“We are sucking our aquifers dry,” the headline reads. Could this be a good thing?

The bad effects of declining groundwater levels are known: land subsidence, the cost of pumping from deeper wells, the drying up of surface springs and streams. But there is a potential gain as well. Using up one resource, the water stored under the ground, we are creating another: storage space far greater than any conceivable new dam could provide. “Historical overdraft,” writes engineer Jay Lund, “may be an effective means of underground reservoir construction.” If so, we have been building like mad.