An equation for the volume of water flowing in an unconfined aquifer. Potentiometric surface - A surface that represents the level to which water will rise in a tightly cased well. If the hydraulic head varies significantly with depth in the aquifer, then there may be more than one potentiometric surface. The water table is a particular potentiometric surface for an unconfined aquifer. An area in which there are downward components of hydraulic head in the aquifer.
Infiltration moves downward into the deeper parts of an aquifer in a recharge area.
An area in which there are upward components of hydraulic head in the aquifer. Groundwater is flowing toward the surface in a discharge area and may escape as a spring, seep, baseflow or by evaporation and transpiration.