GIS-Based Assessment of Flood-Prone Areas in the Sokoto River Rima, North-Western Nigeria

Abstract

Flooding has become one of the most severe and recurrent environmental hazards across Nigeria and West Africa resulting in loss of lives, damage to property, disruption of livelihoods, and environmental degradation. A GIS-based assessment of potential flood-prone areas within the Sokoto River Rima basin was carried out using Digital Elevation Model (DEM) dataset acquired from USGS Earth Explorer website and rainfall data from the Nigerian Meteorological Agency (NIMET). The historic flooding in this River basin in 2010 left the inhabitants devastated as more than 1,200 communities across the surrounding localities were affected. A similar flooding in 2026 also affected the same localities. This GIS-based assessment was conducted in conjunction with a drainage map in a geographical information system (GIS) environment. The suspected flood-risk zones along the river basin were analysed and classified into low, medium high elevations and a multi buffer zone maps of 500m, 1 km, and 2 km around the major river channels were generated to determine g the level of vulnerability of the settlements and farmlands. The 500 m buffer zone are areas of very high vulnerability containing densely populated settlements. The 1 km buffer zone indicated high vulnerability areas including some farmlands and other peri-urban communities such as Kwalkwalawa, Rikaka, and Wurno. On the other hand, areas within 2 km buffer of the river basin fall under moderate vulnerability. However, beyond the 2 km buffer zone vulnerability to flooding decreases substantially due to the increasing elevation and slope. The study identified that the livelihood of the habitants within this study area were generally affected. The study highlighted the flood-prone areas which require structural and non-structural mitigation in order to avoid serious future occurrences.