A numerical model for solute transport in the unsaturated zone has been developed. The model is based on the basic equation for soil water flow in one dimension and the general convection-dispersion equation. These are solved by numerical techniques and coupled under the assumption that the flow equation can be solved independently.

Options for solute-soil reactions are included in the model comprising adsorption, ion exchange and decay. In addition the effect of immobile water may be considered in the calculations.

The model has been applied for simulating field conditions. The model calculations have been compared with measurements of moisture content and the results from a field tracer experiment.