Delta Works

Protecting The Netherlands against water. It is a battle of all times in this low-lying country. Rijkswaterstaat, part of the Ministry for Infrastructure and Water Management, carried out extensive research in 1937 and the conclusion was as clear as it was staggering: The Netherlands is not permanently safe from water and something really has to be done. The Delta Committee - set up a few weeks after the flood of 1953 - is commissioned to make a plan.

Delta Plan 

Simply building new dikes, however, was not possible everywhere  and it was also very expensive. A plan to dam all estuaries – Westerschelde, Oosterschelde, Haringvliet and Brouwershaven Gat – was born. The Delta Plan. A prestigious project. Extensive enough to opt for a gradual implementation at first.

Initially, the Delta Committee advices to close off all areas where the sea water enters. That signals the end of mussel and oyster fishing. Protests result – with  “Oosterschelde Open” as a war cry – and eventually a closable barrier is chosen. Read more about the history of the plan on Delta Plan

The Flood of 1953

After the flood of 1953 – when 1835 people died, hundreds of animals drowned and 150.000 hectares of land covered by sea water – everything changed. Postponing the Delta Plan was no longer an option. Within twenty days of that fatal February night, a Delta Committee was installed to work on a plan to better protect The Netherlands against water.

Delta Act

The Delta Act incorporates an extensive defense system against high water levels from the sea in Zeeland, southern South Holland and North Brabant. Realising the Delta Act was not a simple task because water is an enemy, but also a friend.  A lot of trade is transported via waterways. The Nieuwe Waterweg and the Westerschelde had to remain open for the ports of Rotterdam and Antwerp. In 1959 – six years after the flood disaster – the Delta Act was adopted. A year earlier, to protect the densely populated Randstad (the area between and around the four largest cities) against flooding, the storm surge barrier in the Hollandse IJssel was completed and operable. 


This was followed by the damming of the Veerse Gat and Zandkreek (1961), Haringvliet locks (1971) and Brouwersdam (1972). In order to construct the dams, auxiliary dams were laid in Zandkreek (1961), Grevelingen (1965) and Volkerak (1969). These dams ensured the distribution of  water in manageable quantities (compartments).

Locaties Deltawerken Bron: Rijkswaterstaat
Locaties-deltawerken (C) Rijkswaterstaat

Storm surge barrier

The final part of the Delta Works – the storm surge barrier in the Oosterschelde – was not completed until much later. Both fishermen and conservationists vigorously protested against a plan for a closed dam in the Oosterschelde. Completely damming the Oosterschelde would be detrimental to both the unique salt water environment and the fish stocks. The battle cry OSO (Oosterschelde Open) arose.

In 1976 an alternative plan was launched: a barrier with 62 openings of 40 meters wide. Whenever extremely high tides were forecast, these openings could be closed with hydraulic slides to protect the hinterland. The 2.5 billion euro project was carried out. On October 4, 1986, the barrier – a fine example of Dutch hydraulic ingenuity – was festively opened by (then) Queen Beatrix.

The Delta Works are the Netherlands' largest flood protection system against high water from the sea.

Storm surge barrier’s