CORVALLIS, Ore. - Although declining streamflows and half-full reservoirs have gotten most of the attention in water conflicts around the United States, some of the worst battles of the next century may be over groundwater, experts say – a critical resource often taken for granted until it begins to run out.

Aquifers are being depleted much faster than they are being replenished in many places, wells are drying up, massive lawsuits are already erupting and the problems have barely begun. Aquifers that took thousands of years to fill are being drained in decades, placing both agricultural and urban uses in peril. Groundwater that supplies drinking water for half the world's population is now in jeopardy.

A new analysis by researchers at Oregon State University outlines the scope of this problem, but also points out that some tools may be available to help address it, in part by borrowing heavily from lessons learned the hard way by the oil industry.

"It's been said that groundwater is the oil of this century," said Todd Jarvis, associate director of the Institute for Water and Watersheds at OSU. "Part of the issue is it's running out, meaning we're now facing 'peak water' just the way the U.S. encountered 'peak oil' production in the 1970s. But there are also some techniques developed by the oil industry to help manage this crisis, and we could learn a lot from them."