The Zuiderzee Works are a human-made system of dams, land reclamation and water drainage works. It was the largest hydraulic engineering project undertaken by the Netherlands during the 20th century. The project involved the damming of the Zuiderzee, a large, shallow inlet of the North Sea, and the reclamation of land in the newly enclosed water body by means of polders. The American Society of Civil Engineers has declared the works to be one of the Seven Wonders of the Modern World.
One of most notable features of the Netherlands was the Zuiderzee, which was a shallow bay of the North Sea. While the Zuiderzee was a resource for fishing and allowed access for trade, it could become dangerous whenever one of the frequent North Sea storms would push water through the bay's inlet. Dikes would fail and the resulting floods would kill hundreds or even thousands of people.
In 1421, a seawall on the Zuiderzee dike broke during a storm and flooded 72 villages killing thousands of people. In the 17th century the first plans to address this problem were drawn up. It wasn't until the 19th century, however, that the technology to actually do the job was developed.
Cornelis Lely, a Dutch civil engineer, came up with a plan that proposed building a long dam that would close off the Zuiderzee and turn it into a lake. On June 14, 1918 the project was officially started. Its goals were to protect the region against floods from the North Sea, increase the country's food supply by creating polders that could be turned into farmland and use what remained of the Zuiderzee to improve water management.
The Zuiderzee works
The first step in the plan was to enclose the Zuiderzee by building the Afsluitdijk, a 20 mile long dam across the bay. Experience showed that till, rather than just sand or clay, was the best primary material for a structure like that and work started at four points: on both sides of the mainland and on two purpose-made construction-islands (Kornwerderzand and Breezanddijk) along the line of the future dike. On May 28, 1932 the last connection to the sea was closed and the Zuiderzee became a lake named Ijsselmeer.
Even before the Afsluitdijk was complete, the Dutch started working on the first of the polders, the Wieringermeer, which dikes were completed in 1929. The second polder, the Noordoostpolder, was started in 1936 and draining it finished in 1942. Finally, the Oostelijk Flevoland, the third polder, added 208 square miles of territory to the Netherlands, in 1957. In 1967, the fourth polder was finished, the Zuidelijk Flevoland.
The Zuiderzee today
Zuiderzee is now the Ijsselmeer, which is the biggest lake in the Western Europe. It is an artificial lake of 1100 km² in the central Netherlands bordering the provinces of Flevoland, North Holland and Friesland.Also, in 2010 an artificial island called the IJsseloog was installed on the lake. It is a repository for contaminated material dredged from the bottom of the lake. Once the repository is full, it will be capped and turned into a nature reserve.
If you ever visit the Netherlands or you already live here, you should definitely visit the region and indeed see a World Wonder.
Photo by Martin Terber