Heavy rainfalls in small basins: the flooding of Crotone (October 1996, Italy)

The hydrological analysis of the heavy meteorological storm characterised by high rainfall intensities and short duration, occurred in Esaro di Crotone basin (Calabria, Italy) on 14th October 1996, is shortly presented. The storm gave rise to the large flooding of Crotone that caused six deaths, the collapses of many infrastructures and severe damages to private and public buildings. From a statistical point of view, the rainfall frequency analysis provides the highest return periods for the short duration rainfalls. Nevertheless the frequency analysis of the peak flow, previously estimated through rainfall-runoff simulations, points to a return period more than twice the ones estimated for short duration rainfalls. This was due mainly to the increased capacity of the basin to form runoff when the 14.10.1996 storm occurred, since the high soil moisture content for the antecedent pluviometric conditions of the basin, as revealed by the rainfall and flood frequency analyses of some historical flood events caused by severe storms.