One plausible explanation
for their existence given by Schamp (1977: 12f ) is that the formation of the
depressions of the Western Desert, including Qattara, Wadi en-Natrun, El-
Faiyum and Wadi er-Raiyan, went hand in hand with the formation of the
escarpments in the sedimentary rock layers. Tertiary faults helped expose these
layers to weathering and erosion. The geomorphologically hard layers formed
the escarpments, while those easily erodable formed the foreland basins. The
erosion processes in the forelands came to a standstill when the erosion-base
level reached the groundwater table.
The agricultural exploitation of these vast depressions based on tapping
the Nubian Aquifer System is dealt with in the chapters on groundwater (see
Chapter 6) and land reclamation (see Chapter 8). Since the 1950s the govern-
ment has been cherishing ambitious plans for reclaiming several million acres
of land for agricultural purposes, hoping to settle more than three million
people from the congested Nile valley there. In 1996, however, only about
150,000 persons lived in El-Wadi el-Gedid, and the arable area did not exceed
40,000 acres.