Stable isotopes (δ18ΟH2O, δ²HH2O) and hydrochemical fingerprints of groundwater interactions in the Afram Plains South aquifers, Voltaian Basin

Study region The Afram Plains South District, situated within Ghana’s Voltaian Basin. Study focus Groundwater is the mainstay of domestic supply in this district; however, many boreholes fail during extended dry spells. This study explored aquifer recharge sources and rates using hydrochemical signatures, stable water isotopes ( δ 18 Ο H2O , δ ²H H2O ) and the Chloride Mass Balance technique. Characterizing recharge processes of groundwater in this district is critical for guiding groundwater development and management in this hydrogeologically complex setting. New hydrological insights for the region: Isotope signatures point to a meteoric origin with less evaporative overprinting before recharge. Hydrochemically, three water types emerge: Sodium Chloride (Na-Cl or Na-HCO 3 -Cl), Sodium bicarbonate (Na-HCO 3 - ) and mixed water types dominated by Na + and HCO 3 - . Recharge estimates varied from 21.4 mm/yr to 284.5 mm/yr (1.7–22.8% of annual precipitation), averaging 132.0 mm/yr (10.6%). These rates resemble those reported from other Voltaian Basin studies employing both conventional and tracer-based techniques. The limited evaporative signature coupled with recharge estimates suggests these aquifers could support sustained abstraction; however, this requires integrated monitoring of groundwater levels, abstraction rates, storage capacity, and hydrodynamic properties. This integrated approach has proven valuable and could be employed for groundwater assessment where routine hydrological records are rare.