Oosterscheldekering
Encyclopedia
The Oosterscheldekering (in English: Eastern Scheldt
storm surge
barrier), between the islands Schouwen-Duiveland
and Noord-Beveland
, is the largest of the 13 ambitious Delta works
series of dams, designed to protect the Netherlands from flooding. The construction of the Delta Works
was in response to the North Sea Flood of 1953
.
The nine kilometre-long Oosterscheldekering (kering meaning barrier) 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 kilometres. 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 officially opened the dam for use by saying the well-known words: De stormvloedkering is gesloten. De Deltawerken zijn voltooid. Zeeland is veilig. (The flood barrier is closed. The Delta Works
are completed. Zealand
is safe.)
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" ("Here the tide is ruled, by the wind, the moon and us (the Dutch)").
, Baggermaatschappij Breejenhout, Hollandse Aanneming Maatschappij
, Hollandse Beton Maatschappij, Van Oord-Utrecht
, Stevin Baggeren
, Stevin Beton en Waterbouw
, Adriaan Volker Baggermaatschappij
, Adriaan Volker Beton en Waterbouw
and Aannemerscombinatie Zinkwerken
, started in April 1976 and was completed in June 1986, though the road over the dam was ready for use only in November 1987. The road was opened by the former queen, Princess Juliana
on 5 November 1987, exactly 457 years after the St Felix Day's
flood of 1530 had washed away a large chunk
of Zeeland
, upstream of the new barrier's position.
To facilitate the building, an artificial island Neeltje-Jans
was created in the middle of the estuary. When the construction was finished, the island was rebuilt to be used as education centre for visitors and as a base for maintenance works.
The dam is based on 65 concrete pillars with 62 steel doors, each 42 metres wide. The parts were constructed in a dry dock
. The area was then flooded and a small fleet of special construction ships lifted the pillars and placed them in their final positions. Each pillar is between 35 and 38.75 metres high and weighs 18000 tonne
s.
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 by the American Society of Civil Engineers
.
The dam was designed to last more than 200 years.
The ships are named after various types of shellfish
.
and the local marine ecosystem. It takes approximately one hour to close a door.
The full dam has been closed twenty four times since 1986, due to water levels exceeding or being predicted to exceed the three metres.
The last time was on 8 November 2007.
The cost of operation is €17 million per year.
Oosterschelde
The Oosterschelde is an estuary in Zeeland, Netherlands, between Schouwen-Duiveland and Tholen on the north and Noord-Beveland and Zuid-Beveland on the south.During the Roman Era it was the major mouth of the Scheldt River. Before the St...
storm surge
Storm surge
A storm surge is an offshore rise of water associated with a low pressure weather system, typically tropical cyclones and strong extratropical cyclones. Storm surges are caused primarily by high winds pushing on the ocean's surface. The wind causes the water to pile up higher than the ordinary sea...
barrier), between the islands Schouwen-Duiveland
Schouwen-Duiveland
Schouwen-Duiveland is a municipality and an island in the southwestern Netherlands.The Brouwersdam is a dam, part of the Delta Works, from Schouwen-Duiveland to Goedereede, the west part of the island of Goeree-Overflakkee in South Holland....
and Noord-Beveland
Noord-Beveland
Noord-Beveland is a municipality in the southwestern Netherlands and a former island, now part of the Walcheren-Zuid-Beveland-Noord-Beveland peninsula....
, is the largest of the 13 ambitious Delta works
Delta Works
The Delta Works is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine-Meuse-Scheldt delta from the sea. The works consist of dams, sluices, locks, dikes, levees, and storm surge barriers...
series of dams, designed to protect the Netherlands from flooding. The construction of the Delta Works
Delta Works
The Delta Works is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine-Meuse-Scheldt delta from the sea. The works consist of dams, sluices, locks, dikes, levees, and storm surge barriers...
was in response to the North Sea Flood of 1953
North Sea flood of 1953
The 1953 North Sea flood was a major flood caused by a heavy storm, that occurred on the night of Saturday 31 January 1953 and morning of 1 February 1953. The floods struck the Netherlands, Belgium, England and Scotland.A combination of a high spring tide and a severe European windstorm caused a...
.
The surge barrier
Sluice
A sluice is a water channel that is controlled at its head by a gate . For example, a millrace is a sluice that channels water toward a water mill...
-gate-type doors were installed in the remaining four kilometres. 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 officially opened the dam for use by saying the well-known words: De stormvloedkering is gesloten. De Deltawerken zijn voltooid. Zeeland is veilig. (The flood barrier is closed. The Delta Works
Delta Works
The Delta Works is a series of construction projects in the southwest of the Netherlands to protect a large area of land around the Rhine-Meuse-Scheldt delta from the sea. The works consist of dams, sluices, locks, dikes, levees, and storm surge barriers...
are completed. Zealand
Zeeland
Zeeland , also called Zealand in English, is the westernmost province of the Netherlands. The province, located in the south-west of the country, consists of a number of islands and a strip bordering Belgium. Its capital is Middelburg. With a population of about 380,000, its area is about...
is safe.)
At the artificial island Neeltje-Jans
Neeltje-Jans
Neeltje Jans is an artificial island in the Netherlands in the province of Zeeland, halfway between Noord-Beveland and Schouwen-Duiveland in the Oosterschelde. It was constructed to facilitate the construction of the Oosterscheldedam. The island was named after a nearby sand bar....
, at one end of the barrier, a plaque is installed with the words: "Hier gaan over het tij, de wind, de maan en wij" ("Here the tide is ruled, by the wind, the moon and us (the Dutch)").
Construction
The Oosterscheldekering was the biggest, most difficult to build and most expensive part of the Delta works. Work on the dam itself, which was undertaken by a consortium of contractors comprising Ballast Nedam, Boskalis WestminsterRoyal Boskalis Westminster
Royal Boskalis Westminster N.V. is a Netherlands-based company that provides services relating to the construction and maintenance of maritime infrastructure on an international basis...
, Baggermaatschappij Breejenhout, Hollandse Aanneming Maatschappij
Van Oord
Van Oord is a Dutch contracting company that specializes in dredging and land reclamation. Van Oord has undertaken many projects throughout the world, including land reclamation, dredging and beach nourishment.-History:...
, Hollandse Beton Maatschappij, Van Oord-Utrecht
Van Oord
Van Oord is a Dutch contracting company that specializes in dredging and land reclamation. Van Oord has undertaken many projects throughout the world, including land reclamation, dredging and beach nourishment.-History:...
, Stevin Baggeren
VolkerWessels
VolkerWessels N.V. is a major European construction-services business with Dutch-based headquarters. It is privately owned by the Wessels Family , CVC Capital Partners and management .-History:...
, Stevin Beton en Waterbouw
VolkerWessels
VolkerWessels N.V. is a major European construction-services business with Dutch-based headquarters. It is privately owned by the Wessels Family , CVC Capital Partners and management .-History:...
, Adriaan Volker Baggermaatschappij
VolkerWessels
VolkerWessels N.V. is a major European construction-services business with Dutch-based headquarters. It is privately owned by the Wessels Family , CVC Capital Partners and management .-History:...
, Adriaan Volker Beton en Waterbouw
VolkerWessels
VolkerWessels N.V. is a major European construction-services business with Dutch-based headquarters. It is privately owned by the Wessels Family , CVC Capital Partners and management .-History:...
and Aannemerscombinatie Zinkwerken
Van Oord
Van Oord is a Dutch contracting company that specializes in dredging and land reclamation. Van Oord has undertaken many projects throughout the world, including land reclamation, dredging and beach nourishment.-History:...
, started in April 1976 and was completed in June 1986, though the road over the dam was ready for use only in November 1987. The road was opened by the former queen, Princess Juliana
Juliana of the Netherlands
Juliana was the Queen regnant of the Kingdom of the Netherlands between 1948 and 1980. She was the only child of Queen Wilhelmina and Prince Henry...
on 5 November 1987, exactly 457 years after the St Felix Day's
St. Felix's Flood
The St. Felix's Flood happened on Saturday 5 November 1530, the name day of St. Felix. This day was later known as Evil Saturday . Large parts of Flanders and Zeeland were washed away, including the Verdronken Land van Reimerswaal. According to Audrey M...
flood of 1530 had washed away a large chunk
Verdronken Land van Reimerswaal
The Verdronken Land van Reimerswaal is an area of flood-covered land in Zeeland in the Netherlands between Noord Beveland and Bergen op Zoom. Some of it was lost in the St. Felix's Flood in 1530, and some of it in 1532. The Oosterschelde formerly flowed along its east and north edges...
of Zeeland
Zeeland
Zeeland , also called Zealand in English, is the westernmost province of the Netherlands. The province, located in the south-west of the country, consists of a number of islands and a strip bordering Belgium. Its capital is Middelburg. With a population of about 380,000, its area is about...
, upstream of the new barrier's position.
To facilitate the building, an artificial island Neeltje-Jans
Neeltje-Jans
Neeltje Jans is an artificial island in the Netherlands in the province of Zeeland, halfway between Noord-Beveland and Schouwen-Duiveland in the Oosterschelde. It was constructed to facilitate the construction of the Oosterscheldedam. The island was named after a nearby sand bar....
was created in the middle of the estuary. When the construction was finished, the island was rebuilt to be used as education centre for visitors and as a base for maintenance works.
The dam is based on 65 concrete pillars with 62 steel doors, each 42 metres wide. The parts were constructed in a dry dock
Dry dock
A drydock is a narrow basin or vessel that can be flooded to allow a load to be floated in, then drained to allow that load to come to rest on a dry platform...
. The area was then flooded and a small fleet of special construction ships lifted the pillars and placed them in their final positions. Each pillar is between 35 and 38.75 metres high and weighs 18000 tonne
Tonne
The tonne, known as the metric ton in the US , often put pleonastically as "metric tonne" to avoid confusion with ton, is a metric system unit of mass equal to 1000 kilograms. The tonne is not an International System of Units unit, but is accepted for use with the SI...
s.
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 by the American Society of Civil Engineers
American Society of Civil Engineers
The American Society of Civil Engineers is a professional body founded in 1852 to represent members of the civil engineering profession worldwide. It is the oldest national engineering society in the United States. ASCE's vision is to have engineers positioned as global leaders who strive toward...
.
The dam was designed to last more than 200 years.
Construction fleet
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 denser and more stable.
- Cardium, a ship to transport and lay a special foilFoil (chemistry)A foil is a very thin sheet of metal, usually made by hammering or rolling a piece of metal. Foils are most easily made with malleable metals, such as aluminium, copper, tin, and gold. Foils usually bend under their own weight and can be torn easily. The more malleable a metal, the thinner foil can...
carpet on the seabed for the pillars to rest on. - Ostrea, a ship capable of lifting a concreteConcreteConcrete is a composite construction material, composed of cement and other cementitious materials such as fly ash and slag cement, aggregate , water and chemical admixtures.The word concrete comes from the Latin word...
pillarColumnA column or pillar in architecture and structural engineering is a vertical structural element that transmits, through compression, the weight of the structure above to other structural elements below. For the purpose of wind or earthquake engineering, columns may be designed to resist lateral forces...
from the dry dock and placing it accurately on a special foil on the seabed. The ship is 85 metres long and has a portal of 50 metres high. The ship can only lift 10000 tonnes, but as a large part of the pillar is underwater, it is not necessary for the ship to be able to lift the full 18000 tonnes. This ship is considered the flagship of the construction fleet, mainly because of its larger size and power in comparison to the other ships. - Macoma, a ship that works closely with the Ostrea, cleaning the foil assisting in placing the pillars accurately in their final position.
The ships are named after various types of shellfish
Shellfish
Shellfish is a culinary and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of molluscs, crustaceans, and echinoderms. Although most kinds of shellfish are harvested from saltwater environments, some kinds are found only in freshwater...
.
Operation
The dam is manually operated but if human control fails an electronic security system acts as a backup. A Dutch law regulates the conditions under which the dam is allowed to close. The water levels must be at least three metres above regular sea level before the doors can be completely shut. Each sluice gate is closed once a month for testing. Also emergency procedures are tested on pre-scheduled dates. Once the test is passed, the shutters are immediately opened again to create a minimum amount of impact on tidal movementsTide
Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the moon and the sun and the rotation of the Earth....
and the local marine ecosystem. It takes approximately one hour to close a door.
The full dam has been closed twenty four times since 1986, due to water levels exceeding or being predicted to exceed the three metres.
The last time was on 8 November 2007.
The cost of operation is €17 million per year.
External links
- Satellite view from Google Maps
- DeltaWorks.org - DeltaWorks.Org about Oosterscheldekering. Includes text, photos, video and virtual tour.