ABSTRACTSulfate sorption data determined from laboratory investigations were used to predict movement of sulfate during a field experiment of artificial ground‐water recharge in a basin near Lubbock, Texas. Laboratory studies confirmed that sulfate sorption is controlled in the system by surface area, content of iron oxides and hydroxides, and pH. Predicted sulfate distribution in the unsaturated zone was made by assuming constant one‐dimensional flow. Where these assumptions were met, predictions were generally good at shallow depths and for short times.At greater depths and longer times, these assumptions combined with other factors, such as changes in effective porosity, variable mineralogy, changing hydrodynamic dispersion coefficients, and variable infiltration rates contributed to the failure of the predicted values to match the observed data.It appears that sulfate distribution in the unsaturated zone during artificial recharge can be predicted by using easily derived laboratory data if the flow conditions in the field can be described adequat