Everything about Delta Works totally explained
The
Deltaworks are a number of constructions that were built between
1950 and
1997 in the southwest of
the Netherlands to protect a large area of land from the sea. The works consist of
dams,
sluices,
locks,
dikes, and
storm surge barriers. The aim of the dams, sluices, and storm surge barriers was to shorten the Dutch coastline, thus reducing the number of dikes that had to be raised.
The
American Society of Civil Engineers has declared the works to be one of the
Seven Wonders of the Modern World.
History
The
estuaries of the rivers
Rhine,
Meuse and
Scheldt have been subject to many floodings over the centuries. After building the
Afsluitdijk, the Dutch started studying the damming of the Rhine-Meuse Delta. Plans were developed for shortening the coastline and turning the estuary into freshwater lakes. By shortening the coastline fewer dikes would have to be reinforced.
Due to indecision and the
Second World War, these plans remained studies and little action was taken. In 1950 two small estuary mouths, the Brielse Gat near
Brielle and the Botlek near
Vlaardingen were dammed. After the
North Sea flood of 1953, a commission was installed which had to come up with a plan to research the causes and seek measures to prevent such disasters in future. They revised some of the old plans and came up with the so called "Deltaplan".
The plan consisted of blocking the estuary-mouths of the
Oosterschelde, the
Haringvliet and the
Grevelingen. This reduced the amount of dykes exposed to the sea by approximately 400 miles. The estuary-mouths of the
Nieuwe Waterweg and the
Westerschelde were to remain open because of the shipping routes to the ports of
Rotterdam and
Antwerp. The dikes along these waterways were to be heightened and strengthened. The works would be combined with road and waterway infrastructure to stimulate the economy of the province of
Zeeland and improve the connection between the port of Rotterdam and Antwerp.
Alterations to the plan during the execution of the Works
During the execution of the works alterations were made due to pressure from society. In the Nieuwe Waterweg heightening and the associated widening of the dikes proved very difficult because of many historic buildings that would have to be destroyed. Therefore, a storm surge barrier would be built (the
Maeslantkering) and dikes were only partly built up.
The Oosterschelde was originally to be dammed and turned into a fresh water lake, leading to the loss of the saltwater nature and, consequently, the fishing of oysters. Environmentalists and fishermen combined their efforts to prevent the closure and successfully pressed parliament to make amendments to the original plan. Instead of completely damming the estuary mouth, a storm surge barrier would be built. This exists today as a collection of very large valves.
The storm surge barrier only closes when the sea-level is expected to rise above 3 meters above mean sea-level. Under normal conditions the estuary mouth is open and salt water flows in and out with the tide. Consequently, the weak dikes along the Oosterschelde needed to be strengthened. This strengthening hadn't been done yet because the Oosterschelde would be dammed. Over 200 km of dike needed new revetments. The connections between the Eastern Scheldt and the neighboring
Haringvliet had to be dammed to limit the effect of the salt water. Extra dams and locks were needed at the east part of the Oosterschelde to create a shipping route between the ports of Rotterdam and Antwerp.
Current status
The works were finished after almost fifty years in 1997 with the completion of the Maeslantkering and the Hartelkering. The Dutch government often cites the Delta Works project as the world's largest flood protection project. With over 10,250 miles of dikes (1,500 miles designated as primary dikes and 8,750 miles as secondary dikes) and 300 structures, the project is one of the most extensive engineering projects in the world.
Due to climate change and relative sea-level rise dikes will eventually have to be made higher and wider. This is a long term uphill battle against the sea. The needed level of flood-protection and the resulting costs are a recurring subject of debate. Currently reinforcement of the dyke revetments along the Oosterschelde and Westerschelde is underway. The revetments have proven to be insufficient and need to be replaced. These works started in 1996 and should be finished in 2015. In that period the Ministry of Public Works and Water Management in cooperation with the waterboards will have reinforced over 400 km of dikes.
(External Link
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List of constructions
The works that are part of the Delta Works are listed in chronological order with their year of completion:
Further Information
Get more info on 'Delta Works'.
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