California groundwater levels rose in 2023 for the first time in 4 years

Last winter’s unusual onslaught of rain and snow led to California’s first increase in groundwater levels in four years, state officials reported Monday.

The 2023 water year — which spanned from Oct. 1, 2022, through Sept. 30, 2023 — brought a welcome 4.1 million acre-feet of managed groundwater recharge and a total rise in groundwater storage of 8.7 million acre-feet, according to the California Department of Water Resources.

Managed groundwater recharge involves purposefully replenishing supplies by injecting excess water into an aquifer. The 4.1 million acre-feet recharge volume was equivalent to the entire storage capacity of Shasta Lake, the largest above-ground reservoir in California. 

“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 for the Department of Water Resources, in a statement.

Of the total recharge amount, 93 percent — or 3.8 million acre-feet — occurred in the agriculture-rich San Joaquin Valley, according to the report. For reference, the average American household uses about 1 acre-foot of water each year.

Over the course of the 2023 water year, the state extracted 9.5 million acre-feet of groundwater, a sharp contrast to the 17 million acre-feet withdrawn the previous water year, the report noted.

Gosselin credited “the impressive recharge numbers in 2023” to the proactive work undertaken by local and state agencies, while also warning Californians to avoid becoming complacent.

“We must do more to be prepared to capture and store water when the wet years come,” he added.