Author(s): Marco Pilotti; Gabriele Farina; Riccardo Bonomelli; Luca Milanesi

Linked Author(s): Marco Pilotti, Luca Milanesi

Keywords: Vulnerability; Risk mapping; Flood management; Hydraulic modeling

Abstract: The increasing economic and social impact of floods demands continuous efforts to implement effective countermeasures risk mitigation. In particular, floods in mountain areas often threaten human life that, accordingly, must be considered as the most exposed asset. In spite of the importance of this issue, risk assessment is still often based on vulnerability functions that link the hydraulic results and the damage to the exposed elements through crude conceptualizations devoid of any physical basis. We argue that the development of physically based vulnerability functions targeted to assess human safety is of paramount importance for providing a reliable estimate of the expected damage. Accordingly, we present three approaches that we have recently proposed in the literature to compute the vulnerability of people, cars and masonry buildings. All these elements are linked to human life since people can be directly impacted by floods or dragged away while driving. Finally, high energy flow like debris or dam break flows may have the potential to destroy buildings. A model to compute the limiting stability conditions of a person impacted by a flow was proposed by Milanesi et al. (2015). In this study, the human body was conceptualized as a set of cylinders, placed on a slope, impacted by a flow of given depth, velocity and density. The stability condition was defined by coupling equilibrium conditions to slipping, toppling and drowning. A similar approach was used by Milanesi and Pilotti (2019) to assess the stability of vehicles impacted by a flow. In this case, the geometry of the car is considered as a watertight squared prism at a fixed distance from the ground. The main novelty of this model, was the capability to estimate, from literature experimental data, a set of hydrodynamic parameters representative of the average stability conditions of a wide range of circulating vehicles. Finally, a physically based model to assess the stability of masonry buildings with load bearing walls (Milanesi et al., 2018) allowed to define the maximum water depth that can be supported by each wall of the building as a function its geometrical and structural configuration. The resulting stability curves are provided in dimensionless charts. Further, this model could be directly coupled with hydraulic numerical models to account for the real time removal of buildings during simulations. References Milanesi, L., Pilotti, M., Ranzi, R. (2015). A conceptual model of people’s vulnerability to flood, Water Resources Research, 51, 182– 197. Milanesi L., Pilotti, M., Belleri, A., Marini A., and Fuchs S. (2018). Vulnerability to flash floods: a simplified structural model for masonry buildings. Water Resources Research, 54, 7177– 7197. Milanesi L., and Pilotti M., (2019). A conceptual model of vehicles stability in flood flows, Journal of Hydraulic Research, 58(4).

DOI: https://doi.org/10.3850/IAHR-39WC252171192022458

Year: 2022