Oceans and seas:Arrested salt wedge estuary
Published: March 29, 2010, 12:00 am
Updated: November 28, 2011, 11:28 am
This article has been reviewed by the following Topic Editor:
Peter Saundry
An arrested salt wedge estuary is one of four principal types of estuaries as distinguished by prevailing flow conditions.
|
This article is written at a definitional level only. Authors wishing to expand this entry are inivited to expand the present treatment, which additions will be peer reviewed prior to publication of any expansion. |
This is a type in which there is a relatively stationary interface between an underlying stable salt wedge of sea water and an overlying strong flow of fresh river discharge to the sea. As a result the salinity stratification is extremely strong with an underlying layer of marine saline water, and a surface layer of brackish water. In this regard the salinity stratification most closely resembles that of a fjord, compared to the other two types of estuaries: drowned river valleys and deltaic estuaries.
The quantitative measure of salinity differential of the upper (freshwater efflux to the sea) and lower (marine influx to land) typically ranges from two to ten parts per thousand of salinity.
Types of Estuary
A general definition of an estuary is a semienclosed and coastal body of water with free communication to the ocean; and, within which ocean water is diluted by freshwater derived from land. (e.g., Cameron and Pritchard). Based upon water column stratification or salinity vertical structure, estuaries can
be classified (Valle-levinson) as:
-
salt wedge
-
strongly stratified
-
weakly stratified
-
vertically mixed
Examples of arrested salt wedge estuary
A classic example of an arrested salt wedge estuary is the mouth of the Columbia River separating Oregon and Washington in the northwest USA. The powerful discharge of the Columbia overwhelms the ability of the freshwater discharge to mix completely. The explorers Lewis and Clark were the first to document the powerful flow of the Columbia mouth, when their rafts were hopelessly unmaneuverable and they required rescue by Native Americans, who were familiar with the navigation techniques required in this fast moving surface flow estuary.
Further Reading
-
Cameron, W. M. and D. W. Pritchard. 1963. Estuaries. In M. N. Hill (editor): The Sea vol. 2, John Wiley and Sons, New York, 306 - 324.
-
Clinton J. Dawes. 1998. Marine botany. John Wiley and Sons. 480 pages
-
Valle-levinson, A. 2010. Definition and classification of estuaries, In Contemporary Issues in Estuarine Physics, Edited by A. Valle-Levinson. Cambridge University Press. ISBN:9780521899673
-
Physical Oceanography Index
Are you absolutely sure you want to delete this article? This process cannot be undone and is permanent.
Yes, Delete This Article
Are you absolutely sure you want to remove this article? This process cannot be undone and is permanent.
Yes, Remove This Article
Citation
Steve Baum, C Michael Hogan (Lead Author);Peter Saundry (Topic Editor) "Arrested salt wedge estuary". 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 March 29, 2010; Last revised Date November 28, 2011; Retrieved May 22, 2013 <http://www.eoearth.org/article/Arrested_salt_wedge_estuary?topic=49523>
The Authors
Assistant Research Scientist, Physical Section
Department of Oceanography
Texas A&M University ... (Full Bio)
Standing within a gentoo penguin colony on King George Island, Antarctica, Dr. C. Michael Hogan served a term as Editor in-Chief of the Encyclopedia of Earth which ended in 2012. In addition to authoring a number of papers for the Encyclopedia of Earth, he is a physicist who has published over 1220 peer reviewed articles in other journals and government monographs in the fields of molecular biology, quantum spinwaves, atmospheric physics, biogeochemistry, hydrological modeling, species populat ... (Full Bio)
An arrested salt wedge estuary is one of four principal types of estuaries as distinguished by prevailing flow conditions.
|
This article is written at a definitional level only. Authors wishing to expand this entry are inivited to expand the present treatment, which additions will be peer reviewed prior to publication of any expansion. |
This is a type in which there is a relatively stationary interface between an underlying stable salt wedge of sea water and an overlying strong flow of fresh river discharge to the sea. As a result the salinity stratification is extremely strong with an underlying layer of marine saline water, and a surface layer of brackish water. In this regard the salinity stratification most closely resembles that of a fjord, compared to the other two types of estuaries: drowned river valleys and deltaic estuaries.
The quantitative measure of salinity differential of the upper (freshwater efflux to the sea) and lower (marine influx to land) typically ranges from two to ten parts per thousand of salinity.
Types of Estuary
A general definition of an estuary is a semienclosed and coastal body of water with free communication to the ocean; and, within which ocean water is diluted by freshwater derived from land. (e.g., Cameron and Pritchard). Based upon water column stratification or salinity vertical structure, estuaries can
be classified (Valle-levinson) as:
-
salt wedge
-
strongly stratified
-
weakly stratified
-
vertically mixed
Examples of arrested salt wedge estuary
A classic example of an arrested salt wedge estuary is the mouth of the Columbia River separating Oregon and Washington in the northwest USA. The powerful discharge of the Columbia overwhelms the ability of the freshwater discharge to mix completely. The explorers Lewis and Clark were the first to document the powerful flow of the Columbia mouth, when their rafts were hopelessly unmaneuverable and they required rescue by Native Americans, who were familiar with the navigation techniques required in this fast moving surface flow estuary.
Further Reading
-
Cameron, W. M. and D. W. Pritchard. 1963. Estuaries. In M. N. Hill (editor): The Sea vol. 2, John Wiley and Sons, New York, 306 - 324.
-
Clinton J. Dawes. 1998. Marine botany. John Wiley and Sons. 480 pages
-
Valle-levinson, A. 2010. Definition and classification of estuaries, In Contemporary Issues in Estuarine Physics, Edited by A. Valle-Levinson. Cambridge University Press. ISBN:9780521899673
-
Physical Oceanography Index
Are you absolutely sure you want to delete this article? This process cannot be undone and is permanent.
Yes, Delete This Article
Are you absolutely sure you want to remove this article? This process cannot be undone and is permanent.
Yes, Remove This Article
Site Options
0 Comments
Add Comment