Baseflow index characterization in typical temperate to dry climates: conceptual analysis and simulation experiment to assess the relative role of climate forcing features and catchment geological settings

Low-flow hydrological features are crucial for efficient development and integrated water resources management. Among others, the BaseFlow Index ‘BFI’ is one of the most important low-flow indices. Many studies have demonstrated that it is related to several topographic parameters, climate, vegetation and soil types and to catchment geology. With the aim to enhance the knowledge about the climate and catchment properties’ relative control on the ‘BFI’, an approach consisting of an empirical analysis, applied to a large area located in Southern Italy, characterized by a typical Mediterranean environment, is followed by a simulation experiment, considering climate settings, at the pan-European scale, typical of temperate to dry climate regimes. Main findings have revealed that (i) the correlation structure between the ‘BFI’ and the precipitation volume, at the annual scale, is affected by both climate variability and catchment properties; (ii) the ‘BFI’ variability is strongly conditioned by climate intra- and inter-annual variability; (iii) the major role is, however, assigned to the geological catchment features, with poorly and well-drained catchments behaving differently in response to similar climate forcing variability.