California's groundwater levels recover, but not enough to reverse long-term losses

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California's extraordinarily wet year brought the state vast quantities of water that have soaked into the ground and given a substantial boost to the state's groundwater supplies.

However, it is not nearly enough to reverse long-term losses from over-pumping in many areas, according to a new state report.

Officials with the Department of Water Resources examined water-level measurements in thousands of wells statewide.

They found that from spring 2022 to spring 2023, water levels rose significantly in 34% of wells, and declined in 9%. Others saw little change.

The rise in aquifer levels in many areas represents an improvement from the rapid and widespread declines that occurred during the last three years of extreme drought.

Still, state officials cautioned that California's groundwater remains depleted by decades of overuse.

The report’s authors said it will still require “several more wet years, in addition to more focused efforts to increase recharge and reduce pumping, to recover.”

The report includes data through August, and water managers said it will take more time to see the full effects of water that percolates through soil and sediment to aquifers.

The data show more recovery has occurred in shallow layers of aquifers.

In areas where much of the pumping draws on deeper aquifers (agricultural wells), there has been less of a rise.

The groundwater measurements also show how conditions vary widely from one part of the state to another.

Some of the largest declines in recent years have been driven by heavy agricultural pumping in the San Joaquin Valley, which has left many residents with dry wells.

The state report said that some of the largest recent extractions of groundwater have occurred in the Tulare Lake hydrologic region, in Kings and Kern counties.

It also stated that water levels declined more than 5 feet in nearly a third of the area’s monitoring wells this year, a larger proportion than in any other hydrologic region.

Since 2018, more than 70% of the wells in the region have declined significantly.

In farming areas of the Central Valley, water levels have been helped in some areas by a combination of natural recharge and state-supported recharge efforts.

With more water available from canals, growers and agricultural districts have also been able to reduce groundwater pumping, which has helped to lessen the pressures in some areas.

Over decades, heavy pumping has drained aquifers to a point that clay layers collapse, causing portions of the valley floor to sink, and permanently reducing aquifer storage capacity.

In some areas, the ground has sunk more than 30 feet. The phenomenon of land subsidence has caused damage to canals, roads and other infrastructure.

I hope that the state will take the necessary steps to ensure that California's groundwater resources are managed sustainably in the future.