Difference between revisions of "Revetment"

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{{Definition|title=Revetment
 
{{Definition|title=Revetment
|definition= A revetment is a facing of stone, concrete units or slabs, etc., built to protect a scarp, the foot of a cliff or a dune, a dike or a seawall against erosion by wave action, storm surge and currents. This definition is very similar to the definition of a seawall, however a revetment does not protect against flooding. Furthermore, a revetment is often a supplement to other types of protection such as seawalls and dikes.  
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|definition= A revetment is a facing of stone, concrete units or slabs, etc., built to protect a scarp, the foot of a cliff or a dune, a dike or a seawall against erosion by wave action, storm surge and currents.  
 
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The following article discusses the fixing of the coastline by revetments.
 
  
==Method==
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[[File:DikeRevetment.jpg|thumb|300px|left|Dike revetment.]]
Revetments can be an exposed structure as well as a buried structure.  
 
  
===Exposed revetments===
 
Revetments are always made as sloping structures and are very often constructed as permeable structures using natural stones or concrete blocks, thereby enhancing wave energy absorption and minimising reflection and wave run-up.
 
  
However, revetments can also consist of different kinds of concrete slabs, some of them permeable and interlocking. In this way their functionality is increased in terms of absorption and strength. An example of a permeable and interlocking concrete slap is the so-called Flex Slap.
 
  
Net mesh stone-filled mattresses, such as Gabions, are also used; however, they are only recommended for use at fairly protected locations.
 
  
Revetments can also consist of sand-filled geotextile fabric bags, mattresses and tubes. Such structures must be protected against UV-light to avoid weathering of the fabric. Sand-bagging is often used as emergency protection. Geotextile fabric revetments are fragile against mechanical impact and vandalism, and their appearance is not natural.  
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==Notes==
[[Image:Revetments.jpg|500px|center|Examples of revetments.]]
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This definition is very similar to the definition of a seawall, however a revetment does not protect against flooding. Furthermore, a revetment is often a supplement to other types of protection such as seawalls and dikes.  
:<small>Fig. 1. Examples of revetments.</small>
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<br clear=all>
  
===Buried revetments===
 
[[Image: Emergency revetments.jpg|thumb| Fig. 2. An example of an emergency revetment constructed in concrete blocks, the revetment will later be buried into an artificial dune. (Danish Coastal Authority<ref>Danish Coastal Authority, 1998. "Menneske, Hav, Kyst og Sand". (in Danish), (Man, Sea Coast and Sand in English). Kystinspektoratet 1973-1998.</ref>)]]
 
 
A buried revetment can be constructed as part of a soft protection, e.g. as a hard emergency protection built into a strengthened dune which acts as shore protection and/or sea defence.
 
 
==Functional characteristics==
 
All types of revetments have the inherent function of beach degradation as they are used at locations where the coast is exposed to erosion. A revetment will fix the location of the coastline, but it will not arrest the ongoing erosion in the coastal profile, and the beach in front of the revetment will gradually disappear. However, as a revetment is often made as a permeable, sloping structure, it will normally not accelerate the erosion, as did seawalls; on the contrary, rubble revetments are often used as reinforcement for seawalls which have been exposed due to the disappearance of the beach. Such reinforcement protects the foot of the seawall and minimises the reflection.
 
 
A revetment, like a seawall, will decrease the release of sediments from the section it protects, for which reason it will have a negative impact on the sediment budget along adjacent shorelines.
 
 
==Applicability==
 
A revetment is a passive structure, which protects against erosion caused by wave action, storm surge and currents. The main difference in the function of a seawall and a revetment is that a seawall protects against erosion and flooding, whereas a revetment only protects against erosion. A revetment is thus a passive coastal protection measure and is used at locations exposed to erosion or as a supplement to seawalls or dikes at locations exposed to both erosion and flooding. Revetments are used on all types of coasts, however mainly types 1 - 4.
 
 
Rubble revetments and similar structures have a permeable and fairly steep slope; normally a 1:2 slope is used. This slope is suitable neither for recreational use nor for the landing or hauling of small fishing boats. Consequently, this kind of structure should not be used at locations, where the beach is used for recreation or fishing activities. For such locations, other types of protection measures must be considered, but if a revetment is required, a more gently sloping structure with a smooth surface is recommended.
 
 
==References==
 
<references/>
 
  
 
==See also==
 
==See also==
 
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* [[Revetments]]: article on different types of revetments, characteristics and application in practice.  
''Author: Karsten Mangor, DHI, 2004. km@dhi.dk.''
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* [[Seawalls and revetments]]: article on the effectiveness of seawalls and revetments to solve coastal engineering problems.
 
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* [[Light revetments built-in into artificial dunes]]: Experiences from Polen with the application of light revetments built-in into artificial dunes to complement soft shoreline protection solutions.
''All content is written by Karsten Mangor unless referenced otherwise. Full source: Mangor, Karsten. 2004. “Shoreline Management Guidelines”. DHI Water and Environment, 294pp.''
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* [[Stability of rubble mound breakwaters and shore revetments]]
  
  
  
  
return to
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==Further reading==
:[[Practices – What to do in erosion event]]
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Mangor, K., Drønen, N. K., Kaergaard, K.H. and Kristensen, N.E. 2017. Shoreline management guidelines. DHI https://www.dhigroup.com/marine-water/ebook-shoreline-management-guidelines.
:[[Shore protection]]
 
:[[wiki articles and authors|Theme 5 Articles]]
 

Latest revision as of 10:46, 30 March 2021

Definition of Revetment:
A revetment is a facing of stone, concrete units or slabs, etc., built to protect a scarp, the foot of a cliff or a dune, a dike or a seawall against erosion by wave action, storm surge and currents.
This is the common definition for Revetment, other definitions can be discussed in the article


Dike revetment.



Notes

This definition is very similar to the definition of a seawall, however a revetment does not protect against flooding. Furthermore, a revetment is often a supplement to other types of protection such as seawalls and dikes.


See also



Further reading

Mangor, K., Drønen, N. K., Kaergaard, K.H. and Kristensen, N.E. 2017. Shoreline management guidelines. DHI https://www.dhigroup.com/marine-water/ebook-shoreline-management-guidelines.