Groundwater recharge
The DWR’s emergency pump program diverts rain runoff to fill a basin for groundwater recharge in Fresno County. Courtesy DWR

California’s vital groundwater reserves grew by a record 8.7 million acre-feet — twice the volume of giant Shasta Lake — in the official water year ended Sept. 30, the Department of Water Resources reported this week.

It’s the first time since 2019 that groundwater reserves have increased, another indication that record rains have helped the state emerge from a long-term drought.

Massive rainfall allowed the state to pump less water from the ground, while basins were recharged with 4.1 million acre-feet from runoff.

“California is invested in preparing for weather extremes by maximizing the wet years to store as much water as possible in preparation for the dry years,” said Paul Gosselin, deputy director of sustainable water management at the DWR.

“The impressive recharge numbers in 2023 are the result of hard work by the local agencies combined with dedicated efforts from the state, but we must do more to be prepared to capture and store water when the wet years come,” he said.

Some areas of the state that have experienced ground subsidence actually saw an uplift from reduced pumping and the refilling of groundwater storage.

But the DWR noted that there has been a deficit of nearly 40 million acre-feet of groundwater over the past two decades.

Groundwater is considered vital for California’s agricultural economy, and for natural ecosystems.

Chris Jennewein is Editor & Publisher of Times of San Diego.