الفهرس 
الغلافOnly 14 pages are availabe for public view
 |  | from | 221 |  |  |
| | | from | 221 | | |
Abstract
Abstract
The Nubian Sandstone Aquifer has been the main source of water in the western desert of Egypt since 1985. The hydraulic head drawdown problem in El-Kharga Oasis constitutes a big problem because it threatens the availability. This aquifer is subject to excessive groundwater withdrawal in the region, causing declines in potentiometric heads and a deterioration of groundwater quality. Consequently, investigations were undertaken to provide baseline water quality information for groundwater management. It is essential to understand the hydrogeochemical processes and its evolution that take place in groundwater systems. The objective of the study is to simulate the groundwater flow system by 3D developing a groundwater flow model depending on the wide-scale data collected from different sources. Also, use a combination of major elements from geochemistry and isotopic tools to identify the hydrochemical processes occurring between water and rocks in the aquifers system by providing information about the origins, migration pathways and mixing of groundwater masses. A total 56groundwater samples were collected from wells in the study area (45 for Nubian Sandstone Aquifer System (NSAS) and 11 for Quaternary Aquifer System (QAS)). The chemical studies of the Quaternary aquifer indicate that the major ion dominance is Na+> Mg2+>Ca2+ and SO42-> Cl- >HCO3- with Na2SO4 chemical water type. On the other hand, the Nubian sandstone aquifer indicate the major ion dominance is Na+> Mg2+>Ca2+ and Cl- > SO42->HCO3- with NaCl water type. The hydrochemical processes results suggest that ion exchange, silicate weathering and dissolution of halite, gypsum and anhydrite processes are the main geochemical processes that influence changes in the chemical composition of the NSAS. Also, the resulted.