Flood risk assessment of the river Benue catchment in Adamawa State Nigeria

Abstract

Floods are one of the most devastating natural disasters that occur globally, causing loss of life and property. Adamawa, a state located in north-eastern Nigeria, is prone to flooding due to its location within the floodplains of the River Benue. The research examines the spatial distribution of flood risk, the role of altitude in determining flood risk levels, and the implications for population exposure. The investigation was carried out in the following local government areas, namely Yola-South, Demsa, Numan, Lamurde, Guyuk, Shelleng and Song. The study used a combination of remote sensing and geographic information systems (GIS) techniques to analyze the flood risks extent and exposure within the catchment. SRTM 30 Meters resolution Digital Elevation Model (DEM) data was used to derive catchment boundaries, stream networks and watershed characteristics. 500 years return period flood hazard raster along with a population raster of the settlements within the region of interest were also used. The findings reveal varying flood risk extents, with areas at lower elevations exhibiting higher flood risks. Additionally, the study identifies specific wards within each locality that are situated in different flood risk zones, highlighting the need for localized flood risk assessments. The results demonstrate a correlation between flood risk levels and the percentage of the population exposed to these risks. The study aligns with existing literature on flood risk, altitude, and population vulnerability, emphasizing the importance of considering these factors in flood risk management strategies. The findings contribute to a better understanding of flood risk patterns and can guide policymakers and stakeholders in implementing targeted interventions and developing effective disaster response plans. However, it is essential to contextualize the findings within the specific study areas and complement them with site-specific assessments and further research.