Water bodies and their management are facing major challenges with regard to the predicted climate change. Increasingly intensive extreme events such as floods, heavy rainfall or prolonged dry periods with high temperatures will in future increasingly affect the sensitive ecological balance of surface waters with their flora and fauna. Effective adaptation measures for low water management and drinking water supply will be necessary to maintain the essential basis of life "water" and "biological diversity" in flowing waters and lakes. Scientists, politicians, technical authorities, planners and responsible maintenance authorities are therefore faced with the challenge of understanding the complex interactions of the ecosystems influenced by humans and of improving the adaptability of the water regime within defined spatial boundaries. On the part of the technical instruments of water management, guidelines, laws, ordinances, plans and programmes are available for such regulation and, in cross-reference to nature conservation instruments, provide central frameworks for action to achieve the respective objectives. At the EU level, for example, for the Flood Risk Management Directive (FRMD) and the Water Framework Directive (WFD), the extent to which their methods and evaluation systems prove effective under changing climatic conditions must be questioned.
Based on a comprehensive literature screening and supplementary expert interviews, the state of knowledge and existing knowledge gaps are analysed. Based on this, predictable effects on the future ecological quality of surface waters are examined. The WFD as an instrument of action will be assessed with regard to its future applicability and proposals will be derived for an adaptation of the methodological and assessment system of the WFD. The cause-effect relationships and procedural steps analysed in this way are transferred into a conceptual modelling structure. Essential parameters to be considered for river and lake models as well as for their combination are identified and examined with regard to their predictability. A national case study also reveals options for transferability to specific regions or river basins. The results will be presented and discussed with selected experts in a workshop. Furthermore, a contribution will be made to the determination of the indicator "water stress" according to the Sustainable Development Goals of the United Nations for the Federal Republic of Germany. The focus here is on the methodological approaches for investigating the so-called "environmental flow requirements" for Germany and its trend-related changes due to developments in climate and land use change. All findings are incorporated into recommendations for action and are made available to actors in research, administrative and technical authorities and planning practice. In particular, modules in the field of action "water balance, water management, coastal and marine protection" of the German Strategy for Adaptation to Climate Change (DAS) are addressed.