Assessing Groundwater Contribution to Streamflow of a Large Alpine River with Heat Tracer Methods and Hydrological Modelling

The contribution of groundwater to streamflow in Alpine catchments is still poorly understood, despite the fact that it may heavily impact hydrological balance and stream habitats. This paper presents the results of a field campaign based on experiments with heat tracer methods to assess the hyporheic flow during the low-flow period of a large Alpine river in Italy. These measurements were employed to validate a distributed hydrological model that can be used to asses river-groundwater interaction in both low-flow and high-flow conditions. The results show that groundwater may have a relevant role during low-flow periods, by increasing river discharge and during floods, by subtracting direct run-off that is stored in river banks