INTEGRATED METHODOLOGY FOR URBAN FLOOD RISK MITIGATION IN CITTANOVA, ITALY

Urban growth usually aggravates flooding problems, disrupting city life and requiring engineering works to ensure safety conditions to lower lying city areas. Traditionally, canalisation works were the preferred choice for flood mitigation. However, increased city growth limits the effectiveness of this approach due to the lack of free spaces and local canalisation practices tend to transfer flooding downstream in a non-sustainable way. In the last eighty years, the town of Cittanova, in the province of Reggio Calabria (Italy), has been subjected to several flooding events related to river overflows or storm drain failures causing significant damages to mobility, households and even to public safety. This paper focuses on the Forio Creek, which is a tributary of the Vacale River and runs through the city. The study was carried out using mathematical tools within a conceptual framework with the aim of mapping floods to prevent damage to the city and avoid future losses, thus reducing risks. MODCEL was the hydrodynamic model used to map urban floods and to support the use of the Flood Risk Index (FRI), which is a quantitative multi-criteria tool relating flood levels to socio-economic losses. Both the MODCEL and the FRI were previously available, but their combined use and the final integrated analyses carried in this paper introduce a simple and quantifiable flood risk procedure to identify the present flood risks and to foresee future scenarios whilst supporting alternative design and prioritizing flood control choices. This framework was applied to Cittanova and validated by practical observations.