A rill is very small, steep-sided channel that ocassionally carries water. This landscape feature is intermittent and forms for only a short period of time after periods of rainfall.
Michael Pidwirny (Lead Author);Marty Matlock (Topic Editor) "Rill". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth October 10, 2006; Last revised Date October 10, 2006; Retrieved June 19, 2013 <http://www.eoearth.org/article/Rill>