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

Abstract The study area, Obafemi-owode is one of the important areas of Ogun state due to its proximity to Lagos state, which is 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 from which the study area is not an exception as the residents rely majorly on groundwater for various purposes. Lineaments are capable of providing useful information about the underlying geological structure, which can be very helpful in fault and aquifer identification. Lineament identification using the Digital Elevation Model (DEMs), which involves the creation of shaded relief images of the study area is popular and very effective. 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 angle 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 has it that the lineament trends 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.