Floodplain Mapping of River Ogun Lower Basin Using GIS Model

Floods are the most common natural phenomenon due to relatively higher flows and that temporarily submerges land and habitation endangering both life and properties. River Ogun flood annually with paucity of information on the extent and mitigation approach. In this study, floodplains mapping within River Ogun Lower Basin was done to reduce flooding menance in the area. Catchment delineation of River Ogun requires the imagery of the whole river Ogun catchment and elevation data obtained from Goggle earth. This data were remote sensed and taken to GIS environment. The river was characterized into three basins based using GIS hydrological tool (Upper Basin, Mid-Basin and Lower Basin). The hydrographical delineation entails the flow region of River Ogun, its tributaries and tributaries flow network and pattern. The input for the hydrographical delineation are the Google earth remote sensed elevation data. The Lower basin of River Ogun was identified as the region with highest flow influx. Different maps were derived from the delineation of the lower basin catchment area. The summary of the data were used to generate the following maps which includes contour map, topography map, drainage pattern map, elevation collection points map, land-use map, digital elevation measurement (DEM) and floodplain map. The maps generated can be used as a drainage master plan, Land use monitoring, Channel Improvement and Floodplain zoning to reduce the development-induced impact along the area.