TRANSPORT OF REACTIVE SOLUTES DURING TRANSIENT, UNSATURATED WATER FLOW IN MULTILAYERED SOILS1

Abstract

A numerical model was developed to predict water and reactive solute transport through water-unsaturated, multilayered soils. An explicit-implicit finite difference approximation method was used to solve the water and solute transport equations simultaneously. Calculated results were presented for two- and three-layered soils during water infiltration and redistribution. Linear and nonlinear equilibrium adsorption, first-order kinetic reaction, and irreversible kinetic reaction were used to describe solute adsorption in individual soil layers. It was found that, for all adsorption mechanisms considered, concentration distribution during infiltration and redistribution was significantly influenced by the order in which the soil layers were stratified. A numerical model was developed to predict water and reactive solute transport through water-unsaturated, multilayered soils. An explicit-implicit finite difference approximation method was used to solve the water and solute transport equations simultaneously. Calculated results were presented for two- and three-layered soils during water infiltration and redistribution. Linear and nonlinear equilibrium adsorption, first-order kinetic reaction, and irreversible kinetic reaction were used to describe solute adsorption in individual soil layers. It was found that, for all adsorption mechanisms considered, concentration distribution during infiltration and redistribution was significantly influenced by the order in which the soil layers were stratified. © Williams & Wilkins 1978. All Rights Reserved.