NOTES
Links to summaries of key issues for each topic
VISUALS
Links to images employed in lectures
TEXT
NOTES
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Coasts, Beaches and Estuaries (contd.)
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Notes on Topic:
The notes represent summaries of key issues
for each topic
They emphasize the terminology used to describe
the various phenomena.
| 3. Estuaries, Fjords and Lagoons |
| Learning Objectives: |
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Appreciation of different modes of formation of estuaries
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Understanding of circulation patterns in estuaries
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Recognition of roles of freshwater influx and tidal mixing on circulation
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| Estuaries: |
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Mixing zones of seawater (more dense) and freshwater (less dense)
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form on stable coasts as semi-enclosed embayments
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flooded river valleys
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coastal plain estuaries
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fjords
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tectonic estuaries formed by faulting.
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Described by circulation characteristics.
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salt wedge:
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where river flow is large and tidal range is low
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lower layer of salt water is entrained by freshwater
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gradual mixing
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surface water salinities increase seaward
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well-mixed
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product of strong tides
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river flow is low
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tidal domination reduces stratification
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mixing is turbulent
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volumes of seawater > freshwater
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partially-mixed estuaries:
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fjords:
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mixing may be restricted by sills (submerged ridge)
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limiting outflow and causing mixing at barrier
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Described by water and salt budgets and by flushing time
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where evaporation rates are high inverse estuaries may form
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salinity higher in inland region.
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Department
of Geological Sciences,
1001
E. Tenth Street, Bloomington, IN 47405-1403
Phone:
(812) 855-5582 Last updated: 7 December 2000
Comments:
simon@indiana.edu
Copyright
2000, The Trustees of Indiana University
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