Integrated Methodology for Urban Flood Risk Mitigation in Cittanova, Italy

Abstract

Urban growth usually aggravates flooding problems, disrupting city life and requiring engineering works to ensure safety conditions to lower-lying city areas. Traditionally, canalization 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. In addition, local canalization practices tend to transfer flooding downstream in a nonsustainable way. In the last 8 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 multicriteria tool relating flood levels to socioeconomic 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 present flood risks and foresee future scenarios while supporting alternative design and prioritizing flood control choices. This framework was applied to Cittanova and validated by practical observations.