Analysis of the quality of parameter estimates from repeated pumping and slug tests in a fractured porous aquifer system in Wonju, Korea.

Pumping and slug tests are widely used, relatively simple methods for estimating hydraulic conductivity and storage coefficient. This study tested the reproducibility of pumping and slug tests in estimating aquifer parameters in fractured or fractured porous media. The continuum concept is applied to represent the hydraulic properties by the conventional conductivity and storage coefficient. Repeated tests show discrepancies wider than can be attributed to probable measurement errors or incomplete curve fitting. The sources of discrepancy include turbulent head loss in an observation well, pumping well location, data acquisition period (pumping or recovery), selection of analysis method, test initiation mechanism, applied initial displacement, and selection of data segment for analysis. When we employ a specific test practice or choose a specific analysis method or data segment for the analysis, the resulting parameter estimates show characteristic patterns of distribution with respect to the mean value. This study analyzes the patterns and discusses how to improve the reliability of the parameter estimation.