Interflow

In hydrology, interflow is the lateral movement of water in the unsaturated zone, or vadose zone, that first returns to the surface or enters a stream prior to becoming groundwater.^[1] Interflow is sometimes used interchangeably with throughflow;^[1] however, throughflow is specifically the subcomponent of interflow that returns to the surface, as overland flow, prior to entering a stream or becoming groundwater.^[2] Interflow occurs when water infiltrates (see infiltration (hydrology)) into the subsurface, hydraulic conductivity decreases with depth, and lateral flow proceeds downslope.^[1] As water accumulates in the subsurface, saturation may occur, and interflow may exfiltrate as return flows, becoming overland flow.^[1]

References

1. Ward, A.; Trimble, S. (2004). Environmental Hydrology. Boca Raton: CRC Press. p. 122. ISBN 1566706165.
2. Fetter, C. (2001). Applied Hydrogeology. New Jersey: Prentice-Hall. p. 41. ISBN 0130882399.