Plans were drawn up by various hydraulic engineers, ranging from a complete reclamation with some canals here and there, to a partial reclamation. Ultimately, ir. Cornelis Lely’s plan turned out to be the most suitable. He thought that the Zuiderzee should first be dammed with a dike with sluices to drain excess water, that some kind of inland lake should be maintained for the formation of a freshwater basin and that the Zuiderzee should be impoldered in parts. The biggest opponents of the closure of the Zuiderzee were the fishermen from fishing towns such as Enkhuizen , Hoorn , Stavoren , Urk and Volendam , who feared damage to their income.
As early as 1892, a state commission recommended carrying out ir. Lely’s plan, but it took until 1918 before a law was passed and work could begin. First, a test polder was made at Andijk to gain experience and then work began on the Afsluitdijk , a dike of 32 kilometers long and 90 meters wide. The dike protruded 7.5 meters above sea level, so that no waves could hit the dike during a storm surge. The usefulness of this became apparent in 1953 ; the high dyke prevented the Hollands-Utrecht polder from flooding during a violent storm, while the population in large parts of Zeeland and South Holland was surprised by the water.