Flood risk assessment and mapping in Abidjan district using multi-criteria analysis (AHP) model and geoinformation techniques, (cote d’ivoire)

TLDR

Flood is one of the most destructive natural disasters of climate change effects in West Africa, and its occurrence results from a combination of natural and anthropogenic factors, necessitating better spatial understanding. The aim of this paper is to identify and map areas of flood risk in Abidjan district. The study integrates slope, drainage density, soil type, Isohyet, population density, land use, and sewer density in ArcGIS and applies the Analytic Hierarchy Process to combine hazards and vulnerability for flood risk mapping. The AHP flood risk map shows that 34 % of Abidjan district is at high or very high risk, with eight of thirteen municipalities classified as high risk, indicating a heavy exposure to flooding.

Abstract

Flood is one of the most destructive natural disasters of climate change effects in West Africa. Flood risk occurrence is a combination of natural and anthropogenic factors, which calls for a better understanding of its spatial extent. The aim of this paper is to identify, and map areas of flood risk in Abidjan district. This work is based on the integration of multi-criteria data including slope, drainage density, type of soil, Isohyet, population density, land use and sewer system density within ArcGIS interface. The resulting AHP flood risk map shows that areas under high and very high flood risk covers 34 % of the study area. The Analytic Hierarchy Process (AHP) method used as a multi-criteria analysis allowed the integration of several elements under two criteria, hazards and vulnerability, for flood risk assessment and mapping. Results revealed that, Abidjan district is heavily exposed to the risk of flooding. Eight out of thirteen (8/13) municipalities within the district are at a high risk of flooding which calls for decision makers to effectively develop strategies for future flood occurrences within the Abidjan district (South of Côte d'Ivoire).