Land reclamation

Land reclamation or reclamation means the artificial acceleration of the sedimentation process at suitable locations of coasts in the Wadden Sea in the first place. The word is also used for the heaping up of large areas in the coastal area, eg by means of suction dredgers, and traditionally used for the reclamation of previously agriculturally used land.

Land reclamation by deposition

In the North Sea region, a system of groynes and fascines, is often applied to calm the waters and to retard runoff of suspended particles carried along in the water at low tide for the purpose of land reclamation. In the calm water of these as sediment or silt settle on the seabed.

The flood transported to sand, silt, clay, organic matter and suspended solids other than. During the resting phase of the water during low tides, this material settles out as sludge between the groynes and fences sector and in the bounded basin, the sea floor is gradually increasing. Pioneer plants such as samphire or beach grass can settle.

Reaches the sea floor, the flood height, trenches are dug and spread the excavated silt to further increase in the country. In the trenches, new sediments can be deposited again. The country obtained in this way is usually in front of the protective dyke and is therefore called the foreshore. As such, it also serves to protect the dike, it slows by running toward the dike tidal waves.

Is the foreland large enough and it is to be used permanently, it is protected by levees from storm surges. The diked land is called depending on the region enclosed land (Schleswig -Holstein), Groden (Oldenburg ) or polder ( Netherlands, Ostfriesland ). Only the long-term reclamation allows a complete desalination of the soil. This is done by precipitation, which rinse the salt present in the soil. In general, this rainwater is collected in bettors and derived by sluices, at the same time prevent a new intrusion of salt water. Usually considered the foreland as ripe for reclamation when there blooms of white clover, since this kind a similar salinity tolerated as agricultural crops.

In Germany so far about 180 polders or polders were recovered. In some Eindeichungsprojekten as the Hauke- sharks - the polder Koogland was not used for agriculture, but as a bird sanctuary.

Land reclamation by damming

In the Netherlands has - operated by curbing the IJsselmeer another form of land reclamation by first built the levees in the dammed the sea area and then the thus newly circumscribed polder first with wind pumps, and later with - in conjunction with the Coastal Protection steam or motor-driven pumps pumped empty. The classic, time -consuming and costly reclamation by sediment deposition was not applied here, the soil is therefore still consistently below sea level ( = depression). The disadvantage of this approach is that the rainfall must be permanently drained. In part, this method has also been applied elsewhere ( inter alia the construction of Speicherkooges in the Meldorfer Bay ) when the land reclamation by deposition not yet as advanced as was desired.

Land reclamation by landfill

In some cases, land will also win by massive mound of sand and / or stone, for example, for coastal defense or to gain ground. In Singapore, 135, piled up and secured even 249 square kilometers of land in Tokyo, referred to in Japan as Umetate chi. So 360 acres of land were spouted in Germany for the construction of JadeWeserPort near Wilhelmshaven. Also in the Maldives, a similar approach is followed to exist even against the rise of the oceans. Thus, the airport island Hulhulé and the neighboring island Hulhumalé was enlarged through land reclamation

A similar project was also, for example, the construction of the Palm Islands off Dubai. The construction of Maasvlakte 2 is currently planned to increase the Rotterdam Europoort. Such large-scale projects of the earthworks have become technically possible only in recent years, but they do not represent land reclamation in the strict sense, since it is not original to the sea floor in the new country.

Social discussion

The sense of reclamation is controversial. On the one hand it is to serve the coastal protection by populated areas Köge be preceded, on the other hand are destroyed by land reclamation valuable ecosystems such as the Wadden and salt marshes.

In Germany last 1923/24, the Neufeld enclosed land for purely commercial reasons was applied ( at private expense ). Newer polders as the Hauke- sharks - polder of 1958-1960 include deliberately large bird sanctuaries. The last major diking Germany was the construction of Beltringharder Koog ( seawall 1987) with an area of ​​3350 ha, which today is the largest protected area of Schleswig-Holstein mainland.

Meaning Variant: reclamation of previously unused land

When reclamation is also refers to the recovery of farmland, so the Reclamation of agricultural unused wilderness. Best known Neuland campaigns are (Russian: " Zelina " ) in the former Soviet Union in black soil areas of southern Siberia, Kazakhstan, Uzbekistan and Turkmenistan in the 1920s, 1930s and 1950s. This large-scale land reclamation usually been accompanied by the installation of protective forest belts against wind erosion and in part to the creation of large irrigation systems. The hoped-for increase in yield of agricultural products (wheat, cotton) remained permanently usually made, and there were massive ecological problems, such as the Aral Sea.

However, the recovery of land in Ukraine, southern Russia, the Middle West of the USA, Argentina, parts of Africa and Australia between the 18th century and 20th century followed similar principles.

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