APPLICATION OF STABLE ISOTOPES TO EVALUATE THE INTERACTION BETWEEN SURFACE WATER AND GROUNDWATER IN NORTH EAST OF DIYALA, IRAQ
It had been adopted two reliable techniques which are hydro-chemical and stable isotopes to study the interaction between groundwater and surface water in Wand dam northeastern of Diyala. Eighteen water samples were collected from Wand dam, piezometers, groundwater pumping wells, spring, accumulation basins, and irrigation water during two periods; June and November 2017. The concentrations of cations in Wand dam water order to Ca2+> Na+> Mg2+> K+, SO4> Cl-> HCO3-. The concentrations of cations in the samples collected from groundwater, irrigation water, springs and accumulation basins order to Na> Ca> Mg2+> K+, Ca2+> Na+> Mg2+> K+, Na+> Ca2+> Mg2+> K+ and Ca2+> Na+> Mg2+> K+ respectively and the anions concentrations have order Cl-> SO4> HCO3-, SO4-> Cl-> HCO3, Cl-> SO4> HCO3 and SO4-> Cl-> HCO3- in groundwater, irrigation water, springs and accumulation basins respectively. There are three groups of water types based on isotopic composition; group A which noted in the Wand dam water, the piezometers Nos. 3 and 4, accumulation basin No.7 and irrigation water. Versus standards Group A is enriched by deuterium and oxygen-18, which show the effect of evaporation. Group B is distinguished by isotopic composition enrichment in groundwater as well as piezometer No. 7 than other piezometers due to the difference of the wells depth. Group C shows that the water samples collected from accumulation basin No.1 and springs have enriched stable isotopes. There is a spatial and temporal variation of isotopic contents and hydro-chemical properties of water samples which could be due to different recharge sources, evaporation processes, and origin of the water. Based on concluded information, there is no evidence proving any interconnection between the water of Wand dam and other water resources, except piezometer No. 5 which could be because of the presence of the permeable bed.