Authors: Adeofun C. O., Achi H. A., 2Ufoegbune G. C., Gbadebo A. M. and Oyedepo J. A.
Proceedings of the Environmental Management Conference 12-15 September, pp264-278
Abstract
Waste management problems result from indiscriminate waste disposal which stems from inadequate planning and implementation. This fact led to the present study which applied the techniques of GIS and RS to disposal sites and transport route selection in the emerging megacity of Abeokuta. Spatial data such as land-cover types; road and drainage networks of the city were extracted from a geo-referenced high resolution satellite image through on-screen digitizing using GIS softwares such as ILWIS and ArcView 3.2a. The existing dumpsites were geolocated and added as a layer to the map of the city. The land-cover, drainages, and roads were buffered at 30, 160 and 200 meters respectively using preset criteria such as distance of site from a street at 30 m, surface water at 160 m, major roads at 200 m and absence of important economic or ecological features; to determine candidate sites from the land-cover types. Four legal dumpsites in Saje, Olomore, Totoro and Ita-Oshin and patches of illegal dumpsites were identified. GIS analysis gave a total of nine sites out of which only four met the preset criteria. Saje, Ita-Oshin, Sam-Ewang, and Ita-Ika areas were the most appropriate sites having an area of 19.64 km2 out of the total study area of 79.95 km2. The shortest route connecting the proposed dumpsites gave a total Travel Cost (in distance) of 27.30 km while the cost of making a roundtrip (Tour Route Cost) was 36.00 km. It was therefore concluded that Olomore and Totoro dumpsites should be relocated, while Sam-Ewang and Ita-Ika dumpsites should be upgraded and made to function as legal waste disposal sites.