Long Term Morphological Modelling using a Hybrid Concept

Coastal morphological modelling has made significant progress in the recent years. The understanding of physical processes and their implementation into model systems has been improved, and models combining modules for wave-, current and sediment transport fields and the resulting morphological evolution are often used as engineering tools for the analysis of the effects of coastal structures.

Traditionally two main types of models have been applied: long term models and short-intermediate term models. Long term models will apply a number of simplifying assumptions, for example using a littoral transport model combined with a one-line model for the shoreline evolution. The more detailed area models aim at making as accurate a representation of the physical processes as possible. Improvements in the computer power has allowed longer and longer simulations with the detailed morphological models but there are problems with accumulation of small errors, in particular gradual deterioration of the coastal profiles in the model predictions because the delicate balances behind the cross-shore sediment transport forming the profiles are not represented accurately enough in the area models.