Kroon, A., Kabuth, A.K. and Westh, S., 2013. Morphologic evolution of a storm surge barrier system.
Morphologic evolution of a barrier island system on the southern shore of Zealand, Denmark shows regular inlet breaching and inlet closing over the last centuries. At the same time, the barrier slowly moves in a landward direction at its most exposed stretches. Alongshore wave-driven processes cause shoreline alignment and closure of inlets. A combination of high-energy waves and high water levels induces inlet breaching and overwash processes over the barrier crests. However, local high water levels are often not correlated with storm events in the inner Danish coastal waters. The water level fluctuations along the southern shore of Zealand are strongly influenced by the water level fluctuations in the Kattegat due to wind set-up and seiches in the Baltic Sea; local wind set-up and local wave set-up on the southern shore of Zealand are often of secondary importance. Statistics on extreme water levels based on measured water levels over the last century are often used to express the risk for flooding in a coastal environment. The present study indicates that this approach cannot directly be used in case of coastal erosion and inlet breaching. Extreme water levels and associated exceedance curves may overestimate these risks in cases of de-coupled extreme water levels and storm events.