Approaches to long-term modelling of coastal morphology: A review

Aspects of long-term mathematical modelling of coastal morphology are inventoried and discussed. They concern reduction techniques for input data, process descriptions and output data, as well as model concepts ranging from statistical extrapolation of the past coastal behaviour, via semi-empirical behaviour models, to formally integrated descriptions of the constituent small-scale processes. All approaches have in common that they reduce the need for detailed descriptions in space and time of the underlying physical processes. They lead not only to more transparent and robust models which require less computational effort, but also to a better insight into which aspects of coastal behaviour are relevant from a long-term point of view and which are not ("signal" vs. "noise").