A series of atmospheric rivers slammed California in early 2023, dumping as much as 300% of the historical annual average rainfall on some parts of the state. The rains replenished surface water storage above its historical average, but scientists are still unraveling how the influx of precipitation affected the state’s groundwater, which suffered from extreme drought conditions from 2020 to 2022. In a new study published in Science, researchers used an existing network of seismic instruments to probe that question. They found that surface water, such as lakes, streams, and reservoirs, had recovered above its historical average after the winter storms. But the volume of groundwater—defined in the study as water stored more than 50 meters (164 feet) below the surface—lagged far behind.

Other groundwater news:

• KSEE/KGPE (Fresno, Calif.): Survey shows most valley farmers largely unaware of groundwater act impacts​