Pumping water can cause the earth above an aquifer to slump, collapsing the space left behind by the water that was removed. Once that space is lost, it can no longer hold water.
That process, called subsidence, is happening around the country, and more than 80 percent of it is the result of groundwater use, according to the U.S. Geological Survey. The agency says subsidence has affected more than 47,000 square miles of land and waterways across the United States.
As the land sinks, home foundations, sewer pipes and other structures are damaged. But among the most dramatic consequences of subsidence is a fissure. As softer ground slumps, sometimes an adjacent patch of ground stays put. The resulting movement shears the earth apart.