Facing a future of water scarcity

Enormous savings of the precious liquid are being thwarted by policies and laws that encourage wastefulness and misuse, rather than efficiency and conservation.

Benjamin Franklin once pointed Bout that, "When the well's dry, we know the worth of water." Much of the world is in danger of learning Franklin's lesson the hard way. For decades, water has been wasted, mismanaged, and overused - and the consequences are beginning to hit home.

Water scarcity typically conjures up visions of drought, the temporary dry spells that nature inflicts from time to time. Yet, while droughts capture headlines, the far greater threat posed by escalating water consumption goes largely unnoticed. Despite 1993's floods, water tables are falling, lakes are shrinking, and wetlands are disappearing. Around water-short cities, competition is brewing between city-dwellers and farmers who lay claim to the same limited supply.

In each major area of water use - agriculture, industry, and cities - demands have increased rapidly. Global water use has more than tripled since 1950, and what is removed from rivers, lakes, and groundwater amounts to 30% of the world's stable renewable supply. People actually rely on a far larger share since water bodies dilute pollution, generate electricity, and support fisheries and wildlife. Because of improved living standards, demand has been growing faster than population - per capita use is nearly 50% higher than it was in 1950 and continues to climb in most of the world.

For decades, planners have met this rising demand by turning to ever more and larger water development projects, particularly to dams and river diversions. Engineers have built more than 36,000 large dams around the globe to control floods and provide hydroelectric power, irrigation, industrial supplies, and drinking water to an expanding population and economy. Rare is the river that now runs freely toward the sea, and many that still do are slated to come under control soon.

Limits to this ever-expanding supply are swiftly coming to light, however. Engineers naturally first selected the easiest and least-costly sites for water development. Over time, water projects have become increasingly complex, expensive to build, and more damaging to the environment. Fewer dams and diversion projects are making it off the drawing boards, and most that do will deliver water at a far higher price than in the past.

Meeting human needs while facing up to water's limits - economic, ecological, and political - entails developing an entirely new relationship to the precious liquid. Historically, it has been managed with a frontier philosophy, manipulating natural systems to whatever degree engineering know-how would permit. Modern society has come to view water as a resource that is there for the taking, rather than a life-support system that underpins the natural world humans depend on. Instead of continuously reaching out for more, people must begin to look within their regions, communities, homes, and themselves for ways to meet their needs while respecting water's life-sustaining functions.

Although water is a renewable resource, it also is a finite one. The water cycle makes available only so much each year in a given location. That means supplies per person, a first-order indicator of water security, drop as population grows. Thus, per capita water supplies worldwide are one-third lower than in 1970, due to the 1,800,000,000 people added to the planet since then.

One of the clearest signs of scarcity is the increasing number of countries in which population has surpassed the level that can be sustained comfortably with the water available. As a rule of thumb, hydrologists designate water-stressed countries as those with annual supplies of about 725-1,450 gallons per person a day. When the figure drops below 725 gallons, nations are considered water-scarce - its lack becomes a severe constraint on food production, economic development, and protection of natural systems. Today, 26 countries- collectively home to 232,000,000 people - fall into the water-scarce category. As many of them have very high population growth rates, their problems are deepening fast. Africa has the largest number of water-scarce countries, 11; by 2010, six others will join the list. At that time, the total number of Africans living in water-scarce nations will climb to 400,000,000, approximately 37% of the continent's projected population.

Nine of the 14 countries in the Middle East face water-short conditions, making this the most concentrated region of scarcity in the world. With populations in several of them projected to double within 25 years, a rapid tightening of supplies is inevitable. Since virtually all Middle East rivers are shared by several nations, tensions over water rights are a potent political force throughout the region and could ignite before the end of the century.

Although the population-water equation suggests where to expect trouble, numerous physical symptoms of stress already exist - not just in water-scarce areas, but in parts of water-wealthy ones as well. Among the most pervasive problems is that of declining water tables, which results when groundwater is used faster than nature replenishes it. If pumping is not brought into balance with recharging, the underground supply eventually becomes too expensive to keep tapping, too salty to use as it is pulled up from greater depths, or simply too depleted to serve as a supply. Overuse of groundwater is now ubiquitous in parts of China, India, Mexico, Thailand, the western US., North Africa, and the Middle East.

Some of the most troubling cases of unsustainable groundwater use involve "fossil" aquifers, underground reservoirs that hold water hundreds or thousands of years old and receive little replenishment from rainfall. Like oil reserves, these aquifers essentially are nonrenewable - pumping water from them depletes the supply in the same way that extractions from an oil well do. Farms and cities that depend on this water eventually will face the dilemma of what to do when the well runs dry.

Shrinking groundwater reserves, falling water tables, and projected demands that far exceed available supplies are clear signals of water stress. Perhaps the most worrying sign of trouble comes from examining the health of aquatic environments. The damming, diverting, and polluting of water-courses with little regard for the environmental services they provide and the species they support has wreaked havoc on the planet's wetlands, deltas, lakes, and riverine habitats. Of all the threatened forms of biological diversity on Earth, aquatic life may be the most in jeopardy.

A distressing conflict has emerged over two of water's roles - as a commodity serving the economic aims of greater agricultural productivity, industrial expansion, and urban growth, and as a key life support for all species and natural communities. Mounting scarcity has thrown this friction into sharp relief. More water devoted to human needs means less for sustenance of ecosystems - and, in many areas, nature is losing out fast.

The infamous shrinking Aral Sea in central Asia is the most dramatic in a long list of natural areas destroyed, degraded, or at grave risk from human use and abuse of water. Among them are many unique wild places - including California?s Mono Lake, south Florida!s Everglades, Spain's Donana wetlands, and Sudan's Sudd swamps - that are home to astounding numbers and varieties of bird and wildlife species.

In many areas, there is a tug-of-war between the demands of conventional economic development and those of aquatic ecosystems. A more pervasive sign of the severely compromised health of the water environment is the number of aquatic species now in jeopardy. In North America, for example, the American Fisheries Society lists 364 species of fish as endangered, threatened, or of special concern - the vast majority of them at risk because of habitat destruction. An estimated one-third of the continent's fish, two-thirds of its crayfish, and nearly three-fourths of its mussels are rare or imperiled. They often reach such status by way of incremental human actions that end up undermining their basic habitat requirements - be it the timing, quantity, or quality of water's flow.

Of the many varieties of native fish species at risk in North America, perhaps the most notable for their cultural and recreational values are several species of salmon in the western US. The winter run of the chinook salmon in California's Sacramento River declined from 120,000 in the 1960s to 400 today, and the species was added to the Federal endangered list in 1989. In 1991, just four adult sockeye salmon made it from the Pacific Ocean past eight Federal dams in the Columbia River basin to their primordial spawning ground at Idaho's Redfish Lake. On the brink of extinction, the Snake River sockeye was listed as endangered in November, 1991.

Each wetland, lake, or aquatic species at risk presents a crucial test of whether a region's people and economy can adapt to the ecological needs of a healthy aquatic system. Only in rare instances are public values and future generations winning out over private rights to dam and divert natural watercourses. A growing movement to protect property rights from government actions to safeguard the environment could tip this balance even further away from ecosystem protection. Unfortunately for the future, protecting aquatic environments and their species still often is viewed as a luxury that can be traded off against pressing economic goals, rather than as essential to preserving the environmental foundation all else rests upon.

Water-thrifty food

production

With agriculture claiming two-thirds of all the water removed from rivers, lakes, streams, and aquifers, making irrigation more efficient is a top priority in moving toward more sustainable use. The possible savings - ranging from 10 to 50% - constitute a large and mostly unexploited new source of supply. Reducing irrigation needs by 10%, for instance, would free up enough water roughly to double domestic water use worldwide.

A wide variety of measures exist to boost agriculture's water productivity, including new and improved irrigation technologies, better management practices by farmers and water managers, and changes in the institutions that govern the distribution and use of irrigation water. While gains have been made in each area, there remains a vast untapped potential.

Some of the biggest technological successes in improving irrigation efficiency have occurred where water scarcity poses serious threats to farming. In Texas, for example, many farmers have adapted old-fashioned furrow systems to a new surge technique that reduces percolation losses at the head of the field and distributes water more uniformly. This has cut their water use by 15-50% while reducing their pumping costs. For those in the Texas Plains, where savings have averaged 25%, the initial investment of about $30 per hectare (2.47 acres) normally is recouped within the first year.

Many irrigators in northwest Texas have moved from high-pressure sprinklers, which typically register efficiencies of 60-70%, to low-pressure ones that boost efficiency to around 80%. A relatively new sprinkler design, known as low-energy precision application (LEPA), offers even greater savings. LEPA sprinklers deliver water closer to crops by means of drop tubes extending vertically from the sprinkler arm. When used with water-conserving land preparation methods, LEPA can achieve efficiencies as high as 95%. Adapting an existing sprinkler for LEPA costs Texas farmers $60-160 per hectare; the water, energy, and yield gains typically pay back the initial investment in two to four years.

Elsewhere, Israel has brought about what widely is perceived as an agricultural miracle over the last three decades. Although it remains to be seen whether that nation's success in making the desert bloom will prove sustainable, Israel has developed technologies, methods, and scientific capabilities in irrigation that could prove invaluable to much of the world as the era of water constraints unfolds.

Among the most heralded of its accomplishments is the development of drip irrigation, whereby water is delivered directly to crops' roots through a network of porous or perforated piping installed on or below the soil surface. This keeps evaporation and seepage losses extremely low. Because water is applied frequently at low doses, optimal moisture conditions are maintained for the crop, boosting yields, and salt does not accumulate in the root zone. Modern Israeli farms often have highly automated drip systems, with computers and monitors sensing when and how much water to apply and determining the precise amount of nutrients to add. Israeli farmers liken their irrigation practices to "feeding the plant with a teaspoon."

New technologies that build efficiency into their designs - such as surge, LEPA, and drip irrigation - can help make crop production less demanding of the world's water supply. Equally important is raising the efficiency of the extensive surface canal systems that dominate the world's irrigated lands. Much land slated for irrigation, and often counted as receiving it, gets insufficient water or none at all because irrigation works are poorly maintained and operated.

Many problems with large canal systems arise because irrigation officials rarely have any incentive to improve the performance of projects they administer. Their operating budget may come from a state or national treasury and bear no relation to how well the system functions. Irrigation fees collected from farmers may go back into a general treasury, rather than being used to operate and maintain the local system. Since farmers have little say in how their projects are managed and are not charged for water according to their use, they, too, have few incentives to use water wisely. In short, there is barely any accountability of those in control, and little control by those who are supposed to benefit.

Especially in government-run projects, some form of "water users association" is necessary for farmers to have a say in management decisions. Such an organization also provides a mechanism for collecting fees to cover operation and maintenance costs and involving farmers directly in maintenance activities. Many studies have shown that, when farmers actively participate in projects and have some responsibility for the operation, canals and other infrastructure function better, a greater proportion of the project area gets irrigated, and crop yields rise.

Another way to stretch freshwater supplies is to use treated municipal wastewater for irrigation. Farmers worldwide spend heavily on chemical fertilizers to give their crops the nitrogen, phosphorus, and potassium that domestic wastewater contains in large amounts. By using municipal water supplies twice - once for domestic use and again for irrigation - would-be pollutants become valuable fertilizers, rivers and lakes are protected from contamination, the irrigated land boosts crop production, and the reclaimed water becomes a reliable, local supply.

By not making wastewater reuse a part of water planning and management, developing countries put their urban and rural populations at risk. As World Bank wastewater specialists Carl Bartone and Saul Arlosoroff note, "Examples abound of local farmers breaking into sewer interceptors both within and on the outskirts of urban areas to steal the effluents for watering their crops. These are often vegetable crops destined for local markets that will be consumed raw. In addition ... highly polluted rivers serve as major water sources for large-scale irrigation projects."

When designed and operated properly, waste stabilization ponds that biologically treat wastewater offer a low-cost way to keep sewage out of rivers and streams, safeguard human health from disease-causing organisms, and produce a nutrient-rich source of irrigation water. Studies have shown them capable of treating wastewater up to the World Health Organization's standards for irrigation of crops not eaten raw. Care always must be taken to prevent heavy metals from getting into wastewater destined for irrigation. Cadmium, copper, nickel, zinc, and other heavy metals can accumulate in crops and soils or percolate to groundwater and contaminate a drinking supply. A key to safe reuse is preventing untreated industrial effluent - often containing heavy metals - from mixing with domestic wastewater.

Finally, producing enough food for the world's expanding population while economizing on water will require boosting yields on the 84% of the planet's cropland watered only by rainfall. The drylands of Africa, western India, north-central China, and southwestern Latin America present formidable challenges to crop production. Altogether, arid and semi-arid lands cover about one-third of the Earth's land surface and are home to 600,000,000 people, including many of the world's poorest farmers. For them, conservation and more efficient use of scarce water quite literally is a matter of life and death.

Attention is turning to the potential of smaller-scale projects - micro dams, shallow wells, low-cost pumps, moisture-conserving land techniques, and a wide variety of rainwater harvesting methods - to make food production more secure for dryland dwellers. Many of these efforts have proved more cost-effective and less disruptive to local communities than the massive schemes that dominated development efforts during the past few decades. Their smaller size and use of local resources tend to make them less damaging to the environment.

Industrial recycling

Collectively, industries account for nearly one-quarter of the world's water use. In most industrial countries, they are the biggest user - frequently accounting for 50-80% of total demand, compared with 10-30% in much of the Third World. As developing countries industrialize, however, their water demands for electric power generation, manufacturing, mining, and materials processing are rising rapidly.

In contrast to that used in agriculture, only a small fraction of industrial water actually is consumed. Most of it is utilized for cooling, processing, and other activities that may heat or pollute water, but do not use it up. This allows a factory to recycle its supplies. American steelmakers, for example, have reduced their water intake to 14 tons per ton of steel, securing the remainder from recycling.

So far, the main impetus for industrial water recycling has come from pollution control laws. Most of the world's wealthier countries now mandate that industries meet specific water quality standards before releasing wastewater into the environment. The most effective and economical way to comply with these requirements often is to treat and recycle water, thereby discharging less. Pollution control laws, therefore, not only have helped clean up rivers, lakes, and streams, they have promoted conservation and more efficient water use.

Given the proper incentives, industries of many types have shown they can cut their water needs 40-90% with available technologies and practices, while at the same time protecting water from pollution. Industrial conservation offers cities facing shortages a large untapped new supply. Ensuring that new factories incorporate conservation and recycling from the outset would help delay costly investments in urban water supplies, reduce overpumping of aquifers, lessen competition for water, and help prevent pollution from reaching levels hazardous to people and wildlife. Closing the industrial water and wastewater cycle not only is technically possible, it increasingly makes good economic and environmental sense.

Homes, apartments, small businesses, and other municipal enterprises account for less than one-tenth of the world's total water use. However, their demands are concentrated in relatively small geographic areas, and in many cases are escalating rapidly. As cities expand, they strain the capacity of local water bodies and force engineers to reach out to ever more distant sources.

In addition, the reservoirs, canals, pumping stations, pipes, sewers, and treatment plants that constitute a modern water and wastewater system require huge sums of money to build and maintain. Collecting and treating water and wastewater also takes large amounts of energy and chemicals, adding to environmental pollution and the over-all costs of a community's water system. Under such constraints, many cities are having difficulty meeting the needs of their residents, and large numbers of low-income households in developing countries get no service at all.

Conservation, once viewed as just an emergency response to drought, has been transformed in recent years into a sophisticated package of measures that offers one of the most cost-effective and environmentally sound ways of balancing urban water budgets. Just as energy planners have discovered that it often is cheaper to save energy than to build more power plants, water planners are realizing that an assortment of efficiency measures can yield permanent savings and thereby delay or avert the need for expensive new dams and reservoirs, groundwater wells, and treatment plants. The idea slowly is spreading that managing demand, rather than continuously striving to meet it, is a surer path to water security while saving money and protecting the environment at the same time.

Raising the price of water to reflect its true cost better is one of the most important steps any city can take. Water consistently is undervalued and, as a result, chronically is overused. The water rate structure of many utilities actually reward waste by charging less the more that is consumed.

Many residences in both industrial and Third World cities are not equipped with water meters, making it impossible to charge people appropriately for their water use. Metering not only is a prerequisite to the success of most conservation measures, it encourages savings in and of itself simply by tying the water bill to the amount used.

Raising water prices often can be politically difficult to do. Yet, if accompanied by public outreach explaining the need for the hike and steps consumers can take to keep bills down, higher prices can have a strong positive effect. When faced with dire water supply conditions in the mid 1970s, for instance, officials in Tucson, Ariz., raised rates sharply to make them reflect the true cost of service better. They also ran a public education campaign called "Beat the Peak" with a goal of curbing water use on hot summer afternoons, when the supply was most in danger of running short. The result was a 16% drop in per capita use within a few years, which, along with the lowered peak demand, allowed the Tucson water utility to cut its expansion expenses by $75,000,000.

Since economic incentives and public outreach will not motivate everyone to conserve, setting water-efficiency standards for common fixtures - toilets, showerheads, and faucets - can be a critical component of a reliable conservation strategy. Legislation that would set national standards passed Congress in October, 1992, as part of a broad energy bill. It requires that all new homes and major remodeling nationwide incorporate water-efficient fixtures and appliances.

Effective pricing, regulations, and public outreach also can help curb water use outdoors. In many dry regions, the sprinkling of lawns accounts for one-third to half of residential water demand. Many communities in the U.S. have turned to Xeriscape landscaping that draws on a wide variety of indigenous and drought-tolerant plants, shrubs, and ground cover to replace the thirsty green lawns found in most suburbs. A Xeriscape yard typically requires 30-80% less water than a conventional one and can reduce fertilizer and herbicide use as well.

In addition to cutting indoor and outdoor use, a comprehensive urban conservation effort will curb waste in the water distribution system itself. As urban water systems deteriorate because of age or lack of maintenance, large amounts can be lost through broken pipes and faults in the distribution network. In most cases, finding and fixing leaks rewards a city not only with water savings, but with a quick payback on the investment. At a cost of $2,100,000, the Massachusetts Water Resources Authority's leak detection program cut system-wide demand in the greater Boston area by about 10%, making it one of the most cost-effective measures in a successful conservation strategy.

What does water cost?

Many of the shortages cropping up around the world stem from the widespread failure to value water at anything close to its true worth. Pricing it properly is especially important in agriculture because wasteful irrigation constitutes the single largest untapped new supply. Yet, water subsidies are larger and more pervasive in agriculture than in any other sector. Governments often build, maintain, and operate irrigation systems with public funds, then charge farmers next to nothing for these expensive services.

Undercharging not only fosters waste and the planting of water-intensive crops, it also deprives government agencies of the funds needed to maintain canals and other irrigation works adequately. Correcting the situation requires bucking deeply entrenched and politically influential special interests, instilling irrigation bureaucracies with a broader sense of mission, and decentralizing water management so that local water suppliers and users have more responsibility and accountability for the performance of their operations.

With the pace of development slowing and supplies no longer expanding in places, new demands increasingly must be met by shifting water among different users - irrigators, industries, cities, and the natural environment. In the western US., competition for scarce supplies has spawned an active water market. During 1991, 127 water transactions of various kinds were reported in 12 western states. Almost all the water sold or leased came from irrigation, and two-thirds of the trades resulted in cities getting more water for immediate or future use.

Exactly how far U.S. water trading ultimately will go in reallocating supplies remains unclear. According to some estimates, redirecting seven percent of western agriculture's water to cities could meet the growth in urban demand projected for the end of the decade. After that, larger shifts would be needed. Unless cities stabilize their water use through conservation, reuse, and, where necessary, limits on the size of their populations and economies, agriculture ultimately could lose more water - and land - than is socially desirable, given the challenge that lies ahead of feeding a much larger world population.

Wherever pricing and marketing fail to take into account the full social, environmental, and intergenerational costs of water use, some additional correction is necessary. In areas with declining groundwater levels, for instance, governments can limit the total amount pumped to the average rate of aquifer recharge. In the case of fossil aquifers, a depletion tax might be levied on all groundwater extractions. In this way, those profiting from draining onetime reserves at least partially would compensate society.

Public action also is required to ensure that ecological systems get the water they need to remain healthy. One option is to limit the total amount that can be diverted from a river, lake, or stream. Protecting water systems also depends on regulating the use of those critical areas of land that help moderate its cycling through the environment. Degradation of the watershed - the sloping land that collects, directs, and controls the flow of rainwater in a river basin - is a pervasive problem in rich and poor countries alike. Besides contributing to flash floods and loss of groundwater recharge, which can exacerbate the effects of drought, it leads to soil erosion that prematurely fills downstream reservoirs with silt, shortening the useful life of expensive water projects.

Many of the measures that can help safeguard water supplies enhance crop production in upland areas. Terracing, mulching, agroforestry (the combined production of crops and trees), and planting vegetative barriers on the contour are a few of the ways soil and water can be conserved while improving agricultural output. On lands unsuitable for cultivation, the menu of options for watershed protection includes revegetating deforested slopes, reducing grazing pressures, and altering timber practices. The challenge for governments is to plan the use of watershed lands with soil and water conservation in mind, recognizing that the way uplands are managed greatly affects the livelihoods of people and the integrity of water systems downstream.

The idea is to devote as much human ingenuity to learning to live in balance with water as has been put into controlling and manipulating it. Conservation, efficiency, recycling, and re-use can generate a new supply large enough to get mankind through many of the shortages on the horizon. However, the pace of this transition needs to quicken if the planet is to avert severe ecological damage, economic setbacks, food shortages, and international conflicts. In the end, the time available to adjust may prove as precious as water itself.

COPYRIGHT 1993 Society for the Advancement of Education
COPYRIGHT 2004 Gale Group