ANALYSIS AND MODELLING OF EXTREME LOCALISED DUNE EROSION EVENTS ALONG DENMARK'S NORTH SEA HIGH WATER DUNE BARRIER

Matthew Earnshaw, Holger Toxvig Madsen, Per Soerensen

Abstract


This paper presents the results of an investigation into cases of extreme localised dune erosion along Denmark’s west coast. Cases of extreme dune erosion of over 20m are identified between 1977 and 2012. These are compared to the closest storm events. However, no correlation is found between the occurrence of these extreme erosion events and storm intensity or return period. A general increasing prevalence of sand bars is identified as well as an absence of extreme dune erosion in several of the more recent intense storms. Results of XBeach numerical modelling on a local example of extreme dune erosion showed that the offshore bathymetry and sand bar size has a significant effect on the amount of erosion that occurs at the dune face during a storm.

Keywords


dune erosion; sand nourishment; XBeach modelling

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References


Knudsen, S. Bjerre, H.T. Madsen, and P. Soerensen. 2006. Prediction of Dune Erosion through monitoring of coastline undulations. Proceedings of the 30th Interna-tional Conference for Coastal Engineering, 2792-2804.

Sørensen, C, H.T. Madsen, and S.B. Knudsen. 2013. Højvandsstatistikker 2012 (High sea level statistics 2012) The Danish Coastal Authority.

Unesco-IHE Institute for Water Education, D. a. 2013. XBeach Manual. Avalable from XBeach Open Source Community: http://oss.deltares.nl/web/xbeach/documentation




DOI: https://doi.org/10.9753/icce.v34.sediment.26