Perched Aquifers: Perched aquifers is a special case that is sometimes found to occur within an unconfined aquifer. If within the zone of saturation, an impervious deposit below a previous deposit is found to support a body of the saturated material. This body of the saturated material, which is a kind of aquifer is known as a perched aquifer. The top surface of the water held in the perched aquifer is known as the perched water table.