The studied area represents one of land reclamation projects on both sides of Cairo-Alexandria Desert Road. Groundwater of the Lower Miocene aquifer plays an essential role for satisfying water requirements for different purposes. The people have now over-pumping the aquifer due intensification of cultivation. The well field comprises 23 wells; ten of them were abandoned during the last few years, while the others are subjected to salt water problem.
The objective was to assess the impact of excessive pumping on groundwater quality of the Lower Miocene aquifer and evaluating water suitability for different purposes. To achieve that, thirteen groundwater samples were collected and chemically analyzed. Computer programs are used for graphical presentation of chemical analyses and re-evaluation of step drawdown tests for some selected wells. Construction of depth to water, water level and salinity maps, besides hydrogeological section were also carried out.
Results indicate that most of wells are operated at relatively high pumping rates accompanied with low efficiencies and specific capacities. Besides, decline of well yields and water deterioration. Therefore, reduction of groundwater withdrawal from such wells is recommended to obtain the highest well efficiency and to achieve long operation life with good water quality.
The hydrogeochemical studies revealed that the total salinity of groundwater ranging from 543 to 871ppm, with the exception of a water sample (well No. 2), that has salinity content reaches 1982ppm. The majority of groundwater is characterized by the presence of NaHCO3 and Na2 SO4 water types of meteoric origin. The presence of MgCl2 type in sample No. (2) indicates mixing of meteoric water with marine water, due to local effects. The hydrochemical coefficient (rCl/rCO3+HCO3) indicates the presence of local salt-water problems at some localities. Possible sources of salt-water enrichment in the Lower Miocene aquifer are either from leakage of saline water from shale and clay inter-beds or due to upward-leakage of old marine water along fault planes from the underlying Oligocene aquifer. Generally, the groundwater in the studied area is suitable for drinking, irrigation, livestock and poultry purposes, except well No (2), which suffers from high salinity water.
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