Water Flow and Solute Transport in a Partially Saturated Soil Under Finite Head Condition on the Ground Surface - 22090

The water movement and solute transport downwards due to head condition imposed on the ground surface for several days are investigated by solving the Richards equation and the transport equation in an unsaturated soil by using the software HYDRUS 1D. While the head and moisture content maintains quite constant values at saturation level during wet condition on the ground level, the concentration of the contaminant is maintained constant over a finite durations of time immediately before and after the wet period on the ground surface. The moisture migration and the contaminant transport are solved. Downward penetrations of the hydraulic head, the moisture content, and the contaminant concentration are slowed down as the penetrations proceed vertically. The coupled processes are discussed with special emphasis on the effects of sorption coefficient. Specifically as the sorption coefficient increases the region of contamination tends to be confined in shallow depths below the ground surface. (authors)