Future Trends in Coastal Flood Risk under Climate Change Scenarios along the Port-Bouët Bay (Cote D’ivoire)

Abstract

The increasing risk of coastal flooding in urban areas, driven by climate change and socioeconomic development, underscores the importance of accurate information for adaptation planning and risk mitigation. Yet, in Port-Bouët Bay, Cote d'Ivoire, there is a notable lack of comprehensive studies on coastal flood risk, despite it being a real and pressing concern. Existing research has predominantly focused on coastal erosion and overlooking key aspects like exposure and vulnerability when addressing coastal flood risk. These gaps hinder access to critical information necessary for effective action. Our research seeks to address these knowledge gaps by examining the spatial and temporal evolution of coastal flood risk over the current century using a systematic methodology. Using numerical and GIS-based modelling, empirical computations, statistical analysis, and index calculations, we derived meaningful insights from diverse data sources. Focusing on the neighbourhoods of Vridi, Petit-Bassam, and Sogefiha, our study was conducted at the neighbourhood scale. By incorporating all aspects of risk analysis—hazard, exposure, and vulnerability, we enabled a comprehensive analysis in these specific locations. Our findings reveal that current coastal flood events are linked to relatively high extreme sea level conditions, projected to escalate with rising sea levels. Consequently, flooding will directly affect more areas, populations, and key assets, with the flood-prone area expected to nearly double by 2100, particularly under the SSP5-8.5 scenario. Sogefiha emerges as the most vulnerable neighbourhood, facing higher susceptibility and potential damage than Vridi and Petit-Bassam. While current coastal flood risk appears relatively low based on risk component indices, future trends vary across neighbourhoods and climate change scenarios. By 2100, Vridi is anticipated to have very low risk, but a shift to high risk is conceivable under the SSP5-8.5 scenario. Conversely, Petit-Bassam is expected to sustain low risk under all scenarios, while Sogefiha may face high to very high-risk levels, particularly under SSP5-8.5. The present study provides decision-makers with tools and insights to understand coastal flood risk evolution in the Port-Bouët Bay. It also provides targeted recommendations for adapting to and mitigating coastal flood risks, as well as promoting sustainable coastal management in Côte d'Ivoire and the broader West African region.