In the original plans for the Deltaworks, the Eastern Scheldt would be completely closed off with a regular dam. In the late 1960’s and early 1970’s the construction of this dam was already underway. However, opposition against a complete closure of the Eastern Scheldt mounted, because of the unique ecology in this area that needed to be preserved. In 1978 it was decided that the Eastern Scheldt wouldn’t be completely closed off from the sea. Instead a barrier with movable components would be built, that would only have to be closed in case of storms. To be able to do this, a lot of problems had to be overcome, using completely new technologies. The seafloor of the Eastern Scheldt had to be strengthened to be able to place the very heavy pillars with which the dam was being built, mats had to be placed on the seafloor to be able to place these huge pillars that were constructed in giant docks and moved to the site of the dam. The Eastern Scheldt storm surge barrier was finished in October 1986.