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Sylt ((:ˈzʏlt); (デンマーク語:Sild); Söl'ring North Frisian: ''Söl'') is an island in northern Germany, part of Nordfriesland district, Schleswig-Holstein, and well known for the distinctive shape of its shoreline. It belongs to the North Frisian Islands and is the largest island in North Frisia. The northernmost island of Germany, it is known for its tourist resorts, notably Westerland, Kampen and Wenningstedt-Braderup, as well as for its 40 km long sandy beach. It is frequently covered by the media in connection with its exposed situation in the North Sea and its ongoing loss of land during storm tides. Since 1927, Sylt has been connected to the mainland by the Hindenburgdamm causeway. In latter years, it has been a resort for the German jet set and tourists in search of occasional celebrity sighting. == Geography == With 99.14 km², Sylt is the fourth-largest German island and the largest German island in the North Sea. Sylt is located from 9 to 16 km off the mainland, to which it is connected by the Hindenburgdamm. Southeast of Sylt are the islands of Föhr and Amrum, to the north lies the Danish island of Rømø. The island of Sylt extends for 38 km in a north-south direction. At its northern peak at ''Königshafen'', it is only 320 m wide. Its greatest width, from the town of Westerland in the west to the eastern ''Nössespitze'' near Morsum, measures 12.6 km. On the western and northwestern shore, there is a 40 km sand beach. To the east of Sylt, is the Wadden Sea, which belongs to the Schleswig-Holstein Wadden Sea National Park and mostly falls dry during low tide. The island's shape has constantly shifted over time, a process which is still ongoing today. The northern and southern spits of Sylt are exclusively made up of infertile sand deposits, while the central part with the municipalities of Westerland, Wenningstedt-Braderup and Sylt-Ost consists of a geestland core, which becomes apparent in the form of the Red Cliff of Wenningstedt. The geestland facing the Wadden Sea gradually turns into fertile marshland around Sylt-Ost. Today sources show that Sylt has only been an island since the ''Grote Mandrenke'' flood of 1362. The so-called ''Uwe-Düne'' (Uwe Dune) is the island's highest elevation with 52.5 m above sea level. The island in its current form has only existed for about 400 years. Like the mainland geestland, it was formed of moraines from the older ice ages, thus being made up of a till core, which is now apparent in the island's west and centre by the cliff, dunes and beach. This sandy core began to erode as it was exposed to a strong current along the island's steep basement when the sea level rose 8000 years ago. During the process, sediments were accumulated north and south of the island. The west coast, which was originally situated 10 km off today's shore, was thus gradually moved eastward, while at the same time the island began to extend to the north and south. After the ice ages, marshland began to form around this geestland core. In 1141, Sylt is recorded as an island, yet before the ''Grote Mandrenke'' flood it belonged to a landscape cut by tidal creeks and, at least during low tide, it could be reached on foot.〔 It is only since this flood that the creation of a spit from sediments began to form the current characteristic shape of Sylt. It is the northern and southern edges of Sylt which were, and still are, the subject of greatest change. For example, Listland was separated from the rest of the island in the 14th century and from the later 17th century onwards the ''Königshafen'' (King's Harbour) began to silt up as the "elbow" spit began to form. In addition to the constant loss of land, the inhabitants during the Little Ice Age were constrained by sand drift. Dunes shifting to the east threatened settlements and arable land and had to be stopped by the planting of marram grass in the 18th century. Consequently, though, material breaking off the island was increasingly washed away and the island's extent continued to decrease. Records of the annual land loss exist since 1870. According to them, Sylt lost an annual 0.4 m of land in the north and 0.7 m in the south from 1870 to 1951. From 1951 to 1984, the rate increased to 0.9 and 1.4 m respectively, while shorelines at the island's very edges at Hörnum and List are even more affected. Severe storm surges of the last decades have repeatedly endangered Sylt to the point of breaking in two, e.g. Hörnum was temporarily cut off from the island in 1962. Part of the island near Rantum which is only 500m wide is especially threatened. Measures of protection against the continuous erosion date back to the early 19th century when groynes of wooden poles were constructed. Those were built at right angles into the sea from the coast line. Later they were replaced by metal and eventually by armoured concrete groynes. The constructions did not have the desired effect of stopping the erosion caused by crossways currents. "Leeward erosion", i.e. erosion on the downwind side of the groynes prevented sustainable accumulation of sand. In the 1960s breaking the power of the sea was attempted by installing tetrapods along the groyne bases or by putting them into the sea like groynes. The four-armed structures, built in France and many tons in weight were too heavy for Sylt's beaches and were equally unable to prevent erosion. Therefore, they were removed from the Hörnum west beach in 2005. Since the early 1970s the only effective means so far has been flushing sand onto the shore. Dredging vessels are used to pump a mixture of sand and water to a beach where it is spread by bulldozers. Thus storm floods would only erase the artificial accumulation of sand, while the shoreline proper remains intact and erosion is slowed down. This procedure incurs considerable costs. The required budget of an annual €10 million is currently provided by federal German, Schleswig-Holstein state and EU funds. Since 1972 an estimated 35.5 million cubic metres of sand have been flushed ashore and dumped on Sylt. The measures have so far cost more than €134 million in total, but according to scientific calculations they are sufficient to prevent further loss of land for at least three decades, so the benefits for the island's economic power and for the economically underdeveloped region in general would outweigh the costs. In the 1995 study ''Klimafolgen für Mensch und Küste am Beispiel der Nordseeinsel Sylt'' (Climate impact for Man and Shores as seen on the North Sea island Sylt) it reads: ''"Hätte Sylt nicht das Image einer attraktiven Ferieninsel, gäbe es den Küstenschutz in der bestehenden Form gewiss nicht"'' (If Sylt did not have the image of an attractive holiday island, coastal management in its current form would certainly not exist). The enforcement of a natural reef off Sylt is being discussed as an alternative solution. A first experiment was conducted from 1996 to 2003. A sand drainage as being successfully used on Danish islands is not likely to work on Sylt owing to the underwater slope here. In parallel to the ongoing sand flushing, the deliberate demolition of groynes has begun amid great effort at certain beach sections where they were proven largely ineffective. This measure also terminated the presumably most famous groyne of Sylt, ''Buhne 16'' — the namesake of the local naturist beach. A number of experts, however, fears that Sylt will still have to face considerable losses of land until the mid 21st century. The continuous global warming is thought to result in increasing storm activity, which would result in increased land loss and, as a first impact, might mean the end of property insurance. Measurements showed that, unlike in former times, the wave energy of the sea is no longer lost offshore, today it carries its destructive effects on to the beaches proper. This will result in an annual loss of sand of 1.1 million m³.〔 The dunes of the island constitute nature reserves and may only be traversed on marked tracks. So called "wild paths" promote erosion and are not to be followed. Where vegetation is tread upon, no roots are left to hold the sand and it will be removed by wind and water. The Wadden Sea on the east side between Sylt and the mainland has been a nature reserve and bird sanctuary since 1935 and is part of the Schleswig-Holstein Wadden Sea National Park. The construction of breakwaters in this area will abate sedimentation and is used for land reclamation. Also the grazing of sheep on the sea dikes and heaths of Sylt eventually serves coastal management, since the animals keep the vegetation short and compress the soil with their hooves. Thus they help create a denser dike surface, which in case of storm surges provides less area for the waves to impact. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Sylt」の詳細全文を読む スポンサード リンク
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