Water Use in the US
Is Showing Decline
(reprinted from the New York Times, November 9, 1998)
Click here for another, summary, article
|By WILLIAM K. STEVENS
In a little-noticed environmental turnabout, Federal analysts report that Americans use of water declined dined by about 9 percent from 1980 to 1995 even as the United States population grew by 16 percent over the same period.
The drop in water use, which came after decades of steady increase, is attributed by experts largely to a gradual shift in focus away from finding ways to capture more water building dams, for instance and toward devising ways of using it more efficiently once obtained.
The recent disclosure of the decline, by the United States Geological Survey, runs contrary to a deeply seated conventional belief, namely that water use inevitably rises along with economic and population growth and that priority must there-fore be given to opening up new sources.
But now, agriculture and industry, especially, have become more frugal in using water. As a result, some experts say, the once-solid linkage between water and growth may have been broken.
"The data are showing a fundamental change In the way were using and thinking about water" said Dr. Peter H. Gleick, director of the Pacific Institute for Studies in Development, an environmental research organization in Oakland, Calif. Dr. Gleick is also the author of a new study, "The Worlds Water" (Island Press).
Whether the decline in water use will continue is unclear. Most of the drop occurred in the 1980s, with a decline of only 2 percent reported from 1990 to 1995, the latest year for which numbers are available. Moreover, the numbers are estimates and therefore subject to some error. Nevertheless, the experts say, it seems clear that a steady, century-long upward trend in the use of water has at least been halted.
"We feel pretty confident in saying that things have stabilized over the last 15 to 20 years," said Wayne B. Solley, a hydrologist at the geological surveys main office in Reston, Va. He is the lead author of the agencys report, released last month.
The decline in water use is especially striking when measured against population growth. The use of water per person declined, on average, by about 20 percent from 1980, the all-time peak year, to 1995, Dr. Gleick said. The demand for water is shrinking in Europe as well, he said.
Sandra Postel, director of the Global Water Policy Project, a research group in Amherst, Mass., said, "Globally, were seeing a big slowdown in the expansion of irrigation."
But population pressures and rapid industrialization are expected to put increasing pressure on the water supply in some developing countries,
and Ms. Postel said its inefficient use might eventually cause these countries to "bump up against limits" of the supply.
On the other hand, Dr. Gleick said, developing countries might be able to exploit the gains the United States has made in water efficiency and skip the United States early stage of water profligacy.
"Their steel industry will never use as much water as our old steel industries used," he said.
Despite population gains, more efficient use saves water.
In the first eight decades of this century, as the American economy went through its biggest burst of industrial development, the growth in the use of water was continuous, outstripping population growth by about 5 to 2. Expansion of irrigation, industry and electrical power generation accounted for most of the increase. Then, the experts say, a number of factors combined to reverse the trend. The best sites for dams (the main means of gathering water for use) had been taken, and building new ones became ever more expensive. Widespread concern about the negative environmental effects of dams added to the pressure against building new ones. In the case of industry, it became less expensive to recycle water than to remove pollutants from it and return it to the stream, as required by Federal law. And industrial expansion itself slowed down.
In the West, where most of the United States irrigated land lies and water is scarce relative to the rest of the country, the prospect of shortages, the steady depletion of water under the ground and rising pumping costs prompted users to seek better efficiency in using water.
Western farmers, for example, have increasingly abandoned irrigation systems consisting of long, rotating sprayer arms that waste water by projecting it high into the air, where much is lost to wind and evaporation. In their place are systems that use less water by applying it directly to the root systems of plants. As a result of this and other efficiency gains, the average amount of water used per acre of irrigated land fell by 16 percent from 1980 to 1995. The amount of land under irrigation has remained about constant.
Likewise, the recycling of water and conservation measures, along with new technologies, reduced the industrial use of water by 35 percent, to the lowest level 29 billion gallons a day since record keeping began in 1950. This amount does not include water used for cooling power plants, both nuclear and those powered by fossil fuels like coal. Water used for that purpose the biggest single category of use, at 190 billion gallons a day in 1995 fell by nearly 5 percent in the 1980s and has remained about stable for several years.
The amount of water used for domestic purposes, both inside and outside the home, increased sharply in the 1960s and 1970s as the size of houses grew, along with the number of bathrooms, and homes were stocked with more water-using appliances. Since then, Mr. Solley said, the domestic use of water has stabilized at about 100 gallons per person per day as more water-efficient dishwashers, clothes washers and toiletshave been installed. Even so, domestic use increased as a share of the total, rising to 12 percent in 1995 from 10 percent in 1985.
The use of the public water water withdrawn from natural sources by suppliers and conveyed to users rather than withdrawn directly by users like farmers and factories is one of two categories in which the use has continued to increase. It grew by 18 percent from 1980 to 1995. But because of greater efficiencies, the per-person use in this category has stabilized at about 180 gallons a day.
The amount of water used by livestock and rural households has risen 58 percent since 1980. Much of the jump is attributed to growth in the raising of fish, fur-bearing animals, horses and pets.
Most water is returned to rivers and streams after being used. Consumption of the rest by people, animals and crops dropped by almost 8 percent from 1980 to 1985 but has since rebounded to its 1980 level.
All of these categories apply to water withdrawn from its natural location, or off-stream use. It is this overall category that declined by about 9 percent, to 402 billion gallons in 1995, from 440 billion gallons a day in 1980. Far more water is used without being removed from the source, by hydroelectric power generators. This type of use declined by about 4 percent from 1980 to 1995.
Among regions of the country, the area designated by the geological agency as the Northeastern quadrant (basically, the Midwest, Northeast and Middle Atlantic region) led in the overall drop in off-stream use with a decline of about 17 percent from 1980 and 1995. The decline was nearly 5 percent in 17 states in the Great Plains and West, and nearly 3 percent in the Southeast.