Large-scale stochastic flood hazard analysis applied to the Po River

A Curran,Karin De Bruijn,Alessio Domeneghetti,Sergiy Vorogushyn,Attilio Castellarin,Federica Bianchi,M Kok

doi:10.1007/s11069-020-04260-w

Abstract

Reliable hazard analysis is crucial in the flood risk management of river basins. For the floodplains of large, developed rivers, flood hazard analysis often needs to account for the complex hydrology of multiple tributaries and the potential failure of dikes. Estimating this hazard using deterministic methods ignores two major aspects of large-scale risk analysis: the spatial–temporal variability of extreme events caused by tributaries, and the uncertainty of dike breach development. Innovative stochastic methods are here developed to account for these uncertainties and are applied to the Po River in Italy. The effects of using these stochastic methods are compared against deterministic equivalents, and the methods are combined to demonstrate applications for an overall stochastic hazard analysis. The results show these uncertainties can impact extreme event water levels by more than 2 m at certain channel locations, and also affect inundation and breaching patterns. The combined hazard analysis allows for probability distributions of flood hazard and dike failure to be developed, which can be used to assess future flood risk management measures.

Highlights

1.1 Flood risk analysis and research objectiveEach year flooding causes the most damage of any natural disaster (Jongman et al 2012) and, as such, many Flood Risk Management (FRM) strategies employ a risk-based Germany1 3 Vol.:(0123456789)Natural Hazards (2020) 104:2027–2049 approach (Voortman et al 2009), where risk is the combination of exposure and hazard
The purpose of this analysis is to compare hydraulic loads under deterministic hydrological boundary conditions (Tr500) to those observed from the stochastic boundary conditions developed using the Gaussian copula and the SMHI data
As the synthetic design hydrographs (SDHs) in the Tr500 boundary condition are developed in such a way to reproduce the 500 year return period event at every point along the main channel, the water levels from the Det_Hyd500 simulation can be directly compared to the 500 year return period water profiles from Var_Hyd

Summary

Introduction

1.1 Flood risk analysis and research objectiveEach year flooding causes the most damage of any natural disaster (Jongman et al 2012) and, as such, many Flood Risk Management (FRM) strategies employ a risk-based Germany1 3 Vol.:(0123456789)Natural Hazards (2020) 104:2027–2049 approach (Voortman et al 2009), where risk is the combination of exposure and hazard (with its associated probability). Hydraulic models used to analyse flood hazard and other hydraulic aspects of protected river systems have been developed for the Elbe (Merz et al 2016), the Rhine (Hegnauer et al 2014), the Mississippi (Remo et al 2012), and the Po River in Italy (Castellarin et al 2011), amongst others. Such models are often used to calculate the location-specific hydraulic load associated with a given probability or return period (Vogel and Castellarin, 2017). They are applied to the Po River case study, and the results discussed

Results

Discussion

Conclusion