Determination of the interaction between groundwater and surface water using environmental isotopes (Oxygen-18, Deuterium and Tritium) and chemical analyses in Uluova Region, Elazig, Turkey

In this study, the effects of surface waters on groundwater aquifers were examined via physico-chemical analyses and environmental isotopes. The study was carried out in the Uluova region located 10 km northeast of the city of Elazig (Turkey). Water samples were acquired from the Uluova aquifer, Keban Dam Lake, Hazar Lake and Haringet stream during the wet and dry seasons. The water samples were analyzed for Oxygen-18, Deuterium, Tritium, temperature (T), electrical conductivity (EC) and Chloride (Cl–). According to the results of environmental isotope analysis, three different groups of water masses were identified in the basin in the wet and dry seasons. The equation of the line formed by the points in the Oxygen-18 – Deuterium graph for water samples received from the Uluova region was defined as δD=6δ 18 O – 10.50 for dry season and as δD=6δ 18 O – 8.66 for wet season. Tritium values of water samples were classified as 0-4 TU, 4-6 TU and 6-12 TU for wet and dry seasons, respectively. Consequently, it was found that Uluova groundwater aquifer is fed by daily precipitations. The surface water irrigations from Keban Dam Lake and Hazar Lake affect the aquifer during irrigation season. This has not changed the classification made by the Tritium content of the aquifer.