Discrete time steps in digital computer analysis of aquifers containing pumped wells

Abstract

When digital computers are used in the analysis of time variant groundwater flow in an aquifer, the time is divided into discrete intervals. These discrete time steps can cause oscillations or other errors in the solutions particularly when wells start and stop pumping. A large number of solutions are obtained with a wide range of time steps using three implicit methods, the Crank-Nicholson, the alternating direction implicit and the backward difference methods, and, by comparing the results with theoretical values, recommendations are made to aid the choice of the optimum time interval.