HYDROGEOLOGICAL AND GEOPHYSICAL STUDIES FOR EVALUATION OF GROUNDWATER POTENTIALITIES AT CAIRO-BELBEIS DISTRICT, EGYPT

Abstract

The area of study lies to the northeast of Cairo city between Lat's. 30° 8' and 30° 24' N and Long's 31° 23' and 31° 44' E covers an area of about 700 km2 lsmailia Canal borders the area ti•om the north and Cairo-Suez road from the south. Reclamation of desert lands and establishment of new communities in the studied area constitute an important national target During the last twenty years, several thousands Feddans of the Egyptian desert were reclaimed and new communities were originated. The studied area was given a priority of these developments including the generation of several new communities as EI-Salaam_ El-Obour, EI-Nahda, El-Sherouk and Tenth of Ramadan cities. Most of these communities are based on local groundwater resources. This work aims_ principally, to evaluate the potentiality of the groundwater aquifers of the area using geophysical, hydrogeological and hydrogeochemical investigations Topographically, the studied area represents a wide morphotectonic plain, sloping to the north and northwest At the middle part, structural ridges extending nearly E-W and represented by G Umm-Qamar and G. El-Hamza rise to more than 200 m above sea level at some points. Geomorphologically such ridges separate two wide morphotectonic depressions, Heliopolis depression to the south and the Nile Delta t!-inges to the north. However, the studied area is crossed by dense hydrographic system originating from the scattered ridges at the east, southeast and south of the area and debauching to the northwest direction. Such system reflects the significant role of past recharge during the wet periods of the Pleistocene.

Stratigraphically, the studied area is covered by formations ranging in age from the Quaternary to Cretaceous. The maximum drilled Quaternary succession is 240 m thick in well Nos. 26 and E3 in the north and consists of sands and gravels with clay lenses and represents the Pleistocene age. In addition, sand dunes of El-Khanka and G. El-Asfar represent the Holocene age. The Pliocene section is composed mainly of pyretic clays. The maximum drilled Miocene thickness is 285 in well No. 3 to the south. The exposed lithologic units range from sandstones, sandy limestones, shales and marls of Miocene to sands, clays and gravels with some local scattered Holocene sand dunes and wadi deposits of Pleistocene. Some Oligocene basalts overlying sand beds are exposed at the eastern rim of the area.