Topography and morphodynamic in the German Bight investigated with ERS

The intertidal area of the German Bight is continuously changing its topography due to morphodynamic processes. This fact has serious impact on the German waterways, requiring a huge amount dragging with costs of about 80 mio DM per annum. In order to better monitor these morphodynamic processes and to continuously update the changing bottom topography, Synthetic Aperture Radar (SAR) data of the European Remote Sensing Satellite (ERS)-1 and 2 are used in the estuary of the river Elbe. The SAR is an active sensor and therefore very useful for this study as it is possible to extract the land water boundary --- the shoreline --- during all weather conditions as well as during day and night. In this paper a combination of wavelet and active contour model is used to extract the shoreline information from about 60 ERS SAR images aquired between 1992 and 1999. This shoreline information is used to identify the morphodynamical most active region in the Elbe estuary and to improve the existing bottom topography of the German Federal Waterway Engineering and Research Institute (BAW). An accurate topography is needed as a boundary condition for BAW's hydrodynamic tide model TRIM-2d