Abstract

Floods are among the most devastating natural disasters in the world, claiming lives and causing property damage. In Nigeria, flood affects many urban centres with damages to life and properties. This paper investigates flood vulnerability in Lokoja town, Nigeria, by making use of Remote Sensing and Geographic Information Systems to generate topographical information of the contour, the digital elevation model, the slope and urban growth over time in order to produce flood vulnerability map. Analysis of Landsat images of the study area showed steady increase in the built-up area between 1990 and 2019. Most of this growth is located in marginal developable areas on flood plains.The flood vulnerability map indicated that most of the land that is highly to moderately vulnerable to flooding is located in the low-lying areas along the River Niger at Nataco, Felele, Kabawa, Adankolo, Gadumo, Abuja -Lokoja road, IBB way, Ganaja-Ajaokuta road and along other streams while Mount Patti axis and Zango are not vulnerable. The result indicated that the factors contributing to increasing rate of flooding in Lokoja urban area were the expansion of the built-up area into the flood plains, low relief, and non-compliance with building and environmental regulations and the release of excess water from dams on the upper courses of the rivers rather than increased rainfall. The study made recommendations for the river basin management beyond Lokoja. In addition, suggestion was made for environmental regulation and management, and the resettlement of the population in vulnerable neighbourhoods.

Key Words:  Flood vulnerability, Remote Sensing and GIS, DEM, Flood plains, River basin management, Lokoja