Coastal management and long-term foredune behavior: characterizing semi-natural foredune evolution
Wijnberg, K.M., Bochev-van der Burg, L.M., and Hulscher, S.J.M.H., 2011. Coastal management and long-term foredune behavior: characterizing semi-natural foredune evolution. Journal of Coastal Research, SI 64 (Proceedings of the 11th International Coastal Symposium), ��� – ���. Szczecin, Poland, ISSN 0749-0208 Management interventions applied to foredunes often aim at stabilizing the foredune, restoring a pre-storm situation or stimulating foredune growth. Whether and how the often localized and intermittent interventions may interfere with the evolution of foredune morphology over time spans of many decades, can be investigated trough comparative case studies of managed foredune behavior. At the heart of such studies are analyses of longterm monitoring data sets of foredune topography with sufficient temporal and spatial resolution. A comparative analysis of such large data sets requires a method that can be applied across data sets from different sites. In this paper we explore the use of autocorrelation to characterize spatial and temporal variability in foredune morphology. Application to a 45 year data set of annual elevation surveys across semi-natural foredunes on the island of Schiermonnikoog (The Netherlands), revealed differences between a foredune that was initiated by erecting sand fences on a beach plain (sanddrift dike) and a foredune that developed seaward of it. Differences concerned the persistence in deviations from temporal and alongshore trends in crest elevation and crest position. Besides, it was shown that the sanddrift dike had a gentler seaward facing average slope than the foredune that developed later on. The presented results indicate that autocorrelation, including a procedure to deal with missing data, can be a useful addition to characterize alongshore and temporal variability in foredune behavior.