Flood control in the Netherlands
From Wikipedia, the free encyclopedia
The Netherlands has been struggling against floods since the first people settled here. Over 60% of the country lies beneath mean sea-level. Countless people have lost their homes and their lives to floods from the sea or the rivers that could not be held by the flood-defences. The importance of the protection has led the Dutch to dedicate a Ministry solely to the protection against floods. Furthermore, local waterboards are an extra layer of government specially dedicated to protection against floods and water management. This has resulted in a very high level of flood-protection. Flood-protection remains a continuous point of interest due to the vulnerability of the Dutch economy with regard to flooding.
Contents |
[edit] History
At first the inhabitants of the flood-affected areas built artificial mounds called terpen. On these mounds villages and farms were build. The first terpen were build around 500 BC. Terp building ended with the coming of the dike somewhere around 1200. Some artificial mounds in the Netherlands are called vliedbergen (singular vliedberg, meaning "refuge mountain") or "dobbes" or "stellen". These were made in the Middle Ages, to provide refuge from rising waters. They are found in large numbers in the south and west of the Netherlands. They were not intended for permanent habitation, but provided temporary refuge for local people and livestock. The role of the Dutch in land-reclamation has resulted in the Dutch words being now common usage internationally:-
- Dike (also spelled dyke) (Dutch dijk). A dike, in Dutch usage, is an embankment or wall built to keep water from flooding land.
- Polder. This is an area of land thus defended from flooding.
- Sluice (Dutch sluis or zijl). Often such a sluice gate had a loose flap which let water through at low tide but shut at high tide.
- Dam. A artificial barrier in an estuary, lake or river.
[edit] Drainage Methods
The earliest Dutch polders date from the middle ages. These polders were drained by sluices that opened at low tide to let out water. At the end of the Middle Ages the Dutch started using wind power to drain the land. Windmills pumped water by use of a water wheel or (starting from 1634) the Archimedes' screw. Land below the water level was thus drained. The height at which a single windmill can pump the water is limited. By combining mills, each mill pumps water into a higher reservoir, with the last pumping it out to the river or lake. In the 18th century several molendriegangen (runs of 3 mills), and molenviergangen (runs of 4 mills), were built. The windmills were crucial and essential in reclaiming and preserving the land until the arrival of steam and especially diesel powered pumps.
[edit] Modern developments
The aforementioned steam and diesel pumps led to new developments. Furthermore, mechanization meant that larger projects could be undertaken. The most important are the Zuiderzee Works and the Delta Works.
[edit] Zuiderzee Works
The Zuiderzee Works (Zuiderzeewerken) are a man-made system of dams, land reclamation and water drainage works. The basis of the project was the damming off of the Zuiderzee, a large shallow inlet of the North Sea. This dam is called the Afsluitdijk. It was built in 1932-1933. The dam closed the Zuiderzee and separated it from the North Sea. As result, the Zuider sea became the IJsselmeer — IJssel lake. It is said that during the North Sea flood of 1953 the Afsluitdijk paid for itself in one night, by preventing flooding on the Zuiderzee coast. Following the damming, large areas of land were reclaimed in the newly freshwater lake body by means of polders. The works were performed in several steps from 1920 to 1975.
[edit] Delta Works
In the south-west of the Netherlands a flood defense system was built, called the Delta Works. The Delta Works consist of a series of dams and storm surge barriers. The Delta Works were executed between 1950 and 1997.
[edit] Currently
Flood protection remains an important issue with the Dutch due to relative sea level rise and land subsidence.
[edit] Notorious floods
Among the flood disasters that the Netherlands suffered down the centuries were:-
- St. Lucia's flood (Sint-Luciavloed) in 1287. This permanently lost much land in what is now the Waddenzee and IJsselmeer and enlarged the inland lake Almere into the Zuiderzee.
- St. Elizabeth's flood (1421) (Sint Elisabethsvloed) in 1421. This lost much land in Zeeland. Some of it has been reclaimed since.
- All Saints' flood (Allerheiligenvloed) on 1 November 1 1570. It affected Egmond and Bergen op Zoom and Saeftinghe and permanently drowned land in Zeeland.
- Christmas flood 1717 (Kerstvloed 1717). It was the last large flood in the north of the Netherlands.
- North Sea flood of 1953(Watersnoodramp). On the night of 31 January/1 February 1953 a storm tide surge broke many dikes in the provinces of Zeeland and Zuidholland and Noord-Brabant and caused much flooding and death. This pushed the Dutch government into ordering the Delta Works.
- Also see Floods in the Netherlands.
[edit] Drowned villages
"Drowned village" is the term used in the Netherlands for settlements which have been destroyed by water, either with a natural or human cause, and were not rebuilt but completely destroyed or abandoned by its inhabitants. Thanks to a remarkable amount of Dutch records reaching as far back as the Dark ages much information about these villages is preserved today ranging from the entire story of their destruction to just their name. The last 2 villages to be "drowned by the water" were Schuring and Capelle in the North Sea flood of 1953. See List of settlements lost to floods in the Netherlands.
[edit] External links
- DeltaWorks.Org - Website about the flood of 1953 and the construction of the DeltaWorks.
