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Abstract. The hydrological catchment model WaSiM-ETH (Water Balance Simulation Model) is a spatially distributed, process- and grid-based hydrological catchment model which was primarily developed to simulate the water balance of mountainous catchments. In this study, the ability of WaSiM-ETH was tested to describe the hydrological processes of lowland catchments. In addition, the resulting model performance was related to subcatchment characteristics and the model's sensitivity to possible future land use change. The prediction of the hydrological effects of land use change is a major challenge in contemporary hydrological model applications. The study revealed that WaSiM-ETH is a suitable tool for the simulation of the hydrological behaviour of lowland catchments. However, for a few subcatchments model validation failed. Analysing the correlation between model performance and physiographic catchment characteristics revealed that WaSiM-ETH performs better in sloped catchments compared to plane ones. Modelling results were also better in heterogeneous catchments with respect to soils and vegetation compared to homogenous ones. However, the hydrological reaction to land use change scenarios was similar in all investigated catchments.

Despite abundant data on the early evolution of the Central Alps, the latest stage exhumation history, potentially related to relief formation, is still poorly constrained. We aim for a better understanding of the relation between glaciation, erosion and sediment deposition. Addressing both topics, we analysed late Pliocene to recent deposits from the Upper Rhine Graben and two modern river sands by apatite fission-track and (U-Th-Sm)/He thermochronology. From the observed age patterns we extracted the sediment provenance and paleo-erosion history of the Alpine-derived detritus. Due to their pollen and fossil record, the Rhine Graben deposits also provide information on climatic evolution, so that the erosion history can be related to glacial evolution during the Plio-Pleistocene. Our data show that Rhine Graben deposits were derived from Variscan basement, Hegau volcanics, Swiss Molasse Basin, and the Central Alps. The relations between glaciation, Alpine erosion, and thermochronological age signals in sedimentary rocks are more complex than assumed. The first Alpine glaciation during the early Pleistocene did not disturb the long-term exhumational equilibrium of the Alps. Recent findings indicate that main Alpine glaciation occurred at ca. 1 Ma. If true, then main Alpine glaciation was coeval with an apparent decrease of hinterland erosion rates, contrary to the expected trend. We suggest that glaciers effectively sealed the landscape, thus reducing the surface exposed to erosion and shifting the area of main erosion north toward the Molasse basin, causing sediment recycling. At around 0.4 Ma, erosion rates increased again, which seems to be a delayed response to main glaciation. The present-day erosion regime seems to be dominated by mass-wasting processes. Generally, glacial erosion rates did not exceed the pre-glacial long-term erosion rates of the Central Alps.

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