As the drought deepens, desperate California farmers push deeper into already stressed aquifers.

Climate Central:

California is surviving the drought this summer because it is using its water “bank account” — groundwater. The problem for the state is that nobody knows how big that bank account is because California is the only Western state that doesn’t measure its groundwater, Howitt said.

About 5.5 million acre-feet of the 6.6 million acre-foot loss in surface water is made up for with groundwater pumping, which means that the state is really only feeling a water loss of about 1 million acre-feet, or enough to fill roughly 543,089 Olympic swimming pools.

But groundwater pumping comes at a cost to farmers — $454 million statewide — mainly because of the electricity required.

It’s anybody’s guess how long that use of groundwater can go on for because the state doesn’t know how much groundwater is being used, preventing the state from managing its groundwater effectively, according to the report.

“We’re like somebody who is so rich, they don’t have to balance their checkbook,” Howitt said. “We still think we’re in a groundwater-rich era.”

Report co-author and UC-Davis professor Jay Lund said more groundwater is being pumped for agriculture this year than has ever been delivered by the State Water Project in an entire year. (The Project is in charge of storing and delivering water across the state, with most water going to urban users.)

The report calls on the state of California to more effectively manage groundwater and allow it to replenish in wet years.