Determination of longitudinal dispersivity in an unconfined sandy aquifer

Abstract

Study of the mobility of contaminants in an aquifer is an important issue for the proper remediation of contaminated groundwater. Determination of associated solute transport parameters therefore is essential for investigation of the extent to which-roundwater can be contaminated. This study aimed at determining solute transport parameters for an unconfined sandy aquifer at a laboratory scale through various tracer tests using a conservative solute as a tracer. Tracer tests consisted of both well-tracer tests (single and double wells) and an aquifer tracer test using a plume-capturing device such as time domain reflectometry (TDR). The results showed that longitudinal dispersivities estimated from the single and double well-tracer tests were 2.2 cm and 13.5 cm for a travel distance of 9.3 cm and 13.5 cm from the injection point respectively. These results agreed reasonably well with the results of the aquifer tracer test. The solute transport parameters obtained at multiple points in the aquifer through the aquifer tracer test revealed that the dispersivity length was proportional to the travel distance by a factor of 0.3, which was moderately higher than the value of 0.1 given in the literature. Copyright (C) 2002 John Wiley Sons, Ltd.