Even though immense rains repeatedly pummeled California in 2023, they barely helped recharge aquifers drawn down by decades of drought and human pumping, a new study reveals. About one-third of the water supply in Los Angeles, which is susceptible to long dry spells, comes from groundwater. But in the first three months of 2023, more than a dozen atmospheric rivers — long, narrow weather systems chock full of water vapor — brought rainfall to the West Coast.