A groundbreaking study by Stanford University researchers reveals that despite record-breaking rainfall in 2023, Los Angeles' deepest groundwater reserves remain severely depleted.
Using an innovative method that analyzes seismic wave data, researchers found that while surface reservoirs and shallow aquifers were nearly refilled by 2023's atmospheric river storms and Hurricane Hilary, deeper aquifers only recovered about 25% of water lost since 2006.
"A single epic storm season is not enough to restore the groundwater depletion accumulated over recent droughts," explained lead researcher Shujuan Mao. "It will take many more wet years for the deep aquifers to fully recover."
The study, published in Science, utilized Los Angeles' existing network of seismometers - typically used for earthquake monitoring - to measure groundwater levels. This novel approach allows researchers to monitor entire water basins simultaneously at depths up to 800 meters, offering a more comprehensive view than traditional well-based measurements.
The findings carry particular weight given that California's underground reservoirs can store up to 17 times more water than surface reservoirs. However, researchers warn that prolonged droughts and overuse may have permanently damaged some aquifers' storage capacity.
The research team developed a "Seismic Drought Index" to help water managers and the public better understand water deficits at different depths. This new measurement tool could prove invaluable for future water conservation efforts and management decisions.
As California continues to face water challenges, this innovative monitoring method offers a cost-effective way to track groundwater resources, potentially revolutionizing how water agencies approach conservation and replenishment strategies.