Analysis of data from pumping tests in unconfined anisotropic aquifers

The errors involved in finding the coefficients of transmissibility and storage are briefly discussed. Distance-drawdown data are advocated as generally most suitable for finding the transmissibility.

Procedures based on the Author's previous papers are described, which combine distance-drawdown analysis with constant storage coefficient and time-drawdown analysis with delayed yield from storage. Anomalies which result from well-known methods of analysis, based on a constant coefficient of storage, are thus avoided. The discussion and analysis are illustrated by pumping test data reported by Wenzel.

The methods described assume a fully-penetrating pumped well and shallow observation wells, except in the case of a very deep aquifer. A computer is not required.

An exact equation, allowing for the vertical velocity-component of the flow and delayed yield from storage, is given in Appendix 3.