The water balance in high Alpine regions in its full complexity is so far insufficiently understood. High altitudinal gradients, a strong variability of meteorological variables in time and space, complex hydrogeological situations, unquantified lateral snow transport processes and heterogenous snow cover dynamics result in high uncertainties in the quantification of the water fluxes and storage terms. The investigation area of this project is the Berchtesgaden National Park (Bavarian Alps, Germany). The region is characterized by an extreme topography with mountain ranges covering an altitude from 603 to 2713 m a.s.l. About one quarter of the investigated catchment is terrain steeper than 35°. Due to water soluble limestone being predominant in the region, a high number of subsurface water pathways (karst) exist.
Within the scope of the project WaterNPB, a cooperation of IMK-IFU, the Department of Geography and Regional Science of the University of Graz, and the Administration of the Berchtesgaden National Park, a distributed hydrological model will be applied. The two subprojects SnowNPB (IMK-IFU) and KarstNPB (University of Graz) are intended to explore and analyze the water balance in the Berchtesgaden Alps with a special focus on snow cover dynamics and groundwater flow. A deterministic hydrological model system is implemented to analyze surface and subsurface water processes. The model is optimized and extended to account for the determining hydrological processes in the region. The new model system is forced with scenario data sets of a regional climate model to assess the possible impacts of a changing climate to the regional water balance and to the future availability of water resources.
Snow NPB - Snow cover dynamics and water balance in complex high Alpine terrain
The dynamics of the snow cover and the respective water fluxes highly affect the hydrology of Alpine regions. High altitudinal gradients and small scale orographic effects cause a large temporal and spatial variability of meteorological variables that force the development of the snow pack. A main driver of snow accumulation and ablation processes in complex terrain is the lateral redistribution of snow caused by wind and gravitation. These processes lead to a highly variable distribution of snow on different spatial scales. The integration of a new snow module into an existing hydrological land surface model is supposed to improve the modelling of water fluxes influenced by snow accumulation and ablation, and to analyze its impacts on the local and regional hydrology. We complement the deterministic hydrological model WaSiM-ETH with principles of the high Alpine specific snow model AMUNDSEN. The new approach is based on the calculation of energy fluxes at the snow cover considering terrain-dependent radiation fluxes and lateral snow transport processes.
The subproject KarstNPB aims at understanding the groundwater system of the catchment and at improving the groundwater component of the applied hydrological model. This part of the project is carried out by the Department of Geography and Regional Science, University of Graz.
Berchtesgaden National Park Administration (Helmut Franz)
Department of Geography and Regional Science, University of Graz (Prof. Dr. Ulrich Strasser, M.Sc. Gabriele Kraller)
Landesamt für Umwelt, Hydrogeologie (Dr. Günter Kus)