A Multiregion Model Describing Water Flow and Solute Transport in Heterogeneous Soils

Abstract

AbstractMany different processes influence chemical breakthrough patterns from soil columns, including chemical kinetics, diffusion, matrix geometry, and flow heterogeneity. TRANSMIT, a multiregion model that reflects many of these features, was used to simulate a suite of solute breakthrough curves from soil columns subjected to both transient and steady‐state flow. When utilized as a two‐region model. TRANSMIT matched analytical solutions for steady‐state flow through two‐region soils. The TRANSMIT model is easily expanded to describe a wide range of multiregion and two‐dimensional geometries and is applicable to transient and steady‐state flow typical of both laboratory experiments and field situations. Sorption and degradation parameters can be varied, and nonuniform surface boundary conditions, resulting from irrigation method and banded chemical placement, can be described.