Here is an excellent, sober, persuasive, and worrisome report at Science 360 about the accelerated decline of the Ogallala Aquifer from 2011 to 2013, because of drought on the Great Plains.
In the summer of 2010, I drove across the country visiting farms, markets, agricultural research stations, and other food policy sites. One of the most interesting stops was a visit with a large-scale corn farmer in southern Nebraska, who showed me the modern irrigation equipment and careful monitoring system he used in an effort to waste as little water as possible from the Ogallala Aquifer. He argued that aquifer declines were really only a problem further south, in Kansas and Oklahoma, not in his part of Nebraska. He said farmers have a strong economic incentive to conserve water, because of the electricity costs and other variable costs from pumping water. I think many farmers in his situation don't want government regulation or too much attention from worried environmentalists.
At the time, I wondered if these internalized costs really provided a strong enough incentive. The big cost of irrigation is the value of the aquifer water itself. Without coordination among farmers, each farmer has an incentive to use too much water. I thought at the time that environmentally aware corn farmers in Kansas and Nebraska should go a little softer in their ferocious criticism of government environmental regulations, because without these regulations their own livelihoods are in jeopardy.
Climate science includes big uncertainties, but it seems likely that global climate change is causing more frequent droughts in the Great Plains. I hope scientifically savvy and pragmatic corn farmers who rely on the Ogallala Aquifer have the political courage to resist the temptation to ally with anti-government conservatives who flirt with climate denialism. Even though it takes some work and some compromise, and even some tolerance for cultural differences between heartland folks and city dwellers, I think farmers have a more promising long-term future allied with the pragmatic wing of the environmental movement.