The main scientific objectives of this research proposal can be summarised in the question why certain sandy coasts are dynamically stable and others are not. The following tools will be used to search for the answer:•Literature study•Building of a framework to model sediment transport in the near shore zone•Incorporation of the influence of complex spectra in the formulation of sediment transport influenced by currents and waves• Synergy of understanding of the physical processes (theoretical basis), numerical and physical modelling• Qualitative confrontation with available in situ measurementsSince we are convinced that the planned research activities are of international value, not only in terms of scientific merits but also from the point of view of sustainable coastal development, the following objectives form also part of this proposal:•Collaboration with other research teams in Europe who deal with this topic, for example by participating in experiments in the framework of TMR-LSF•Writing and submitting of a problem oriented and interdisciplinary research proposal to the E.U.•Dissimination of the results through conferences and by publication in international journal