Oosterscheldekering
One of the most imposing Delta works is the Oosterscheldekering. A giant 3 km long, existing of 65 huge concrete columns. The Oosterscheldekering is an immense let-through construction that can be closed off when there is a storm. This way safety is guaranteed.
As last part of the Delta works, the Oosterschelde would be closed of by a dam. This was considered to be the most difficult part of the Delta plan. But with all the experience of closing the other projects, this was not seen as a problem. As a nature reservation this was and is a one of a kind in the Netherlands. The clean sea water provides an abundance of food for many animals. Fish use the sea arm as a spawning ground and there are many mussel and oyster cultivation areas. Mud flats, marshes and sand banks form an important area for birds.
If the Oosterschelde would be closed off by a dam, the Netherlands would loose all of this. The unique mud flats and marshes landscape would disappear by the loss of the tide. The water would become fresh and salt water flora and fauna would disappear too. The salt water fish, mussel and oyster culture would also disappear.
Soon however people started to ask themselves if it would be better to have the Oosterschelde open, so that the tides could help keep the original environment. The public opinion became so strong that the government had new studies made, investigations were made if an open Oosterschelde could be technically possible. Important was that the safety of Zeeland would be maintained as well as the original natural habitat. Studies showed that is was indeed technically possible and a choice was made to have a storm protection barrier with sliding doors. Another alternative , to keep the sea arm open and build the dikes up to Delta height, approximately 150 km along the islands, was not accepted. The already contracted plan to completely shut of the sea was now stopped. The Oosterschelde was to remain open but had to be able to be shut when a storm blew.
With the decision to build the Storm protection barrier , the plans for building the Philipsdam and the Oesterdam as added works were also made. These would be constructed at the same time as the Storm protection barrier. They had 2 purposes : firstly the tidal basin behind the barrier would be smaller, this would keep the tide differences in Yerseke down by a third (3.00metres). Secondly these dams would make the shipping route no longer subjected to tide differences between Antwerpen and the Rijn. This was a n agreement made in 1963 between Belgium and the Netherlands.
