scholarly journals Geological conditions and characteristics of the Nubia Sandstone aquifer system and their hydrogeological impacts, Tushka area, south Western Desert, Egypt

2012 ◽  
Vol 50 (1) ◽  
pp. 27-37
2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Saad Younes Ghoubachi

El-Oweinat area is located in southwestern Egypt and is considered to be one of the new land reclamation projects in the Western Desert. The Nubian Sandstone aquifer has high potentiality and good groundwater quality. The results of geologic and hydrogeologic studies reveal that the Six Hills sandstone aquifer represents the sole groundwater resource used for all purposes (agriculture, drinking, domestic, livestock and poultry) in East El-Oweinat area. The Six Hills sandstone aquifer overlies directly the Precambrian basement rocks. The concerned aquifer exists under unconfined conditions as it is exposed on the surface. The hydrogeological cross sections show that the fully saturated thickness of the Six Hills sandstone aquifer ranges between 150.2 m and 651 m and increases towards the west. The groundwater generally flows towards the northeast direction with an average hydraulic gradient of 0.6 ‰. The calculated groundwater volume of the Six Hills sandstone aquifer in East El-Oweinat area (4,340 km2) reaches 350 bcm of fresh water. The comparison of the depth to water in the same monitoring wells during 14 years (2003 and 2016) reveals that the head decline rate in groundwater depths were ranging between 5 cm/year and 80 cm/year. The pumping rate increased from 600,000 m3/day in year 2003 to 3,600,000 m3/day in 2016. The average transmissivity attains 2,060 m2/day reflecting the high potential of the Six Hills sandstone aquifer in East El-Oweinat area. The groundwater flow model (MODFLOW) has been used to investigate the impact of groundwater withdrawal on groundwater levels for sustainable groundwater management. Four scenarios were applied to predict the probable head changes in the Six Hills sandstone aquifer and their impact on the availability of groundwater. The fourth scenario is recommended in order to sustain the groundwater resources in the study area and keep the drawdown rates in the range of 0.66 m/year through reducing the present discharging rates (10,000 m3/day/well) by about 40%.


2020 ◽  
Vol 8 (12) ◽  
pp. 1018
Author(s):  
Panayota Makri ◽  
Eleni Stathopoulou ◽  
Demetrios Hermides ◽  
George Kontakiotis ◽  
Stergios D. Zarkogiannis ◽  
...  

The study area is the Thriassion Plain, an important area, in antiquity, surrounding the famous ancient town of Eleusis, 20 km west of Athens. The modern town and port and the entire area were heavily industrialized (1965–1995) coupled with unregulated urban and agricultural development. The presence of two crude oil refineries and other oil-related industries have strongly impacted the entire environment, including soils, waters and sediments of the broader area. The purpose of this work is to better understand how a multi-layered groundwater system affects the potential underground spread of certain fuel volatile compounds, namely the BTEX (benzene, toluene, ethylbenzene and total xylenes) as well as their attenuation after their direct or indirect release into the aquifer system. The spatial distribution of BTEX in groundwaters show that they were concentrated mainly in four rather restricted locations. Three of them were spotted, as expected, in the close vicinity of known pollution sources (a military airfield and two crude oil refineries). The other one corresponds to an abandoned site with no outstanding pollution sources where wells exist, eventually used for illegal dumping of oily wastes. It is important that the concentrations decrease significantly from autumn to spring. This decline could be characterized as natural attenuation, related to natural dilution phenomena and a flushing out of pollutants discharging through underwater springs to the sea during the rainy period (October to April). This, in turn, could be associated to the specific geological conditions affecting the hydrology, such as the unconsolidated non-permeable deposits and the multi layered formations of the area’s aquifers.


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