Deeper well drilling an unsustainable stopgap to groundwater depletion

Abstract

Groundwater depletion is causing wells to run dry, affecting food production and domestic water access. Drilling deeper wells may stave off the drying up of wells—for those who can afford it and where hydrogeologic conditions permit it—yet the frequency of deeper drilling is unknown. Here, we compile 11.8 million groundwater-well locations, depths and purposes across the United States. We show that typical wells are being constructed deeper 1.4 to 9.2 times more often than they are being constructed shallower. Well deepening is not ubiquitous in all areas where groundwater levels are declining, implying that shallow wells are vulnerable to running dry should groundwater depletion continue. We conclude that widespread deeper well drilling represents an unsustainable stopgap to groundwater depletion that is limited by socioeconomic conditions, hydrogeology and groundwater quality.