Project part-financed by the European Union (European Regional Development Fund)

The Interreg IVB North Sea Region Programme

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Realignment Wrauster Bogen

Expected effect

Different monitoring programs were carried out. In 1992 an ecological study was conducted, and amongst others the succession of the vegetation was investigated (Golombek et al. 1993). The shore and aquatic vegetation developed in a very good way but the water level in the creek proved to be too low for a permanent colonization by fish. Due to the slope steepness and high flow velocities in the creek, erosion occurred at the creek banks and the slopes. As a result sand from the creek was transported into the Elbe estuary at low tide. A balance could not be reached, and even more erosion was caused by high flow velocities. Only monotonous biotope structures developed under these circumstances. Specific protected species did not develop due to the high flow velocities.

The problem was solved in 1994 by a morphological rearrangement of the creek. One side of the creek was closed in order to decrease the flow current. The slope of the embankments was flattened. A positive influence on the erosion and sedimentation processes was observed. Fine and silt sands deposited, which led to the development of heterogeneous biotope structures.

The effect of the morphological rearrangement on the development of the area and especially on the current regime, as well as on the morphological stability inside the creek was monitored (Golombek et al., 1996). Furthermore the development of the macro fauna and other important parameters like O2 content, pH and water temperature were studied. In 1997 the abundance and distribution of fish species at this location was compared to several similar inlets elsewhere in the river (Thiel et al., 1998). As a result it could be concluded that the population of fish reached a good status, and that the new design of the measure resulted in a geomorphologic ideal shore habitat.

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Report: Management measures analysis and comparison