Technical-biological bank protection measures

The banks of waterways in Germany are exposed to high hydrodynamic loads from ship-induced waves and natural currents. In estuarine areas, there are additional impacts from tides. Usually, technical riprap is used to stabilise banks and protect the adjacent terrain as well as maintain the ease and safety of navigation. However, more nature-orientated designs for the banks of waterways are envisaged for the future to restore habitats for animals and plants and increase their structural diversity.

Ecological enhancement of riparian zones can usually be best achieved by removing and not replacing existing riprap, which enables river banks to evolve naturally. This is not always possible of course. In areas where bank protection is indispensable, riprap should be replaced with more environmentally friendly and nature-orientated measures that use vegetation and dead wood. For instance, living willow brush mattresses and vegetated riprap are suitable protection measures for the banks of inland waterways whereas brushwood boxes and dead wood mattresses tend to be used in estuarine areas. The objective of these measures is the ecological enhancement of riparian zones in combination with the necessary level of bank protection.

In cooperation with the Federal Institute of Hydrology (BfG), the BAW studies the applicability, robustness and ecological effectiveness of these technical-biological bank protection measures. To this end, we conduct special laboratory and model tests as well as large-scale field studies, for example on the River Rhine. The results are used to develop planning aids and basic dimensioning guidelines for the German Federal Waterways and Shipping Administration (WSV). All the relevant findings and a collection of protection measures that have already been implemented are freely available to all interested parties on our information portal: