Flood risk assessment using an integrated hydrological and hydraulic modelling approach: a case study

This paper describes an integrated hydrological and hydraulic modelling approach for the risk assessment of a flood-prone area and its application to analysing the effects of extreme flood events on the Montalto di Castro thermoelectric power plant. The approach is based on four major steps. The first step entails a detailed analysis of available critical events as well the collection of hydro-meteorological and cartographic data to perform a statistical evaluation of extreme rainfall events and an estimation of the probable maximum precipitation (PMP). The second step involves the calibration of a rainfall—runoff model for the upper catchment area based on the data observed during a recent flood event. The third step involves the calibration of a two-dimensional hydraulic model for simulating the flood plain inundation using the previously reconstructed runoff and a comparison of the results with the maximum flood levels observed during the same event. The fourth and final step concerns the simulation by the two-dimensional hydraulic model of the flood wave obtained via the rainfall—runoff model using the extreme and PMP values of rain defined in the first step. The results of this approach appear to be extremely useful and easily transferable to other areas.