Quantification of flood risk mitigation benefits: A building-scale damage assessment through the RASOR platform. (1st February 2018)

• Record Type: Journal Article
• Authors: Arrighi, Chiara; Rossi, Lauro; Trasforini, Eva; Rudari, Roberto; Ferraris, Luca; Brugioni, Marcello; Franceschini, Serena; Castelli, Fabio
• Is Part Of: Journal of environmental management. Volume 207(2018)
• Page Start: 92
• Page End: 104
• Publication Date: 2018-02-01
• Subjects: Cost-benefit analysis -- Exposure -- Recovery cost -- Retention basin -- GIS; Environmental policy -- Periodicals; Environmental management -- Periodicals; Environment -- Periodicals; Ecology -- Periodicals; 363.705
• DOI: 10.1016/j.jenvman.2017.11.017
• Languages: English
• ISSNs: 0301-4797

Abstract

Abstract: Flood risk mitigation usually requires a significant investment of public resources and cost-effectiveness should be ensured. The assessment of the benefits of hydraulic works requires the quantification of (i) flood risk in absence of measures, (ii) risk in presence of mitigation works, (iii) investments to achieve acceptable residual risk. In this work a building-scale is adopted to estimate direct tangible flood losses to several building classes (e.g. residential, industrial, commercial, etc.) and respective contents, exploiting various sources of public open data in a GIS environment. The impact simulations for assigned flood hazard scenarios are computed through the RASOR platform which allows for an extensive characterization of the properties and their vulnerability through libraries of stage-damage curves. Recovery and replacement costs are estimated based on insurance data, market values and socio-economic proxies. The methodology is applied to the case study of Florence (Italy) where a system of retention basins upstream of the city is under construction to reduce flood risk. Current flood risk in the study area (70 km 2 ) is about 170 Mio euros per year without accounting for people, infrastructures, cultural heritage and vehicles at risk. The monetary investment in the retention basins is paid off in about 5 years. However, the results show that although hydraulic works are cost-effective, a significant residual risk has to be managed and the achievement of the desired level of acceptable risk would require about 1 billion euros of investments. Highlights: The assessment of residual flood risk and costs of achieving acceptable risk is described. Flood risk is estimated at building-scale. Flood exposure is extensively characterized by merging several sources of open GIS data. Residual risk and benefits of hydraulic works are evaluated for a case study.