Mapping of Flood-Prone Areas Along the Benue River Corridor Using GIS

The Benue River is one of Nigeria's major tributaries of the Niger and is responsible for annual flooding that affects communities across Benue, Anambra, Delta, and Kogi states. This study maps flood-prone areas along a selected 200-kilometre stretch of the Benue River corridor using GIS integration of hydrological, topographic, and land use data. SRTM digital elevation model data are used to delineate the river floodplain and compute flood inundation extents for 10-year, 25-year, and 100-year return period flood scenarios using the HEC-HMS and HEC-RAS hydrological modelling tools. Land use data from Sentinel-2 imagery identifies settlements, agricultural land, and critical infrastructure within simulated inundation zones. Results demonstrate that approximately 78,000 hectares of agricultural land and 47 communities fall within the 25-year flood inundation zone. Flood depth maps are produced and linked to a vulnerability matrix incorporating community livelihood profiles. The study provides actionable flood risk intelligence for the Benue State Emergency Management Agency and the National Emergency Management Agency's pre-disaster planning activities. Keywords: flood mapping, Benue River, GIS, hydrological modelling, floodplain