The development of simple methodologies for the management and risk assessment of flood events is a topic of interest for administrators, economists and engineers. In this paper, flood prone areas are identified on the basis of codified return periods of flood events, leading to the identification of appropriate river bands, relative to determining the most appropriate measures in territorial planning and risk mitigation. Hydraulic risk is determined by evaluating the expected damage to vulnerable elements -first and foremost anthropic elements -resulting from the occurrence of an event of known hazard. The risk is determined by means of matrixes that, even if characterized by intrinsic limitations, make it fairly straightforward to estimate a small number of parameters and hence evaluate risk level and attention level in flood phenomena.