Groundwater storage in high Alpine catchments and sensitivity to climate change

High alpine areas are highly sensitive to climate change. Corresponding studies suggest a general decrease in snow accumulation and a shift of snow-influenced discharges towards earlier periods of the year, which can be combined with warm and dry summers. The magnitude of change of discharge dynamics in alpine areas will most likely be influenced by groundwater storage and its buffering capacity. However, hydrogeological data are very limited in these areas mainly because they are difficult to access during half of the year. The dynamics of alpine discharge generating processes remain therefore poorly understood. A high alpine catchment located in the Swiss Alps has been followed during several years and the knowledge acquired by the combination of geochemical and hydrological data, geological observations and water balances allows the development of a simplified hydrogeological model. This model is then run with recent climate change scenarios for Switzerland (CH2O18) to determine how groundwater will influence discharge regime changes. The link with geology will then be highlighted and the implications for water management at larger scale will be discussed.