Assessment of Coastal Flooding on Victoria Island in Eti-Osa Local Government Area, Lagos State, Nigeria

摘要

The coastal flooding is a major issue for multiple places around the world with many experiencing increases in the severity and frequency of extreme events. This is consistent with current climate change projections and is expected to worsen in future as global temperatures increase. This paper examines the socio-economic impact of coastal flooding on Vitoria Island, Lagos, Nigeria. The research was conducted using questionnaire and Geographic Information System (GIS) to collect the required data for the purpose of fulfilling the objectives of the study. The Coastal flooding of Victoria Island, Lagos for a period of twenty nine years was analyzed using topographic map of 1962 and multi-temporal and multi-source satellite imageries of Landsat TM of 1984, ETM+ 2000 and 2011. The study employed supervised digital image classification method using ILWIS 3.2 and ArcGIS 3.9. The topographic map of 1962 and the imagery of 1984 was glued and crossed; 1984 and 2000; and the 2000 and 2011 were also crossed to get the changes in the shorelines in these years. The results of the analysis reveal that between 1962 and 1984 there was loss in landmass while between 1984 and 2011 there was increase in land gain overtime. About 31.4% of landmass was lost between 1962 and 1984 while between 1984 -2000 and 2000-2011 there was gain in landmass of about 81.89% and 62.11% respectively. Findings show that, narrow drainages coupled with high rainfall in the study area are the major causes of flooding. To reduce the effect of flooding in the study area, policy measures were recommended based which include construction of standard paved surface and drainages, law enforcement on waste disposal, integrated approach to flooding management and control and flood insurance policies.