Coastal Megacity of Lagos: A review of the Problems and Challenges of Flooding.

Abstract

Lagos the mega-city of slums, with millions living in and around the lagoons with no access to roads, clean water, electricity or waste disposal with rapid urbanization, exposure of people, infrastructure and the tourism industry to the risk of flooding induced by climate change. This paper studies the risk and vulnerability of Lagos as a megacity in Nigeria to flooding as a result of climate induced rainfall being one of the major environmental
problems of coastal areas. Statistical, GIS (Geographic Information System) and remote sensing techniques was adopted to map urban growth, while changes and the impact of flood level from HEC-RAS simulation was modeled for 1990 and 2011. Rainfall distribution, trend
and temporal variations were studied. Flood hazard was computed and the result reveals that flood incident is higher for 2011 than in 1990. Furthermore for Lagos, flood vulnerability
and risk indicators were selected using Principal Components Analysis (PCA) to represents each of the three major components of vulnerability (which include exposure, sensitivity and
adaptive capacity) and risk. Based on these, flood vulnerability index was computed as well as the flood risk index and Ordinary Least Squares (OLS) regression techniques was used to test the validity of the model to represent the phenomena in question. Flood risk drivers was determined for Lagos which includes insecurity, ecosystem degradation, lack access to
sanitation, lack good drink water and transportation infrastructure, drainage infrastructure and poorly governed rapid urbanization. In bid to mitigate and adapt to flood control and management in Lagos optimal performance would be insightful to consider policies institutionalization and structural decentralization of operations along the governance framework identified.