Dike (construction)
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A dike (or dyke) is a stone or earthen wall constructed as a defence or as a boundary. The best known form of dike is a construction built along the edge of a body of water to prevent it from flooding onto an adjacent lowland. However dikes have also been built as field boundaries and as military defences. More on this type of dike can be found in the article on dry-stone walls.
Dikes can be permanent earthworks or emergency constructions (often of sandbags) built hastily in a flood emergency. Also dikes were built to reclaim land from the sea. For instance, the Zuiderzee Works (North Sea Reclamation Works) in the Netherlands are an immense series of dikes built primarily to shorten the coast line and make it safer. This dike sytem goes further to the east and north via nearly the whole German coast up to Esbjerg in Denmark. The estuaries of the flatland rivers Rhine, Elbe, Ems, Weser and Eider are also protected from storm tides by dikes, which can be more than 9 m high.
The Netherlands also has some 13,000 km of boezem dikes, secondary dikes typically of 1.5 - 4 m high, and essential to the continued drainage of reclaimed land. The dikes are typically merely simple earth embankments, though 20% are constructed from peat; two collapses of boezem dikes in 2003 have prompted urgent investigation of the entire network.
The city of Richmond, British Columbia in Canada is an island of 129.666 km2 at the delta of the Fraser River protected by a system of dikes. The first dikes were created by individual farmers in 1861 to reclaim land. Pumps are still used to this day to keep water out, and there are still uncovered ditches throughout much of Richmond. Many of the ditches are being replaced with pipes with sidewalks on top.
See also
External links
- Richmond's Dyke system (http://www.discovervancouver.com/GVB/richmond.asp)bg:Дига