The movement of moisture content and dispersion of salts in unsaturated groundwater systems were studied in this investigation. The subject was studied both as a hydrologic phenomenon and as a dispersion phenomenon caused by the quantity and the rate of application of water, together with solutes. From theoretical considerations, equations were derived to predict the moisture contents and the concentrations as a function of time and space. Finite element solutions were obtained for a composite system of moisture content and water quality. The generalized programs are capable of simulating and predicting the transport and distribution of solutes in water, under a variety of boundary conditions in the field and laboratory. In order to verify the simulation process of the developed numerical models, laboratory experiments were conducted. Natural soils, coarse sand, and fine sand were used as porous media in the column experiments. The observed data on moisture content and concentration for one-dimensional cases are in agreement with the finite element solutions. (Modified author abstract)