Historic 2023 Rainfall Fails to Fully Replenish Los Angeles Groundwater

A Stanford-led study reveals that deep aquifers remain significantly depleted despite record-breaking precipitation and innovative seismic monitoring methods.

A series of atmospheric rivers and Hurricane Hilary in 2023 brought over 140% of California's 20th-century annual average precipitation, refilling surface reservoirs and shallow aquifers nearly to capacity.
Deep aquifers, located 50 meters or more below the surface, regained only 25% of the groundwater lost since 2006, highlighting the long-term effects of drought and groundwater overuse.
Researchers utilized decades of seismic data to develop a new 'Seismic Drought Index,' enabling high-resolution measurements of groundwater levels across entire basins without the need for costly monitoring wells.
The study warns that some aquifers may have suffered irreversible damage due to prolonged depletion, reducing their capacity to store water in the future.
The findings underscore the need for sustainable water management practices and strategies to enhance groundwater recharge in California's aquifers, which are critical to the state's water supply.