“For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled.”

Richard Feynman


THE LAST OASIS: Facing Water Scarcity

by Sandra Postel


Water scarcity may be to the nineties what the oil price shocks were to the seventies—a source of international conflicts and major shifts in national economies. Water scarcity will affect everything from prospects for peace in the Middle East to global food security, the growth of cities, and the location of industries.

Already, 26 countries have more people than their water supplies can adequately support. Tensions are mounting over scarce water in the Middle East and could ignite during this decade. And competition for water is intensifying between city dwellers and farmers around Beijing, New Delhi, Phoenix, and other water-short areas.

Even as supplies tighten, the Ford Foundation-funded study finds that building large new dams and river diversions is becoming prohibitively costly and environmentally damaging.

In most cases, measures to conserve water and use it more efficiently are now the most cost-effective and environmentally sound ways of meeting water needs. Together they constitute our ‘last oasis’—and they have barely been tapped.

LAST OASIS finds that, with techniques available today, farmers could cut their water demands by 10-50 percent, industries by 40-90 percent, and cities by a third with no sacrifice of economic output or quality of life.

Since 1950 global water use has more than tripled. Traditionally, engineers have met rising demands by building larger water projects and drilling ever more groundwater wells. But limits to expanding the supply are swiftly coming to light.

Falling water tables from the overpumping of groundwater are now ubiquitous in parts of China, India, Mexico, Thailand, the western United States, north Africa, and the Middle East. From the Aral Sea in central Asia to south Florida’s Everglades, the diversion of water for farms and cities threatens to destroy irreplaceable ecosystems that support valuable fisheries and treasure troves of wildlife. And the cost of building new irrigation projects has risen markedly, contributing to a 6 percent decline in per capita irrigated land since 1978.

Africa currently has 11 water-scarce countries—nations with renewable supplies of less than 725 gallons per person per day, a minimum benchmark for being able to meet food, industrial, and household water needs while maintaining a healthy aquatic environment. By the end of this decade, four others will join the list, and the total number of Africans living in water-scarce countries will climb to 300 million, a third of the continent’s projected population.

The Middle East, where 9 out of 14 countries are water-scarce, suffers the most concentrated scarcity in the world today. By the end of the nineties, water problems in the Middle East will lead either to an unprecedented degree of cooperation or a combustible level of conflict.

LAST OASIS makes clear that today, “instead of continuously reaching out for more water, the challenge is to do more with less—by conserving and recycling water and using it more efficiently.” The book shows that currently available technologies and methods can cut water demand dramatically, and gives numerous examples.

In the Texas High Plains, supplied by the dwindling Ogallala aquifer, many farmers have adapted old-fashioned furrow irrigation systems to a new “surge” technique that distributes water more uniformly and reduces waste. Water savings have averaged 25 percent, and the initial investment of about $30 per hectare is typically recouped within the first year.

Israel pioneered the use of highly efficient drip irrigation; Israeli farmers cut average water use on each irrigated hectare by a third, even while raising crop yields. Worldwide, use of drip irrigation has grown 28-fold since the mid-seventies, but still accounts for less than 1 percent of world irrigated area.

Industry has achieved some of the most dramatic gains in conservation, LAST OASIS shows. In Japan, total industrial water use peaked in 1973 and then dropped 24 percent by 1989. Industrial output, meanwhile, climbed steadily. As a result, the value of output from each cubic meter of water supplied to Japanese industries rose from $21 in 1965 to $77 (in real terms) in 1989—a more than tripling of industrial water productivity.

Cities as diverse as Singapore, Los Angeles, Mexico City, and Jerusalem have shown conservation to be a money-saving way of meeting their residents’ water needs. In the greater Boston area, for example, public education, the installation of water-efficient fixtures in homes, industrial water audits, and system-wide leak repair reduced total annual water demand by 16 percent in about 5 years, bringing it down to the level of the late sixties and postponing the need to develop costly new water sources.

The key to realizing these savings is putting in place pricing strategies, policies, and management practices that promote efficiency rather then wastefulness. It’s particularly important to end the widespread practice of heavily subsidizing irrigation, which accounts for two-thirds of the world’s total water use.

The U.S. Congress recently took an important step in this direction with the October passage of legislation reforming operation of the federal Central Valley Project in California. Among other initiatives, it establishes a tiered pricing system to encourage more efficient water use by California farmers, thereby freeing up supplies for cities and improving the environment. Part of an omnibus water bill, the act was awaiting President Bush’s signature at the time this release went to press.

Also in October 1992, a new federal law set national water efficiency standards for new home fixtures and appliances. The standards will gradually cut average indoor water use by 30 percent, helping lower water and wastewater costs nationwide.

LAST OASIS suggests that governments, the World Bank, and development agencies make a complete accounting of the environmental and social effects of large water projects. A more accurate tally of costs and benefits would tip the scales toward efficiency, conservation, and smaller-scale projects.

LAST OASIS also calls for more open markets for buying and selling water. By creating incentives for farmers to irrigate more efficiently and to switch to less thirsty crops, water trading can free up water to meet rising demands without building large new dams. In the United States, 127 water transactions were reported in 12 western states during 1991, with most water being sold by farms and bought by cities. Shifting 7 percent of western agriculture’s water to cities could meet the growth in urban demand projected until the year 2000.

Achieving water balance in some regions will not be possible without a slowdown in population growth. At current growth rates, the populations of 18 of the 20 countries now qualifying as water-scarce in Africa and the Middle East will double within 30 years. No set of technological feats, however imaginative, can win such a race.

LAST OASIS concludes with a call for a new “water ethic” that has the protection of natural ecosystems and equitable use of water at its core. Water is the basis of life, and our stewardship of it will determine not only the quality but the staying power of human societies.

The challenge now is to put as much human ingenuity into learning to live in balance with water as we have put into controlling and manipulating it. In the end, the time available to make this shift may prove as precious as water itself. –END–

“Last Oasis: Facing the Limits”, published in 1992 Buy At Amazon


The data from all graphs and tables contained in this book, as well as from those in all other Worldwatch publications, are available on diskette for use with IBM-compatible computers. This includes data from the State of the World series of books, Vital Signs series of books, Worldwatch Papers, World Watch magazine, and the Environmental Alert series of books. The data are formatted for use with spreadsheet software compatible with Lotus 1-2-3, including Quattro Pro, Excel, SuperCalc, and many others. Both 3 1/2 and 5 1/4 diskettes are supplied. To order, send check or money order for $89, or credit card number and expiration date (Visa and MasterCard only), to Worldwatch Institute (see below or topic “Order and Subscription Information” for ordering information).


Worldwatch Institute is dedicated to fostering a sustainable society—one in which human needs are met in ways that do not threaten the health of the natural environment or future generations. To this end, the Institute conducts interdisciplinary research on emerging global issues, the results of which are published and disseminated to decision-makers, the media, and the public.