Underflow 2 : The lateral motion of water through the upper layers until it enters a stream channel. This usually takes longer to reach stream channels than runoff. This also called subsurface storm flow
National Weather Service NWS Forecast Office, National Oceanic and Atmospheric Administration NOAA, SH Manual, Glossary of Hydrologic Terms, Washington, DC, USA 2015. http://www.nws.noaa.gov/om/hod/SHManual/SHMan014_g lossary.htm, (HydroI - Amer) {889}
