Presentation and evaluation of a new multi-stage parameter estimation method using advective transport observations

Observations of advective groundwater transport, generally inferred from concentration measurements, have been found to help in the estimation of groundwater flow parameters. Transverse dispersion, however, can make it difficult to determine the location of the groundwater advective front directly from concentration measurements. A three-stage iterative procedure is developed to estimate groundwater flow and transport parameters from head and concentration data, and is tested using an analytical model. The results are compared to those obtained when advective and dispersive transport parameters are estimated simultaneously. The iterative procedure can be effective at estimating advective and dispersive parameters that improve the fit to the concentration data, but the simultaneous procedure generally produces a better, optimal fit to the concentration data and, therefore, estimates more accurate and precise parameters values. This is accomplished in fewer iterations. It had been anticipated that this iterative procedure might be effective and efficient for using concentration data to estimate parameters of numerical models, but these preliminary results suggest that its utility is limited.