Impermeable layer

Impermeable layer: A layer of material (such as clay) in an aquifer through which water does not pass.

The impermeable layers in an aquifer. Consent Decree A legal document, approved by a judge, ...

Water Table, Perched (Perched Ground Water Table) The upper surface of a local zone of soil water saturation held above the main body of groundwater by an impermeable layer or stratum, ...

The upper surface of the zone of saturation of groundwater above an impermeable layer of soil or rock (through which water cannot move) as in an unconfined aquifer. This level can be very near the surface of the ground or far below it.

perched water table A water table due to the "perching" of water on a relatively impermeable layer at some depth within the soil. The soil within or below the impermeable layer is not saturated with water.

Confined Aquifer: An aquifer where the water is located between two impermeable layers. These are the source of artesian wells. (See: Aquifer) ...

See also: Standards, Pollution, Wetlands, Atmosphere, Condition