A non-linear runoff generation model in small Alpine catchments

We present a simple non-linear hydrological model that conceptualizes the processes controlling runoff generation at the hillslope scale by using a pragmatic ‘‘downward” approach where only the most relevant processes are considered. The core of our model is the relationship between subsurface response and soil water content, which embeds the complex dynamics occurring at the hillslope scale and it is related to the external climatic forcing through the mass balance equation. We tested this model in four small Alpine catchments located in the North-Eastern part of Italy: the Prese Val karst spring, characterized by the absence of a surface river network; and three typical Alpine creeks: Fersina, Tresenga and Rio Rislá. We show that the model is able to reproduce the observed streamflow signals, despite meteorological data are sparse and uncertain. In particular, in all cases the model provides a good reproduction of the cumulative streamflow volume.