An aggregated mixing zone model of solute transport through porous media

Abstract

A new investigative modelling procedure for transport of solutes through undisturbed soil is described. The Aggregated Mixing Zone (AMZ) model makes minimal a priori assumptions about the nature of the flow processes in the sample. Both model structure and parameter values are determined from observed breakthrough curve data using advanced recursive instrumental variable techniques. The AMZ approach is similar to the Jury transfer function model approach, but allows a considerable degree of flexibility in model structure within a consistent framework. The AMZ model generally yields very good fits to the observed breakthrough curves including curves that are not consistent with the traditional convective-dispersion model. Examples are given of models for breakthrough curves showing bimodal impluse response functions.