Solving for Dispersivity in Field Dispersion Test of Unsteady Flow in Mixing Flow Field: Mass Transport Modeling

A combined groundwater flow and mass transport model was constructed to simulate the migration of contaminants and to obtain dispersion parameters from a field dispersion test in unsteady flow in mixing flow field in groundwater. Aquifer parameters were obtained by a pumping test. Tracer tests were carried out in order to characterize the characteristics of groundwater flow and to determine the velocity of the pollutant diffusion process from the source to the pumping well. Groundwater head and velocity were analyzed in the groundwater flow model and the total dissolved solids (TDS) concentration was computed in the mass transport model. The observed drawdown and the observed TDS concentration were found to respectively match closely with the computed drawdown and TDS concentration.