Why pumping groundwater isn’t a long-term solution to drought

SIGNS OF DROUGHT proliferate across the American West. California is rationing water for farmers in the state’s Central Valley. Salmon are dying en masse in the Pacific Northwest as river temperatures climb. Lake Mead, on the border of Nevada and Arizona, is drying up. The country’s largest reservoir is so depleted that the Bureau of Reclamation, an agency within the Interior Department, declared the first-ever water shortage for the Colorado River on August 16th. Facing cuts to their supplies of surface water, some farmers in the region are pumping more groundwater. Is pumping a sustainable way to weather the drought?

Groundwater is stored in aquifers (bodies of porous rock) that can be tapped by wells and used for drinking water or irrigated agriculture. Groundwater is the source of drinking water for half of Americans, and nearly all of the country’s rural communities. Worldwide, about 70% of the groundwater pumped is used for agriculture. But groundwater has become dangerously depleted in places where pumping has exceeded the rate at which aquifers are naturally replenished.