As the drought outlook for the Western U.S. becomes increasingly bleak, attention is turning once again to groundwater—literally, water stored in the ground. It is Earth’s most widespread and reliable source of fresh water, but it’s not limitless.
Wells that people drill to access groundwater supply nearly half the water used for irrigated agriculture in the U.S. and provide over 100 million Americans with drinking water. Unfortunately, pervasive pumping is causing groundwater levels to decline in some areas, including much of California’s San Joaquin Valley and Kansas’ High Plains.
We are a water resources engineer with training in water law and a water scientist and large-data analyst. In a recent study, we mapped the locations and depths of wells in 40 countries around the world and found that millions of wells could run dry if groundwater levels decline by only a few meters. While solutions vary from place to place, we believe that what’s most important for protecting wells from running dry is managing groundwater sustainably—especially in nations like the U.S. that use a lot of it.