Comparison Between Two GIS Flood Models of the Magra River

Floods are frequent and widespread phenomena with a devastating impact on the environment, infrastructures, buildings, croplands and, in the worst cases, involving animal and human lives. The paper focuses on this issue in a specific area in Italy: for this reason, at first it is illustrated a detailed analysis of the territory at the estuary of the Magra river, in the Liguria region, an area affected by this problem for a while. Then it is introduced a GIS river flood model developed with the software ArcGIS, with the support of a hydraulic model provided by the HEC-RAS software, which can be used in ArcGIS thanks to the HEC-GeoRAS component. This model is then compared to another one, provided by the University of Genova, and realized with the GRASS software, also with the support of a hydraulic model provided by the HEC-RAS package. The results show a good level of agreement. A further validation is also carried out with a comparison to the official expected flooding map provided by the Basin Authority and it shows to be quite satisfactory.