Unsaturated flow effects on solute transport in porous media

A major contaminant transport process in soils is hydrodynamic dispersion by affecting the spreading and arrival of surface-applied pollutants at underlying groundwater reservoirs. When a soil unsaturated, very much affected water saturation. Centimeter- decimeter-scale column experiments were carried out to explore effects fluid saturation particle size on unsaturated solute dispersivity. Measured in-situ breakthrough curves analyzed terms both classical advection–dispersion dual-porosity (mobile-immobile) type equations. clear non-monotonic relationship was found between dispersivity The extent non-monotonicity more pronounced for relatively coarse-textured sand compared finer sand. This finding has been reported rarely before; it explains some inconsistencies saturation-dispersivity relationships literature.