Editing Estuary (section)

===Drowned river valleys===
{{main|Ria}}
Drowned river valleys are also known as coastal plain estuaries. In places where the sea level is rising relative to the land, sea water progressively penetrates into river valleys and the topography of the estuary remains similar to that of a river valley. This is the most common type of estuary in temperate climates. Well-studied estuaries include the [[Severn Estuary]] in the [[United Kingdom]] and the [[Ems Dollart Region|Ems Dollard]] along the Dutch-German border.

The width-to-depth ratio of these estuaries is typically large, appearing wedge-shaped (in cross-section) in the inner part and broadening and deepening seaward.  Water depths rarely exceed {{convert|30|m|ft|-2|abbr=on}}. [[Ria#Locations|Examples of this type of estuary]] in the U.S. are the [[Hudson River]], [[Chesapeake Bay]], and [[Delaware Bay]] along the [[Mid-Atlantic states|Mid-Atlantic]] coast, and [[Galveston Bay]] and [[Tampa Bay]] along the [[Gulf Coast]].<ref>{{cite journal |last1=Kunneke |first1=J. T. |first2=T. F. |last2=Palik |year=1984 |url=http://www.nwrc.usgs.gov/wdb/pub/others/85_15.pdf |title=Tampa Bay environmental atlas |journal=U.S. Fish Wildl. Serv. Biol. Rep. |volume=85 |issue=15 |pages=3 |access-date=January 12, 2010 }}</ref>