Commentary: Water, water
Farther upstream, Lake Powell, the gigantic reservoir formed by Glen Canyon Dam, sports a permanent “bathtub ring” extending 70 or 80 feet up the sides of the rock cliffs along its boundaries, marking the depths to which water levels have sunk in the last couple decades.
The wholesale extraction of Colorado River water is similar to the problems of a number of other river systems around the world, including the Yellow River, the largest river in northern China; the Nile River in Egypt; the Indus River, which supplies most of Pakistan’s irrigation water; and the Ganges River that runs through India’s most populous region—none of which flow normally to their final destination.
It’s symptomatic of a larger problem: The overuse of water for agricultural, industrial and residential uses, exacerbated by surging population growth and more affluent lifestyles.
“There’s just not enough fresh water to handle nine billion people at current consumption levels,” Patricia Mulroy, a board member of the Colorado-based Water Research Foundation, stated in a recent Smithsonian magazine article on the subject. In the southwestern United States, Mulroy argued that “People need a fundamental, cultural attitude change about water supply. It’s not abundant, it’s not reliable, it’s not going to always be there.”
The emergence of “peak water” parallels the energy crisis, in which oil is more difficult and more costly to extract from rock shale and tar sands—only with one difference: We can’t just switch over to some other source for agricultural, industrial and residential usage that requires generous amounts of H2O.
For agriculture, the impact may be severe. In California, according to data compiled by the Earth Policy Institute, a combination of aquifer depletion and diversion of surface water to urban uses has reduced irrigated farmland from nearly 9 million acres in 1997 to an less than 7.5 million acres today. In Texas, irrigated farmland peaked 30 years ago at 7 million acres; it’s now down to less than 5 million acres, as the Ogallala aquifer underlying the Texas panhandle continues to be depleted.
Other important agricultural states with shrinking irrigated acreage include Colorado, Florida and Arizona, all three faced with aquifer depletion and the effects of diversion of irrigation water to cities. Even farm states that were previously expanding irrigated acreage—such as Nebraska and Arkansas—are seeing irrigated farm acreage quickly leveling off.