definition

A dike or levee is an elongated artificially constructed embankment, which protects low-lying areas against higher water levels. It is usually made of clay and sand. Rock or concrete are used to protect the water facing outer slope against waves. Most dikes are constructed parallel to the course of a river in its floodplain or along low lying coastlines.
(Wikipedia, Levee, accessed on Sept. 2016)
Similarly to dikes, the primary function of sea dikes is to protect low-lying, coastal areas from inundation by the sea. It is a predominantly earth structure consisting of a sand core, a watertight outer protection layer, toe protection and a drainage channel. These structures are designed to resist wave action and prevent or minimise overtopping. They can be realised as linear structures (even closed dike line) or as a closed circular structure (ring dike). Additionally, dikes can be used for land reclamation by diking of marshes.
(ClimaTechWiki, Sea dikes, accessed Sept. 2016)

Co-benefits and impacts

Dikes can form a lingering feature in the landscape and can be used for both recreational and infrastructural needs. Sea Dikes provide a high degree of protection against flooding in low-lying coastal areas. They often form the cheapest hard defence when the value of coastal land is low and construction materials and specialised machinery are locally available. The sloped seaward edge of a dike leads to greater wave energy dissipation and reduced wave loadings on the structure compared to vertical structures. The reduced wave energy assists in the occurrence of less negative effects such as erosion of the shoreline. By reducing wave loadings, the probability of catastrophic failure or damage during extreme events is also reduced. When compared to vertical structures, dikes also have reduced toe scour. This is because the wave downrush is directed away from the base of the structure. This is beneficial for structural stability and helps to reduce the risk of undermining.
(ClimaTechWiki, Sea dikes, accessed Sept. 2016)

conditions

The high space requirement for sea dikes is one barrier to implementation. This factor will be especially important in areas where the value of the coastline plays an important role in deciding adaptation technologies. The availability of materials, labour and specialised machinery for the construction of dikes may also pose a barrier to the implementation of this technology. The cost of implementing an effective dike system can prove a barrier in some cases. The most effective dikes are those designed in accordance with good quality, long-term environmental data, such as wave height and extreme sea level information. One of the main barriers to the building of an effective dike which accounts for local conditions is therefore the availability of long-term datasets. The cost of collecting such data can be expensive. However, by accounting for these local conditions, dike design is typically more effective. The additional costs of data collection and exclusive design may for a barrier to implementation in some circumstances.
(ClimaTechWiki, Sea dikes, accessed Sept. 2016)

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Last modified: Sept. 16, 2016, 10:30 a.m.