A rock, such as chalk, which will hold water and let it through. Water runs into aquifers where the rock is exposed to the surface or lies below the water-table. See Water Science and Technology Board (2008), Prospects for Managed Underground Storage of Recoverable Water. A confined aquifer is sandwiched between two impermeable rocks, and the water-table marks the upper limit of an unconfined aquifer. See A. Klimchouck, ed. (2000).
Subjects: Earth Sciences and Geography — Biological Sciences.