term,name,definition,category,provenance,provenance_uri,note estuary,Estuary,"A coastal inlet of the sea or ocean; esp. the mouth of a river, where tide water normally mixes with stream water (modified, Webster). Salinity in estuaries typically ranges from 1 to 25 Practical Salinity Units (psu), as compared oceanic values around 35-psu. See also: tidal stream and coastal.",Surface Water Sites,Adapted from USGS Site Types.,,http://wdr.water.usgs.gov/nwisgmap/help/sitetype.html