Recharge Sources and Hydrogeochemical Evolution of the groundwater in the Quaternary Aquifer El Gallaba Plain, Southwestern Desert, Egypt

Abdalla, Samar; Mohallel, Saad; Hassan, Essam

doi:10.21608/ejchem.2024.263609.9206

Recharge Sources and Hydrogeochemical Evolution of the groundwater in the Quaternary Aquifer El Gallaba Plain, Southwestern Desert, Egypt

Document Type : Original Article

Authors

¹ Hydrogeology and Environment Department, Faculty of Earth Sciences, Beni Suef University, Beni Suef Egypt.

² Hydrogeochemistry Department, Division of Water Resources and Desert Soil, Desert Research Center, Cairo, Egypt.

10.21608/ejchem.2024.263609.9206

Abstract

Groundwater has been regarded as the primary source of fresh water for agriculture and daily use purposes in El-Gallaba Plain, West Kom Ombo, Aswan. Recently, this plain has been considered as one of the most promising areas for government development projects. To develop a sustainable management plan for groundwater in the region, it is necessary to identify the main sources of recharge for this reservoir. Expect the extent to which the water level in the reservoir is related to the water level in River Nile, as well as Lake Nasser and the Nubian aquifer in the Western Desert. Due to the presence of more than one source, which may be single or combined, through which the Quaternary aquifer is recharged, the geochemical development of the groundwater is one of the most important means by which the main recharge source could be expected which is either Nile water or Nubian groundwater. Then, it will be clear to develop a permanent plan to exploit this reservoir based on determining its source of recharge. Three water types are detected along El-Gallaba Plain, using hydrochemical Facies Evolution Diagram: T1 (Ca-Mg-HCO3), T2 (Ca-Mg-SO4), (Ca-Mg-Cl) and T3 (Na-K-Cl), (Na-K-SO4). In which, the salinity of groundwater varies between 843 and 4960 ppm. The mineralization of the aquifer groundwater is believed to be from fossilized meteoric water of Nubian aquifer. Under an open system and reverse cation exchange, the Nubian water mixes with agricultural return water in the eastern part of the plain close to the Nile floodplain resulting in high TDS groundwater rich in Ca and Mg (T2 water type). The close system and cation exchange with sulphate reduction develops the Nubian groundwater water to high TDS groundwater rich in Na and Cl with subordinate SO4 (T3 water type). It is clear that the main source of recharge for the Quaternary aquifer in El-Gallaba Plain area is the Nubian reservoir. Therefore, a plan must be developed for the optimal exploitation of the aquifer, based on the water needs required for future expansions and the ability of the aquifer to recover.

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