Mapping flood vulnerable areas in a developing urban centre of Nigeria.

Abstract

This study exploits the integrated approach of Remote Sensing and GIS techniques in flood management with the goal of mapping areas vulnerable to flood hazard in Gwagwalada urban area. Topographic Map and Landsat TM image of 1991 and 2001 respectively were processed, scanned, digitized, interpolated, classified and overlaid using ILWIS GIS software modules to generate classified Land use/land cover map, Digital Terrain Map and Flood vulnerability map of the study area. The results obtained shows that, areas lying along the banks of River Usuma are most vulnerable to flood hazards with the vulnerability decreasing towards the northern part of the town, much of the area is built up and this gives rise to high vulnerability to flash flood hazards. The old town is the most vulnerable to flood threat. Phase 1, 2 and 3 are free from flood threat except for the extreme Northwestern part of Phase 3. The incessant violation of landuse plan, unchecked population growth, old nature of the structures and poor materials used in the construction of the houses exacerbate Old Town vulnerability to flood hazard. In reducing the vulnerability of the town from flood there is need for improved land use planning, removal of structures from River Usuma flood plains around the town, intensify environmental education residents and enhance the active participation of government agencies in the continual generation of Flood vulnerability maps of urban centres.