“Analyses on the spatial variability of hydrological losses during flood events”

In the framework of studies dealing with the development of flood return period esti- mation procedures, the recent scientific research is aimed to confer physical meaning to the probabilistic model parameters, in order to supply objective methods based on the physical and climatic information. In addition, it is a consolidated idea that the knowledge of climate-soil-vegetation interaction represents an essential factor in un- derstanding hydrological processes. In this fashion, the remote sensing technique and the geographical information systems play an important role to improve the environ- mental monitoring reliability. In this view, particular attention is paid to the descrip- tion of thematic maps of vegetational coverage (by using the NDVI index), geology, pedology and digital elevation models (DEM). In the present work the possibility to estimate, on physical bases, the parameters of the theoretical probabilistic model pro- posed by Iacobellis and Fiorentino (Water Resour. Res., 36(2), 469-482, 2000), has been considered. In particular, we investigated the impact of the geomorphological, physical and climatic characteristics with respect to: i) the variability of the expected value of the source areas contributing to the flood peak discharge; ii) the characteristic hydrological losses; iii) the spatial variability of the expected value of the annual number of independent events. The analyses have been carried out over a large area in southern Italy comprising basins of Puglia and Basilicata. These catchments are characterised by strong vari- ability in climate ranging from humid to arid moving from South-West to North-East.