Alternative measures for the improvement of the harbour entry conditions of Friedrichskoog, North Sea

The motivation for the investigation is the sedimentation of the entry to the harbour Friedrichskoog, North Sea, which is an unfavourable development for shipping and drainage of the hinterland. The investigation was conducted to evaluate the effectiveness of several constructive measures to improve the waterway situation by reducing sedimentation tendencies in the harbour entry and maintaining the inland drainage. To this end a morphodynamic model (Delft-3D) was developed and subsequently calibrated and validated with the help of field data.

Entry to Friedrichskoog harbour in 2006
Entry to Friedrichskoog harbour in 2006 © GeoBasis-DE/LVermGeoSH

Duration: 2008-2010

Five training options were examined in total. Three of them are based on the established harbour layout. In this option modifications of the ground level in the narrow harbour channel are implemented by defining critical depths-levels for the periodic maintenance dredging works.

Subject to the fourth option is a polder that is opened during ebb tide to flush out previously deposited sediments from the narrow channel in order to reduce an accumulation of sediments close to the harbour area. Furthermore the effectiveness of connecting the harbour to the deeper offshore area by an angled side canal was examined.

Overall, it was noted that the deepening of the harbour channel by defining different dredging levels only delays the problem of sedimentation but does not solve it permanently. A flushing polder proved to be quite effective for reducing the sedimentation in the harbour entry area.

However, sedimentation is expected to occur inside the polder. An angled side canal is assessed to have positive effects on the offshore topography of 2004, but its long term impact depends on the developments of hydrodynamics and water levels seaward of the harbour entry.

Research division:


  • Prof. Dr. R. Mayerle


  • G. Bruss
  • T. Etri
  • J. Block
  • K.H. Runte


  • Landesbetrieb für Küstenschutz, Nationalpark und Meeresschutz Schleswig-Holstein