Towards a proper coastal defence management of the Belgian East coast.

Along the Flemish East coast, the morphological equilibrium, as a combination of wave induced on- and offshore transport and tidal longshore now mobility, is greatly disturbed by the recent port extension of Zeebrugge. Indeed, the seaward harbour breakwaters intersect the easterly longshore drift and focus diffracted incident waves directly to the coastline before Knokke-Zoute. As a result, a severe erosion of the local beach area is noticed during the last twenty years. The persistent regression of this coastal zone between Knokke-Heist and the Zwin entrance at the Dutch border forms an accute threat to the touristical and ecological values of the region. Therefore, in order to identify the drastic instability and the morphological impact in this area, an extended research program is set up to explore a better understanding of the local beach morphology. This fundamental study of a proper coastal defence strategy is developed in the framework of a general protection plan "COAST 2002" for the Flemish coastal zone. Through physical and numerical modelling together with appropriate field registrations, a better insight into local hydrodynamic and morphological features is gained to support a proper beach protection management for the region. By that, research results will help to deploy a more reliable and scientifically based design of a local beach protection system for the Flemish East coast, resulting in an economical and ecological coastal zone management.