Environmental Change and Ecological Services in System I Drainage Area of Lagos

Abstract

The study examines the implications of urban land uses on hydrological processes and ecological services in system I (Odo Iya Alaro Channel) of Lagos Drainage Master Plan.  Aerial Photography (1965) and Ikonos Imagery (2008) were used to assess the land use and land cover changes in a GIS environment. Field survey to inventories plant and fish species within the wetlands was carried out. Study of land use-land cover changes between 1965 and 2008 shows that about 79% of the area has been built-up. Based on environmental change projectisons using precipitation and land use drivers it is expected that runoff and peak flow would increase by 6.34, 14.24, and 20.36% for 50 years medium climate change, 50 years high climate change and 100 years high climate change respectively. Some of the flora expected to be lost from wetland and creeks based on landuse changes include Thuja sp and Ficus sp. This would affect some of the ecological services offered by these plants. Effluent discharge from industries is also putting the fish supply at risk, as species such as Sarotherodon melanotheron and Liza falcipinnis are reducing. The study advocates conservation approach for sustainable urban land uses.

Keywords: Land Use-Land Cover Change; Wetland; Ecosystem; Urbanisation; Watershed