Flood Inundation Mapping of Gbaganu Area Minna, Niger State

Abstract

Flooding in recent times has become a critically problematic phenomenon of spatio-temporal order and considerably high frequency of occurrence worldwide. Gbeganu area of Minna covering an area of 16.389 hectares within Niger State. Nigeria has witnessed and is still witnessing multivariate cases of flooding, which peak in the rainy season (April-October) of every year, resulting in loss of life and economic valuables/properties. To curb this menace, an integrated solution of drainage morphometric parameters with remote sensing and geographical information system capacity is thus herein presented using the downloaded Shuttle Radar Topography Mission (SRTM) of 1-arc second (30 m resolution) which covers nearly the entire Niger State and the DEM of the study area was extracted and digital elevation model (DEM) generated from topographical point data (position and elevation of points within the area) taken with Differential Global Positioning System receivers and the satellite image of the study area to delineate watershed, contributing area, flow direction and flow path/channel. The Height Above the Nearest Drainage (HAND) tool was used on the ArcGIS software for analyses. The study produced a map depicting regions within the study area: regions that are highly susceptible to flooding. The morphometric analysis of flood inundation hazard in the area watershed shows that the risk to buildings will be more serious shortly, meanwhile, the implementation of flood countermeasures and the identification of priority areas for flood risk reduction using the flood inundation map will also help to reduce the flood impacts within the study area.