Large-scale water projects have been widely promoted and subsidized as catalysts for economic growth during the twentieth century. Both the economic and environmental costs of developing and diverting additional water supplies for agricultural, industrial, and municipal use have risen markedly in recent decades. This reality and the increasing competition for the economic, environmental, and human health services provided by water suggest that more efficient and sustainable management of existing water supplies is needed. This management must take into account the limits of and ecological processes underlying natural water systems as well as the indigenous knowledge, resources, and supply and demand conditions of individual localities.
The capacity to control water supplies for human purposes has increased markedly during the twentieth century. But as water development has expanded, the opportunities for adding to water supplies have declined, the economic and environmental costs of new supplies have risen sharply, and the threats to supplies from pollution and groundwater depletion have mounted. Demand for water has continued to grow with increases in population and incomes. Despite this rising demand and the increasing scarcity of supplies, fresh water is commonly treated as a free resource.
Some of the environmental and development goals of the United Nations Conference on Environment and Development will not be achieved without adequate incentives to conserve water and to protect the aquatic ecosystems on which future supplies depend. In the developed countries, where high-quality water is taken for granted, the challenge is to manage and use the resource efficiently and sustainably. Developing countries face the additional task of providing all of their people with the minimum supplies of high-quality water that are essential to good health and important to economic development. This task is formidable—31 percent of the people in the developing world lack access to safe drinking water, and 44 percent lack sanitation facilities. Moreover, in developing countries waterborne diseases and illnesses are responsible for diminished economic prospects as well as high mortality and morbidity rates.
Water and economic development
Technological and scientific advances in earth moving, dam construction, pumping, and hydrology have greatly increased the capacity to control the flow of surface waters and to utilize groundwater, which is less susceptible to the vagaries of climate. Although the total quantity of water in the global hydrologic system has not been altered, the location and quality of the resource, as well as the timing of its use, have changed in both developed and developing countries.
Water projects have been viewed as catalysts for broadening economic growth. In the United States, subsidized irrigation projects encouraged the settlement and development of the West. When the U.S. economy sank into a deep depression during the 1930s, water projects were an important part of the strategy for increasing employment and stimulating overall economic recovery. While the United States has developed the world's most extensive system of water projects, efforts to control and divert water for human uses have occurred worldwide. Some of the largest water projects, such as the Aswan Dam on the Nile River, are in the developing countries.
Large-scale water projects have become the accepted strategy for solving most water problems. The distinguished geographer Gilbert F. White has observed that for several decades ending in the 1960s large multipurpose dams were widely viewed as symbols of farseeing, humane management of natural resources. The rapid growth of such projects reflects this view. The number of reservoirs with a minimum storage capacity of 100 million cubic meters began to grow rapidly during the first half of this century in North America, and after 1950 in the world as a whole. From 1950 to 1985, the number of such reservoirs increased threefold and their storage capacity increased ninefold worldwide. Water diversions also rose sharply. Scientists in the former USSR have estimated that global withdrawals increased nearly fivefold between 1900 and 1980, with three-fourths of this increase occurring just within the last three decades.
While drinking is the most critical use of water for sustaining life, by far the largest use is irrigation, which accounts for about 70 percent of all water withdrawals. Agriculture is particularly sensitive to the availability of water. Reliable supplies are essential to the introduction of high-yield farming. Irrigation, which makes farming less susceptible to variability of precipitation, encourages yield-increasing investments and expands the area capable of supporting productive agriculture. Worldwide, the area of land irrigated increased from about 48 million hectares at the start of the twentieth century to 94 million hectares in 1950, and to 250 million hectares currently.
Rising water costs and high government debt burdens make it unlikely that new irrigation projects will receive the generous subsidies that have fostered the worldwide growth of irrigation to date.
Generous subsidies, and institutions that ignore some of the costs associated with agricultural water use, have fostered the growth of irrigation throughout the world. However, rising water costs, high government debt burdens, increasing competition for scarce water supplies, and growing awareness of environmental problems make it less likely that new irrigation projects will benefit from such government largess and myopia. Moreover, high and rising salinity levels in water, dependence on nonrenewable groundwater stocks, and pressures to reallocate water from agriculture to other uses are forcing some previously irrigated lands out of production. In most areas of the world, further expansion of irrigation will depend largely on improved management of existing water supplies rather than on the development of additional supplies.
All irrigation water contains salts that are left behind when water is transpired by plants and evaporated from fields. If allowed to accumulate in the soil, the salts retard and eventually kill the plants. Sustainable irrigation requires application of enough water to leach the salts out of the root zone and then removal of the drainage water from beneath the field. Poor drainage leads to waterlogging, which also destroys the productivity of the land. Salinity has resulted in the abandonment of irrigation on millions of hectares of land and reduced yields on millions more. For instance, in the Aral Sea basin of the former Soviet Union, waterlogging had forced about 1 million hectares out of production by the mid-1980s, and high salt levels reduced crop yields on about 60 percent of the 7.6 million hectares irrigated in the basin.
In parts of the United States, India, and China, and in many other areas, current water use depends on nonrenewable supplies. Although the extent of groundwater supplies worldwide is unknown, groundwater use exceeds recharge on about 4 million hectares in the United States—20 percent of the total area irrigated in the United States. Depletion of the Ogallala aquifer already has contributed to the termination of irrigation on about 1 million hectares in the U.S. High Plains.
As water becomes increasingly scarce, pressures will mount to develop additional supplies and to transfer water from agriculture to other uses. Transfers are already occurring in the western United States, and the high costs of new supplies will make water marketing increasingly attractive in other places. Rising water costs are inevitable for three reasons. First, because the best sites are developed first, subsequent additions to a basin's water storage capacity are increasingly expensive. Second, storage increases a river basin's safe yield only at a diminishing rate. And at some point evaporation losses can more than offset any gains in safe yield associated with additional surface storage. Finally, the social costs of storing and diverting water for offstream use rise as streamflows are depleted.
Water development and the environment
Water projects and water use alter the natural environment. The environmental impacts can be good and bad. For example, a reservoir creates a new environment that favors some organisms at the expense of others and replaces the esthetic and recreational benefits of a free-flowing stream with those of a lake. As water use intensifies, however, the net effects are likely to be negative, particularly when water development and use proceed without adequate regard for ecological processes and for the environmental values provided by natural water systems.
Among other reasons, increasing competition for water will make expansion of irrigation largely dependent on improved management of existing water supplies rather than on development of additional supplies.
These processes and values often are overlooked in plans designed to use water as a catalyst for economic development. Planners and managers routinely emphasize the positive and ignore or understate the negative impacts of water projects. For instance, reduced flooding and more reliable supplies for offstream use might be viewed as unmitigated benefits of dams and reservoirs, while any adverse impacts on the ecology of downstream areas dependent on annual flooding and silt deposition are ignored. Likewise, the negative impacts on aquatic ecosystems of withdrawing water from and returning contaminated effluents to streams or lakes are often excessively discounted.
The U.S. experience up to the passage of the Clean Water Act in 1972 illustrates how a strong development bias combined with policies that foster an illusion of unlimited supplies of inexpensive fresh water can erode the productive, recreational, and esthetic values of a nation's water resources. In the fifteen years following passage of the act, the nation has spent more than $100 billion to limit and treat industrial and municipal wastes discharged into lakes and streams. Although the act's goal of restoring all navigable water to fishable and swimmable condition has not been reached, the overall quality of these wa-ters has improved markedly since the early 1970s. Changes in public attitudes and policies prompted by environmental concerns have altered water use and development patterns significantly. Water project construction peaked in the late 1960s, per capita water withdrawals peaked in 1975, and total withdrawals peaked in 1980.
Despite the overall improvement in water quality, many lakes and streams remain too polluted to fully support their designated uses. Nonpoint pollutants such as runoff from farms, urban areas, and construction sites are now the primary sources of pollutants reaching the nation's waters. The United States has not developed an effective strategy for curbing these pollutants. Moreover, investments to control municipal and industrial pollutants are yielding diminishing returns.
Large-scale water projects have played a prominent role in development efforts throughout the developing world in recent decades. Unfortunately, disappointing economic benefits and unanticipated environmental costs have characterized many of these projects. Thayer Scudder, an anthropologist with the California Institute of Technology, has documented how the hydroelectric potential of the river basins in tropical Africa has been developed largely for the benefit of the cities at the expense of the ecology and most of the rural people. Even when irrigation has been included as an important project objective, the resulting agricultural benefits often fail to compensate for the negative impacts on the productivity of riverine habitats that previously supported millions of people.
Drinking water and human health
The differences between the developed and developing countries are many, but few have more impact on human welfare than the access of people to safe drinking water and adequate sanitation. Most residents of the industrialized world take for granted that virtually unlimited supplies of high-quality water can be available at the turn of a tap and that human and household wastes are removed quickly from their homes and neighborhoods. In contrast, more than 1.2 billion people in the developing world do not have access to safe drinking water supplies, and 1.7 billion do not have decent sanitation (see table, p. 24).
Inadequate drinking water supplies and sanitation facilities can have devastating impacts on mortality and morbidity and can seriously impede economic development.
Inadequate drinking water supplies and sanitation facilities can have devastating impacts on mortality, morbidity, and the economy. Water-related diseases and illnesses are responsible for the deaths of most of the 5 million children under five who die annually in Africa. Guinea worm and schistosomiasis, parasitic diseases propagated by poor sanitation and unsafe water supplies, are often painful and debilitating. Guinea worm reportedly afflicts about 20 million people in sub-Saharan Africa, India, and Pakistan. The schistosome parasite is believed to infect more than 200 million people, 20 million of whom suffer from chronic schistosomiasis. Poor sanitation and drinking water are largely responsible for the deadly cholera epidemic currently spreading through several countries in Latin America and Africa.
Economic prospects are seriously impeded by poor health conditions as well as by the countless hours that people in developing areas must spend carrying water. In western Nigeria, for instance, farmers afflicted with Guinea worm typically lose 100 work days a year. And in villages lacking water supplies, families may spend many hours each day carrying the minimum quantities of water for drinking and domestic uses from distant and often contaminated sources.
Water and sanitation services in the developing world (millions of people)
The lack of basic water and sanitation facilities in the developing countries and their importance to human welfare and sustained development prompted the United Nations to designate the 1980s as the International Drinking Water Supply and Sanitation Decade. During that decade, global efforts extended water service to an additional 1.3 billion people and sanitation service to another 748 million in the developing world. While impressive, these results fall well short of the U.N. goal of providing clean drinking water and sanitation for all by 1990. Sanitation facilities failed even to keep pace with population growth, as the number of people lacking these services increased by 6 million during the decade. And the provision of both water and sanitation facilities lagged behind the explosive growth of urban areas, where another 31 million were without adequate water supplies and 85 million were without sanitation (see table, p. 24).
Among analysts, there is a growing belief that more efficient water management practices and sounder funding arrangements are required to provide water and sanitation services in the developing world.
The largest shortfalls were in Africa, where population growth in excess of 3 percent annually and an 80 percent increase in urban population during the "water decade" overwhelmed capacity to provide water and sanitation services. The number of people without safe water rose by 20 million and those with inadequate sanitation increased by 30 million. In May 1990, delegates from 46 African nations met in Ivory Coast to develop a strategy to reverse this trend. The delegates recommended that future investments in water and sanitation be based on effective demand and recovered through user fees—a surprising outcome in view of the extreme poverty that characterizes their countries. Moreover, they supported privatization of these services as a means of promoting greater efficiency. These recommendations run counter to the tradition of providing highly subsidized water through government agencies. But they reflect a growing belief among analysts that more efficient water management practices and sounder funding arrangements are required to provide water and sanitation services to the developing world's rapidly growing population.
Improving water management
The demands for water and the services it provides will continue to grow. In the developing areas of the world, population growth and economic development efforts suggest that domestic, industrial, and agricultural water demands will grow rapidly. In the developed countries, demands for the environmental services provided by clean streams and lakes may grow more rapidly than the demand for withdrawal uses. In most areas, allocating water for one use—whether it is for irrigating crops or preserving instream flows—will involve tradeoffs. There is no free water. Moreover, the costs of meeting new water demands are generally high relative to the prices people are accustomed to paying for water use. And these costs will rise as the demand for water increases.
Efficient and sustainable water development and use must take into account the limits of and the ecological processes underlying natural water systems. The traditional structural response to increasing water demands has often ignored these limits and processes, resulting in some unfortunate environmental and human consequences. Greater emphasis should be given to improving the management of the existing supplies and infrastructure and to allocating scarce supplies effectively among competing uses.
Two factors are fundamental to improved water management. First, because all the water resources within a basin—precipitation, runoff, water in lakes and streams, and groundwater—are interrelated, evaluation of a water project or water use should take into consideration potential impacts on the entire hydrologic system and on the ecological system of which it is an integral part. Basinwide management is particularly difficult to achieve when rivers and aquifers cross international borders, as they commonly do. Yet it is in such situations that improved management may be needed most to avoid dangerous conflicts over scarce water supplies. Second, local people must be integrated effectively into the planning, management, and maintenance processes. The failure to take adequate account of indigenous knowledge, resources, and demands underlie many of the inefficiencies and adverse environmental impacts that have plagued water projects.
Consideration of the potential impacts of water use on ecological systems, and integration of indigenous knowledge, resources, and demands into water projects are fundamental to improved water management.
Solutions to water problems can no longer ignore the need to limit use and to reallocate supplies over time in response to changing supply and demand conditions. The underpricing of water for uses such as irrigation or waste disposal reduces the quantity and quality of water available for other uses. It also dissipates an opportunity to provide funding for maintaining and building supply facilities. Similarly, locking water into particular uses regardless of the underlying supply and demand conditions becomes increasingly costly over time. Water markets and efficient pricing policies deserve a more prominent role in future water planning and management than they have been accorded in the past.
Kenneth D. Frederick is a senior fellow in the Energy and Natural Resources Division at RFF.
A version of this article appeared in print in the January 1992 issue of Resources magazine.
A version of this article appeared in print in the January 1992 issue of Resources magazine.
