A study done by Rijkswaterstaat in 1937 showed that the sea defenses in the southwest river delta were inadequate to withstand a major storm surge . The proposed solution was to dam all the river mouths and sea inlets thereby shortening the coast . However , because of the scale of this project and the intervention of the Second World War its construction was delayed and the first works were only completed in 1950 . The North Sea flood of 1953 gave a major impulse to speed up the project . In the following years a number of dams were built to close off the estuary mouths . In 1976 , under pressures from environmental groups and the fishing industry , it was decided not to close off the Oosterschelde estuary by a solid dam but instead to build the Oosterscheldekering , a storm surge barrier which is only closed during storms . It is the most well-known ( and most expensive ) dam of the project . A second major hurdle for the works was in the Rijnmond area . A storm surge through the Nieuwe Waterweg would threaten about 1.5 million people around Rotterdam . However , closing off this river mouth would be very detrimental for the Dutch economy , as the Port of Rotterdam — one of the biggest sea ports in the world — uses this river mouth . Eventually , the Maeslantkering was built in 1997 , keeping economical factors in mind : the Maeslantkering is a set of two swinging doors that can shut off the river mouth when necessary , but which are usually open . The Maeslantkering is forecast to close about once per decade . Up until January 2012 , it has closed only once , in 2007
North Sea flood of 1953
North Sea flood of 1953
Flood control in the Netherlands