In the northern part of the Nile delta severe intrusion of the salty Mediter-
ranean water into this aquifer is taking place due to over-exploitation. On
the newly reclaimed land of Gharb en-Nubariya north of the Natron valley,
a vast saline lake has developed owing to both over-pumping and insufficient
drainage.
The fissure limestone (karstic) aquifers
To these belong many wells and springs in different parts of Egypt in the
Western as well as in the Eastern Desert, on Sinai and in the Nile valley,
as for example the springs of Deir Anba Pola and Deir Anba Antonius, the
desert monasteries near the Red Sea, and the mineral springs of Siwa and at
Helwan south of Cairo.