2025-04-04https://repository.covenantuniversity.edu.ng/handle/123456789/43002The characteristics of the groundwater system in Iresa-Apa, Oyo state, Nigeria, were studied using the Piper linear approach. Twenty-four water samples were randomly collected to cover the area of study. The analyzed cations from the samples are Mg2+, Na+, K+, and Ca2+, while the anions are CO32−, HCO3−, SO42−, and Cl−. The three hydrochemical facies identified are Ca–Mg–Na, Ca–Mg–Na–SO4, and Na–K–Cl–SO4 types. The similarities in the observed water types suggest that almost the same geochemical processes are controlling the cation-anion reaction of the groundwater system in the study area.application/pdfQ Science (General), QC PhysicsBook Section