Urban flood vulnerability mapping of part of the Lagos metropolis

Abstract. Flooding is the most common of all environmental hazards with vast devastating effect due to enormous losses to lives and properties world-wide, annually. Thus, the effect of extreme flooding is dramatic, not only at the individual household level, but in the country as a whole. This study focuses on flood risk assessment based on urban and coastal flood estimation due to the physical peculiarity of the Lagos region and her urbanization characteristics. It involves creating a flood change detection using GIS approach with the aid of a Cellular Automation Framework to simulate flooding in Lagos Metropolitan area, mapping out the flood prone areas and generating a flood vulnerability map for flood management and planning purposes. At twenty minutes intervals the discharge distribution for the different flow regimes (Low, Medium and Extreme) display flow duration between 60–120 min while the time of concentration is attained at 1 h 20 min (80 min).