Individual decisions to adapt to flooding: the case of residents in flood-prone areas in southern France.

Summary In France, one inhabitant out of four is exposed to floods. In this thesis, we are interested in the mechanisms of individual adaptation to these natural risks. More precisely, we examined the influence of the characteristics of individuals and their situations with respect to risks on their adaptation decisions. To this end, we conducted a quantitative survey of 331 people living in flood-prone areas in the departments of Aude and Var. The questionnaire used in this survey was developed from the literature and from the analysis of an exploratory survey by semi-structured interviews. According to our results, the perception of the threat related to floods and the perception of the severity of the flood experienced have a positive effect on adaptation intentions, as described in the Protection Motivation Theory adapted to the flood domain (Grothmann and Reusswig, 2006). Our results also suggest the existence of a negative feedback of the implementation of a prevention measure on the perception of the flood threat. This suggests that empirically observed relationships between perceptions and past adaptation decisions should be viewed with caution. Furthermore, our results show a positive relationship between indicators of flood frequency and severity and respondents' perceptions of these characteristics. Because these perceptions have a positive effect on intention to adapt, this means that those most likely to adapt are those exposed to the most severe and frequent floods in the study sample. We also examined the relationships between perceptions and attitudes in the areas of financial and flood risk and investigated the influence of these variables on individual adaptation. To do so, we used the psychometric subscale concerning financial risks of the DOSPERT scale (Weber et al., 2002; Blais and Weber, 2006) and developed a psychometric subscale based on the same model, but concerning flood risks. The latter presents satisfactory internal and external consistency. Analysis of the data collected using the financial and flood risk subscales suggests that these two types of risk tend to compete. Thus, the importance that individuals place on financial risks relative to flood risks appears to have a negative effect on adaptation intentions. As a result, preventive measures cannot be considered as forms of self-insurance, which only reduce the risk of financial losses. Thus, our results suggest that individual adaptation depends, among other things, on individuals' perceptions and attitudes regarding financial risks, flood risks, but also on their perceptions regarding the means of adaptation to floods. According to the social amplification theory of risk (Kasperson et al., 1988), perceptions and attitudes can be modified by direct or indirect experience of a risk. Our results support the hypothesis that having experienced a flood alters perceptions and attitudes not only in the area of flood risk, but also in the area of financial risk. To examine the influence of indirect flood experience on individual coping, we developed a theoretical model that describes the relationships among the components that should be considered when studying the diffusion of coping within a social network. In particular, this model takes into account social interactions.