A Probabilistic Framework for Risk Analysis of Widespread Flood Events: A Proof‐of‐Concept Study

Abstract

This article presents a flood risk analysis model that considers the spatially heterogeneous nature of flood events. The basic concept of this approach is to generate a large sample of flood events that can be regarded as temporal extrapolation of flood events. These are combined with cumulative flood impact indicators, such as building damages, to finally derive time series of damages for risk estimation. Therefore, a multivariate modeling procedure that is able to take into account the spatial characteristics of flooding, the regionalization method top-kriging, and three different impact indicators are combined in a model chain. Eventually, the expected annual flood impact (e.g., expected annual damages) and the flood impact associated with a low probability of occurrence are determined for a study area. The risk model has the potential to augment the understanding of flood risk in a region and thereby contribute to enhanced risk management of, for example, risk analysts and policymakers or insurance companies. The modeling framework was successfully applied in a proof-of-concept exercise in Vorarlberg (Austria). The results of the case study show that risk analysis has to be based on spatially heterogeneous flood events in order to estimate flood risk adequately.

Sources of uncertainty in a probabilistic flood risk model

“…flood defence planning 100 years; solvency consideration of insurers 200 years.) (Schneeberger et al , 2017. In contrast to the methodology of risk curves (e.g.…”

Generation of Spatially Heterogeneous Flood Events in an Alpine Region—Adaptation and Application of a Multivariate Modelling Procedure

“…Besides the generation of synthetic flood events, the adverse consequences of flooding have to be quantified (e.g., the monetary damage of buildings) and the overall flood risk within a region has to be assessed. Schneeberger et al [33] introduces a probabilistic framework for risk analysis, which takes into account all relevant aspects and requires a set of spatially distributed flood events.…”

“…The severity of events can be determined using the proxy called unit of flood hazard (UoFH) [33,39]. The UoFH is defined as the number of sites that experience runoff that equals or exceeds a certain threshold i.e., a runoff that corresponds to aspecific T).…”

“…Thus, a probabilistic flood risk analysis model was developed to analyse the risk of flooding. The model consists of three major modules: (i) a hazard module where a data set of synthetic flood scenarios is generated which serves as surrogate to determine the probability of widespread flooding; (ii) an impact module with results being loss-probability-relations on a community level representing the potential flood damages; and (iii) a risk assessment module in which the probability of flood risk in the study area is evaluated statistically [33]. The present paper focuses on the generation of spatially heterogeneous flood events.…”

Advances in Spatial Risk Analysis

“…The article provides a review and a taxonomy of a wide variety of available modeling techniques, as well as recommendations to guide the choice of an appropriate model for a given context. Schneeberger et al (2019) provide a proofof-concept study on the use of a probabilistic framework for risk analysis of widespread flood events. The study introduces a flood-risk modeling framework consisting of three components: a hazard module for the expected water levels for all points in the considered area; an impact module is used to characterize potential adverse consequences of flooding; a risk assessment module combines the results to calculate expected and maximum values of flood impact indicators.…”