Loss of Wetlands in Lagos (Nigeria) and the adjacent territory: Implications for flood control

Abstract

Population growth, with its concomitant pressure for more housing developments and eventual urban sprawl have been touted as chief contributors to the problem of urban flooding in Lagos (Nigeria). It has, therefore, become necessary in the light of the frequent flooding in Lagos in the recent years, to study one major surface feature by which nature has always managed the occasional abundant surface water flow (flooding) within the urban space - wetlands. Landsat TM and Sentinel-2 images obtained via remote sensing and processed with ENVI software were used to study the loss of wetlands in the Lagos conurbation and the adjoining areas within the last 30 years to see how this loss of wetlands has impacted the ability of the environment to manage superfluous surface water flow. Using the Supervised Maximum Likelihood classifier technique, it was found that within the 30-year period, the study area has lost about 59% (representing about 540.8 Km²) of its original area mainly to the built-up area, ostensibly for housing and infrastructural development. The implications of this tragic situation for flood control and other ecosystem services are discussed. Recommendations have also been put forth for future research.