ANALYSIS OF ONE-DIMENSIONAL GROUNDWATER-FLOW IN A NONUNIFORM AQUIFER

A one-dimensional (1D) flow, resulting from a sudden rise or decline i n the water stage of a flood channel in a composite aquifer, which con sists of two different regions separated by a linear discontinuity par allel to the channel, is considered. Governing equations are solved an alytically for appropriate initial and boundary conditions. The obtain ed solution allows the determination of water level fluctuations in bo th regions of the composite aquifer and the time-dependent flow rate t o (or from) the aquifer. It is shown that three other solutions found in the literature (solutions for uniform finite aquifer with imperviou s boundary, uniform finite aquifer with recharge boundary, and uniform semiinfinite aquifer) are special cases of the proposed solution, and they are unified in one form. The proposed solution is a relatively s imple means of predicting the variations in the water levels in the aq uifer as well as evaluating the time-dependent flow rate. It may also be used for the identification of the aquifer properties and for numer ical model validation.