Integration of Flood Losses in Risk Analysis

Abstract

Flood risk is generally defined as the combination of the probability of a flood event and the potential adverse consequences for human health, the environment, cultural heritage, and economic activities. Flood losses might be divided into two categories, namely tangible and intangible depending on whether or not the losses can be assessed in monetary values. Tangible losses are evaluated in monetary values and hence commonly incorporated in flood risk analysis. Generally, intangible losses are recorded by non-monetary measures such as the number of human lives lost or injured, and the square meters of ecosystems affected. To date, intangible losses are not or only partially incorporated in flood risk analysis due to the lack of appropriate and generally accepted evaluation and integration methods. This research focuses on the development of suitable methods to evaluate intangible losses and an integration method to incorporate these intangible losses with other tangible losses in an overall flood risk analysis. For this purpose, five categories of intangible losses are considered: loss of life, physical injuries, mental health impacts, cultural losses, and environmental losses. First, a comprehensive literature study is carried out in order to identify the available methods for the evaluation of all the aforementioned losses and their integration. Among the numerous methods available for the evaluation of the loss of life and physical injuries, the method proposed by Penning-Rowsell is selected and further developed for application in spatial analysis. A novel method is developed for the evaluation of mental health impacts, which includes the main causes for mental disorders of flood victims such as loss of family and friends, physical injuries, economic losses, and exposure to flooding. Moreover, for the evaluation of cultural losses, a new method is developed to consider not only the physical damage but also their cultural values. The ecosystem services approach is incorporated for the evaluation of environmental losses and a new method is developed to assess the loss of ecosystem services. A combined MAUT-AHP approach (Multi-Attribute Utility Theory–Analytic Hierarchy Process) is selected for the integration of losses within a multi-criteria analysis (MCA) framework, which includes the development of single-attribute value functions for the standardization of criteria. The developed methods are applied in two pilot sites in Germany as a case study conducted along with the Joint Research Project XtremRisK.