TITLE:
Geophysical Evaluation for Evidence of Recharging the Pleistocene Aquifer at El-Nubariya Area, West Nile Delta, Egypt
AUTHORS:
Ahmed Khalil, Khamis Mansour, Taha Rabeh, Alhussein Basheer, Mohamed Abdel Zaher, Kamal Ali
KEYWORDS:
Geoelectric; Geomagnetic; Aquifer; Groundwater; Hydrogeology
JOURNAL NAME:
International Journal of Geosciences,
Vol.5 No.3,
March
27,
2014
ABSTRACT:
With ever
increasing demands on water resources, Egypt is facing increasing water needs,
demanded by a rapidly growing population, by higher standards of living and by
an agricultural policys. West Nile Delta represents a new agricultural area
where the reclaimed lands are irrigated with groundwater in addition to surface
water. The evaluation of groundwater aquifers in West Nile Delta area requires
information about the extension, depth and distribution and source of
recharging these aquifers. In this work, an integrated study using geoelectric,
geomagnetic, hydrogeologic and hydrochemistry investigations has been applied
to evaluate groundwater aquifers and to delineate subsurface structures
predominant in the basement rocks at El-Nubariya area, West Nile Delta, Egypt.
Thirty-five Vertical Electrical Soundings (VES) have been applied to identify
the subsurface geoelctric layers predominant in the study area. As well as a
detailed land magnetic survey has been carried out along the study area using
two automatic proton precession magnetometers with an accuracy of 1 nT. These
surveys allowed us to establish the subsurface structures and their relation
with the detected aquifers. The geoelectric results are illustrated along seven
geoelectric profiles and correlated with the lithologic and hydrogeologic data
of drilled wells. The third geoelectric layer represents the water saturated
zone (aquifer) with thickness varies from 14 m to 58 m, increasing to east and
southeast directions. The hydrchemisty anlysis shows that the salinity of the
water aquifer ranges from 600 ppm in the southeast to 3900 ppm in the south.
The major dominant dissolved salt is Nacl. In the east and southeast, the water
type becomes more NaSO4 which refers to dissolution of gypsum in
addition to fertilizers. The magnetic data have been analyzed using horizontal
gradient and 3D magnetic modeling along the locations of geolectric profiles.
The results indicate that the fault structures are trending in E-W, NW-SE and
NE-SW directions. These faults confirm the results obtained from the well
geolectric interpretation. These fault structures act as recharging paths from
lower brackish to upper fresh water aquifers.