Definition: A depression caused by erosion by water or ice. Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet.
Definition: A seep is a spring in which water has filtered through permeable earth to the surface. [ https://en.wikipedia.org/wiki/Spring_(hydrology) ]
