Author(s): Stefano Cipollini; Aldo Fiori; Elena Volpi

Linked Author(s): Stefano Cipollini, Aldo Fiori

Keywords: Hydraulic Structures; Design and Risk assessment; Offline reservoirs; Flood mitigation; Multivariate environment

Abstract: The design or risk assessment of hydraulic structures is in general a complex problem involving several processes and variables. (i) The probability of occurrence of the hydrological load to the system (Exposure), (ii) the intermediate processes and elements (e.g. hydrological-hydraulic load/structure interaction) that modify the exposures (Resistance), and (iii) the vulnerability of the considered area (Robustness), are the main descriptors of the problem at hand. The damage is the random variable that takes into account all the previous mechanisms, and represents the ultimate quantity that guides the design of a new structure or the assessment of an existing one. The complexity of the evaluation of the probability distribution of the damage is mainly linked to the number of random variables describing the hydrological load (e.g. peak and volume of the flood), and to the number of geometric parameters of the structure at hand. In this work we provide a general framework for hydraulic structure design (or risk assessment) using a structure-based risk approach, that combine the multivariate statistical representation of the hydrological process of interest and the hydraulic response of the structure to the environmental load. The framework allows to distinguish the statistical behavior of the failure mechanism form the one of the hydrological load (that are assumed equal in the traditional event-based approach) and it remarkably reduce the potential complexity of the whole system to the univariate statistical distribution of the damage, and then of the risk, i.e. its expected value. The framework is exemplified for an offline detention basin for flood mitigation, assuming a bivariate hydrological load acting on the system and several geometric parameters describing the structure. Moreover, the approach is applied adopting both a simplified analytical model and a Monte Carlo procedure. Results demonstrate the potential of the framework for the design and risk assessment of hydraulic structures reducing the general complexity of a multivariate problem. Moreover, the application of the approach for an offline detention basin provide a clear indication about the roles of the parameters involved.

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221283

Year: 2022