Assessing the environmental and social co-benefits and disbenefits of natural risk management measures.

Risk management measures (RMM) participate in the sustainability of cities and communities through the protection of these socio-eco-environmental systems against threatening events, and by ensuring system recovery. They include structural measures that are grey or green/blue solutions, or hybrid solutions combining the two former types. These measures can provide environmental and social co-benefits (e.g., improved biodiversity, recreational services) and disbenefits (e.g., the development of unwanted flora, concentrations of pollutants). The aim of this article is to provide an approach to assess and compare RMMs by considering these different dimensions. An application to three natural hazards - floods, coastal floods and wildfires - is proposed. The approach takes the form of a procedure to assess the co-benefits/disbenefits of the various RMMs and some technical specifications. It allows comparing the performances of one RMM against another and collectively discussing the choice of RMMs that takes into account a wide range of dimensions. The approach is based on the formulation of eight sustainability criteria and thirty-one indicators. The results were graphically displayed as several types of diagram: one radar chart per RMM, compiling all the indicators; one radar chart by type of risk studied (flood, wildfire and coastal flooding) based on averages of indicators per criterion; a table of the global score assigned to each RMM calculated with an arithmetic mean or a weighted mean. The approach relies on an interdisciplinary research team and involves end-users in a focus group for the validation step. This approach constitutes a transparent base for decision-making processes in the context of sustainable spatial planning against natural risks.

Confianza en la gestión pública del riesgo y dinámica social en caso de inundación / Trust in Public Risk Management and Social Dynamics in the Case of Flood Risk

Resumen El cambio climático está forzando a los expertos en inundaciones costeras a involucrar a los residentes en la prevención de riesgos, en particular, a través de comunicaciones oficiales que incluyen recomendaciones de comportamiento. Este estudio tiene como objetivo comprender la integración que hacen los residentes de esta información oficial en relación con el riesgo de inundación. Se realiza un estudio cualitativo sobre el postulado teórico que considera que la dinámica social que se crea entre los gestores de riesgos y los residentes ayuda a explicar la relación con el riesgo de inundación. Estas dinámicas se analizan a través del tipo de confianza que los residentes depositan en los actores públicos de la gestión y el nivel de conocimiento que afirman tener. Se realizaron 20 entrevistas semiestructuradas con residentes de una ciudad costera expuesta al riesgo de inundaciones, reclutados mediante el método de bola de nieve hasta el punto de saturación. Los resultados sugieren que los residentes que sienten tener poco conocimiento confieren confianza social a los gestores de riesgos y una visión positiva de las comunicaciones sobre este riesgo; mientras que los que sienten tener mucho conocimiento sobre las inundaciones apoyan una confianza calculadora sobre los aspectos técnicos de la gestión y una visión negativa de las comunicaciones. Estos tipos de confianza reflejan una relación con el riesgo de inundación anclado en el espacio social donde los grupos toman posición en la dinámica social. En este sentido, para ser eficaz, la comunicación preventiva debería tener en cuenta no solo el contenido real del mensaje sino también los mecanismos sociales que apoyan su interpretación, en particular la confianza entre el mensajero y el destinatario.

Abstract Climate change forces coastal communities exposed to floods to involve residents more actively in risk prevention, notably through official communication including behavioral recommendations. In order to improve prevention impact, this study aims to understand how inhabitants deal with this official information and integrate it into their relation to flood risk. This qualitative study is based on the theoretical postulate that the social dynamics nested in the relations between risk managers and inhabitants contributing to explain inhabitants' relationship to flood risk. These social dynamics are analysed through the type of trust granted by inhabitants to risk managers and the level of knowledge inhabitants state to have. 20 semi-structured interviews were conducted with inhabitants of a coastal city subject to flood hazards, recruited through snowballing method until saturation point. Results suggest that inhabitants who feel that they have little knowledge are prone to display social trust toward risk managers and a positive vision of communications provided on this risk, while those who are aware about floods, endorse a calculating trust based on the technical aspects of management, and eventually a form of distrust about communications delivered by public actors. These types of trust reflect a relation to flood risk embedded in the social space where individuals and groups take positions in social dynamics. In this sense and to be successful, preventive communication should consider not only the actual content of the message but also the social mechanisms that support its interpretation, in particular the trust between the messenger and the receiver.