Beyond the Expected\u2014Residual Risk and Cases of Overload in the Context of Managing Alpine Natural Hazards

Sönke Hartmann,Stefan Schneiderbauer,Lydia Pedoth,Cristina Dalla Torre

doi:10.1007/s13753-020-00325-3

Abstract

Structural protection measures are designed to protect the population and infrastructure against natural hazards up to a specific predefined protection goal. Extreme events with intensities that exceed the capacity of these protection structures are called “cases of overload” and are associated with “residual risks” that remain after the implementation of protection measures. In order to address residual risks and to reduce the damages from overload events, a combination of structural protection measures with additional, nonstructural measures is required. Based on data collected through a literature review, a questionnaire survey, expert interviews, and an expert workshop we highlight the status quo as well as key challenges of dealing with residual risks and cases of overload in Alpine countries in the context of geohydrological hazards and gravitational mass movements. We present a holistic conceptual framework that describes the relationships of residual risks, cases of overload, and protection goals in the context of both risk governance and integrated risk management. This framework is valuable for decision makers aiming at an improved management of natural hazards that takes adequate account of residual risk and cases of overload in Alpine countries and mountain areas worldwide.

Highlights

Residual risk and cases of overload are still rather new and complex terms for most actors involved in risk management
We present a holistic conceptual framework that describes the relationships of residual risks, cases of overload, and protection goals in the context of both risk governance and integrated risk management
We carried out four main methodological steps that allowed us to work towards our defined objectives in a coherent and cumulative way: (1) a literature review to gain an extensive overview of risk management practices with respect to residual risk and cases of overload in the Alpine region; (2) development of a questionnaire to collect additional required data and information; (3) selected expert interviews; and (4) an expert workshop to identify research and management gaps, and possibilities to improve the management of residual risk and cases of overload in the context of natural hazards

Summary

Introduction

Residual risk and cases of overload are still rather new and complex terms for most actors involved in risk management. Several authors define residual risk as the risk that remains after the implementation of protection measures (Buchele et al 2006; Bornstein 2010; BAFU 2016a). How to address residual risk and cases of overload to ensure enough protection for society and infrastructure is a great challenge, in particular in the face of uncertainties related to climatic and sociodemographic changes. Geohydrological hazards such as river and torrential floods, as well as gravitational mass movements including rockfalls, avalanches, and landslides are common natural threats in the European Alpine region. Despite further measures during the twentieth century that were aimed at deflecting hazard processes away from residential areas, the amounts of loss and damage due Hartmann et al Beyond the Expected—Residual Risk, Cases of Overload, and Natural Hazard Risks to natural hazards and the investments necessary to protect society from them kept increasing

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