Hydrogeochemistry and isotope hydrology of surface water and groundwater systems in the Ellembelle district, Ghana, West Africa

Abstract

An integrated approach based on the hydrogeochemistry and the isotope hydrology of surface water and groundwater was carried out in the Ellembelle district of the Western Region of Ghana. Measurement of physical parameters (pH, temperature, salinity, total dissolved solutes, total hardness and conductivity), major ions (Ca2+, Mg2+, Na+, K+, HCO3−, Cl−, SO42− and NO3−), and stable isotopes (δ2H and δ18O) in 7 rivers, 13 hand-dug wells and 18 boreholes were taken. Na+ was the dominant cation and HCO3− was the dominant anion for both rivers and groundwater. The dominant hydrochemical facies for the rivers were Na–K–HCO3− type while that of the groundwater (hand-dug wells and boreholes) were Na–Cl and Na–HCO3− type. According to the Gibbs diagram, majority of the rivers fall in the evaporation–crystallization field and majority of the hand-dug wells and the boreholes fall in the rock dominance field. From the stable isotope composition measurements, all the rivers appeared to be evaporated, 60 % of the hand-dug wells and 70 % of the boreholes clustered along and in between the global meteoric water line and the local meteoric water line, suggesting an integrative and rapid recharge from meteoric origin.