WELL RESPONSE TEST .3. THE INVERSE PROBLEM

In part I, a model was developed for describing the behaviour of the p iezometric head during slug or displacement tests in a well-aquifer sy stem where the well fully penetrates a confined aquifer. Assuming the parameters in the system are known, a theoretical solution was derived . In part II, a numerical procedure which implemented these results wa s given and in particular it was shown how to calculate the fluctuatio ns in the elevation of the water surface in the well. In this paper, w e take up the inverse problem of estimating the aquifer transmissivity and storativity from field measurements of the depth of the water sur face elevations inside the well. We assume that these measurements hav e been taken at discrete points in time and then prove the continuous dependence of the aquifer characteristics on the data and the time int erval. Furthermore, we present and test a numerical procedure for esti mating the aquifer transmissivity and storativity. Although this work focuses on radial flow problems, it is evident that the basic analysis of the procedure applies equally well for any well-aquifer model. A f ield example illustrating the applicability of the method is presented .