The effects of wave chronology on medium and long term coastal morphology

The sequencing, or chronology, of wave events plays an important role in determining how coastlines and nearshore regions evolve over medium and long timescales (from weeks to decades). However, present-day computer models of coastal morphology treat the input wave conditions in either a deterministic (i.e. a single wave sequence) or a probabilistic manner. In neither method are the effects of the full range of possible future wave sequences, for given overall statistical values, calculated. The methodology presented here addresses this problem by multiple model runs using different re-orderings of a wave sequence. A series of tests demonstrate different aspects of wave chronology and its importance in the prediction of seabed and beach levels. The method provides a means both for understanding wave chronology effects and for predicting these effects in practical engineering problems involving medium and long timescale changes to coastal morphology.