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April-June, 2020

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Hydrogeochemical Study for sustainable development in Wadi El-Mathula, East Qift city, Eastern Desert, Egypt

Saad A. Mohallel

ABSTRACT: Wadi El-Mathula is one of the promising basins in Upper Egypt. Rain fall, River Nile and return irrigation water represent the main recharging sources for groundwater aquifers in particular Quaternary water bearing. The hydrogeological data of the main aquifers, namely Quaternary and Nubian sandstone water bearing formations were discussed. The Quaternary aquifer occupying delta of Wadi El-Mathula, where it represented by 18 samples has a salinity ranges from fresh (6% of samples) to brackish water (55%) then saline water (39%) showing an increase due east towards the new reclaimed and desert lands, where the values vary from 1320 mg/l to 10622 mg/l with mean value 5381 mg/l. In the Nubian sandstone aquifer (represented by 6 samples) all the groundwater samples are brackish water where the salinity ranges from 1836 to 2682 mg/l with a mean value of 2072 mg/l. Chloride – Sodium water type is considered the main water type where it characterized the majority (67%) of the Quaternary groundwater samples and the majority of Nubian groundwater samples (83%). Calcite and Dolomite dissolution beside the dissolution of halite are the main hydrochemical processes affecting groundwater quality. The chemical types and hypothetical salts as well as the ion ratios indicate meteoric origin for groundwater and dissolution of terrestrial salts. Hydrogeochemical model (PHREEQC 2.8) was used to calculate saturation indices of minerals to the Quaternary and the Nubian sandstone aquifers. The results indicated that the groundwater in the two aquifers is undersaturated with respect to Gypsum and Anhydrite indicating the capacity of groundwater for more mineral dissolution. All samples of the Nubian sandstone and the most samples of the Quaternary groundwater are supersaturated with reference to Calcite, Aragonite and Dolomite. The results of the environmental stable isotopes indicated that the groundwater in study area is discriminated into two distinctive groups. Group (I) belonging to the deep flowing well in Laqita area (Nubian aquifer) and group (II) of samples is enriched in their isotopic compositions (Quaternary aquifer). The investigated groundwater is not suitable for drinking purposes. Only 28% of the Quaternary groundwater samples are considered very satisfactory for all classes of livestock and poultry. On the other hand, all the groundwater samples of the Nubian sandstone aquifer are considered very satisfactory for all classes of livestock and poultry. About 5% of the Quaternary groundwater samples are Intermediate quality for irrigation. In addition the majority of the Nubian sandstone groundwater samples (67%) are moderate water quality for irrigation and 17% of the groundwater samples in the same aquifer are Intermediate quality

[ FULL TEXT PDF 60-82 ] DOI: 10.36632/ije/2020.9.2.5

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