In the planning of the Delta-works, carried out in the Southwestern Netherlands, the Eastern Scheldt was the largest and therefore last tidal basin to be fully closed mainly to protect the area from floods. Increased recognition for the natural value of estuaries and a strong lobby from nature conservationists and shellfish producers led to a reconsideration of original plans, confirmed by a series of governmental decisions. Per consequence execution of the present plans will result in a storm-surge barrier at the entrance of the tidal basin together with two partitioning dams, separating the (reduced) tidal Eastern Scheldt from a new freshwater lake. Attention is paid to the present values in the Eastern Scheldt and briefly to changes involved by the project. The decisionmaking process is described and discussed: In the course of the project the majority of decisions taken were prepared by teams of ecologists, civil engineers, hydrologists and financial experts using policy-analysis methods. For guidance of developments in the influenced area the local government accepted a policy plan, in which human uses are regulated. Operations of the barrier are designed such that safety from flooding is guaranteed, while adverse effects for the tidal ecosystems are minimized.