Today, resilience in the face of cyclone risks has become a crucial issue for our societies. With climate change, the risk of strong cyclones occurring is expected to intensify significantly and to impact the way of life in many countries. To meet some of the associated challenges, the interdisciplinary ReNovRisk programme aims to study tropical cyclones and their impacts on the South-West Indian Ocean basin. This article is a presentation of the ReNovRisk programme, which is divided into four areas: study of cyclonic hazards, study of erosion and solid transport processes, study of water transfer and swell impacts on the coast, and studies of socio-economic impacts. The first transdisciplinary results of the programme are presented together with the database, which will be open access from mid-2021.

Abstract. Estimating flood damage, although crucial for assessing flood risk and for designing mitigation policies, continues to face numerous challenges, notably the assessment of indirect damage. It is widely accepted that damage other than direct damage can account for a significant proportion of total damage. Yet due to scarcer data sources and lack of knowledge on links within and between economic activities, indirect impacts have received less attention than direct impacts. Furthermore, attempts to grasp indirect damage through economic models have not gone below regional levels. Even though local communities can be devastated by flood events without this being reflected in regional accounts, few studies have been conducted from a microeconomic perspective at local level. What is more, the standard practices applied at this level of analysis tackle entities but ignore how they may be linked. This paper addresses these two challenges by building a novel agent-based model of a local agricultural production chain (a French cooperative wine-making system), utilized as a virtual laboratory for the ex ante estimation of flood impacts. We show how overlooking existing interactions between economic entities in production chains can result in either overestimation (double counting) or underestimation (wrong estimation of the consequences for the activity) of flood damage. Our results also reveal that considering interactions requires thorough characterization of their spatial configuration. Based on both the application of our method and the results obtained, we propose balanced recommendations for flood damage estimation at local level.

The evaluation of potential damage of future floods is an essential part of flood management project appraisals. Analysis results reliability is an important issue when comparing flood risk reduction project scenarios. Geographic Information System (GIS) technology plays a crucial role on flood risk analyses. On one hand, the evaluation process requires data on flood hazard and on vulnerability of assets at risk, both spatial data. On the other hand, this data must be combined in order to evaluate flood risk. Even though the role of GIS is central in the evaluation process, GIS software does not offer specific tools for achieving flood damage analysis. The use of standard methods for assessing and combining different data influences accuracy and comparability of evaluation results. Few countries in the world have developed national standard methods to assess flood damage potential. The construction of GIS-based methodologies and GIS models can be the first step toward standardisation of the whole evaluation process. In this purpose, this article presents the development of a GIS tool for evaluating future flood damage potential: F.R.A. GIS tool extension, for use with ArcGIS (ESRI). It first explains how GIS technology is used in flood risk analysis procedures. Then, the tool pre-and post-functions as well as structure of the model are detailed. Finally, a brief case study is presented in order to illustrate the functionalities of the model developed in this article. The methodology described here can be used to guide analysts on the realisation or the automation of flood risk analysis using other GIS software.