Difference between revisions of "Coastal zone characteristics"
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*sand transport (littoral transport or littoral drift) is driven by the breaking waves and the longshore currents in the wave breaking zone | *sand transport (littoral transport or littoral drift) is driven by the breaking waves and the longshore currents in the wave breaking zone | ||
| − | '''Natural sandy beaches:''' | + | '''Natural [[sandy beaches]]:''' |
*Their appearance is determined by hydrographic conditions and geology | *Their appearance is determined by hydrographic conditions and geology | ||
*Any interference will cause a reaction in the form of a shoreline response | *Any interference will cause a reaction in the form of a shoreline response | ||
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===Barrier coasts=== | ===Barrier coasts=== | ||
| − | *barrier islands are parallel to the shore, separated from mainland by a lagoon | + | *[[#barrier coast diagram|barrier islands]] are parallel to the shore, separated from mainland by a lagoon |
*in a profile with a more gentle slope than the equilibrium profile, sediments will be moved onshore, as waves on the shoreface will primarily transport sand towards shore attempting to build up equilibrium profile. Waves lose their energy over the gentle shoreface and deposition occurs some distance from shoreline | *in a profile with a more gentle slope than the equilibrium profile, sediments will be moved onshore, as waves on the shoreface will primarily transport sand towards shore attempting to build up equilibrium profile. Waves lose their energy over the gentle shoreface and deposition occurs some distance from shoreline | ||
**eventually develops into a barrier island (cross-shore transport) | **eventually develops into a barrier island (cross-shore transport) | ||
*transport of sand by longshore transport will add to barrier formation, a combination of sand spit and barrier island processes, normally occurring under type 1 and 2 conditions | *transport of sand by longshore transport will add to barrier formation, a combination of sand spit and barrier island processes, normally occurring under type 1 and 2 conditions | ||
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*are normally vegetated e.g. mangroves fronted by very flat slopes or tidal flats | *are normally vegetated e.g. mangroves fronted by very flat slopes or tidal flats | ||
*a muddy coast with mangrove vegetation is characterized by a muddy shoreface, sometimes in the form of muddy tidal flats, and the lack of a sandy shore | *a muddy coast with mangrove vegetation is characterized by a muddy shoreface, sometimes in the form of muddy tidal flats, and the lack of a sandy shore | ||
| − | + | *[[cohesive sediments]] have special properties | |
| − | [[ | ||
===Rocky coasts=== | ===Rocky coasts=== | ||
===Arctic coasts=== | ===Arctic coasts=== | ||
Revision as of 12:41, 11 January 2007
This one should be relatively short - with links to more specific entries.
Contents
Land-sea interaction
Dynamic (or ever changing) environment
Different coastal types:
Sandy beaches
- sand is a very common marine sediment and is transported along the shoreline by littoral transport
- sand transport (littoral transport or littoral drift) is driven by the breaking waves and the longshore currents in the wave breaking zone
Natural sandy beaches:
- Their appearance is determined by hydrographic conditions and geology
- Any interference will cause a reaction in the form of a shoreline response
Therefore:
- Understanding of physical processes is important
- Development of suitable solutions required, supported by numerical modelling if needed
Barrier coasts
- barrier islands are parallel to the shore, separated from mainland by a lagoon
- in a profile with a more gentle slope than the equilibrium profile, sediments will be moved onshore, as waves on the shoreface will primarily transport sand towards shore attempting to build up equilibrium profile. Waves lose their energy over the gentle shoreface and deposition occurs some distance from shoreline
- eventually develops into a barrier island (cross-shore transport)
- transport of sand by longshore transport will add to barrier formation, a combination of sand spit and barrier island processes, normally occurring under type 1 and 2 conditions
Muddy coasts
- are only found in environments that are fairly calm with respect to wave conditions; or there is abundant supply of fine sediments
- are normally vegetated e.g. mangroves fronted by very flat slopes or tidal flats
- a muddy coast with mangrove vegetation is characterized by a muddy shoreface, sometimes in the form of muddy tidal flats, and the lack of a sandy shore
- cohesive sediments have special properties
