Abstract. In this study two approaches are presented to identify Dominant Runoff Processes (DRP) with respect to regionalization. The approaches are a simplification of an existing method to determine DRP by means of an extensive field campaign. The first approach combines the permeability of the substratum, land-use and slope of the basin in a GIS-based analysis. The second approach makes use of discriminant analysis of the physiographic characteristics of the basin and links it to the GIS analysis. The results of the developed approaches are maps, which identify dominant runoff processes and represent a spatial distribution of the hydrological behaviour of the soil during prolonged rainfall events. The approaches have been developed in a micro-scale basin (Germany). An additional meso-scale basin was introduced in which the two approaches were applied for quality control. The thus generated maps for the micro-scale basin were compared with an existing DRP map, which was derived with the existing method. The first approach showed a resemblance of 79% when compared to this map, whereas the second approach showed only a resemblance of 51%. The generated maps for the meso-scale basin were compared to DRP that were determined point wise according to the existing method. The first approach showed in this case a resemblance of 81%, whereas the second approach showed a resemblance of 68%. Therefore, the first approach is preferred to the second approach when accuracy, data input and calculation time are concerned.

Climate change has serious impacts on forest services with regard to the spatial and temporal distribution of water within catchments. Hence, combined forest and catchment management in a changing climate is a crucial concern for people and society. To assess hydrological processes and water resources in two forested headwater catchments in south-west Germany the physical based hydrological model ArcAPEX was calibrated to investigate climate change scenarios for the near (2021-2050) and far (2071-2100) future. Even though the trend in temperature is positive in most regional climate change scenarios for south-west Germany, the precipitation trend is quite ambiguous. Different precipitation scenarios give access to the possible bandwidth between water stress and flood generation. Our results can be used to describe water resources and discharge characteristics under conditions of different land use change scenarios.Management option for a sustainable forestry and flood mitigation will be to "spread the risk" by creating forests with a high biodiversity and a prioritization of forest services and functions. The principle is to find "no-regret" decisions. In this sense, final decisions should not be taken too early, and several options should be kept open, such as dealing with increasingly frequent droughts on one hand and increased runoff generation on the other hand. Thus, it should remain possible for forest and catchment management authorities to react to possible developments in an uncertain future.

Abstract. In this study two approaches are presented to model Dominant Runoff production Processes (DRP) with respect to regionalization. The approaches have been developed in the micro-scale experimental Zemmer basin (Germany). The first approach combines the permeability of the substratum, land-use and slope of the basin in a GIS-based analysis. The second approach makes use of discriminant analysis of the physiographic characteristics of the basin and links it to the GIS analysis. The net results were two maps indicating modelled DRP for the Zemmer basin, which were then compared to an existing DRP map of the Zemmer basin. Both approaches provided satisfactory results when compared to this existing DRP map. The first approach was strongly linked to the geological conditions of the basin while the second approach revealed a strong dependence on the topography. Therefore, impermeability of the substratum and the topography of the basin were used as suitable parameters for modelling dominant runoff processes.