Seven Western states have just received an overdraft notice from nature's water bank, written in red ink, all caps. It turns out that three-fourths of the water they've been using during the American West's record drought (14 years and counting) has been drawn from their precious savings account: not the Colorado River itself but aquifers below ground.
The significance of this discovery, by scientists looking at a series of satellite measurements of the river basin, can hardly be overstated. The West has to measure and manage its underground water at least as carefully as it does the surface supply.
Until now, no one realized the extent to which Westerners were using underground water to make up the water shortfall. That knowledge required NASA satellite measurements of water mass below the surface. Since the end of 2004, the researchers found, two Lake Meads' worth of water have been drained from Colorado Basin aquifers.
The states are in charge of managing their own underground water, and many of them don't. No one knows how much of it is left, or if the withdrawals of recent years will soon be replenished.
One creative strategy to reduce demand is the Colorado River System Conservation Program, a pilot project in which water users in Denver, Las Vegas, Los Angeles and Phoenix will pay regional farmers and industries millions of dollars to use less water more efficiently. Farms, after all, account for 80 percent of Colorado River water use.
In California this summer, water authorities have proposed emergency water restrictions, with heavy fines imposed for overuse. If more effective voluntary measures are not taken to manage the Colorado's ebbing supply, then the entire U.S. Southwest could find itself facing the same predicament.
Editorial on 08/05/2014