Within the scope of the long-term vision for the Schelde estuary, ecosystem goals will be formulated for the system based on the natural functional and structural characteristics of the estuary. These goals will be formulated focussing on the naturalness of the system, whereby the estuarine coupling between the river and the North Sea is centralized. Finally the goals will result in certain requirements for the total estuary or for certain regions within the estuary. Beside this a method is being developed to find out which requirements are needed to obtain these ecosystem goals. This method is using scientific knowledge of as well physical, chemical as biological processes. Finally the method must become a tool to see whether human interventions do not interfere with the ecosystem requirements.