Risk flood areas, a study case: Basilicata Region

Recent hydrological events have increased both public interest and that of the Scientific Community in a more accurate study of flooding areas. The aim of this work is to define the inundation risk along the main rivers of the Basilicata Region in order to create flooded area maps for different flow rates corresponding to different return periods. Three different software have been used for hydrodynamic simulation: Hec Ras (River Analysis System) produced by United States Army Corps of Engineers River Analysis System and developed by the Hydrologic Engineering Center, Mike 11 produced by the Danish Hydraulic Institute, and Mike 21 bi-dimensional model produced by the Danish Hydraulic Institute to compare the different behaviour of the models and evaluate the most suitable. The simulations have been carried out on more then 1500 river cross sections to define the geometric characteristics of streams. Peak flows with 30 year, 200 year and 500 year return periods have been considered as upstream boundary conditions, and for the bi-dimensional simulations, data was surveyed with laser scanning techniques. The integration of hydrodynamic models and very detailed data, such as laser scanning data, is very difficult and requires a great deal of pre-processing. Here we have put forward a method of integration.The water surface elevation and top width achieved in riverbeds for each simulation has been used with GIS software to draw the different flooded area maps.