Morphological and Sedimentological Development of a Tidal Inlet and its Catchment Area (Otzumer Balje, Southern North Sea)

Abstract

Morphologicalaod sedimentological changes over the last 30 years of the catchment area of the tidal inlet Otzumer Balje between the East Frisian Islands at Langeoog and Spiekeroog have been studied by using older topographic maps and former investigations of sediment distribution. Also, a topographic survey and aerial interpretation of the sediment distribution of the tidal flats and inlet were done in 1990 to obtain an actual basis and to test the use of aerial photos for the sedimentary survey. Another purpose of the study was to develop fundamental methods for the interpretation of sedimentological results for future use as a functioning instrument for the analysis of morphological developments in the coastal zone.

Various sediment classifications complicate a direct comparison. Therefore, the results of the sedimentological investigations give only a rough reference to the development of sediment distribution. The tidal inlet is characterized by a sinistral rotation associated with a straightening of the transition to the tidal channel of Schillbalje. There is also a general shifting of tidal channels and flats to the southeast. The tidal flats near the island of Spiekeroog and the mainland coast are under continuous erosion.