The San Joaquin Valley floor has been sinking for decades. So much water has been pumped out of wells in this arid agricultural zone that the land’s surface has caved downward almost 30 feet in places. As groundwater pumping continues amid the ongoing drought, it’s still sinking as rapidly as two inches per month. On the surface, the subsidence is causing roads and canals to crack as the earth collapses. Below the surface, much of the aquifer space is being lost and can never be recovered.