Date of Award

12-2015

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Ahmed Murad

Second Advisor

Ala Aldahan

Third Advisor

Chunmiao Zheng

Abstract

Al Hayer is located in the northeast of Al Ain area, Eastern region of the United Arab Emirates. Groundwater abstraction for domestic, agricultural and industrial uses has led to major depletion in the aquifer resulting in groundwater quality deterioration. This study aims to identify the factors affecting the groundwater quality in this area, and to determine the recharge mechanism for the study area to understand the behaviour of major ions in regional groundwater by using hydrogeochemical and isotopic approaches. The hydrochemical analysis of 37 collected samples of groundwater revealed that the groundwater is characterized by moderate salinity and high concentrations of cadmium in some of the samples. Therefore, Al Hayer groundwater is not suitable for domestic uses. Groundwater samples were evaluated for agricultural uses by calculation of SAR, TH, Na+ percentage and MAR. By using these parameters, Al Hayer groundwater was found to be acceptable for agricultural purposes in 60% of the samples. Three water geneses have been identified; the first one is paleo-marine water, which is originated from magnesium chloride water type, indicating over pumping of deep water. The second is meteoric water, which is originated from sodium sulphate-water type, indicating an occurrence of infiltration of rainfall and ion exchange processes. The third one is meteoric water, which is originated from sodium bicarbonate-water type, found only in few samples. The hydrochemical analyses showed that the dominance of sodium and chloride in the area is due to agricultural effluents and provides indication of moderate-to-high salinity water in the studied area. Isotope analyses of hydrogen and oxygen of twenty-nine groundwater samples suggested that the study area has two different zones. The first one is represented by majority of groundwater samples and located below the LMWL and to the west of the study area, which suggests high rate of evaporation. Meanwhile, the second zone is located above the LMWL and to the east of the study area in close proximity to Northern Oman Mountains, which reveals quick infiltration to rainfall into major aquifer of the study area without evaporation.

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