ABSTRACT
A ‘‘groundwater level’’ is the elevation of water in a well tapping an aquifer. Well construction in addition to hydraulic conditions in the aquifer influence measured groundwater levels. Hydraulic head, the mechanical energy per unit weight of water,[1] is equal to the elevation to which water rises in a cased well open to a ‘‘point’’ in an aquifer. The hydraulic head measurement pertains only to that point and is normally expressed in units of length above mean sea level. Groundwater levels from several cased wells, at several points in time, illustrate spatial and temporal patterns in hydraulic head within an aquifer.
