HR: 0800h
AN: OS21B-1227    [Abstracts]
TI: Development of a Dynamic Barrier Island (Sylt, Eastern North Sea) Based on High-Resolution Aerial Photographs and GIS
AU: Dolch, T
EM: tdolch@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Wadden Sea Research Station, Hafenstrasse 43, List/Sylt, D-25992 Germany
AU: * Hass, H C
EM: chass@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Wadden Sea Research Station, Hafenstrasse 43, List/Sylt, D-25992 Germany
AB: Wind and currents are the driving forces for the morphological development of coastlines and islands by giving them their shape, run and structure. This is especially true in highly dynamic areas such as the Wadden Sea in North-Western Europe. In this unique environment changes are continuous and distinct developments can be noticed within decades. The Island of Sylt, located in the Wadden Sea near the German-Danish border, is a sandy barrier island that protects the mainland against storm floods and waves. Thus, it experiences strong erosion (about 1 m coastal retreat per year). The North Atlantic Oscillation (NAO), that controls the atmospheric circulation over the North Sea, and northerly currents are the driving forces for the morphological development. Rising sea-level due to global change amplifies the erosion processes and forces people to protect the coastline (in this case beach nourishment). The Koenigshafen, a protected, semi-enclosed bay in the north of the Island of Sylt, can be regarded as representative for the study of many coastal processes that affect the island. In this case study, a long-term series of high resolution aerial photographs of the Koenigshafen (starting in 1936) shows the development of the survey area. Wind and currents affect not only the run of the coastline but also sediment composition and biodynamics in the bay. Looking at the hydrodynamics governing the bay, it should have mostly muddy sediments. Strong westerly winds, however, supply the bay with large amounts of sand from inland dunes and create sandy tidal flats. The long-term development of seagrass and mussel beds can also be retrieved from aerial photographs. In both cases a distinct decline in size can be noticed. Remote sensing and GIS techniques allow monitoring the conditions as well as to reconstruct the past development and to predict future developments.
DE: 4219 Continental shelf processes
DE: 4546 Nearshore processes
DE: 4558 Sediment transport
DE: 1815 Erosion and sedimentation
DE: 1640 Remote sensing
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting