The use of a numerical model to evaluate flood hazard in a small catchment of central Italy; the role of anthropic pressure

Hydrogeological risk prediction and prevention are more and more reason of study and human and economic engagement of resources, from both scientific and professional world. Concerning the study of flood occurrences, catastrophic events recorded during last years in central Europe and locally in many other countries as in Italy, evidenced the importance of systematic approaches for their study, for a right interpretation and for a correct planning and management of fluvial systems. The present work represents one of the first attempts of flood event modeling in a small catchment of central Italy. Differently from other studies, also because of lack of detailed values concerning some fundamental parameters (i.e. thalweg geometry and effective infiltration value), numerical model has been here used only for estimate water maximum height during a flood, with the aim of recognize possible flooded areas; as a consequence, evaluation about flood peak propagation, water volume involved or damages on bridges, check dams etc., has been not considered. The correspondence between numerical model and real fluvial dynamics has been verified during a flood event whose maximum discharge has been estimated; this parameter, as well as extension of flooded areas, showed values similar to those of theoretical model. River discharge monitoring and considerations about flood event, allowed to evidence the influence of anthropization (hydraulic works and pumping wells along the river beds) on natural fluvial regime.