Water, Water, Nowhere?
(Continued from previous page)

What's life like for these people? Difficult, says Vörösmarty. Since there is inadequate water for irrigation, it is hard to grow sufficient food, and food imports are often necessary. There may be restrictions on water use, as the domestic, industrial and agricultural sectors compete for what water is available. Human health is affected by pollution problems, because there isn't enough unused water to dilute waste.

Signs of stress

While few areas in the United States are currently experiencing this degree of difficulty caused by extreme water shortages, some signs of stress can be seen. Cities and rural areas are increasingly in conflict over water in Southern California. Los Angeles has built pipelines to rivers and lakes hundreds of miles away, diverting water that used to irrigate cropland and orchards. Some years ago there was even talk of building a pipeline to Alaska.

The Colorado River offers a dramatic example of what happens when demand exceeds water supplies. The once-mighty river is literally sucked dry as it winds through the Southwest. Every drop of its flow--150,000 gallons a second--is gradually drawn off, primarily for irrigation, until the river slows to a trickle and finally stops miles short of the Gulf of Mexico.

In the Midwest, the Ogallala Aquifer--one of the world's largest stores of groundwater--is being depleted at an alarming rate. The aquifer lies beneath eight U.S. states, an area just slightly smaller than Texas. In the 1940s, farmers began to notice that they were having to drill deeper to reach water for their irrigation pumps. From then until the early '90s, the water level in the aquifer dropped at an average rate of less than half a foot each year. But by 1995, well measurements showed that the level was dropping three feet a year, causing the land above the aquifer to subside dramatically in places. Since then, irrigation has been cut back, and Texas, Oklahoma, Kansas and Colorado have all been losing irrigated land over the last two decades.

Fortunately, the United States has the natural and the economic resources to compensate for these changes. A country that is both dry and poor faces much greater difficulties.

A 1997 trip to drought-stricken Kenya gave Vörösmarty a first-hand view of just such a situation. "We saw people with buckets on their heads traveling several kilometers to go to a single drain pipe that could give them clean water, because all their surface water supplies had dried up," he says. "People were spending large parts of their day getting their buckets of water. It's a different set of challenges if you're in the developing world, where you don't have the economic infrastructure to buffer you against these difficulties."

Many other nations also see a water crisis impending if not already present. For example:

• Since 1985, the Huang Ho (Yellow) River running through the heart of China has run dry at least part of each year, and for seven months in 1997.
• Water tables are falling throughout China. Since 1965, the water table under Beijing has fallen by nearly 200 feet, and it's even been suggested that China's capital may need to be moved. (See sidebar.) Northern China, which includes Beijing and Shanghai, has 45 percent of China's 1.25 billion people, two-thirds of the nation's cropland, but only one-fifth of its water.
• India uses water at about twice the rate it is naturally replenished, and underground aquifers there are dropping by three to 10 feet a year.
• Lake Chad in central Africa, once Africa's fourth-largest lake, covering an area the size of New Hampshire, has shrunk to one-twentieth of its original size since the early 1960s. Scientists say the outlook for recovery is bleak; the lake is likely to end up a puddle, and the ecosystem that developed around it over millennia has essentially disappeared.
• Rivers feeding the Aral Sea between Kazakhstan and Uzbekistan have been diverted for cultivation of rice and cotton in the Karakum Desert. This has caused increased evaporative loss of water, with the result that the entire Aral Basin is drying up. The level of the sea dropped more than 52 feet and the surface area shrank by half (12,740 square miles) between 1960 and 1990. Cities that were once on the coast are now miles inland.
• In some parts of the world, rising sea levels threaten to accelerate the saline contamination of freshwater aquifers and river deltas. This is already happening in Florida, Gaza and the Nile River delta. Indeed, in the last 20 years, farmers in the Gaza Strip have come to favor salt-tolerant vegetables and flowers instead of saline-sensitive citrus fruit.

The amount of water available for the future is only part of the equation. The quality of that water must also be carefully considered, as it affects human health. As many as 1.2 billion people lack access to clean drinking water, according to Peter Gleick, director of the Pacific Institute for Studies in Development, Environment and Security. Nearly half the world's population lives without sanitation--no sewers, toilets or latrines--and preventable water-related diseases kill an estimated 10,000 to 20,000 people every day.