Isotopic signatures and hydrochemistry in assessing groundwater occurrence in the desert environs west Qena, Egypt

Abstract

Developing the desert zone outside the flood plain of the Nile River and targeting the reclamation of about 12,500 feddan in the desert environs of Qena governorate are considered one of the top priorities of both government and the private sectors. The present study is based on qualitative analyses of the groundwater of the Quaternary aquifer in the desert environs west Qena. Groundwater was chemically and isotopically analyzed to determine the origin of groundwater and assess its occurrence. The obtained results indicate that the Quaternary aquifer represents the most important groundwater aquifer in the area. The water level ranges from + 40 to + 67 m above sea level. The groundwater movement direction in the study area is mainly from southeast to northwest direction, with some local flow groundwater directions from Nile River at the north to old alluvial plain and desert environs at the south. The hydraulic conductivity of the aquifer is determined from the pumping test range from 17.63 to 42.86 m/day, with an average value of 27.04 m/day, while the transmissivity ranges between 2142.8 and 1128.3 m2/day, with an average value of 1456.74 m2/day. The total dissolved solids range from 589 to 3832 mg/L. Isotopic analysis (oxygen eighteen and deuterium) of fifteen groundwater samples was carried out to define the recharge source of the Quaternary aquifer. The groundwater isotopic data reflect variability in recharge conditions during different ages and different climatic regimes. According to the minor and trace elements concentration and US Salinity Laboratory Staff nomogram, most water samples are suitable for drinking purposes, domestic use and irrigation. The current research concluded that from the foregoing hydrological study and the determined values of hydraulic conductivity and transmissivity, the Quaternary aquifer is classified as ranging between moderate and high potential aquifer. The high potentiality of the aquifer is detected close to the Nile River. In addition to the representative groundwater samples showing the isotope signature of the Nile River sample, this means that all these wells have the same source of recharge (meteoric water of the Nile River).