ABSTRACT
Facing i.a. the European Water Framework Directive, more environmental friendly bank protection measures will be demanded for, not only for small waters, but also for inland waterways. These measures should contain as much as possible living or at least dead plants, combined with technical building materials, if necessary, to avoid erosion from the natural and vessel-induced flow and wave field. These measures will be called “technical-biological” and shall replace technical protection methods as riprap or sheet piling, if applicable. Numerous experiences and corresponding guidelines for such alternative measures are available for waters without navigation. For large and generally navigable inland waters as those in German waterways, reliable design rules are lacking up to now, especially if living plants shall take over the protection function. For this reason the German Association for Water, Wastewater and Waste (DWA) founded in 2008 a working group named “Alternative Bank Protection Measures”. The aim was to collect and condense the existing knowledge in this field, to evaluate the ecological value and efficiency of these measures and to assess the construction and maintenance expenses, especially of measures with living plants. The main idea was to transfer existing experiences from waters without navigation to those with significant impact from vessel-induced waves and currents and to account for first results of an ongoing mutual research project of the German Federal Waterways Engineering and Research Institute (BAW) and the German Federal Institute of Hydrology (BfG) concerning the same subject for waterways only. The results should be published in a design guideline for technical-biological bank protection measures to make it usable for planners of waterway infrastructure. The guidelines are available now. The present paper demonstrates the way how to use the new guidelines for designing technical-biological bank protections, considering relevant local boundary conditions, decisive design aspects, the hydraulic and geotechnical impacts in comparison to load thresholds, the demands of bioengineering constructions and ecological aspects, to find out an optimal solution from a list of recommended constructions. The latter concern to measures to protect the bank slopes, not to reduce impacts. The paper also presents some results of the a.m. research project.
