Transient well-flow in an unconfined-confined aquifer system

Equations for transient flow to a well penetrating two aquifers - a water table aquifer overlying a confined aquifer - are derived. Two cases are considered for analysis. In the first case flow towards a well of zero discharge with different initial heads is analysed. In the second case the solution is obtained for a well penetrating two aquifers with a constant discharge and identical initial heads. Schapery's method of inversion for Laplace transform is used in the analysis. Solutions of these two cases are combined to obtain general solutions for different field conditions. From the equations derived, it is also possible to calculate the contributions from individual aquifers to the total discharge. Important results of the analysis are given in tables and charts using the usual range of values of different parameters. © 1975.