11. Aqueous Solutions

 

Drilling to China — More water than rivers — Saving the aquifer — Drying with Xeriscapes — Everywhere in the house — Rainwater and graywater — Creating urban watersheds — Wastewater equals food — Watering the community


We live on the water planet. Three-fourths of the earth's surface is covered by water. Yet fresh, clean water is scarce and getting more so. Of all the water on earth, less than 3 percent is fresh, and all but three-thousandths of that is locked up in glaciers and icecaps or is too deep in the earth to retrieve. The freshwater available in rivers, lakes, and accessible groundwater is increasingly polluted. Despite nearly 200,000 square miles of reservoirs to store more than 1,400 cubic miles of water a redistribution of natural flows that has measurably changed the orbital characteristics of the planet—even whole cities the size of Mexico City are steadily becoming shorter of water, and water scarcity has changed global patterns of grain trade. As the land's water-holding green skin changes to water-losing brown scabs, water tables are retreating on every continent, with 70 percent of the pumping to irrigate crops. Tucson's water table is retreating toward the People's Republic, while Beijing's water table is getting closer to the United States. The consequences are not merely local. Water is becoming a significant cause of international conflict. To make matters worse, global climate change could intensify the droughts that have sporadically devastated and desertified subcontinental areas.

The answer to decreasing supplies of freshwater is not to try to supply more. Human beings already use one-fourth of the earth's total water in natural circulation, and over half of the accessible runoff. New dams might modestly increase available runoff but are costly and environmentally damaging. Even if most of the good sites had not already been taken long ago, no supply strategy could keep pace with the present rate of population growth and demand. While population will probably increase 45 percent in the next thirty years, increases in accessible runoff are projected to be only 10 percent. Even after investing some $400 billion in water supply over the past century, the United States, with all its wealth and technical prowess, faces shortages that have no easy remedies. As one authority put it in 1984, "The water supply of the West is nearly fully utilized. It is difficult to see major construction projects which will add significantly to the current supply." Moreover, America's eighty thousand dams and reservoirs were not entirely benign: During the boom years of water-capturing projects, the United States lost over 60 percent of its inland wetlands, polluted half its stream-miles, and lost or badly degraded many major fish runs. At home and abroad, with water as with energy, the only practical, large-scale solution is to use what we have far more efficiently.

Most, especially industrialized, countries, still make all the same mistakes with water that they made with energy. They deplete nonrenewable supplies and seek more water instead of using inexhaustible sources more productively and enhancing their capture by restorative grazing, farming, and forestry. They rely on the highest-quality water for every task, flushing toilets and washing driveways with drinking water. They build big dams and water projects by reflex, rather than asking what's the best solution and the right size for the job.

Fortunately, this mind-set is changing. A host of available and emerging techniques is making it possible to increase radically the productivity of water directly where it's used. These technologies and management methods, and new ways to implement and reward them, can enable countries to deliver worldwide on South Africa's water-policy promise, "Some, for all, for ever." These breakthroughs come none too soon. All the water that can reasonably be obtained will be needed to feed the world in the coming century while protecting the natural capital on which all life depends.

RUNNING DRY
Agriculture is responsible for about twice as much of total U.S. water withdrawals as all buildings, industry, and mining combined. It accounted for 81 percent of all 1995 consumptive use. Eighty-eight percent of the nation's 1995 irrigation water went to 17 western states, where the great majority of all water districts were mining groundwater faster than it was being recharged. This is a long-standing pattern. Freshwater flows from rivers are provided to agriculture under a program of federal subsidies that go back to the nineteenth century. California has built a vast agribusiness sector on water so heavily subsidized that 57 percent of its agricultural water grows four crops that produce only 17 percent of its agricultural revenue. Arizona has long used subsidized water to flood-irrigate cotton and alfalfa in a desert. The states along the Colorado River, including five of the ten fastest-growing states in the United States, have already allocated on paper more water than is actually in the river, and in many years, the river never reaches the sea.

Many gargantuan water projects have failed to pass the giggle test. The Army Corps of Engineers wanted to pump the Missouri River uphill to recharge aquifers in and beyond west Kansas, even though there was no legal crop that farmers could grow with that water to earn enough to afford the pumping energy. The 1968 Texas Water Plan would have needed seven Chernobyl-sized power plants to pump water about 3,000 feet up from the Mississippi River to a region of west Texas. The ultimate wet dream, the North American Water and Power Alliance, would have replumbed western North America. It proposed to dam the 500-mile-long Rocky Mountain Trench near Banff and Jasper National Parks, and to divert the major rivers of Alaska, the Yukon, and British Columbia to supply water to all of Canada, the western and midwestern United States (pumping over the Rockies as needed), and northern Mexico. This massive project, which was ultimately killed, would have cost the best part of a trillion dollars. Proposed with a straight face, this plan was the ultimate expression of how far some people are willing to go to put water where it isn't.

Under America's High Plains, extending from north Texas to the Dakotas, lies the Ogallala Aquifer, a deposit of Pleistocene groundwater spanning an area larger than California. By 1990, it was being drawn down at a rate of 3 to 10 feet a year to provide 30 percent of America's groundwater-based irrigation. Recharged at a rate of less than a half inch per year, parts of the aquifer were getting badly depleted; half to two-thirds of the economically recoverable Texas portion was already drained by 1980. Nevertheless, two-fifths of America's feedlot cattle were being fed grain made of Ogallala groundwater. Growing enough of that grain to add sufficient weight on a feedlot steer to put an extra pound of beef on the table consumed up to a hundred pounds of lost, eroded topsoil and over eight thousand pounds of Ice Age–vintage groundwater.

The initial "water rush" that dotted the High Plains with center-pivot irrigation (those are the circular areas of irrigated land you see when flying across the country) from the 1950s to the 1980s presumed that water resources were inexhaustible. A study of High Plains farmers and ranchers found that only half had adopted as many as three of thirty-nine available irrigation-efficiency practices. By the early 1990s, depletion and pumping costs had forced hard-hit towns to rediscover dryland farming. Some, like Hays, Kansas, where water was considered abundant twenty years ago, are now turning toward water efficiency for their very survival. Often the problem is not just whether the groundwater exists but also whether one can afford to pump it to the surface.

Dependence on increasingly scarce supplies is not limited to agriculture: Providing water to Las Vegas has become a regional obsession. Every drop that can be saved, bought, borrowed, or otherwise appropriated from other areas in Nevada or the rest of the West is used to fuel the city's subsidized sprawl, creating, in effect, a second Los Angeles in a country that has one too many. Even in the rainy eastern states, most cities, even those with relatively static populations, have recently suffered water shortages.…

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