In the framework of a scientific-technical collaboration between IOW and BAW (Bundesanstalt für Wasserbau) we design an interaction between the large-scale oceanographic model systems at IOW and the regional, coastal engineering model systems at BAW. The scientific challenge is the identification of an optimal interface of both model systems. The one-way coupled model system will then be tested for realistic case studies. The core idea of the collaboration is to transfer fundamental research methods of coastal oceanography to applied coastal engineering models. The ultimate goal is to improve the enginering models of BAW by a higher degree of physical and numerical consistency and to increase their predictability.