term,name,definition,category,provenance,provenance_uri,note sinkhole,Sinkhole,"A crater formed when the roof of a cavern collapses; usually found in limestone areas. Surface water and precipitation that enters a sinkhole usually evaporates or infiltrates into the ground, rather than draining into a stream.",Land Sites,Adapted from USGS Site Types.,,http://wdr.water.usgs.gov/nwisgmap/help/sitetype.html