Author(s): Pushpa Dissanayake; Harshinie Karunarathna
Linked Author(s):
Keywords: Storm cluster; Dune erosion; XBeach; Formby Point; Sefton coast
Abstract: Storm clustering effects on beach/dune morphodynamics were investigated by applying the state-of-the-art numerical model XBeach to the Sefton coast, northwest England. The adopted storm cluster consisting of seven storms was established by analysing the observed winter storms from December 2013 to January 2014. No individual storm occurred during this period is regarded as exceptionally intense, whereas the occurrence of such a cluster of seven events is very unusual. 1D models were setup at a number of highly dynamic cross-shore locations. After initial calibration of the model parameters against available post-storm profile data, the models were used to reproduce beach/dune evolution due to the storm clustering effects. The final predicted post-storm profile of the previous storm was used as the initial profile configuration of the subsequent storm. The predicted evolution during each storm was influenced by the preceding storms in the cluster. Due to the clustering effect, the erosion volume was not proportional to the storm power of the cluster, as expected an individual storm case. The clustering effect on morphology dominates at Formby Point and north therein while decreasing to south. The predicted profile evolution is useful to interpret the morphodynamic processes of beach/dune systems during a storm cluster to develop sustainable coastal management tools.
Year: 2015