Afsluitdijk

Afsluitdijk
Afsluitdijk
	Afsluitdijk in red
Country	Netherlands
Coordinates	53°0′N 5°10′E / 53.000°N 5.167°E
Purpose	flood protection and land reclamation
Construction began	1927
Opening date	1932
Dam and spillways
Length	32 km (20 mi)
Elevation at crest	7.25 m (23.8 ft) above sea level
Width (crest)	90 m (300 ft)

The Afsluitdijk (Dutch: [ˈɑfslœydɛik] ^ⓘ; West Frisian: Ofslútdyk; Dutch Low Saxon: Ofsluutdiek; English: "Closure Dyke") is a major dam and causeway in the Netherlands. It was constructed between 1927 and 1932 and runs from Den Oever in North Holland province to the village of Zurich in Friesland province, over a length of 32 kilometres (20 mi) and a width of 90 metres (300 ft), at an initial height above Amsterdam Ordnance Datum of between 6.7 metres (22 ft) along the section at Friesland, and 7.4 metres (24 ft) where it crosses the deep channel of the Vlieter. The height at the greater sea depths west of Friesland was required to be a minimum of 7 metres everywhere when originally constructed.

Increases to the height of the Afsluitdijk have been made several times since 1958, when height increases were undertaken during regular maintenance periods as a result of the North Sea Flood of 1953, with the section between the Stevinsluizen and Lorentzsluizen sluice complexes seeing the crest level raised to 7.8 metres.^[1] Major upgrade works commenced in 2019, with one of the design conditions being that only limited wave overtopping during the design storm condition be permitted. The design proposed by the successful contractor to meet this criterion will see a further increase in the height of the dam, by approximately 2 metres.^[2]

The Afsluitdijk is a fundamental part of the larger Zuiderzee Works, damming off the Zuiderzee, a salt water inlet of the North Sea, and turning it into the fresh water lake of the IJsselmeer. It is a major landwinning project and a quicker road-connection between the North and West of the Netherlands.

The highway on the Afsluitdijk was the initial demonstration site for a 130 km/h (81 mph) speed limit in the Netherlands.^[3]

^ Thijsse, J. Th. (1972). Een halve eeuw Zuiderzeewerken 1920-1970 [A half century of the Zuiderzee Works 1920-1970] (in Dutch). H.D. Tjeenk Willink B.V., Groningen. pp. 156–160. OCLC 5439270. Retrieved 3 April 2023.
^ Rijkswaterstaat, Ministerie van Infrastructuur en Waterstaat. "Project Afsluitdijk" ["Afsluitdijk Project"]. www.rijkswaterstaat.nl (in Dutch). Retrieved 4 April 2023.
^ "Holland's first 130 km/h road is the Afsluitdijk". DutchNews.nl. 1 March 2011. Retrieved 20 February 2012. The speed limit on the Afsluitdijk, the stretch of the A7 on the dyke between Wognum in North Holland and Zürich in Friesland, has been increased to 130 km/h from Tuesday.

[thijsse-1] Thijsse, J. Th. (1972). Een halve eeuw Zuiderzeewerken 1920-1970 [A half century of the Zuiderzee Works 1920-1970] (in Dutch). H.D. Tjeenk Willink B.V., Groningen. pp. 156–160. OCLC 5439270. Retrieved 3 April 2023.

[2] Rijkswaterstaat, Ministerie van Infrastructuur en Waterstaat. "Project Afsluitdijk" ["Afsluitdijk Project"]. www.rijkswaterstaat.nl (in Dutch). Retrieved 4 April 2023.

[3] "Holland's first 130 km/h road is the Afsluitdijk". DutchNews.nl. 1 March 2011. Retrieved 20 February 2012. The speed limit on the Afsluitdijk, the stretch of the A7 on the dyke between Wognum in North Holland and Zürich in Friesland, has been increased to 130 km/h from Tuesday.

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