Evaluation of groundwater potential of Ogbomoso using stepwise weight assessment ratio analysis (SWARA) model

Abstract

This research utilized various data types, including remote sensing (RS), aeromagnetic (AM), vertical electrical sounding (VES), and hydrogeological (HG) information, to create a groundwater potential map (GPM) of the Ogbomoso region in southwestern Nigeria. The lineaments obtained from the RS and AM results were merged to produce the lineament density (LD) map of the Ogbomoso area. One hundred and sixty-five VES data were collected for this study. The Ogbomoso area has a distinct geoelectric sequence that consists of various layers. These include the topsoil, weathered/saprolite, saprock, fractured basement, and fresh basement rock. Eight groundwater conditioning factors (GwCFs) were considered to ensure an accurate assessment of the groundwater potential (GP) in the Ogbomoso area. Stepwise weight assessment ratio analysis (SWARA), a multicriteria decision analysis (MCDA) technique, was used to assign weights to each GwCFs. The given weight was normalized, and a coefficient of coherence was established. SWARA helped characterize GP in the Ogbomoso area into different categories. It was discovered that there is a 0.63-degree correlation between well locations and GPM produced for the Ogbomoso area. This confirms that the SWARA modeling technique is reliable for predicting groundwater potential in any typical basement complex terrain worldwide.