Evaluating Urban Flood Vulnerability in Benin City Using GIS and Remote Sensing

Benin City in Edo State experiences recurrent urban flooding due to a combination of inadequate drainage infrastructure, high impervious surface coverage, and intense convective rainfall. This study evaluates urban flood vulnerability in Benin City using an integrated GIS and remote sensing framework. Sentinel-2 imagery is classified to produce impervious surface and green cover maps at 10-metre resolution. SRTM-derived topographic attributes including slope, flow accumulation, and depression storage are integrated with drainage network data and rainfall intensity records. A composite flood vulnerability index is constructed from physical exposure indicators including elevation, slope, impervious fraction, and drainage proximity combined with socioeconomic sensitivity indicators including poverty rates and housing quality. Ward-level vulnerability scores are spatially analysed to identify priority intervention zones. Results classify 28 percent of Benin City's residential wards as highly vulnerable, concentrated in the GRA and Oliha areas characterised by low elevation and poor drainage capacity. The study recommends drainage infrastructure investment priorities for the Edo State Ministry of Works. Keywords: urban flooding, vulnerability assessment, GIS, Benin City, impervious surface