Possible Sources of Salinity in the Upper Dibdibba Aquifer, Basrah, Iraq

Ahmed Abdulameer,Wael Kanoua,Jassim Mohammed Thabit,Oliver Wiche,Broder Merkel

doi:10.3390/w13040578

Ahmed Abdulameer, Wael Kanoua + Show 3 more

Open Access

https://doi.org/10.3390/w13040578

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Abstract

Salinity increase in groundwater was investigated in the area between Al-Zubair and Safwan, and close to the Khor Al-Zubair Channel of southern Iraq. Thirty-nine groundwater samples from the shallow aquifer and one sample from the Khor Al-Zubair Channel were analyzed. The mean total dissolved solids are 7556 mg/L. The δ2H and δ18O plot in two groups are below the global meteoric water line. Group A indicates the evaporation effect of irrigation return-flow, while group B is characterized by depleted δ18O values due to recharge under colder climate. Deuterium excess values plot within the region of modern precipitation and dilution of groundwater by precipitating water. The groundwater residence time is between 1000 and 2000 years and combining 14C -age with SO42− shows a contrasting effect on groundwater on both sides of Khedr Almai Fault and the Zubair anticline, which indicates the role of these geological structures on the hydrochemical evolution in the western part. Jabal Sanam shows no clear effect in this regard. The ratio Cl−/Br− and sulfate in groundwater showed that the measured salinity in groundwater is the result of a mixing process between groundwater, seawater intruding from Khor Al-Zubair Channel, and water from septic tanks in addition to dry and wet sea spray, and irrigation return-flow.

Highlights

Groundwater is a valuable source of life and sustainability in arid and semi-arid regions
According to the tectonic divisions of Iraq, the area of interest (AOI) is located within the Al-Zubair secondary zone, which exists within the Mesopotamia zone, belonging to the stable shelf characterized by the disappearance of complex geological structures and thick cover of sediments
A total of 39 groundwater samples were collected from the Upper Dibdibba aquifer and one sample from the Khor Al-Zubair (KhZ)

Summary

Introduction

Groundwater is a valuable source of life and sustainability in arid and semi-arid regions. The overuse of groundwater, combined with the increase in the annual average of temperatures and a severe drop in the precipitation and recharge, cause evident qualitative and quantitative deterioration in groundwater, which negatively affects economic systems in arid and semi-arid regions [2]. Iraq, in this regard, is not an exception, especially in the southern parts of the country, as groundwater demand has increased in the last decades. More than 5000 wells have been drilled in the AOI (area of interest), tapping the upper unconfined aquifer to meet part of the region’s water demand [3]

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