Slug tests in site characterization; some practical considerations

Abstract

Abstract The slug test is currently the most common method for the in situ estimation of hydraulic conductivity at sites of suspected groundwater contamination. However, it is widely recognized that the quality of the parameter estimates obtained using this technique can vary tremendously. The success of a program of slug tests critically depends on well installation and development procedures, as field data have shown repeatedly that low-permeability (low-K) well skins are the largest source of error in slug test estimates. Theoretical analyses have demonstrated that hydraulic conductivity estimates from slug tests in wells with low-K skins are often of limited value, regardless of the particular approach used to analyze the response data. It is therefore imperative that a low-K skin be identified through a program of repeat slug tests. Recently, a series of practical guidelines for the performance and analysis of slug tests has been developed at the Kansas Geological Survey in an attempt to improve the quality of slug test estimates. A subset of these guidelines was presented in Butler et al. (1996). Additional guidelines of relevance to the field practitioner are described here.