The former Zuiderzee region was prone to flooding. Plans for a dam date back to the 17th century, but the technology was still underdeveloped, meaning that the plans were never executed.
Due to a combination of a storm at sea and a massive flow of water from the river IJssel, large parts of the Zuiderzee region once again flooded in 1916. Dykes burst, people were killed and the damage was huge. Engineer Cornelis Lely then drew up a plan for the construction of the Afsluitdijk. The work started in 1927 and the last hole was closed in 1932. Since then there has been no further flooding in the IJsselmeer region.
The Afsluitdijk provides water safety. The dam provides protection from the Wadden Sea and should be strong enough to withstand very severe storms. The dam is now over 80 years old. It is time to reinforce it. The dam will be made overflow-resistant, which means that the dam will not be raised, but will be given a more sturdy top layer. If water flows over the dam during a severe storm, the dam will remain intact. The locks at Den Oever and Kornwerderzand will also be reinforced.