ABSTRACT
Water movement in soils is a key process that affects water quantity and quality in the environment. Since the transport of solutes is closely linked with the soil water fl ux, any quantitative analysis of solute transport must fi rst evaluate water fl uxes into and through soil. Soil water movement occurs under both saturated and unsaturated conditions. Saturated conditions occur below the water table, where water movement is predominately horizontal, with lesser components of fl ow in the vertical direction. While unsaturated conditions generally predominate above the water table (the vadose zone), localized zones of saturation can exist, especially following precipitation or irrigation or above an impermeable zone. As a general rule, water movement in the unsaturated zone is vertical, but can also have large lateral components.
