history, water management has focused on bringing water under human control and transferring it to expanding cities, industries and farms via dams, large water-transfer projects and wells that tap underground aquifers. Major water programs have allowed cities like Phoenix and Las Vegas to thrive in the desert, the expansion of world food production, and rising living standards for hundreds of millions. But globally, they have worsened social inequities as tens of millions of poor people are dislocated from their homes to make way for dams and canals, while hundreds of millions in downstream communities lose the currents that sustain their livelihoods.
Such approaches also ignore water’s limits and the value of healthy ecosystems. Today, many rivers flow like plumbing works, turned on and off like water from a faucet. It’s tougher for fish, mussels, river birds and other aquatic life to survive; a 2008 assessment led by the USGS found that 40 percent of all fish species in North America are at risk of extinction.
Meanwhile, many leaders and localities are calling for even bigger versions of past water management strategies. By some estimates, the volume of water relocated through river transfer schemes could more than double globally by 2020. But mega-projects are risky in a warming world, where rainfall and river flow patterns are changing in uncertain ways and require costly power for pumping, moving, treating and distributing at each stage.
Some planners and policymakers are eyeing desalination as a silver bullet solution to potential water shortages. But they miss—or dismiss—the perverse irony: by burning more fossil fuels and by making local water supplies more and more dependent on increasingly expensive energy, desalination creates more problems than it solves. Producing one cubic meter of drinkable water from salt water requires about two kilowatt-hours of electricity, using present technology.
Water for People and Nature
Thus, a vanguard of citizens, communities, farmers and corporations are thinking about water in a new way. They’re asking what we really need the water for, and whether we can meet that need with less. The result of this shift in thinking is a new movement in water management that focuses on ingenuity and ecological intelligence instead of big pumps, pipelines, dams and canals. These solutions tend to work with nature, rather than against it, making effective use of the “ecosystem services” provided by healthy watersheds and wetlands. Through better technologies and informed choices, they seek to raise water productivity and make every drop count.
Communities are finding that protecting watersheds is an effective way to make sure water supplies are clean and reliable; plus, they can do the work of a water treatment plant in filtering out pollutants at a lower cost. New York City is investing $1.5 billion to restore and protect the Catskill-Delaware Watershed, which supplies 90 percent of its drinking water, in lieu of constructing a $10 billion filtration plant that would cost an additional $300 million a year to operate. Research published in Natural Resources Forum further shows that a number of other U.S. cities—from tiny Auburn, Maine, to Seattle—have saved hundreds of millions of dollars in capital and operating costs of filtration plants by instead opting for watershed protection.
Communities facing increased flood threats are achieving cost-effective protection by restoring rivers. After enduring 19 floods between 1961 and 1997, Napa, California, opted for this approach over the conventional route of channeling and building levees. In partnership with the U.S. Army Corps of Engineers, a $366 million project is reconnecting the Napa River with its historic floodplain, moving homes and businesses out of harm’s way, revitalizing wetlands and marshlands and constructing levees and bypass channels in strategic locations. Napa residents will benefit from increased flood protection and reduced flood insurance rates, plus new parks and trails for recreation, higher tourism revenues and improved habitats for fish and wildlife.
Communities prone to excessive storm water runoff can turn existing structures into water catchments. Portland, Oregon, is investing in “green roofs” and “green streets” to prevent sewers from overflowing into the Willamette River. Chicago now boasts more than 200 green roofs—including atop City Hall—that collectively cover 2.5 million square feet, more than any other U.S. city. The vegetated roofs are providing space for urban gardens and helping to catch storm water and cool the urban environment. Parking lots, too, can be harnessed.
Water managers in 36 states expect shortages by 2013.
Source: The Wall Street Journal
Many communities are revitalizing their rivers by tearing down dams that are no longer safe or serving a useful purpose, thus opening up habitats for fisheries, restoring healthier water flows and improving aquatic quality. In the 10 years since the Edwards Dam was removed from the Kennebec River, near Augusta, Maine, populations of alewives and striped bass have returned in astounding numbers, reviving a recreational fishery that adds $65 million annually to the local economy.
Conservation remains the least expensive and most environmentally sound way of balancing water budgets. From Boston to San Antonio to Los Angeles, water consumption has decreased via relatively simple measures like repairing leaks in distribution systems; retrofitting homes and businesses with water-efficient fixtures and appliances; and promoting more sensible and efficient outdoor water use.
But the potential for conservation has barely been tapped. It is especially crucial in agriculture, because irrigation accounts for 70 percent of water use worldwide, and even more in the western United States. Getting more crop per drop is central to meeting future food needs sustainably. California farmers are turning to drip irrigation, which delivers water at low volumes directly to the roots of crops. According to U.S. Department of Agriculture figures, between 2003 and 2008, California’s drip and micro-sprinkler area expanded by 630,000 acres, to a total of 2.3 million acres—62 percent of the nation’s total drip irrigation.
Community-based education and rebates to encourage water-thrifty landscapes can help. Las Vegas, for example, pays residents up to $1.50 for each square foot of grass they rip out, which has helped shrink the city’s turf area by 125 million square feet and lower its annual water use by 7 billion gallons.
The water crisis requires us to pay attention to how we value and use water. Across the country, it’s essential that communities work to take care of the ecosystems that supply and cleanse water, to live within their water means and to share water equitably.
Sandra Postel is director of the Global Water Policy Project, a fellow of the Post Carbon Institute and a Freshwater Fellow of the National Geographic Society. She adapted this article, based on her chapter, “Water – Adapting to a New Normal,” in The Post Carbon Reader: Managing the 21st Century’s Sustainability Crises, edited by Richard Heinberg and Daniel Lerch, and a piece published in Yes! (YesMagazine.org). For more information, visit GlobalWaterPolicy.org and NationalGeographic.com/freshwater.
Humans need five to 13 gallons of clean water a day for basic needs.
Source: United Nations Educational, Scientific and Cultural Organization
Indoor direct water use for the average American is 69.3 gallons a day. That’s equal to the combined daily use of one person each in China, Pakistan, Bangladesh, Paraguay, Afghanistan and Somalia.
Primary Source: Residential End Uses of Water, by Peter Mayer
Direct water use for a family of four in the United States is 400 gallons a day. Thirty percent of that is for outdoor use alone, or 30 gallons per person, the same amount a person uses for all daily needs in Algeria.
Source: U.S. Environmental Protection Agency’s Water Sense program
A 1 percent increase in organic matter allows soil to hold 16,000 more gallons of water per acre.
Source: National Sustainable Agriculture Project
One billion people around the world lack access to safe drinking water.
Source: World Health Organization