FLOODPLAIN MANAGEMENT STRATEGIES FOR FLOOD ATTENUATION IN THE RIVER PO

This paper analyses the effects of different floodplain management policies on flood hazard using a 350 km reach of the river Po (Italy) as a case study. The river Po is the longest Italian river, and the largest in terms of streamflow. The middle-lower Po flows East some 350 km in the Pianura Padana (PoValley), a very important agricultural region and industrial heart of Northern Italy. This portion of the river consists of a main channel (200–500m wide) and a floodplain (overall width from 200m to 5 km) confined by two continuous artificial embankments. Floodplains are densely cultivated, and a significant portion of these areas is protected against frequent flooding by a system of minor dykes, which impacts significantly the hydraulic behaviour of the middle-lower Po during major flood events. This study aims at investigating the effects of the adoption of different floodplain management strategies (e.g. raising, lowering or removing the minor dyke system) on the hydrodynamics of the middle-lower Po and, in particular, on flood-risk mitigation. This is a crucial task for institutions and public bodies in charge of formulating robust flood risk management strategies for the river Po. Furthermore, the results of this study are of interest for other European water-related public bodies managing large river basins, in the light of the recent European Directive 2007/60/EC on the assessment and management of flood risks. The analysis is performed by means of a quasi-2D hydraulic model, which has been developed on the basis of a laser-scanning DTM and a large amount of calibration data recorded during the significant flood event of October 2000