Use of Hydrochemistry and Stable Isotopes for Groundwater Evolution and Contamination Investigations, Jabal Hasouna Reservoir

Hydrochemical and isotopic studies in groundwater was attempted in Jabal Hasouna reservoir to gain knowledge on geochemical evolution and water quality status. The results of the chemical analysis indicate the sources of ions into the groundwater are from dissolution and leaching from source rocks, cation exchange. The saturation index calcu-lated specify over-saturation of carbonate species and undersaturation of amorphous silica indicating groundwater chemical evolution controlled by water rock interactions. Water type alters from Ca-HCO3 to Na-Cl indicating groundwater chemistry controlled by rock-water interaction. The plots of various ionic ratios point out groundwater chemistry affected by ion exchange process, silicate and carbonate weathering. The water type's classification designate 5 distinct groups ranging from low EC and highly depleted isotopes to very high EC with enriched stable isotopic composition indicating longer residence time of groundwater.