Urban resilience against natural disasters: Mapping the risk with an innovative indicators-based assessment approach

The increase in the frequency and intensity through which natural disasters have hit cities in the last twenty years has created the need to prefigure a model of sustainable urban development not only consistent with the goals promoted by the Agenda 2030, but also efficient in the regulation of the main cause of the natural disasters: consumption of natural soil. Therefore, the aim of the research is to define an indicators-based methodology for determining a synthetic natural risk index, which represents the degree of territorial exposure to multiple natural disasters in the different sub-urban areas within a vulnerable city. The proposed methodology is structured into eight sequential and ordered phases that comply a system of 23 indicators for the three main components of natural risk (hazard, exposure and vulnerability). Their importance is accounted in the final aggregation of the index through the application of the Analytic Hierarchy Process multi-criteria evaluation technique. The validated results achieved by the application of the proposed methodology to the city of Rome (Italy), represented in a georeferenced map of the risk level of natural disasters, allow to immediately identify the most critical suburban areas on the west coast of the “Tevere” river. The proposed risk index may be useful for public and private subjects involved in the predisposition of sustainable urban plans and projects, aimed at improving the level of urban resilience connected to natural disasters aggravated by land consumption. In this way the targets of Goals n.13 “Reducing climate change” and n.15 “Life on Earth” of the Agenda 2030 can be applied at the suburban scale.