Geographic Information System-Based Multi-Criteria Decision Analysis of Flood Risk Zones in Madagali, Adamawa State, Nigeria

Abstract

The main purpose of this research was to apply geospatial methods to map flood risk zones within Madagali Local Government Area in Adamawa State of Nigeria towards developing enhanced measures for flood risk mitigation. Core variables assessed included topographic elevation, land use/land cover dynamics, rainfall variability, and characteristics of the drainage network. The study combined Landsat 8 satellite images, Digital Elevation Models (DEMs), and rainfall data using Multi-Criteria Decision Analysis (MCDA) with a weighted overlay method to assess flood susceptibility in the study area. The results indicate that approximately 35% of the study area is situated within high to very high flood risk categories, predominantly low-lying areas subject to intensive land-use patterns and variability in rainfall distributions. The vulnerability assessments undertaken in this study revealed distinct classifications such as: 18.53% of areas exhibit low vulnerability, 30.50% moderate vulnerability, 52.8% high vulnerability, and 60.7% very high vulnerability.  In conclusion, the geospatial methods applied in this study provide evidence-based insights for policymakers thereby, supporting effective flood risk management and enhancing community resilience within Madagali Local Government Area. Key recommendations emerging from this study underscore the need for stakeholders to pursue afforestation interventions, river channel maintenance, development of contextually appropriate hydraulic infrastructure, and drainage infrastructure near Madara Mountain which can serve dual purposes of flood mitigation and dry-season agricultural water storage.