2012 NGWA Ground Water Summit: Innovate and Integrate

This talk will focus on two simple yet powerful interpretative tools that every practicing hydrogeologist should employ in pumping test data evaluation: diagnostic flow plots and derivative analysis. Diagnostic flow plots use elementary data transformations to promote rapid identification of flow regimes commonly encountered in pumping test interpretation, including wellbore storage and linear flow. Derivative analysis, which combines drawdown and its semilog derivative on a single plot, goes even further in the diagnosis of flow regimes and detection of aquifer boundaries. Interestingly, a derivative technique first appeared in the groundwater literature (Chow 1952), but only later through the work of petroleum engineers did derivative analysis gain broader use as a versatile diagnostic tool (Bourdet et al. 1983; Bourdet et al. 1989). After introducing the fundamentals of these diagnostic techniques, Glenn will demonstrate their potential to enhance pumping test data analysis in a series of practical examples.