Polder
Apolder(Dutch pronunciation:[ˈpɔldər]) is a low-lying tract of land that forms an artificialhydrologicalentity, enclosed by embankments known asdikes.The three types of polder are:
- Land reclaimedfrom a body of water, such as a lake or theseabed
- Flood plainsseparated from the sea or river by a dike
- Marshesseparated from the surrounding water by a dike and subsequently drained; these are also known askoogs,especially in Germany
The ground level in drained marshessubsidesover time. All polders will eventually be below the surrounding water level some or all of the time. Water enters the low-lying polder throughinfiltrationand water pressure ofgroundwater,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 openingsluicesatlow tide.Care must be taken not to set the internal water level too low. Polder land made up ofpeat(former marshland) will sink in relation to its previous level, because of peat decomposing when exposed to oxygen from 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 the structure; themuskratis known for this activity and hunted in certain European countries because of it. Polders are most commonly, though not exclusively, found in river deltas, formerfenlands,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 theYserRiver duringWorld War I.Opening the sluices at high tide and closing them at low tide turned the polders into an inaccessible swamp, which allowed theAllied armies to stop the German army.
TheNetherlandshas 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.IJsselmeeris the most famous polder project of the Netherlands. Some other countries which have polders areBangladesh,Belgium,CanadaandChina.Some examples of Dutch polder projects areBeemster,Schermer,FlevopolderandNoordoostpolder.
Etymology
[edit]TheDutchwordpolderderives successively fromMiddle Dutchpolre,fromOld Dutchpolra,and ultimately frompol-,a piece of land elevated above its surroundings, with theaugmentativesuffix-erandepenthetical-d-.The word has been adopted in thirty-six languages.[1]
Netherlands
[edit]
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TheNetherlandsis 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 the world, but the Dutch created the Netherlands".[2]
TheDutchhave a long history of reclamation of marshes and fenland, resulting in some 3,000polders[3]nationwide. By 1961, about half of the country's land, 18,000 square kilometres (6,800 sq mi), was reclaimed from the sea.[4][better source needed]About half the total surface area ofpoldersin northwest Europe is in the Netherlands. The firstembankmentsin Europe were constructed in Roman times. The first polders were constructed in the 11th century. The oldest extant polder is theAchtermeerpolder, from 1533.
As a result of flooding disasters,water boardscalledwaterschap(when situated more inland) orhoogheemraadschap(near the sea, mainly used in theHollandregion)[5][6]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 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 ofthird-way politics—thePolder Model.
The1953 flood disasterprompted 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 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 includeBeemster(1609–1612),Schermer(1633–1635), andHaarlemmermeerpolder(1852). Polders created as part of theZuiderzee WorksincludeWieringermeerpolder(1930),Noordoostpolder(1942) andFlevopolder(1956–1968)
Examples of polders
[edit] | This sectionneeds additional citations forverification.(July 2021) |
Brazil
[edit]Several cities on theParaíba Valleyregion (in theSão Paulo (state)) have polders on land claimed from the floodplains around theParaíba do Sulriver.
Bangladesh
[edit]Bangladeshhas 139 polders, of which 49 are sea-facing, while the rest are along the numerousdistributariesof the Ganges-Brahmaputra-Meghna River delta. These were constructed in the 1960s to protect the coast from tidal flooding and reduce salinity incursion.[7]They reduce long-term flooding and waterlogging followingstorm surgesfromtropical cyclones.They are also cultivated for agriculture.[8]
Belgium
[edit]
- De Moeren, nearVeurneinWest Flanders
- Polders along theYserriver betweenNieuwpoortandDiksmuide
- Polders of Muisbroek and Ettenhoven, inEkerenandHoevenen
- Polder of Stabroek, inStabroek
- Kabeljauwpolder, inZandvliet
- Scheldepolders on the left bank ofthe Scheldt
- Uitkerkse polders, near Blankenberge in West Flanders
- Prosperpolder, near Doel, Antwerp and Kieldrecht.
Canada
[edit]China
[edit]History
[edit]TheJiangnanregion, at theYangtze River Delta,has a long history of constructing polders. Most of these projects were performed between the 10th and 13th centuries.[10]The Chinese government also assisted local communities in constructing dikes for swampland water drainage.[11]The Lijia ( lí giáp ) self-monitoring system of 110 households under alizhang( lí trường ) headman was used for the purposes of service administration and tax collection in the polder, with aliangzhang( lương trường, grain chief) responsible for maintaining the water system and atangzhang( đường trường, dike chief) for polder maintenance.[12]
Denmark
[edit]- Filsø
- Kolindsund
- Lammefjorden
Finland
[edit]- Söderfjärden
- Munsmo
- Two polders (three square kilometres or 1.2 square miles in total) nearVassorinKorsholm
France
[edit]- Marais Poitevin
- Les Moëres,adjacent to the Flemish polderDe Moerenin Belgium.
- Polders de Couesnon nearMont-Saint Michelin Normandy[13]
Germany
[edit]
In Germany, land reclaimed by diking is called akoog.The GermanDeichgrafsystem was similar to the Dutch and is widely known fromTheodor Storm's novellaThe Rider on the White Horse.
- Altes Land near Hamburg
- Blocklandand Hollerland near Bremen
- Nordstrand, Germany
- Bormerkoog and Meggerkoog nearFriedrichstadt
- 36koogsin the district ofNordfriesland
- 12koogsin the district ofDithmarschen
In southern Germany, the termpolderis used forretention basinsrecreated by opening dikes during riverfloodplain restoration,a meaning somewhat opposite to that in coastal context.
Guyana
[edit]- Black Bush Polder, Corentyne, Berbice.
India
[edit]Ireland
[edit]Italy
[edit]- Delta of the riverPo,such as Bonifica Valle del Mezzano
Japan
[edit]- Around theAriake Seain Kyushu, mainly inSagabut also inFukuokaandKumamotoPrefectures
Lithuania
[edit]Netherlands
[edit]
- Achtermeer,the oldest polder, from 1533
- Alblasserwaard,containing the windmills ofKinderdijk,aWorld Heritage Site
- Alkmaar
- Andijk
- Anna Paulownapolder
- Beemster,a World Heritage Site
- Bijlmermeer
- Flevopolder,the largestartificial islandin the world, last part drained in 1968
- 's-Gravesloot
- Haarlemmermeer,containingSchipholairport
- Krimpenerwaard
- Lauwersmeer
- Mastenbroek,one of the oldest medieval polders, drained around 1363-1364.[17][18]
- Noordoostpolder
- Prins Alexanderpolder
- Purmer
- Schermer
- Watergraafsmeer
- Wieringermeer
- Wieringerwaard
- Wijdewormer
- Zestienhoven, home of theRotterdam The Hague Airport(Overschie), in the city ofRotterdam.
- Zuidplaspolder,along withLammefjordin Denmark the lowest point of the European Union
Poland
[edit]- Vistuladelta nearElblągandNowy Dwór Gdański
- Wartadelta nearKostrzyn nad Odrą
Romania
[edit]Singapore
[edit]- Parts ofPulau Tekong
Slovenia
[edit]- TheAnkaran/AncaranoPolder (Slovene:Ankaranska bonifika),SemedelaPolder (Semedelska bonifika), and Škocjan Polder (Škocjanska bonifika) in reclaimed land aroundKoper/Capodistria.
South Korea
[edit]- Parts of the coast ofGanghwa Island,adjacent to the riverHaninIncheon
- Delta of the riverNakdonginBusan
- SaemangeuminNorth Jeolla Province
Spain
[edit]- Parts ofMálagawere built on reclaimed land
United Kingdom
[edit]- Traeth Mawr
- Sunk Island,on the north shore of theHumbereast ofHull
- Caldicot and Wentloog Levelsalong theSevern Estuaryin South Wales
- Parts ofThe Fens
- Branston Island,by theRiver Withamoutside the conventional area of the fens but connected to them.
- Parts of the coast ofEssex
- Some land along theRiver PlyminPlymouth
- Some land aroundMeathopeast ofGrange-over-Sands,reclaimed as a side-effect of building arailwayembankment
- TheSomerset LevelsandNorth Somerset Levels
- Romney Marsh
- Sealand, Flintshire
- Humberhead Levels
United States
[edit]See also
[edit]References
[edit]- ^Sijs, N. van der, 2010. Nederlandse woorden wereldwijd, 747 pp. Sdu Uitgevers bv, Den Haag.ISBN9789012582148,https://pure.knaw.nl/portal/files/458170/Nww_compleet_archief.pdf,page 155
- ^Cf. Forrest Clingerman, Brian Treanor, Martin Drenthen, David Utsler,Interpreting Nature: The Emerging Field of Environmental Hermeneutics,Fordham University Press, 1 sep. 2013. The sentence stems from a poem by Archibald Pitcairn (1652–1713):Tellurem fecere dei, sua littora Belgae.C.D. van Strien,British Travellers in Holland During the Stuart Period: Edward Browne and John Locke as Tourists in the United Provinces,Leiden 1993, 164.
- ^"Kijk naar de geschiedenis".Rijkswaterstaat.Retrieved2008-01-21.[permanent dead link]
- ^Ley, Willy (October 1961)."The Home-Made Land".For Your Information.Galaxy Science Fiction.pp. 92–106.
- ^"waterschap".Archived fromthe originalon 2012-11-02.
- ^Reh, W., Steenbergen, C., Aten, D. 2007. Sea of Land, The polder as an experimental atlas of Dutch landscape architecture. 344 pp, Uitgeverij Architectura & Natura.ISBN9789071123962
- ^"Bangladesh polders under threat",Irin News
- ^"Bangladeshi project to enhance polders amidst climate woes"Archived2014-04-08 at theWayback Machine,Unearth News
- ^"CRCWSC Trade Mission to Kunshan"(PDF).2016-12-01.Archived(PDF)from the original on 2017-04-09.
- ^Liao, Qiyu mâu khải du (1985).Taihu Tangpu Weitian Shi Yanjiu thái hồ đường phổ vu điền sử nghiên cứu [The research of the dikes and polders of Lake Tai].Beijing: Nongye Chubanshe.
- ^Xie, Shi tạ thực (2010). ""11 Shiji Taihu Diqu Nongtian Shuili Geju de Xingcheng" 11 thế kỷ thái hồ địa khu nông điền thủy lợi cách cục đích hình thành [The formation of water management system in the farmland of the Lake Tai region in the eleventh century] ".Journal of Sun Yat-sen University.50(5): 94–106.
- ^Hamashima, Atsutoshi tân đảo đôn tuấn (1982).Mindai Kōnan nōson shakai no kenkyū minh đại giang nam nông thôn xã hội の nghiên cứu [Rural Society in Jiangnan during the Ming Dynasty.Tokyo: Tokyo University Press. pp. 9–65.
- ^"les polders"(PDF).littoral-normand.n2000.fr.Retrieved2023-03-25.
- ^"Rain continues to throw a challenge in Kuttanad".The Hindu.The Hindu Group. 2011.Retrieved2011-06-10.
- ^Thampatti, Manorama (March 1999)."Rice Bowl in Turmoil: The Kuttanad Wetland Ecosystem".Resonance.Indian Academy of Sciences. Archived fromthe originalon 2010-12-16.Retrieved2011-06-10.
- ^"Inch Wildfowl Reserve History".Inch and Foyle Wildfowl Project.Archived fromthe originalon 7 September 2015.Retrieved5 June2015.
- ^"De Mastenbroekerpolder".
- ^"Polder Mastenbroek".
Further reading
[edit]- Derex, Jean-Michel, Franco Cazzola (eds.) 2004. 2nd ed. 2013.Eau et développement dans l'Europe moderne.Paris, Maison des Sciences De L'Homme
- Farjon, J.M.J., J. Dirkx, A. Koomen, J. Vervloet & W. Lammers. 2001.Neder-landschap Internationaal: bouwstenen voor een selectie van gebieden landschapsbehoud.Alterra, Wageningen.Rapport 358Archived2012-10-28 at theWayback Machine.
- Stenak, Morten. 2005.De inddæmmede Landskaber – En historisk geografi.Landbohistorik Selskab.
- Polders of the World. Keynotes International Symposium.1982. Lelystad, The Netherlands
- Ven, G.P. van de (ed.) 1993, 4th ed. 2004.Man-made Lowlands. History of Water Management and Land Reclamation in the Netherlands,Matrijs, Utrecht.
- Wagret, Paul. 1972.Polderlands.London: Methuen.
External links
[edit]
- Polder landscapes in the Netherlands–in a northwest European and a landmark context.
- How to make a polder – online filmArchived2021-04-17 at theWayback Machine
