Evaluating the Groundwater and Surface Water Interaction in Southwest Iraq Using Environmental Isotopes Technique

Abstract

This study aims to use the environmental isotopes technique to evaluate the interaction between groundwater and surface water at a location between two cities in the southwest of Iraq; namely Al-Kifl and Al-Samawa. The salinity of the Euphrates River water increases sharply as it passes in this area, to a level that affects its usage for municipal purposes. A total of 111 samples were collected from the rivers, drainages, springs, shallow and deep wells, and from Sawa Lake, and all the samples were subjected to chemical (TDS, SO4, Cl, and B) and isotopic (deuterium and oxygen-18) analyses. The chemical and isotopic results showed no interference between the quality of the groundwater (from wells and springs) and Sawa Lake water with the Euphrates River water, in the study area, and hence, neither the groundwater nor Sawa Lake affects the river water quality. Statistically, the t-test analysis showed significant differences among those water samples (p-values less than 0.05 for almost all the chemical and isotopic parameters). On the other hand, drainage water showed a strong relationship to the river water, which indicates a high and strong influence of the drainage water on the river water quality when it mixes with the Euphrates River water.