The Delta Works are a series of dams and storm surge barriers, designed to protect the Netherlands from flooding from the North Sea. The construction of the Delta Works was a response to the widespread damage and loss of life in the North Sea flood of 1953.
The longest dam in the Delta Works is the Oosterscheldekering, located between the islands Schouwen-Duiveland and Noord-Beveland. This nine-kilometre (5.6-mile) -long storm surge barrier was the most difficult to build and most expensive part of the Delta works: construction started in April 1976 and was completed in June 1986 but the road over the dam was ready for use only in November 1987. Its cost of operation is €17 million per year.
The dam is based on 65 concrete pillars; each pillar is between 35 and 38.75 metres (114.8 and 127.1 ft) and high and weighs 18,000 tonnes. It is fitted with 62 steel doors, each 42 metres (137.8 ft) wide. These doors are normally open, but can be closed under adverse weather conditions. Due to the weight of the doors, it takes approximately one hour to close a door.
Since 1986, the full dam has been closed twenty-seven times due to water levels exceeding or being predicted to exceed the three metres. The last time was on 10 February 2020, because of Storm Ciara.
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.