Identification of Groundwater Potential Zones Using Lineament Analysis in Parts of Ilesa Metropolis, Southwestern Nigeria

Abstract

This paper is focused on mapping of lineaments within the Schist Belt of Ilesa using Geographic Information System (GIS) and Remote Sensing (RS) tools. An approach which involved studies of lithology and lineaments were useful for a proper assessment of groundwater bearing potential zones in the study area. The study area is within Ilesa metropolis, which lies within the Precambrian Basement Complex, hosting fracture zone aquifers which are promising sites for groundwater exploration. The rock types within the study area can be grouped into migmatite-gneiss complex, mafic-ultramafic suite (or amphibolite complex), metasedimentary assemblages and an intrusive suite of granitic rocks. The mapped structural lineaments were analysed using lineament density and lineament frequency analyses on ILWIS 3.1 Academic and ArcGIS 10.1. The lineament density values ranged from 0.00003 to 0.001 km/km2. These indicate areas of poor water-bearing potential to areas of high water-bearing potential. Presentation of the detected lineaments shows two possible orientations in the directions of NE and SW which are also principal directions of the regional structures in basement complex of Nigeria. Conclusively, axial directions present the direction of groundwater flow in the area.