Seminar 1st June 2015 11 a.m. John Swallow Room (054/06) at the National Oceanography Centre, Southampton
Coastal Seminar: Numerical modelling on storm driven beach/dune evolution
Dr. Pushpa Dissanayake
Swansea University
- Categories
- NGCM
- Submitter
- Luke Goater
Abstract
Beach/dune systems are natural barriers against coastal flooding, often under threat due to storm driven erosion and therefore, erosion is of concern for coastal safety and sustainable development in the areas where frontal dune systems are present. Numerical simulations were used to investigate the impacts of storms/storm cluster on beach/dune evolution applying the Sefton coast (Liverpool Bay, UK) as the case study area and the storms occurred during the 2013/2014 winter period. The XBeach model was used to simulate beach/dune change from 1) the storm sequence (Cluster) and 2) the same storms considering them as isolated events. Offshore metadata was transformed to the nearshore area using the Delft3D and SWAN models. Analysis of the Clustered and Isolated simulations showed the effect of clustering on the Sefton beach/dune system when compared to the impact of isolated events occurred on a fully recovered beach system. Morphodynamics during each event in the Cluster were influenced by the preceding storm(s), such that the evolution is not proportional to the severity of each storm event, as it would be for Isolated events. The Cluster prevented system recovery extending the erosion area continually southward along the coast compared with that in Isolated events. Storm chronology in a storm cluster had a little effect on the cumulative evolution within storm clusters whereas the bed evolution during a storm event depends on the sequence of occurrence within a storm cluster. Results enhance the understanding of beach/dune response to storm clusters, to interpret observed morphological changes and to develop tools for sustainable coastal management particularly in the Sefton coast and generally in similar systems.
Key words: storm cluster, beach/dune erosion, XBeach, Sefton coast
About Dissa:
Dr. Pushpa Dissanayake (‘Dissa’) is presently a postdoc in Swansea University and has more than 10 years of experience investigating different physical processes of coastal systems in Sri Lanka, the Netherlands, Germany and UK. He graduated as a Civil Engineer with BSc (Hons) in Sri Lanka and obtained MSc and PhD in Coastal Engineering, in the Netherlands. He has authored 10 journal articles and nearly 30 conference proceedings, and reviewed articles from a number of journals. He teaches under graduate and post graduate levels and contributes to the research proposals, while undertaking collaborative research with the Netherlands, Germany and Japan apart from his primary assignment in Swansea University.