Transient flow to a horizontal water well

Equations that approximately relate the transient head in a horizontal well to a constant well discharge are selected from the petroleum literature and converted from the notation and eclectic system of units used in the oil industry to ground water notation with consistent units. A homogeneous but not necessarily isotropic aquifer is assumed. Depending on the time since the start of discharge, the equations are basically the same in form as for flow to either a fully penetrating channel or to a vertical well, but they contain an additional term accounting for vertical flow. A modification is introduced to make the equations, which were derived for confined flow, approximately applicable to unconfined ground water conditions. The simple form of the equations makes their use practical.