Infiltration

Infiltration is the flow of water across the ground surface into the soil. This process provides a critical link between surface hydrologic processes and subsurface soil and groundwater systems. While this flux occurs at the ground surface, full understanding of infiltration requires the energy status of water in the shallow subsurface, as well as insight into how these conditions change as infiltration continues. This article explains the basic concepts, and provides the foundational equations, needed to understand infiltration. These insights apply both to those who have a primary interest in infiltration as a mechanism that removes water from the surface as well as for those who are interested in the delivery of water to the soil.