Water resources management on the river-basin scale as the EC Water Framework Directive demands, flood control, and also the maintenance of rivers as navigable waterways constitute together a highly complex task. The understanding of the consequences of anthropogenic interventions in river ecosystems presupposes knowledge of the impacts that have to be expected. Only then decisions can be taken that ensure adequate consideration of the interests of river-landscape protection as well as the social use interests. For this reason the German Federal Institute of Hydrology (BfG) initiated the development of a Decision Support System (DSS) with the example of the River Elbe in the process of pooling the results achieved within the BMBF Research Association "Elbe Ecology". The DSS pilot version has the purpose to make knowledge on the interactions of natural and anthropogenic factors available for administrative tasks and policy decision making in a userfriendly and practice-oriented way.
Further a DSS is also a tool for communication and discussions between scientists and decision-makers. Now, this approach has to stand the practical test to identify options for further developments. In the present version, the functionalities are organised in form of examples covering the topics water quality/reducing pollutant loads, flood control/flooding risks, ecological state of floodplains, navigability, as well as external scenarios such as climate change, agricultural policy, and demographic developments.