Now, California water agencies are scrambling to line up replacement supplies. But instead of looking east and north, as they always have, they're looking west, to the shimmering Pacific Ocean. Water officials are talking with unbounded enthusiasm about what one observer calls "aquatic alchemy."
The key is desalination, which forces seawater through special membranes, squeezing out the salt and creating fresh water. Though it sounds far-fetched, desalination is already reality. In Saudi Arabia, 27 desalination plants provide about 70 percent of the country's drinking water supply. This March, Tampa, Fla., fired up a huge new desalination plant. And in California, there are now proposals or plans for 13 such plants.
The only thing standing in the way is money. Desalination is energy-intensive: When it was first proposed in the 1950s, it was closely linked with the developing nuclear power industry, which means it has never been anything but costly. But as traditional water projects like dams become more expensive, desalination is becoming comparatively attractive.
In San Diego, where officials have studying seawater desalination for more than a decade, the water authority is forging ahead with a $270 million plant that should be operational by 2008.
"Seawater desalination is very cost-competitive with developing new water supplies," says the San Diego Water Authority's Dennis Cushman. "It's a drought-proof supply of water backed up by the largest reservoir on earth -- the Pacific Ocean."
A turn toward desalination would be the capstone of an expensive, almost century-long drive to keep the growth euphoria going in Southern California. First, the region tapped the eastern Sierra with the Los Angeles Aqueduct; then, after the construction of Hoover Dam, it funneled water across 242 miles of unrepentant desert in the Colorado River Aqueduct; in the 1960s, it began drawing water from California through the State Water Project.
But if we make this next leap without stopping to appreciate what it represents, we're sure to lose all sense of perspective for the future. These days, the term "era of limits" is being bandied about so much that it's become a cliché. Yet it is the defining formulation of the 21st century world in which we live. Turning to the sea seems to ignore those limits.
Adrift on the ocean, the thirst-crazed protagonist of Samuel Coleridge's "Rime of the Ancient Mariner" made his famous lament in 1798: "Water, water, everywhere, nor any drop to drink." Two centuries later, we can squeeze a drink from the sea, though it means pushing the natural boundaries farther than they've ever been pushed before.
In essence, we're refining water, or beating it out of its natural environment, and we are overrunning the carrying capacity of the arid West. Maybe, when a glass of water with a salted rim becomes standard fare, the concept of "limits" might finally begin to dawn on our growth-addled minds. Then, we might temper our relentless sense of optimism in the face of clear signs that we're pushing the limits of the earth.
For now, precisely the opposite thing is happening. A pair of desalination boosters wrote in the San Diego Union-Tribune: "Ironically, as a result of global warming, sea level is likely to rise two feet along most of the U.S. coast. Therefore, Southern California should be looking to the ocean to supply its water demand."
The image is almost heroic: coastal Californians drinking their way to salvation. As for the human byproduct of all that consumption, the water wizards are working on that, too. If all goes according to plan, water once flushed away will be the raw material for the next leap over conventional environmental limits. Engineers are perfecting "toilet to tap" technologies to turn treated sewage back into drinking water.
Water managers talk about the need to overcome the "yuck factor" to win public acceptance of such programs. But as for hard questions about hitting the earth's natural limits? Well, we'll defer those to the future.