California’s Central Valley has lost roughly 85 cubic kilometres of groundwater storage since 2004 due to intensive pumping during periods of drought.
The Central Valley is one of the most productive agricultural regions in the world, growing 40 per cent of the fruit and nuts produced in the US. When surface water is inadequate to irrigate all those crops, farmers pump groundwater from the region’s aquifer. For more than a century, farmers have pumped more groundwater than was replaced by snowmelt and rainfall, …