TITLE:
Integrated Landsat Imagery and Geophysical Exploration for Groundwater Potential Evaluation of Okene and Its Environs, Southwestern Nigeria
AUTHORS:
John Olurotimi Amigun, Richard Ajibola Faruwa, Akinola Adesuji Komolafe
KEYWORDS:
Groundwater, Basement Complex, Aeromagnetic, Geo-Electrics, Remote Sensing, GIS
JOURNAL NAME:
International Journal of Geosciences,
Vol.6 No.3,
March
12,
2015
ABSTRACT: In this study, an integrated remote
sensing and geophysical (aeromagnetic and geo-electric) methods was employed to
assess the potential of groundwater in a basement complex terrain of Okene and
its environs, Southwestern, Nigeria. Landsat imagery acquired over the study
area was processed in the Geographic Information Systems (GIS) environment to
delineate the surface lineaments, drainage networks and their orientations.
Aeromagnetic data over the area were analyzed
and its derivative maps were interpreted to further map the structures and the
geology in the subsurface; depths to magnetic sources were determined using
spectral analysis. Vertical Electrical Sounding (VES) of geo-electric method
was interpreted to map the subsurface geology layers. The results of the
integrated data were correlated with borehole yield data of the area for
effective interpretation. Delineated lineaments from the azimuth, frequency plot showed dominant trends in the NE-SW and
NNE-SSW directions. Radial average power spectrum revealed the depth to magnetic
sources between 100 and 2500 m
and the interpreted VES data characterized the area into three to four
subsurface layers. In correlating the results with borehole yield data, the
zones with high lineament density and low/negative magnetic anomaly were
categorized as high groundwater potential zones while areas with low lineament
density and high/positive magnetic anomaly as low groundwater potential zones. This
study will guide efficiently subsequent groundwater drilling program in the
study area.