When the rain and snow don't fall and the reservoirs don't fill up, people will pump water out of the ground for their needs. But that practice has its limits, as underground aquifers get depleted, similar to how we squeeze water out of a sponge.
In drought, there's little water to refill that sponge. And new research suggests that in prolonged drought, groundwater may simply not recharge.
Hydrologists at the University of California-Riverside studied wells across the country, not just in dry California.
We get details of the findings from Professor Hoori Ajami and former post-doctoral researcher Adam Schreiner-McGraw.