Application of Remote Sensing (RS) and Geographic Information Systems (GIS) in flood vulnerability mapping: Case study of River Kaduna

Adequate geographic information on hazards and areas vulnerable to hazards is required to be able to prepare for disasters. Flood vulnerability mapping is fundamental in flood risk management because it identifies areas vulnerable to flood disaster. In Nigeria, flood maps for many areas are lacking and the available ones are obsolete. Recent flood disasters along River Kaduna in Nigeria has claimed many lives and properties, and threatened the ecological biodiversity. This study applies remote sensing and GIS techniques to produce flood map of the Middle Course of River Kaduna. The Middle Course of the river is considered due to its very large area which passes through Kaduna metropolis and its potential to cause devastating effect to communities around the basin in the event of flood disaster. Using High resolution imagery, a Digital Elevation Model was developed with ArcGIS to identify flood prone areas along the Middle Course of the river. A flow accumulation model was created using the DEM and the DEM was reclassified into high risk, moderate risk and low risk zones using equal interval of separation based on elevation. This was overlaid on the map of the area to produce a vulnerability map of the area. The study also conducted interviews with a sample of residents of certain areas that are at risk from flooding to identify elements-atrisk of flood. We discovered that a flood map can be used effectively in public enlightenment, disaster response planning and flood risk management.