Small hydrological research basins in Germany

Small research basins are hotspots of hydrological research. They are extensively equipped to measure different hydrological parameters with high temporal and spatial resolution. The resulting data are the basis for the identification of regional basin characteristics and hydrological processes, statistical analyses, model development and parameter identification. Altogether these comprehensive research activities address a wide range of objectives and goals, such as analyses of initial landscape genesis, water and nutrient balance, or current climate projections on runoff patterns. The German IHP/HWRP working group "FRIEND/ERB" supports such research activities in small hydrological basins in Germany and contributes to UNESCO’s International Hydrological Program (IHP) as well as the Hydrology and Water Resources Program (HWRP) of WMO. Its focus is on catchments smaller than 50km²with continuous data acquisition of time series longer than 5 years. They are operated by universities, environmental authorities and other research institutions. This presentation illuminates the German research in selected small hydrological research basins ranging in size from 0.06 km² to 50 km². It summarizes the objectives, measured variables and chosen methodical aspects. Continuous measurements at the respective gauges will in future be more and more supplemented by spatially and temporally higher resolution measurement campaigns. The advancement of sensor and IT technologies promotes a continuous increase in data volumes, allowing for more precise and specific analyses and predictions as well as the possibility of a better understanding of the prevailing hydrological processes including their spatio-temporal variability. But often this requires the development of new evaluation methods. The use of models supports these goals. Scenarios allow the evaluation of different land use and management strategies and of possible impacts caused by climate change.The evaluation of the German IHP/HWRP working group "FRIEND/ERB" emphasises an increasing need for high resolution measurements and long time series as well as regular updates of all research activities in small hydrological basins. Only their continuation will also in future provide valuable contributions to research, teaching and the management of environmental problems. Their integration into a research network increases the efficiency of the activities and provides opportunities for joint evaluations.