Solute transport through unsaturated soil due to evaporation

A new method for predicting upward solute movement in unsaturated sand soil due to evaporation is developed and tested. Laboratory experiments were co nducted in an unsaturated uniformly packed sand column with a cross section of 1.20 X 0.50 m(2) and a constant shallow ground-water table. Evaporation was measured by a new ventilated chamber system. Solute movement from the ground water upward was monitored, Water and solute movement could be accur ately reproduced by numerically solving Richards' equation and the convecti on-dispersion equation in one-dimension. The experimentally measured disper sivity for the unsaturated homogeneous sand agreed closely with the values which are available in the literature. This paper offers a new approach for investigating dispersion phenomena in unsaturated porous media exposed to evaporation.