A Computer Method for Pumping‐Test Analysis

Abstract

AbstractThe knowledge of aquifer parameters is invaluable for quantitative description of geohydrologic systems and for optimal utilization of ground‐water resources. The classical methods of pumping‐test analysis are mostly graphical in nature and there is room for error in individual judgment in the geographical analysis. The computer method for aquifer evaluation comes under the inverse analysis techniques and is based on the classical principle of least squares. The sum of the weighted squares of differences between the observed drawdowns and the drawdowns calculated using the theoretical drawdown equations for the flow system under consideration is minimized, treating the aquifer parameters as decision variables. The method can be applied to any flow system for which analytical expressions for the potential distribution are known. The method was successfully applied to four pumping tests, two in nonleaky confined flow 1 systems, one in a leaky confined flow system, and one in an anisotropic nonleaky confined flow system. The percentage differences between the values of storativity and of transmissivity arrived at by the two methods are found to be as much as 24‐and 1.6 percents, respectively.