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23-480: The Flevopolder is an island polder forming the bulk of Flevoland , a province of the Netherlands . Created by land reclamation , its northeastern part was drained in 1955 and the remainder—the southwest—in 1968. Unlike other major polders, it is surrounded by lakes and below-sea-level channels. By some definitions, it is the world's largest artificial island . Levees, dikes, and pumping were used to drain

46-553: A meaning somewhat opposite to that in coastal context. Beemster Beemster ( Dutch pronunciation: [ˈbeːmstər] ) is a former municipality in the Netherlands , in the province of North Holland . The Beemster is the first polder in the Netherlands reclaimed from a lake, the water extracted by windmills between 1609 and 1612. The original well-ordered landscape of fields, roads, canals, and dykes has been preserved intact. A grid of canals parallels

69-421: A new approach to the design of dikes and other water-retaining structures, based on an acceptable probability of overflowing. Risk is defined as the product of probability and consequences. The potential damage in lives, property, and rebuilding costs is compared with the potential cost of water defences. From these calculations follows an acceptable flood risk from the sea at one in 4,000–10,000 years, while it

92-407: A piece of land elevated above its surroundings, with the augmentative suffix -er and epenthetical -d- . The word has been adopted in thirty-six languages. The Netherlands is frequently associated with polders, as its engineers became noted for developing techniques to drain wetlands and make them usable for agriculture and other development. This is illustrated by the saying "God created

115-608: Is one in 100–2,500 years for a river flood. The particular established policy guides the Dutch government to improve flood defences as new data on threat levels become available. Major Dutch polders and the years they were laid dry include Beemster (1609–1612), Schermer (1633–1635), and Haarlemmermeerpolder (1852). Polders created as part of the Zuiderzee Works include Wieringermeerpolder (1930), Noordoostpolder (1942) and Flevopolder (1956–1968) Several cities on

138-580: The IJsselmeer , the Veluwemeer , Ketelmeer , and Gooimeer . By some definitions, it is the largest artificial island in the world. Levees and dikes were first built around the polder. However, unlike similar projects, the internal water was then drained by diesel and electric pumps. Its name refers to the ancient Lake Flevo . The Flevopolder together with the Noordoostpolder forms

161-786: The Paraíba Valley region (in the state of São Paulo ) have polders on land claimed from the floodplains around the Paraíba do Sul river. Bangladesh has 139 polders, of which 49 are sea-facing, while the rest are along the numerous distributaries of the Ganges-Brahmaputra-Meghna River delta. These were constructed in the 1960s to protect the coast from tidal flooding and reduce salinity incursion. They reduce long-term flooding and waterlogging following storm surges from tropical cyclones . They are also cultivated for agriculture. The Jiangnan region, at

184-486: The Yangtze River Delta , has a long history of constructing polders. Most of these projects were performed between the 10th and 13th centuries. The Chinese government also assisted local communities in constructing dikes for swampland water drainage. The Lijia (里甲) self-monitoring system of 110 households under a lizhang (里长) headman was used for the purposes of service administration and tax collection in

207-431: The province of Flevoland , the most recent province to be added to the Netherlands . Its southwestern point is close to Amsterdam and its opposite end is close to Kampen, Overijssel . It has three highly dominant settlements in terms of distribution of population. Polder The ground level in drained marshes subsides over time. All polders will eventually be below the surrounding water level some or all of

230-542: The 11th century. The oldest extant polder is the Achtermeer polder, from 1533. As a result of flooding disasters, water boards called waterschap (when situated more inland) or hoogheemraadschap (near the sea, mainly used in the Holland region) were set up to maintain the integrity of the water defences around polders, maintain the waterways inside a polder, and control the various water levels inside and outside

253-428: The air. Polders are at risk of flooding at all times, and care must be taken to protect the surrounding dikes. Dikes are typically built with locally available materials, and each material has its own risks: sand is prone to collapse owing to saturation by water; dry peat is lighter than water and potentially unable to retain water in very dry seasons. Some animals dig tunnels in the barrier, allowing water to infiltrate

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276-685: The area is still largely intact, the Beemster was added to the UNESCO World Heritage Site list in 1999. Justification for inclusion is as follows: In addition in the Beemster Polder, there are five fortresses as part of the Stelling van Amsterdam , another UNESCO World Heritage Site . The Beemster Polder combines two UNESCO World Heritage Sites . The municipal council of Beemster consisted of 13 seats which at

299-530: The entire Beemster polder has been on the UNESCO world heritage list. The Beemster polder is home to CONO Kaasmakers, maker of the Beemster brand of cheeses. This co-op was formed in 1901 to create cheese made from milk that comes from the Beemster polder. Today Beemster Cheese is sold in Europe, as well as the U.S., Canada, Japan, and China. Because of its historical relevance, and as the original structure of

322-404: The grid of roads in the Beemster. The larger feeder canals are offset by approximately one kilometer from the larger roads. Beemster merged into the existing municipality of Purmerend on 1 January 2022. The former municipality of Beemster contained the following small towns and villages: Around 800 AD the area of the modern municipality of Beemster was covered in peat . The name "Beemster"

345-585: The land. The polder's name references the ancient Lake Flevo . The Flevopolder, along with the Noordoostpolder , forms the Flevoland province, which is located near Amsterdam in the southwest and Kampen, Overijssel in the northeast. Unlike other major polders, such as Noordoostpolder and Wieringermeer , the Flevopolder is surrounded by bordering lakes or below-sea-level channels. These are

368-551: The polder, with a liangzhang (粮长, grain chief) responsible for maintaining the water system and a tangzhang (塘长, dike chief) for polder maintenance. In Germany, land reclaimed by diking is called a koog . The German Deichgraf system was similar to the Dutch and is widely known from Theodor Storm 's novella The Rider on the White Horse . In southern Germany, the term polder is used for retention basins recreated by opening dikes during river floodplain restoration ,

391-485: The polder. Water boards hold separate elections, levy taxes, and function independently from other government bodies. Their function is basically unchanged even today. As such, they are the oldest democratic institutions in the country. The necessary cooperation among all ranks to maintain polder integrity gave its name to the Dutch version of third-way politics —the Polder Model . The 1953 flood disaster prompted

414-799: The polders into an inaccessible swamp, which allowed the Allied armies to stop the German army . The Netherlands has a large area of polders: as much as 20% of the land area has at some point in the past been reclaimed from the sea, thus contributing to the development of the country. IJsselmeer is the most famous polder project of the Netherlands. Some other countries which have polders are Bangladesh , Belgium , Canada and China . Some examples of Dutch polder projects are Beemster , Schermer , Flevopolder and Noordoostpolder . The Dutch word polder derives successively from Middle Dutch polre , from Old Dutch polra , and ultimately from pol- ,

437-581: The ring-dike a meter high above the surrounding country. In 1612 the polder was dry and the land was divided among the investors. In the earlier days of the polder, farmers occupied its lands for growing the crops necessary for long sea journeys by the VOC to the East Indies. The farmland was so good that the project was considered an economic success, in contrast to, e.g., the Heerhugowaard . Since 1999

460-569: The structure; the muskrat is known for this activity and hunted in certain European countries because of it. Polders are most commonly, though not exclusively, found in river deltas, former fenlands , and coastal areas. Flooding of polders has also been used as a military tactic in the past. One example is the flooding of the polders along the Yser River during World War I . Opening the sluices at high tide and closing them at low tide turned

483-500: The time. Water enters the low-lying polder through infiltration and water pressure of groundwater , or rainfall, or transport of water by rivers and canals. This usually means that the polder has an excess of water, which is pumped out or drained by opening sluices at low tide . Care must be taken not to set the internal water level too low. Polder land made up of peat (former marshland) will sink in relation to its previous level, because of peat decomposing when exposed to oxygen from

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506-541: The world, but the Dutch created the Netherlands". The Dutch have a long history of reclamation of marshes and fenland, resulting in some 3,000 polders nationwide. By 1961, about half of the country's land, 18,000 square kilometres (6,800 sq mi), was reclaimed from the sea. About half the total surface area of polders in northwest Europe is in the Netherlands. The first embankments in Europe were constructed in Roman times. The first polders were constructed in

529-513: Was derived from "Bamestra", the name of a small river in the area. In the period 1150–1250 peat-digging and storm floods enlarged that small river into an inland sea, a lake connected with the Zuiderzee . Around 1605 private investors started to drain the Beemster lake. In 1610, this was almost complete, but the lake re-filled because of a breach in the Zuiderzee dikes . It was decided to make

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