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==Biogeomorphology of aquatic systems==
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==Application of breakwaters==
  
[[Image:seagrasswaddensea.jpg|thumb|20x|Seagrass meadow]]
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[[Image:artifical headland.jpg|300px|thumb|Fig. 2. Optimisation of coastal breakwater to artificial headland, applicable for moderately exposed to exposed coasts for small angles of incidence.]]
  
[[Biogeomorphology]] considers the interactions between the ecology and geomorphology of a system. Ecology is the study of relationships between the biota and their environment, and geomorphology examines landforms and how they are formed. Biogeomorphology can be studied in terrestrial as well as aquatic systems. Within aquatic systems biogeomorphological relationships can be found for both hard substrates (rocky shores / coral reefs) and soft substrates (muddy / sandy coastal sediments). Biota can alter geomorphology by creating hard substrates (e.g. coral reefs) or by modifying the stability or erodability of soft substrates.  Key species in the benthic communities of sediment shores can influence geomorphology by acting as '''biostabilizers''' or '''biodestabilizers''' of sediment. The impact of organisms on coastal morphology can be both dramatic (e.g. coral reefs, [[saltmarsh]]es, mussel beds) and more subtle by modifying rates of sediment [[erosion]] and accretion.  Biota are not only influenced by various environmental factors (abiotic – physical & chemical; biotic – other organisms; [[anthropogenic]] – humans), but organisms also act as [[ecosystem]] engineers and modify their environment (physical, chemical and biological aspects). [[Ecosystem]] engineers create valuable habitats (e.g. coral reefs and saltmarshes) that are important for fish and birds and serve as a vital part of our natural coastal defence against storm surges and [[sea level rise]].
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Breakwaters aim to protect a coast or activities along the [[coastline]] (e.g. ports, ship wharf) from wave action. Different types of breakwaters exist, from which [[detached breakwater]]s are the most common type of breakwater. This article provides a general introduction of breakwaters and describes submerged or low-crested breakwaters, floating breakwaters and special type breakwaters. The characteristics and application of [[detached breakwater|detached breakwaters]] are described in other articles: [[Detached breakwaters]], [[Applicability of detached breakwaters]] and [[Detached shore parallel breakwaters]]. 
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Breakwater schemes have many variables, which determine the impact on the shoreline. The variable parameters are outlined in the following:
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*Emerged, submerged or floating
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*Distance from shoreline and location relative to the [[surf zone]]
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*Length and orientation
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*Single or segmented
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*Special shapes
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There are further descriptions in the article [[Detached breakwaters]] for combinations of all these parameters.
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A shoreline management breakwater serves two purposes:
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*To provide shelter from the [[waves]]
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*Through this shelter, to manipulate the littoral transport conditions and thereby to trap some sand

Revision as of 11:29, 5 January 2009

Application of breakwaters

Fig. 2. Optimisation of coastal breakwater to artificial headland, applicable for moderately exposed to exposed coasts for small angles of incidence.

Breakwaters aim to protect a coast or activities along the coastline (e.g. ports, ship wharf) from wave action. Different types of breakwaters exist, from which detached breakwaters are the most common type of breakwater. This article provides a general introduction of breakwaters and describes submerged or low-crested breakwaters, floating breakwaters and special type breakwaters. The characteristics and application of detached breakwaters are described in other articles: Detached breakwaters, Applicability of detached breakwaters and Detached shore parallel breakwaters.

Breakwater schemes have many variables, which determine the impact on the shoreline. The variable parameters are outlined in the following:

  • Emerged, submerged or floating
  • Distance from shoreline and location relative to the surf zone
  • Length and orientation
  • Single or segmented
  • Special shapes

There are further descriptions in the article Detached breakwaters for combinations of all these parameters.

A shoreline management breakwater serves two purposes:

  • To provide shelter from the waves
  • Through this shelter, to manipulate the littoral transport conditions and thereby to trap some sand