Flood control in the Netherlands
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Flood control in the Netherlands is an important issue for the Netherlands as about half of the country lies beneath mean sea-level. Natural sand dunes and man made dikes, dams and floodgates provide the defense against storm surges from sea. River dikes prevent flooding from water flowing into the country by the major rivers Rhine and Meuse, while a complicated system of drainage ditches, canals and pumping stations (historically: windmills) keep the low lying parts dry for habitation and agriculture. Water control boards are the independent local government bodies responsible for maintaining this system. In modern times flood disasters coupled with technological development have led to large construction works to reduce the influence of the sea and prevent future floods.
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[edit] History
At first the inhabitants of the flood-affected areas built artificial dwelling hills called terpen or wierden. On these mounds villages and farms were built. Artificial dwelling hills were built from roughly 500 BC until the coming of the dike somewhere around 1200. Some artificial mounds in the Netherlands "dobbes" or "stellen" 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 which lays below sea-level and which is 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. An 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 constructed 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 are:-
- Eerste Grote Watersnoodramp (First Great Water Disaster) of December 26, 838. Bishop van Troyes wrote in his diary that all of Frisia was flooded and 2,437 lives were lost. Almost all of the low lying areas were known as Frisia then (nearly 50% of the Netherlands).
- Tweede Vloed (Second Flood) of September 28, 1014. The Abby of Quedlinburg in Saksen spoke of thousands of lost lives.
- St. Martin's flood (Sint Martinvloed) November 11, 1099. Not much is known but it was recorded in the Anglo-Saxon Chronicle that the sea was higher and the flooding more extensive than ever before.
- Holland flood of 1212. This flood hit mostly in the north and is said to have claimed 60,000 victims.
- St. Marcellus flood (Sint Marcellusvloed) January 18, 1219 hit the north again as well as the Zuiderzee areas; some 36,000 lives were lost.
- St. Lucia's flood (Sint-Luciavloed) in 1287. Much land was lost in what is now the Waddenzee and IJsselmeer and it enlarged the inland lake Almere into the Zuiderzee.
- Eerste Sint Elizabethvloed (First St. Elizabeth Flood) of November 19, 1404. Much of Zeeland and Holland was flooded. This was especially bad for Zeeuwsch-Vlaanderen which had already been flooded in 1375 and was again in 1421. The cities IJzendijke and Hugevliet disappeared and the Zuudzee was formed until repoldered.
- St. Elizabeth's flood (1421) (Sint Elisabethsvloed) in 1421. Much land in Zeeland was lost to the sea, some of it has been reclaimed since.
- Sint Felix Vloed (St. Felix Flood) of November 5, 1530. Oost-Watering was lost and the islands Noord-Beveland and Schouwen-Duiveland were severely damaged.
- All Saints' flood (Allerheiligenvloed) on 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 until the Zuiderzeevloed of 1916.
- Haarlemmermeer storms of 1836. Since 1530 the lake Haarlemmermeer covering some 6,000 acres (24 km²) had been known as "Waterwolf." It ate up nearby land, other lakes, villages, and ships (hence "Schiphol" or "ship hole") and grew to 42,000 acres (170 km²). Two hurricanes in November and again on Christmas Day sent floods to the gates of Amsterdam and down the streets of Leiden. King Wilhelm I & the government in 1838 legislated its draining. A 61 km. long canal and dike were built to surround the lake, and with the largest reciprocating steam engine ever built (and two slightly smaller) some 800,000,000 tons of water (average 13 ft. deep) were pumped out between 1848-52. This was the first real use of mechanical power other than windmills.
- Zuiderzeevloed of January 14, 1916. This flood broke a number of dikes and caused extensive flooding in the immediate low lands (Noord Holland & Friesland). This resulted in passing of the Laws of 1918 which mandated the Afsluitdijk (Closure Dam). Preliminary work was started in 1920 with the 2.5 km. Wieringendam and the actual work on the 30 km. Afsluitdijk began in 1927 through 1933. It reduced the exposed (Zuiderzee) shore from 300 km. to just 45 km. across; changing the Zuiderzee into a lake named "IJsselmeer".
- 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 never rebuilt. 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.
- Podcast episode on the history of Dutch Flood defences - Exploring Environmental History Podcast
