Throughflow

In hydrology, throughflow, a subcomponent of interflow, is the lateral unsaturated flow of water in the soil zone, where a highly permeable geologic unit overlays a less permeable geologic unit, and which returns to the the surface, as return flow, prior to entering a stream or groundwater . Once water infiltrates into the soil, it is still affected by gravity and either infiltrates to the water table or travels downslope . Throughflow usually occurs during peak hydrologic events, and flow rates are dependent on the hydraulic conductivity of the geologic medium .