Investigating Groundwater Challenge in Crystalline Basement Complex Terrain of South-Western Nigeria: Case Study of Aagba and Environs

In an attempt to investigate the groundwater challenge in communities around Aagba and its environs despite their close proximity, hydrogeophysical and geological studies were carried out using an integrated approach that integrate the use of electrical resistivity method with flow direction determination. Nine (9) vertical electric soundings were carried out across the communities all of which are separated by short distances. Forty eight (48) hand dug wells were selected for the flow direction determination. Iteration and interpretation was done using the IPI2Win software while Surfer 12 used to generate a 2D isopach map, pseudo-section, 3D aquifer transverse resistance map, overburden anisotropic coefficient map. Well data were used to generate a 3D flow direction map of the study area. The result showed that the area is underlain by granite gneiss that exhibit shallow fracture around Iragbiji and Ororuwo located at the North western part of the study area while there are no shallow fracture in the eastern part of the area where communities such as Ada and Aagba are located. This accounts for the low groundwater potential in these two communities. Investigation of the flow direction reveals that the groundwater flow from east to west, an indication of a gaining stream at Iragbiji where River Ogun drains all the available water