Scientists said they've analyzed the depletion rates caused by pumping groundwater for irrigation in California's Central Valley and the High Plains of the central United States.
While they say they hope their findings will lead to more sustainable use of water in these areas, they are concerned irrigated agriculture may be unsustainable in some parts.
"We're already seeing changes in both areas," study author Bridget Scanlon of the University of Texas at Austin's Bureau of Economic Geology said.
"We're seeing decreases in rural populations in the High Plains. Increasing urbanization is replacing farms in the Central Valley. And during droughts some farmers are forced to fallow their land. These trends will only accelerate as water scarcity issues become more severe," she said in a university release Monday.
California's Central Valley, sometimes called the nation's "fruit and vegetable basket," and the High Plains, which run from northwest Texas to southern Wyoming and South Dakota and are sometimes called the country's "grain basket," account for a large proportion of U.S. food production.