Water bodies have always been of special importance for humankind in their role as a source of water, as transportation routes, as sources of energy and, not least, for leisure and recreational purposes. To meet these demands, their natural state has frequently been subject to measures which have modified and dammed the waterways. These measures have had and still have a major impact on the natural habitats of animals and plants. Barrages, in particular, impose severe restrictions on the ecological connectivity of rivers for all kinds of organisms, as well as on the natural transportation of fluvial sediments. These structures are especially disadvantageous for fish, which are dependent on the possibility to move over large distances between spawning, breeding and feeding habitats.
For this reason, European environment standards, such as the Water Framework Directive (WFD), the Fauna-Flora Habitat Directive and the Eel Regulation call for the restoration of the ecological connectivity of the waterways and the protection and nurturing of their fauna and flora. In Germany, Section 34 of the Federal Water Act (WHG) from the year 2009 requires that the Federal Waterways and Shipping Administration (WSV) implement the necessary measures for the restoration of the ecological connectivity on federal waterways at the barrages which have been constructed or are operated by the WSV.
On behalf of the Federal Ministry of Transport and Digital Infrastructure (BMVI) the Federal Waterways Engineering and Research Institute (BAW), in association with the Federal Institute of Hydrology (BfG), supports the WSV in the necessary designing, planning and building tasks. To this end the BAW has published the „Guideline: Upstream Fishways on German Federal Waterways“ and „Requirements for the Planning of Fish Lifts and Fish Locks“. Additionally, Research and Development projects on hydraulics in fish passes as well as on fish behaviour are conducted. For this purpose numerical and/or hydraulic modelling and additional investigations at pilot sites are conducted. Currently the main concerns of these investigations are attraction/ attraction flow and passability of fish passes.
An interactive real-time visualization system illustrates the complex topic of upstream fish migration and ecological connectivity in a simplified and descriptive manner.
The BAW also provides technical expertise to a number of working groups which focus on ecological issues, among these the interministerial working group for the Federal program "Blaues Band Deutschland" (Blue Belt Germany - A Federal Government Programme: Taking a new look at our waterways and their floodplains), the "Fachkreis Naturschutz und Landschaftspflege" (expert group on nature protection and conservation) of the WSV or the working group on the implementation of the WFD. Moreover, the BAW takes part in standardization processes.