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Delta Works

In the North Sea flood of 1953, breaks in the dikes and seawalls in the Netherlands Netherlands

The Netherlands is the Europe [i]an part of the Kingdom of the Netherlands [i] , which is formed ... 

 killed 1,835 people and forced the evacuation of 70,000 more. 10,000 animals drowned, and 4,500 buildings were destroyed. To prevent such a tragedy from happening again, an ambitious flood defense system was conceived and deployed, called the Delta Works . This project was intended to improve the safety of the lower areas of the Netherlands against severe storms and flood Flood

A flood is an overflow of water [i], an expanse of water submerging land, a deluge. ... 

ing; since more than one third of the nation's land lies below sea level Sea level

Mean sea level is the average height of the sea [i], with reference to a suitable reference surface. ... 

, this is no simple task. Dune Dune

In physical geography [i], a dune is a hill [i] of sand [i] built by eolian processes [i]. ... 

s along the entire seashore were raised by as much as 5 metres, while the islands in Zeeland Zeeland

[i], is a province of the [[Netherlands]... 

 province were joined together by dam Dam

A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir [i] ... 

s and other large scale constructions to shorten the coastline.

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In the North Sea flood of 1953, breaks in the dikes and seawalls in the Netherlands Netherlands

The Netherlands is the Europe [i]an part of the Kingdom of the Netherlands [i] , which is formed ... 

 killed 1,835 people and forced the evacuation of 70,000 more. 10,000 animals drowned, and 4,500 buildings were destroyed. To prevent such a tragedy from happening again, an ambitious flood defense system was conceived and deployed, called the Delta Works .

This project was intended to improve the safety of the lower areas of the Netherlands against severe storms and flood Flood

A flood is an overflow of water [i], an expanse of water submerging land, a deluge. ... 

ing; since more than one third of the nation's land lies below sea level Sea level

Mean sea level is the average height of the sea [i], with reference to a suitable reference surface. ... 

, this is no simple task. Dune Dune

In physical geography [i], a dune is a hill [i] of sand [i] built by eolian processes [i]. ... 

s along the entire seashore were raised by as much as 5 metres, while the islands in Zeeland Zeeland

[i], is a province of the [[Netherlands]... 

 province were joined together by dam Dam

A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir [i]... 

s and other large scale constructions to shorten the coastline. The most sophisticated and famous of these dams is the Oosterscheldekering Oosterscheldekering

The Oosterscheldekering, between the islands Schouwen-Duiveland [i] and Noord-Beveland [i], is the large ... 

, which can be opened and closed to keep the sea at bay while preserving the saltwater river delta River delta

A delta is a triangular shaped landform where the mouth of a river [i]
... 

 for wildlife and the fishing Fishing

Fishing is the activity of hunting [i] for fish [i]. ... 

 industry. Less known, but not less impressive, is the Maeslantkering Maeslantkering

The Maeslantkering is a storm surge [i] barrier in the Nieuwe Waterweg [i] waterway located between the ... 

storm surge barrier near the port of Rotterdam Rotterdam

Rotterdam , located in the province of South Holland [i], is the second largest municipality in the Netherlands [i]... 

.

However, there is an ongoing fundamental discussion about the basics of the Delta Works: the mainland is subsiding Subsidence

In geology [i], engineering [i], and surveying [i], subsidence is the motion of a surface as it shifts d ... 

 and due to climate change Climate change

Climate change refers to the variation in the Earth [i]'s global climate [i] or in regional climates ove ... 

s sea levels are rising Sea level rise

Sea level rise is an increase in sea level [i]. ... 

. Eventually the dikes will have to be made higher and wider. This is a long term uphill battle against the sea, which many feel cannot be won. Some people argue that relocation of population centres and giving up land to the sea would be a longer lasting solution than to 'fight the sea'. However, the Netherlands has a very high population density Population density

Population density is a measurement of population [i] per unit area or unit volume. ... 

 and cannot afford the loss of habitable and arable land.


The Maeslant Barrier

The construction of the Maeslantkering was a part of the "Europoortkering"-project which, in turn, was the final stage of the Delta Works. The main objective of this Europoortkering-project was improving the safety against flooding Flood

A flood is an overflow of water [i], an expanse of water submerging land, a deluge. ... 

 of the Rotterdam Rotterdam

Rotterdam , located in the province of South Holland [i], is the second largest municipality in the Netherlands [i]... 

 harbour, of which the Europoort Europoort

|}
Europoort is a very large harbour [i] and industrial area [i] part of the port of Rotterdam [i] in th ... 

 is an important part, and the surrounding towns and agricultural areas. This had to by carried out by the reinforcement of existing dikes as far as 50 kilometers inland. During the 1980s 1980s

The 1980s [i] officially refers to the years from 1980 [i] to 1989 [i]. ... 

 it became clear that this project would take at least 30 years and would cost a huge amount of money. It would also mean that historic town centres, sometimes built more than four centuries ago, had to be broken down and rebuilt behind renewed, larger dikes. This storm surge barrier had to be located in the Nieuwe Waterweg Nieuwe Waterweg

he Nieuwe Waterweg is a ship canal [i] in the Netherlands [i] from het Scheur [i] west of the town [i] ... 

 waterway. This played an important role in the planning stage of the construction, as this waterway is the main route to the port of Rotterdam, the world's second largest port. Therefore a barrier like the Dutch Oosterscheldekering Oosterscheldekering

The Oosterscheldekering, between the islands Schouwen-Duiveland [i] and Noord-Beveland [i], is the large ... 

 and the Thames Barrier Thames Barrier

The Thames Barrier is a flood [i] control structure on the River Thames [i] at Woolwich [i] Reach in London [i] ... 

 could not be constructed, as such a barrier would block the shipping route.
The construction of the barrier started in 1991. First the dry docks were constructed on both shores and a sill was constructed at the bottom of the Nieuwe Waterweg. Then the two 22 meter high and 210 meter long steel gates were built. After this, 237 meter long steel trusses Truss

In architecture [i] and structural engineering [i], a truss is a static structure [i] consisting of stra... 

 were welded to the gates. Standing upright, these arms would be as high as the Paris Paris

native_name = Ville de Paris
|common_name = Paris
... 

 Eiffel Tower Eiffel Tower

The Eiffel Tower is an iron [i] tower [i] built on the Champ de Mars [i] beside the River Seine [i] ... 

, but each one weighs four times more than the Eiffel Tower. The main purpose of the arms is transmitting the immense forces, exerted on the gates while closed, to one single joint at the rear of each gate. During the closing or opening process, this ball shaped joint gives the gate the opportunity to move freely under the influences of water Water

Water is a taste [i]less, odor [i]less substance that is essential to all known forms of life [i] and i ... 

, wind Wind

Wind is the roughly horizontal movement of air [i] caused by uneven heating of the Earth's surface. ... 

 and waves WAVES

The WAVES were a World War II [i] era division of the U.S. Navy [i] that consisted entirely of women. ... 

. It acts like the ball shaped joint between a human’s arm and shoulder. After six years of construction the storm surge barrier was finished.
At May 10, 1997, Queen Beatrix Beatrix of the Netherlands

Queen Beatrix of the Netherlands, has been the Queen regnant [i] of the Kingdom of the Netherlands [i] s ... 

 opened the Maeslantkering. From that moment the barrier was in full operation. The barrier is connected to a self-operating computer system which is linked to weather and sea level data. When a storm surge of 3.00 meter above normal sea level is anticipated in Rotterdam the barrier will be closed automatically. Four hours before the actual closing procedure will begin, in and out going ships are warned. Two hours before closing the traffic at the Nieuwe Waterweg will come to a stand still. Thirty minutes before closing the dry docks that bear the gates are inundated. After this the gates start to float and two so called "locomobiles Locomobile

Locomobile was a company that produced automobile [i]s in the United States of America [i] ... 

" will move both the gates towards each other. When the gap between the gates is about 1.5 meter wide, the gates are submerged to the bottom of the waterway, thus protecting the inland. Under normal weather conditions the two doors themselves are well protected in their dry docks and a 360 meter wide gap in the waterway gives ships enough space to pass without any inconvenience.
The Maeslantkering is expected to be closed once every ten years due to a storm surge. With the rise in sea levels the storm surge barrier will need to close more frequently in 50 years time, namely once every five years. Until this date the barrier had never been closed due to a storm. The barrier is closed for testing once a year, usually in September or October, just before the beginning of the storm season in November.
Oosterscheldekering
The Oosterscheldekering , between the islands Schouwen-Duiveland Schouwen-Duiveland

[i]
... 

 and Noord-Beveland Noord-Beveland

*Geersdijk [i]
  • Kamperland [i]

... 

, is the largest of 13 ambitious Delta works Delta Works

In the North Sea flood of 1953 [i], breaks in the dike [i]s and seawalls in the Netherlands [i] killed 1, ... 

 series of dams, designed to protect a large part of the Netherlands Netherlands

The Netherlands is the Europe [i]an part of the Kingdom of the Netherlands [i] , which is formed ... 

 from flooding. The construction of the Delta Works was a response to the North Sea Flood of 1953.



The nine kilometer-long Oosterscheldekering was initially designed, and partly built, as a closed dam, but after public protest huge sluice-gate-type doors were installed in the remaining four kilometers. These doors are normally open, but can be closed under adverse weather conditions. In this way the saltwater marine life behind the dam is preserved and fishing can continue, while the land behind the dam is safe from the water.

On 4 October 1986 Queen Beatrix Beatrix of the Netherlands

Queen Beatrix of the Netherlands, has been the Queen regnant [i] of the Kingdom of the Netherlands [i] s ... 

 officially opened the dam for use.

At the artificial island Neeltje-Jans, at one end of the barrier, a plaque is installed with the words: "Hier gaan over het tij, de wind, de maan en wij" .

The Oosterscheldekering was the biggest, most difficult to build and the most expensive part of the Delta works. Work on the dam itself started in April 1976 and was completed in June 1986, though the road over the dam was completed only in November 1987. To facilitate the building, an artificial island Neeltje-Jans was first created in the middle of the estuary.

Four ships were custom designed and built for this project:
  • Mytilus, a ship equipped with various groundworking tools, such as needles to make the seabed more dense and stable.
  • Cardium, a ship to transport and lay a special foil carpet on the seabed for the pillars to rest on.
  • Ostrea, a ship capable of lifting a concrete pillar from the dry dock and placing the pillar within a tiny margin on a special foil on the seabed. The ship is 85 meters long and has a portal of 50 meters high. The ship can lift 10000 tonnes, the pillars are under water for a large part and require less lifting power than the 18000 tonnes. This ship is considered the flagship of the construction fleet mainly because of its impressive size and power.
  • Macoma, a ship that works closely with the Ostrea, cleaning the foil and helping in navigating the pillar to the final place.


The ships are named after various types of shellfish Shellfish

[i]s, [[crustacean]... 

.

The dam is constructed out of 65 concrete pillars with 62 steel doors of 42 meters wide. The parts were constructed in a dry dock Dry dock

A dry dock is a narrow basin or vessel that can be flooded to allow a load to be floated in, then draine... 

. The area was flooded and a small fleet of special construction ships would lift the pillars and place them on their final place. Each pillar is between 35 and 38,75 meter high and weighs 18000 tonnes.

The Oosterscheldekering is sometimes referred to as the eighth Wonder of the World, and has been declared one of the modern Seven Wonders of the World Seven Wonders of the World

The Seven Wonders of the World is a widely known list of seven popular sites of [[classical antiquity]... 

 by the American Society of Civil Engineers.

The dam was designed to last 200 years.

The dam is operated by humans but if human controls fail an electronic security system acts as a backup. A Dutch law Law

Law is the set of rules or norms [i] of conduct which forbid, permit or mandate specified actions... 

 regulates the conditions under which the dam is allowed to close. The water levels must be at least 3 meters above regular sea level before the doors can be completely shut. For testing, all doors are shut once in a while . Also emergency procedures are tested on prescheduled dates. Once the test is passed, the shutters are immediately opened again to create a minimum impact on tidal movement Tide

The tide is the cyclic rising and falling of Earth's ocean [i] surface caused by the tidal force [i]s of ... 

s and the marine ecosystem. It takes approximately one hour to close one of the doors.

The dam has been closed 23 times since 1986, due to water levels exceeding or being predicted to exceed the 3.00 meters.

The cost of operation is 17 million Euro Euro

The euro is the official currency [i] of the European Union [i] member states of Austria [i], Belgium [i]... 

 per year.

External links



See also

  • Zuiderzee Works Zuiderzee Works

    The Zuiderzeewerken are a man-made system of dam [i]s, land reclamation [i] and water drainage works, a ... 

  • Flood control in the Netherlands Flood control in the Netherlands

    The Netherlands [i] has been the site of an endless battle between the people and the water. ...