Coastal management
With coastal protection measures for a low-lying, being used by the people to be protected from close to the sea from flooding during storm surges in productivity ( flood protection), on the other, the coasts themselves before bank decline and loss of land.
In the military context, coastal protection refers to the protection of a coast from attack or invasion, mainly through the construction of coastal forts and the holding of troops to combat a possible invasion. For example, let the Wehrmacht in occupied France in 1940 to build the Atlantic Wall as coastal protection and held numerous military units along the coast in position. (see also Border Protection )
Causes of storm surge water levels are wind congestion or pelvic oscillations ( seiches ) in inland seas. In tidally influenced coastal areas and estuaries, these phenomena superimposed on the periodic water level fluctuations (ebb and flood ). Close up coastal land and buildings are therefore usually protected with dikes and flood barriers against floods and storm surges.
Through the construction of dikes, sluices ( waste systems ) and pumping stations (water behind the dam ) to create new coastal residents or preserve old habitat.
In Germany, the federal states of Bremen, Hamburg, Mecklenburg -Western Pomerania, Lower Saxony and Schleswig -Holstein operate coastal protection.
In the Netherlands, coastal protection is also necessary, since large tracts of land have been reclaimed from the sea and behind the dikes often lie below sea level.
The care of the holms off the north German coast is also part of coastal defense. These green sandbanks off the coast of the waves breaking storm surges and thus protect the dikes along the coasts.
The East Frisian Islands are part of coastal defense, they become so complex protected not only because of their great importance for the Lower Saxony tourism, they break forth like the holms accruing from the North Sea to the mainland waves and thus reduce the pressure on the dikes on the mainland.
Another coastal protection measure is to wash up of sand, so as to produce the flattest possible angle before the dike. Dunes are a natural as unstable coastal protection and are available in Germany generally protected. Since the dunes are protected only by plants as the aster beach from erosion by wind and waves, the entry into which is prohibited by law. Where the sand is washed away quickly and no stones to break the waves are present in sufficient quantity, is aided by the concrete (see Breakwater )
The principles of flood protection be applied along rivers. By Snow melt and / or massive rain in the catchment area tidal waves can occur in rivers that make the levels go quickly.
In general, the levees are designed to withstand the pressure of the inflowing water. If the dike flooded the dike can be back- flushed quickly and break. Then the water flows freely into the hinterland. Therefore, the dike crowns are often specially protected and may not be mechanically stressed. Sheep are ideal to keep the sward short and simultaneously determined. ( Musk ) rats in the dike, however, jeopardize the stability, since through the corridors of the dike quickly draws water and becomes unstable.
The action of the sea and coastal protection measures
The North Sea coast is at risk not only during storm surges. Since the North Sea is a marginal sea that form here by the tidal currents, which often run parallel to the coast. Due to the arrangement and the high number of North Sea islands must be the water that is between the islands and the mainland, in the ebb and flow through the narrow channels ( gating ) to flow through between the islands; these currents can be strong, for example, the Wichter Ee is not considered navigable as between the islands of Norderney and Baltrum with a width of only 800 yards on the ground because of the strong currents constantly changing morphology.
These currents can move significant amounts of sand and lead in this way to an erosion in the Coast Range. You can even put entire islands. This is done by one hand, they erode sand, transport it and then redeposit in another place. This caused at least sandbanks at a remote location.
The East Frisian islands move through the flow ( in the first sense, however, by the Gulf Stream and the situation in the westerlies ) to the east, by the removal of material (sand ) at the western head of the island and deposit at the eastern end, which is why with you almost all the islands now the place is on the west side. In order to protect the settlements before or during flood events, the western head of the islands is protected in most cases by massive barriers against further coastal erosion. These include the groynes, which usually reach far out into the Wadden Sea, followed then in a vertical arrangement, for example, Basalt or granite stone materials, concrete paving and other structures that serve the refraction of water waves.
The water levels in storm surge alone would probably endanger the coast less if they were not accompanied by tremendously strong waves. A proper storm surge can be caused by strong winds evenly in one direction for one to two days; a brief gust of wind makes no wave. To be really big and strong, a wave must be possible over long distances by the wind push. This is also the reason that the dikes of the mainland coast are protected by the North Sea islands. Accruing here waves namely only the distance between the island and mainland to absorb energy. They are thus far much less than the waves that run the islands from the seaward side.
In a wave, a large amount of energy to be stored, almost everything that man opposes it, can destroy it. The steeper the coastline the more energy the wave per meter, which they attribute specifies exits. In this case, they can seem to be much destructive and erosive. On an inclined plane low slope, the wave runs dead, but at a steep profile, it can easily wash over an equally high dike and with their power increasingly destroy the dam and finally break through. Why is that a dike in profile should be on the side facing the sea have the minimum possible incline. That makes him, however wide, so space-consuming and expensive. Also, flow obstructions such as Mussel beds, sandbars, breakwaters or tetrapods of the shaft take the force.
To counteract the Sandabtrag near the beach by coastal parallel flows and associated steepening of the coast, groynes are often introduced. At the points where a broad and high dune belt is still present, is often sufficient to stabilize the dunes by planting. At the points where the space for wide dikes is not present, you have to choose a steeper profile that needs to be but then also secured by a revetment of concrete or solid stone blocks. Normally you build a wide dike with a sand core and an outer layer of clothing against the erosion and planted the dike, to further protect it with the roots from erosion. At sites with strong tidal currents can occasionally be useful, a sand nourishment to the flattening of the coastal profile.
Coastal protection in art and literature
A literary analysis of the coastal protection can be found in the novel " The Ghost Rider " by Theodor Storm and the Mystery of the author Kari Koester - Delete with the protagonist Sönke Hansen, who works as an inspector during Hydraulic Water Board Husum.