ASSESSMENT OF CLIMATE CHANGE ON FLOOD ANALYSIS ON RIVER BENUE BASIN AND ITS EFFECT ON THE LIVELIHOODS

Abstract

Flooding is a recurrent and increasingly severe hazard in the River Benue Basin of Nigeria, driven by intense seasonal rains and upstream dam releases. This study analyzes the spatial and temporal patterns of climate change on flooding in the Benue Basin from 2016 through 2025, with particular focus on peak flood seasons (August and September) in 2016–2025. High-resolution Sentinel-1 Synthetic Aperture Radar (SAR) imagery was processed in the Google Earth Engine (GEE) platform to map annual flood inundation extents. These flood maps were used to assess flood frequency and impacts by overlaying population, cropland, and urban land cover data. The results reveal that the Benue Basin experienced flooding every year in the study period, with a clear intensification of flood magnitude in recent years. The September 2022 flood was by far the most extreme event recorded, inundating over 2,633 km² and exposing approximately 725,500 people to floodwaters; it also submerged 587 km² of cropland and 84 km² of urban land. Other severe floods occurred in 2018, 2020, 2023, and 2024, whereas 2016 and 2019 saw relatively modest flood extents. In every year, September floods were substantially larger than those in August, reflecting peak rainfall and river discharge late in the rainy season. These findings underscore that changing climate patterns (increasing rainfall variability) and dam management practices (such as Lagdo Dam releases) are exacerbating flood frequency and severity. The use of SAR imagery and cloud-based GIS processing proved crucial for timely, accurate flood monitoring and hotspot mapping. The insights from this study have important implications for flood risk management, informing early-warning systems, land-use planning, and community preparedness in the Benue Basin.