Integrating hydrological and hydrodynamic models in river flooding simulation system

A modelling system integrating hydrologic and hydrodynamic models for river flooding simulation and related risk evaluation is presented. The hydrological procedures take as input large scale rainfall rate, downscale the rainfall field with a multifractal model, and calculate a set of equally probable hydrographs at the outlet applying the SCS abstraction method and the Unit Hydrograph convolution. Synthetic hydrographs with given exceedance probability are derived and used as input of a two-dimensional, semi-implicit hydrodynamic model. Results of application of the modelling system to a river located in the south-eastern coast of Sardinia, Italy, are presented and discussed. Simulations were carried out to evaluate the effect of tide, wind, storm surge and structural works on the extension of flooded areas