Floods in Abidjan and global changes at the neighborhood level

In Africa, floods have become “classic” hazards (David, 2004) due to climate change. If this trend continues, modeling predicts that in 2050 West Africa will experience a warming of 0.5 to 2 ° C with dramatic consequences. Galloping and poorly regulated urbanization amplifies urban runoff, exposure of the most precarious habitats and modifies the water cycle through massive deforestation and the modification of the destination of associated land uses (Montanari et al. 2013) , (Jourdan, 2019). Over a million and a half people are affected each year in Africa by flooding following heavy rains. Over the period from 2009 to 2014, there were a total of 74 deaths caused by flooding in the District of Abidjan.

In the framework of operational and scientific research actions around the updating of hydrological standards in West Africa (ActNAO Project) funded by the Institute of Research for Development, the University of Montpellier and the UNESCO ICIREWARD center, and in response to the WMO call, we carried out a study the aim of which is to define a method for characterizing the hydrological response of the watersheds of Abidjan in the face of intense rain, interpreting the states of surface and d 'land use, applicable at the level of the municipality and the district, and adapted to the nature and availability of data. The impact of past and future climate and land uses changes are studied. Ultimately, this study should make it possible to determine the runoff scenarios under various constraints of global changes and the conditions of resilience of the territory.