Assessment of Land Use Vulnerability to Flood Disaster Management; and Control in Ikirun, Osun State, Nigeria

Abstract

Flooding has recently emerged as one of the most devastating threats to life, property, and environment in most cities in developing countries requiring attention. This study evaluates land use vulnerability to floods in Ikirun, Osun State with a view to generating GIS-based vulnerability maps for effective urban management. A total of 157 questionnaires were administered randomly on respondents within a 100 m radius buffer along natural drainage channels. The Shuttle Radar Topography Mission (SRTM) data 90 m Digital Elevation Model (DEM) of the study area was used to create flood vulnerability maps. Result of cross-tabulation of the nature of the terrain and the incidence of flood reveals that 88% of respondents in areas with flat terrain experienced serious flooding, 68.2% in areas with steep slope also experienced flooding while 40% of those living on higher grounds experienced some degree of flooding. The result corroborates with the flood vulnerability map produced categorizing the area into high (311–329 m), medium (329–347 m), and low (>348 m) risk zones. Similarly, results show that 59.2% of the buildings were less than the standard 15 m from natural drainage channels which fall within the flood plains prone to disasters while 40.8% were above and have building permits. The study identified anthropogenic activities such as unapproved development on flood plains, residential development, and indiscriminate waste disposal as factors responsible for flooding. The study recommended environmental education, proper waste disposal, channelization, and stronger development of control measures as a way forward to better environmental management.