The West is America's driest region but also its fastest-growing. Its most parched state, Arizona, alone is now crammed with 55 percent more people than lived there in 1990. There's been a flood of new businesses, resorts and ordinary people in housing developments that are sprawling into the desert and up mountainsides around places like Phoenix, Arizona and Las Vegas, Nevada. And they're all using a whole lot more water than do roaming cattle or sheep.
Thanks to modern engineering, western cities divert and store precious river water and mountain runoff. A single rushing river, the Colorado, supplies water to 30 million people in seven states and Mexico. In 1922, the seven U.S. states signed a compact in which those in the upper reaches of the Colorado agreed to allow enough flow to supply New Mexico, the now hyper-growing Arizona and Nevada, and finally, Mexico to the south.
Yet a prolonged drought has dramatically reduced water levels in reservoirs such as Lake Powell in Arizona and Lake Mead in Nevada. And a study published last year in Science magazine found that manmade greenhouse gases have raised wintertime temperatures in the western mountains, diminishing the winter snowpack and spring runoffs that normally replenish rivers.
To reduce reliance on river water, if only slightly, one state, Colorado, for the first time is now allowing citizens to catch and store rainwater. This, after a study there showed that 97 percent of rainwater evaporates in the region's sandy soil or is sucked up by thirsty plants. So why not allow homeowners to set up barrels and tubs under their downspouts?
This might help gardeners, but it won't solve the bigger question of how the West's struggle to find more water will be won.