Morphological response of a barrier island system on a catastrophic event: the AD 1634 North Sea storm

摘要

The AD 1634 North Sea storm is one of the most catastrophic storms along the Wadden Sea coast of Denmark. In this study we show how pre-1634 storm morphology exerted a strong control on the resulting post-storm coastal morphology. Erosional responses associated with the storm were barrier breaching, dune scarping and shoreface erosion and accretionary responses were washover deposition, shoreface healing and barrier-island formation. Local sediment sources appeared to have a particularly strong influence on post-storm coastal evolution and allowed a very rapid formation of a barrier shoal which resulted in several kilometres of coastal progradation. Sediment budgets suggest that formation of the barrier shoal was possible, but the sediment transport rates in the decades after the 1634 storm, must have been two to three times higher than present-day rates. The study demonstrates that catastrophic storms are capable of moving large amounts of sediments over relatively short time-periods and can create barrier shoals, whereas moderate storms mostly rework the shoal or barrier and create more local erosion and/or landward migration. Catastrophic storms substantially influence long-term and large-scale coastal evolution, and storms may positively contribute to the sediment budget and promote coastal progradation in coastal areas with longshore sediment convergence. Copyright (c) 2015 John Wiley & Sons, Ltd.