A dyke (v. down-German dik: more dug/outdone pond) is a building, which as artificially up-poured dam lies along a river or a sea bank. In Austria it is called rather Schutzdamm.

In the technical linguistic usage is the dyke at a natural waters (e.g. River, sea) and serves the protection from temporary dangers (flood protection). However are the dam usually at an artificial waters (e.g. Water retaining structure, dam, channel) or serves the durable steering of the water in a natural waters (Leitdamm).

A dyke protects, as for instance in the Netherlands or at the German North Sea Coast (East Frisia, Oldenburg, circle Dithmar, circle Nordfriesland) more deep-seated area from flooding or in most cases country, that scarcely over the sea level lies before storm tides or inundations.

Dyke constructions at the coasts are systems thought out meanwhile, which do not only consist of the main dyke. Usually dyke before country before the dyke, which breaks the waves, lies and which attack of the water decreases. If the dyke must be built directly at the water edge, a Schardeich is necessary. Partly still another overflow dam can lie here. This is relatively low, so that he stops only smaller tides. It was not up to to the heavier tides, which occur at the German coast usually in the autumn or spring, however. This dyke has a flat construction, since it is inundated regularly by the water and no larger damage by the Flutwelle to take is. On the Halligen the overflow dam is the only dyke, with heavy tides is dependent the Halligbewohner on the protection by Warften.

The actual main dyke is the largest dyke in the row. The water side of the dykes is flatter than the land side, in order to offer to waves less attack region. Theodor Storm describes this descriptive in its novella of the mould riders: "Before thirty years the old dyke is broken; then backwards before thirty-five, and again before forty-five years. "Â… The new dyke however is to stand despite such hundreds and over one hundred years; because it will not be broken through, because the mild waste does not set a point of attack to the waves against after the sea-side." Dykes consist usually of a sand core, which is covered by a layer from bindigem material, thick up to two meters. Whereupon for the avoidance of erosion and/or for the increase of stability grass is cultivated. Both around the grass scar short and close to keep and around the soil dykes will trample firmly often from sheep beweidet. Few dykes have a tar cover. The dyke height depends on the respective landscape and tide danger. The stream dikes at the Elbe have in certain sections a height of 8 m, dykes are e.g. more highly and partly over 100 m broad.

The land side of the dyke must possess a dyke military way (dyke defense way), at which for example sand bags can be transported near. In the hinterland continues to follow a second dyke line, which consists of Schlafdeichen. These prevent that after a Deichbruch larger surfaces are flooded. Besides the surfaces between first and second dyke line are settled usually thinly or serve at some rivers directly as balancing reservoir possibly which can be opened, in order to lower the water level. At the coast the field of the far force of the waves and the water breaks. Schlafdeiche are often the old dyke at the former coastal line, which moved by land reclamation in the inland.

Terms

The attachment of new dyke distances with straw is called "embroidering ".

A stairway or a ramp to the dyke is called also as "act ".

History

Up to the Middle Ages humans knew no dyke construction, but built their houses and settlements on Warften - up-poured earth hills. The first dyke form were ring dykes, which closed at a settlement or a pasture place for the animals. In the course of the centuries these dykes were connected, until they formed a common line. If they broke, far parts of the country were flooded. Since these regions often lay below the sea level, it was a large problem, the water the country to wars. Often hardly more highly than two meters, but in the profile the today's dykes similarly, the technology of the stack dykes became generally accepted goods early dykes in the late Middle Ages. These had a vertical edge manufactured from wood to the Wasserlinie, which often rose several meters over the Watt. They were however both complex in the building and in the care, besides it proved that they could be more easily under-rinsed. If the waves broke against the stack dyke, the water squirted up and sizzled on the dyke down, so that this fast aufweichte.

After the Burchardiflut 1634 one changed at the German and Danish coast again to flatter dykes and began to let dyke construction and drainage of commercial entrepreneurs who were lured with Oktroy from the Netherlands to Germany lead. When with the storm tides of 1717 and 1825 it proved in each case that the dykes were too low was adapted, them to the new tide height. With the Hamburg storm tide of 1962 it proved that they were in many places still too low.

If dykes had to be built in former times still by the inhabitants of the coastal regions themselves, then the coastal protection belongs in the industrialized countries since the industrialization to the state functions.

If by land reclamation new is won, these are again eingedeicht. The dyke must be equipped with a Siel for regular drainage. The old dyke receives the designation Schlafdeich.

A problem, in particular with stream dikes, is at some places undermining the plants by the rooting activity of Bisamratten. Thereby high costs of repair and maintenance work arise for the deep and hydraulic engineering.

In Germany the DIN finds 19712 "stream dikes "for the dyke new building application.

Web left

List of the maintenance associations in Lower Saxony (drainage federations, water, siel and dyke respecting)

See also: Smoke dyke, emergency dyke, main dam

Articles in category "Dyke"

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