Dispersion of Trace Solutes in Flowing Groundwater

Abstract

Generalized Taylor dispersion theory is used to identify the dispersion characteristics of simple stratified aquifers. The parameters routinely estimated from field tests are shown to be influenced in a nontrivial way by the inhomogeneity of the aquifer as well as by the initial distribution of solute and by the sampling techniques used in their determination; both the dispersion coefficient and apparent convective velocity can exhibit important transients. These factors are sufficient to explain the well‐known scale effect for the idealized system analyzed. Furthermore, sampling procedures may require addition of a reaction term to the contracted diffusion equations normally used for analysis of field data if the model is to represent faithfully the dispersion processes occurring within the aquifer.