A geological formation that may contain groundwater but is not capable of transmitting significant quantities of it under normal hydraulic gradients. May function as a confining bed.

After spending much of the past year trying to allay the concerns of residents living near a contaminated former industrial ...

Dry season flow is mostly dominated by input of groundwater from the two underlying limestone aquifers, Tindall and Oolloo (see Figure R5 below), which have an intervening siltstone aquitard.