A seawall is a form of hard coastal defence constructed on the inland part of a coast to reduce the effects of strong waves and are built in the water. In some jurisdictions the terms sea defense and coastal protection are used to mean respectively defence against flooding and erosion The coast is defined as the part of the land adjoining or near the Ocean. A wave is a disturbance that propagates through Space and Time, usually with transference of Energy.
In Britain, "sea wall" also means an earth bank used to create a polder – a dike. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located A polder is a low-lying tract of land enclosed by embankments known as dikes, that forms an artificial hydrological entity meaning it has no connection with LeveeEmbankmentDitch A dike (or dyke) levee, levée, embankment, floodbank or stopbank is a natural or artificial
Seawalls may be constructed from a variety of materials: most commonly, they are constructed of reinforced concrete, boulders, steel, or wire cages filled with pebbles. Reinforced concrete is Concrete in which reinforcement bars (" Rebars quot or fibers have been incorporated to strengthen a material that would otherwise be Steel is an Alloy consisting mostly of Iron, with a Carbon content between 0 Additional seawall construction materials include: vinyl, wood, aluminum and fiberglass composite. A vinyl compound is any Organic compound that contains a vinyl group (also called ethenyl) &minus C[[Hydrogen H]] =CH sub>2 Wood is hard fibrous lignified structural tissue produced as secondary Xylem in the stems of Woody plants notably trees but also shrubs WikipediaNaming Poorly designed seawalls require constant maintenance, as the waves can constantly attack the base of the seawall. A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. Seawalls can be expensive to build, costing between £4000 to £7000 per metre. Modern concrete sea walls tend to be curved to deflect the wave energy back out to sea, reducing the force.
Contents |
Design principles and types
A range of seawall types can be envisaged in relation to wave energy, resembling cliff and beach profiles. Vertical seawalls are built in particularly exposed situations. These reflect wave energy and under storm conditions standing waves (clapotis) will develop. A standing wave, also known as a stationary wave, is a Wave that remains in a constant position In Hydrodynamics, the clapotis (from "lapping of water" is a non-breaking Standing wave pattern caused for example by the reflection of a traveling surface In some cases piles are placed in front of the wall to lessen wave energy slightly. Curved or stepped seawalls are designed to enable waves to break and to dissipate wave energy. The curve can also prevent the wave overtopping the wall, and provide additional protection for the toe of the wall.
A series of rubble mound-type structures (or revetments, riprap) are used in lesser energy settings. Revetments, or revêtements (following the original French spelling are structures placed on banks or cliffs in such a way as to absorb the energy of incoming water Riprap — also known as rip rap, rubble, shot rock or rock armour — is rock or other material used to armor The least exposed sites involve the lowest-cost technology, bulkheads or revetments of sand bags or geotextiles. These serve to armour the shore and impede erosion. They may be either watertight, covering the slope completely, or porous, to allow water to filter through after the wave energy has been dissipated.
 |  |  |
History
Pondicherry
On December 26, 2004, when towering waves of the 2004 Indian Ocean earthquake crashed against India's south-eastern coastline killing thousands, the former French colonial enclave of Pondicherry (now Puducherry) escaped unscathed. The 2004 Indian Ocean earthquake was an undersea Earthquake that occurred at 005853 UTC on December 26 2004 with an Epicentre off the west coast of Puducherry (formerly; புதுச்சேரி or பாண்டிச்சேரி పాండిచెర్రి പുതുശ്ശേരി Pondichéry is a During the city's nearly three centuries as a French colony, French engineers had constructed and maintained a massive stone seawall, which kept Pondicherry's historic center dry even though tsunami waves drove water 24 feet above the normal high-tide mark. A tsunami ((tsuːˈnɑːmi is a series of waves created when
The barrier was initially completed in 1735. Over the years, the French continued to fortify the wall, piling huge boulders along its 1. 25-mile (2-kilometer) coastline to stop erosion from the waves pounding the harbour. At its highest, the barrier running along the water's edge reaches about 27 feet above sea level. The boulders, some weighing up to a ton, are weathered black and brown. The sea wall is inspected every year. Whenever gaps appear or the stones sink into the sand, the government adds more boulders to keep it strong.
The Union Territory of Pondicherry recorded some 600 deaths from the huge tsunami waves that struck India's coast after the mammoth underwater earthquake (which measured 9. 0 on the moment magnitude scale) off Indonesia, but most of those killed were fishermen who lived in villages beyond the artifical barrier. TalkMoment magnitude scale#Real world examples please.--> The moment magnitude scale
See also
- Retaining wall
- Accropode
- Dike
- Alaskan Way Seawall
- Galveston Seawall
- Georgetown Seawall
- Gold Coast Seawall
- Saemangeum Seawall
- Vancouver Seawall
References
- De Centre d'études maritimes et fluviales. A retaining wall is a structure that holds back Soil or rock from a Building, structure or area Accropode blocks are man-made unreinforced Concrete objects designed to resist the action of waves on Breakwaters and coastal structures LeveeEmbankmentDitch A dike (or dyke) levee, levée, embankment, floodbank or stopbank is a natural or artificial The Alaskan Way Seawall is a Seawall which runs for 7000 feet along the Elliott Bay waterfront southwest of downtown Seattle from Bay Street to S The Galveston Seawall is a Seawall in Galveston Texas, USA that was built after the Galveston Hurricane of 1900 for protection from future Hurricanes The most famous stretch of seawall in Guyana is the Georgetown Seawall. The Gold Coast Shoreline Management Plan (GCSMP is an ICZM plan to manage the coastal resources of Gold Coast City The Saemangeum Seawall, located on the southwest coast of the Korean peninsula, is the world's longest man-made dyke, measuring 33 kilometres The seawall in Vancouver, Canada is a stone wall that was constructed around the perimeter of Stanley Park to prevent the erosion of the park's foreshore (2007). Rock Manual. The use of rock in hydraulic engineering. Ciria. ISBN 0860176835.
- N. W. H. Allsop. (2002). Breakwaters, coastal structures and coastlines. Thomas Telford. ISBN 0727730428.
External links
- Channel Coastal Observatory - Seawalls
- Constructing a new sea wall and defences at Lyme Regis in Dorset
Gallery
 Seawall in production in Galveston, TX, USA, 1905 |  Remains of the first seawall of Canvey Island built c. Canvey Island (area 1845 km² pop 37479is a reclaimed island in the Thames estuary separated from the mainland of south Essex by a network of creeks 1622. |  Seawall in Bembridge, UK |
 Seawall in Sicily |  Seawall in Poland |
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic