Groundwater Potential Zone Identification by Lineament Mapping using Shaded Relief Images Derived from Digital Elevation Model (DEM)

Abstract

The study area, Obafemi-owode, is an important area of Ogun state due to its proximity to Lagos State, a major industrial hub of Nigeria. Being a developing country, most parts of Nigeria do not have access to quality water, both for domestic and industrial uses. The study area is not an exception, as the residents rely mainly on groundwater for various purposes. Lineament identification using the Digital Elevation Model (DEMs) can provide useful information about the underlying geological structure, which can be very helpful in fault and aquifer identification. It involves the creation of shaded relief images of the study area from the DEM. In the present work, four shaded relief images were produced with sun azimuth angles and elevations of 315˚ and 45˚, 200˚ and 60˚, 100˚ and 60˚ and lastly 60˚ and 80˚. The various azimuth angles and elevation combinations enhanced distinct relief and topography for better lineament extraction. Lineaments (linear and curvilinear) were extracted from the four generated relief images, and the lineament density map was plotted. The result showed that the lineaments trend dominantly in the NNE-SSW direction, which could be considered to be an effect of the Mesoproterozoic Benin-Nigeria block of the West Africa orogeny. The area of lineament density is underlain by the Abeokuta formation, and the zone with high lineament intersection within this area is identified as the region of high groundwater potential.