Record storms refilled LA reservoirs, but deep groundwater recovered just 25%

Los Angeles was drenched by historic storms, yet much of its lost groundwater stayed missing. Record-breaking rainfall in 2023 brought dramatic relief to drought-stricken Southern California, nearly restoring water stored in Los Angeles-area reservoirs and shallow aquifers. But the recovery was far less complete underground. A study published in Science found that aquifers deeper than about 50 metres remained substantially depleted. Researchers estimated that only about 25% of the groundwater lost from these deeper aquifers since 2006 was restored after the exceptionally wet year.Extreme rain brought rapid reliefThe 2023 storms were remarkable in both intensity and duration. A series of intense atmospheric-river storms brought exceptionally heavy precipitation to California in early 2023, rapidly improving surface-water conditions after years of drought, according to Stanford researchers. The enormous volume of water rapidly improved surface conditions, filling reservoirs and allowing shallow groundwater systems to recover substantially.