The determination of aquifer anisotropy by transmissivity tensor analysis.

Abstract

The Papadopulos method analyzes pumptest data from a homogeneous anisotropic aquifer to determine the direction and magnitude of the transmissivity in the major and minor directions of hydraulic conductivity of the aquifer. To test the practical applicability of this method, pumptest data is generated by a digital computer program, representing a homogeneous anisotropic aquifer which is analyzed by the Papadopulos method. The resulting transmissivity values and storage coefficient are compared to the original inputs. A procedure for the design and validation of the computer programs appears in the text. To demonstrate the usefulness of the method, an analysis of existing field data is presented. A complete mathematical derivation leading to the analytic solutions of the equations used in the Papadopulos method is listed as an appendix. The Theis non-equilibrium analysis of pumptest data of a homogeneous anisotropic aquifer will not yield a representative value for transmissivity. The Papadopulos method will. The error in the transmissivity values caused by this application of an incorrect method of pumptest data analysis is investigated. A mathematical proof is given of the existence of a non-unique relationship between the drawdown and transmissivity of an aquifer system in a non-steady state.