Revisiting the advection-diffusion model for estimating evaporative discharge through soil profiles

Abstract

The application of the general advection-diffusion equation to model evaporatively-driven, groundwater flux rates from solute concentration soil profiles was developed in the 1980's and has been applied to a variety of arid zone locations, including salt lakes, valley floors and discharge zones of regional groundwater. In this paper we revisit and extend the model by accounting for the effects of variable water content and sediment type on the impedance factor, and in turn, effective diffusion coefficient. We also explore the sensitivity of the extended model to its major assumptions and parameter values. Early studies typically used a Penman tortuosity value of 0.66 to account for the imped..