Constraint map for landfill site selection in Akure Metropolis, Southwestern Nigeria

Abstract

An integration of remote sensing, soil type, geological, geoelectrical, hydrogeological and geotechnical data was carried out in a GIS environment with a view to developing a constraint map for the location of landfill (waste disposal) site(s) in Akure, Metropolis.. Geomorphological features identified from satellite images include  residual hills, pediments, pediplain and etchplain . The slope (gradient) map displays surface gradients of 0 - 2.5^o  along river channels while areas with moderate and high relief have surface gradients of 2.5 - 6.35^o and 6.35 -  29.53^o respectively. Satellite-imagery-delineated lineaments predominantly trend NNW-SSE, ENE-WSW and NNE-SSW with subsidiary NW-SE and W-E trends that are typical of the Basement Complex region of Nigeria. The engineering geotechnical results show that charnockite-derived soils are very clayey and silty in nature (with % clay content > 18%) with low permeability, and are therefore more suitable for waste disposal (landfill) site than the sandy and gravely (with low % clay content < 7%) granite and migmatite gneiss-derived soils. VESderived topsoil and weathered layer are characterized by relatively low layer resistivity values (< 100 ohm-m) over basic charnockitic rocks. The synthesis of the above results enables the classification of the Akure metropolis into three landfill suitability zones – unsuitable (28.6%); moderately suitable (40.4%), and suitable (13%) for waste disposal (landfill) sitting.

Keywords: GIS, Remote Sensing, Geoelectric, Geotechnical, Constrain Map, Landfill Site.