When does risk become residual? A systematic review of research on flood risk management in West Africa

This systematic review seeks to approach the notion of residual risk by reviewing information on flood impacts, common measures, and recommendations in academic literature. This review comes as flood events in West Africa have devastating impacts on the lives of people. Additionally, developments such as climate change, settlement expansion into flood-prone areas, and modification of rivers are expected to increase flood risk in the future. Policy documents have issued calls for conducting local risk assessments and understanding disaster risk in diverse aspects, leading to an increase in such research. Similarly, in a shift from flood protection to flood risk management (FRM), the consideration of various dimensions of flood risk, the necessity of addressing flood risk through an integrated strategy containing structural and non-structural measures, and the presence of residual risk are critical perspectives raised. However, the notion of “residual risk” remains yet to be taken up in FRM-related academic literature.

The review found that residual risk and its management are treated implicitly, if at all. An explicit focus is missing in the current FRM-related research carried out in West Africa and will deserve more attention in future. Also, the review identifies that FRM measures frequently comprise of infrastructural measures, maintenance activities, mutual support (in particular seeking support from the social environment), and the preparation/provision of assistance and response measures both before and after the most recent food event mentioned in case studies. Recommendations provided in selected documents to reduce residual food risk were mainly categorised as adjustments of policies, infrastructural measures, awareness-raising, training and education, and spatial planning interventions. Future studies could either embark on more complex modelling that approaches residual food risk by researching the synergies of FRM-measures, their limitations in reducing the risk of flooding, and the various dimensions of impacts that arise from it.