Theis Parameter Evaluation from Pumping Tests by Sensitivity Analysis

Through the years the Theis equation has played an important role in ground-water hydrology. Comparison of experimental pumping-test data with this theoretical curve by graphic means has been a standard method of determining aquifer transmissivity and storage. The purpose of this paper is to present a technique and an algorithm to automatically fit experimental pumping-test data to the Theis equation by obtaining the “best” transmissivity and storage in the least squares sense through the use of sensitivity analysis. The automated fit for pumping-test data developed in this work should be a useful tool for the ground-water hydrologist. Use of the technique is simple, quick, and inexpensive, and has the advantage of always being objective. As a measure of the error in fitting, the rms deviation in drawdown is calculated for the “best” transmissivity and storage.