- A layer of rock having low
permeability that stores groundwater but delays its flow.
- Low-permeability bed, in a stratigraphic sequence, of sufficient
permeability to allow movement of contaminants, and to be relevant to
regional ground-water flow, but of insufficient permeability for the
economic production of water. See also: aquifer; aquiclude.
CF: confining bed
Dictionary of Mining, Mineral, and Related Terms