6. Workshop Alpine Hydrologie

Changes in winter precipitation, snow accumulation and the timing of snowmelt affect streamflow responses and groundwater storage, to which, for instance, summer low flows can be sensitive. Previous studies have examined the effects of snow cover on the groundwater storage dynamics in specific mountainous catchments, others examined the long-term annual changes in groundwater levels without explicit consideration of snow.

In this study, we use a dataset combined by CAMELS-CH catchments and quality-checked groundwater level data situated in or close to these catchments. The catchments cover different hydrological regimes, ranging from snow dominant, over transient to rain dominant. With this dataset, we aim to gain a better understanding of how the groundwater dynamics respond to changes in snow accumulation and snowmelt timing and how well we can simulate that with a conceptual hydrological model. For this we use simulations of the semi-distributed hydrological model HBV and evaluate them against the observed groundwater level data. For the catchments where the simulations are insufficient to capture groundwater dynamics, we look specifically at the reasons why. For example, there might be a close interaction between surface water and groundwater which is not represented in the model, or the groundwater dynamics are part of a larger system and disconnected from the fast processes within the catchment. For the catchments where the simulations are sufficient, the model set-up can be used to study how future changes in snow may affect catchment storage.