Digital Signal Processing Reference
In-Depth Information
5.1.
INTRODUCTION
The Nile Delta and the Nile river valley of Egypt is one of the oldest agricultural areas in the world,
having been under continuous cultivation for at least 5000 years. The arid climate of Egypt,
charaterised by high evaporation rates (1500-2400 mm/year) and little rainfall (5-200 mm/year) leaves
the river as the main fresh water supply. Under these arid conditions, no natural soil development can
take place,
figure (5-1)
shows the Nile Delta
region and Nile valley. The river Nile, therefore,
is the life of the country providing:
Fresh
water
supply
for
agriculture,
industry
and
domestic use;
Hydro-electric power generation;
Navigation
Available information shows that the river Nile,
its branches, canals and the drains are suffering
from an alarming increase in pollution through
wastewater. Total Dissolved Solids (
TDS
) range
from 130 mg/l in Lake Nasser to 200-250 mg/l at
the Delta barrages. The pH increases from 7.7 at
High Aswan Dam to 8.5 in the Nile Delta. The
BOD
as a result of human activities mainly shows
a random distribution but only occasionally
exceeds the standard of 6 mg/l (especially in the
downstream sections). The random distribution is
the result of point discharges and self-purification
of the river.
Figure (5-1): Nile river valley and delta
As a result the dissolved oxygen only drops in exceptional cases below the threshold of 5 mg/l. Nitrate
and ammonium show hardly any exceedence of the current standards, except for ammonium at one
certain locations. The spatial distribution of faecal coliform varies strongly. The standard is
significantly exceeded during the summer months at a few locations in Upper as well as Lower Egypt.
It is most important that the Nile maintains its self-purification capacity. However, enormous loads of
pollutant matter are released to the system. To what extent the Nile sediment is contaminated with
accumulated constituents is not known.
5.2.
THE PRESENT STATUS OF THE NILE DELTA AS AN IRRIGATED AGRICULTURAL
WATERSHED
The Nile Delta extends between Latitudes 30
o
10
/
N and 31
o
30
/
N about 23 Km. To the north of
Cairo, where the Nile Valley opens out to form a triangular area of about 49600 km
2
. This area is
considered one of the most fertile and intensively cultivated regions of the world. Many centuries ago
seven branches of the Nile used to flow through the delta, but during time and different geological
eras, many geological changes and formations have taken place and the Nile river has been diverted
into two main branches, the Rosseta branch on the west side of the Delta, and the Damietta branch on
the east side. The Delta Barrages about 26 Km. North of Cairo, control the water supply to these two
branches. The Delta has a slope of about 9 cm./km. To the north west, it is bordered by higher deserts
from east and west. On the northern estuarine boundaries a series of shallow lakes occupy a great part
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