SINGLE-WELL INJECTION-DRIFT TEST TO CHARACTERIZE GROUNDWATER VELOCITY AND DISPERSIVITY

A method to characterize the magnitude of groundwater velocity and longitudinal dispersivity based on a single-well injection-drift test will be presented. The method utilizes the transport data (concentration versus time) of a non-reactive groundwater tracer during its forced-gradient injection into a single well followed by its natural-gradient drift back through the same well. The method then utilizes a transport model (implicit finite difference) to fit the single-well transport data for the magnitude of groundwater velocity and longitudinal dispersity. The single-well model fits of velocity and dispersivity will be compared to those calculated from the transport data in down-gradient multi-well transects of observation wells. The method presented here is relatively simple, rapid, and cost-effective because it utilizes a single-well, as opposed to multiple wells, to characterize two fundamental physical transport parameters; groundwater velocity and longitudinal dispersivity.