A spatio-temporal analysis of the risks of flooding and landslides in Greater Abidjan, Ivory Coast, by applying a multi-risk framework. Analyse spatio-temporelle des risques d'inondation et de glissement de terrain dans le Grand Abidjan, Côte d'Ivoire, par l'application d'un cadre multirisque. En Fr

Résumé En

Most scientific research acknowledges the overall complexity of the interaction mechanisms between different natural hazards, as well as complex interdependencies with societal drivers such as exposure and vulnerability. Comprehensive understanding of multi-risk dynamics remains crucial for sustainable development in many parts of the world. Moreover, the integration of multi-risk approaches into the planning and implementation of adaptation, resilience and disaster risk reduction measures remain a priority, specifically in developing countries.Located in West Africa, Ivory Coast faces recurring floods and landslides, mainly due to heavy rainfall during the rainy season. These hazardous events have significant consequences, particularly in coastal urban areas such as Greater Abidjan, where continued and uncontrolled urbanization increases disaster risk, as highlighted in the Disaster risk profile of Ivory Coast by UNDRR in 2019. In this context, a multi-risk approach is essential to deal with the complexity of these interacting threats and their interdependencies with dynamic social and demographical conditions. The limited availability of open disaster risk data, such as the ‘Desinventar’ database endorsed by the UNDP and UNDRR, hinders a comprehensive assessment of risks in the country, particularly in Greater Abidjan, the most populated area. In addition to this gap, there is minimal research focused on conducting a multi-risk analysis on the scale of Greater Abidjan.By applying the multi-hazard impact framework developed by De Angeli et al. (2022), we seek on the one hand to carry out a multi-hazard assessment with an emphasis on the causal dependencies between heavy rains, floods and landslides. In a second part, we carry out an assessment of the impact of these hazards, focusing on their spatial and temporal evolution, by including an assessment of the physical vulnerability of the built environment and the socio-economic vulnerability of affected populations. Our research draws on various georeferenced data sources, including historical meteorological data, satellite images, digital elevation models, as well as field surveys. These sources enable an in-depth understanding of the spatial and temporal dynamics of flood and landslide risk in the region.