Impact of Lake Nasser on the groundwater of the Nubia sandstone aquifer system in Tushka area, South Western Desert, Egypt

AbstractLake Nasser recharges the aquifers in study area by large amount of water increasing the groundwater level upward in the study area and decreasing groundwater salinity. The main result of the current study shows that the seepage water from Lake Nasser attains 24×106m3/year. Lake Nasser is located within the Abu Simbil and Sabaya Formations, which are characterized by a high hydraulic permeability and affected by E–W fault system. The groundwater is exploited from Abu Simbil and Sabaya sandstone aquifers. These aquifers exist under confined to unconfined conditions. The groundwater flows towards the north and northwest direction from Lake Nasser.The groundwater salinity increases towards the northwest direction coinciding with groundwater flow. This water salinity is probably decreased with time. This is mainly referred to the seepage of fresh water from Lake Nasser. The same hypothetical salts are detected in the water of Lake Nasser and the aquifers indicating that the groundwater in the study area is directly recharged from Lake Nasser

Geology of groundwater occurrences of the Lower Cretaceus sandstone aquifer in East Central Sinai, Egypt

The present study focused on investigating the impact of geological setting on the groundwater occurrences of the Lower Cretaceous sandstone aquifer (Malha). The Lower Cretaceous sandstone aquifer is subdivided into 3 units according to their lithological characters for the first time in this present work. The study area is dissected by normal faults with their downthrown sides due north direction. The groundwater flows from southeast recharge area (outcrop) to the northwest direction with an average hydraulic gradient of 0.0035. The hydraulic parameters of the Lower Cretaceous sandstone aquifer were determined and evaluated through 7 pumping tests carried out on productive wells. The Lower Cretaceous aquifer in the study area is characterized by moderate to high potential. The calculated groundwater volume of the Lower Cretaceous aquifer (6300 km2) in the study area attains about 300 bcm, while the estimated recharge to the same aquifer reaches about 44,500 m3/day with an annual recharge of 16 mcm/year. Expended Durov diagram plot revealed that the groundwater has been evolved from Mg-SO4 and Mg-Cl dissolution area types that eventually reached a final stage of evolution represented by a Na-Cl water type. This diagram helps also in identifying groundwater flow direction. The groundwater salinity ranges from 1082 ppm (Shaira) to 1719 ppm (Nakhl), in the direction of groundwater movement towards north