FLOOD SUSCEPTIBILITY MAPPING USING THE GEOGRAPHIC INFORMATION SYSTEM AND ANALYTIC HIERARCHY PROCESS TECHNIQUE: CASE OF OUAGADOUGOU MUNICIPALITY IN BURKINA FASO

Abstract

Ouagadougou is highly exposed to the risk of natural disasters such as flooding as a result of poor
urban planning, the physical environment and climate change. The aim of this study is to use
remote sensing and Geographic Information System (GIS) tools combined with multi-criteria
analysis using Saaty's AHP method to map flood-prone areas in the municipality of Ouagadougou.
The methodological approach adopted is a combination of GIS and Saaty's AHP analysis method.
Seven decision criteria considered to be risk factors were selected. These are the hydrographic
network, altitude, slope, rainfall, soil types, land use and soil moisture index. These various factors
were mapped and classified using the open source software QGIS; standardised, prioritised and
aggregated in a GIS environment and analysed using the AHP method. The results obtained show
the map of different flood susceptibility zones in the Ouagadougou municipality. These flood
vulnerability zones were classified into five classes of flood susceptibility zones. These are zones
of very low vulnerability to flooding (24.48%), low vulnerability (27.93%), medium vulnerability
(23.01%), high vulnerability (17.11%) and very high vulnerability (7.47%). Since data is the
foundation of GIS application studies, we suggest collecting and regularly updating satellite
images, making high-resolution and precise drone images available for the Ouagadougou
commune, creating a free-access data geoportal, and training and raising awareness among
professionals and disaster managers about the effective use of data. It will also enhance their
technical skills in risk mapping and spatial analysis. This work is a real decision-making tool for
the management, prevention and mitigation of flood disaster risks in the Ouagadougou
municipality.