Quantifying impacts of climate variability and human activities on the streamflow of an Alpine river

In this study, we present a review of the current state-of-the-art research on streamflow alteration assessment, and examine the impact of climate variability and human activities on the natural streamflow of a tributary of Lake Maggiore (north-western Italy). The recent concept of climate elasticity of streamflow was used to indicate in which parameters the streamflow is more sensitive. First, a statistically identified change point was used to define the base period. Methods including hydrological sensitivity, climate elasticity and hydrological modelling then allowed us to estimate the anthropogenic and climatic effects on streamflow and to have an idea of the complicated non-linear relationship among streamflow, precipitation and temperature. Our results suggest that climate variability accounted for 85% of the decrease in streamflow. The remaining change could result from land cover-use change. The climate elasticity method used in this study could predict streamflow for future climatic change scenarios.