Digital Signal Processing Reference
In-Depth Information
loads. The other main variable is salinity. There is much evidence to show that differences in salinity
tolerance lead to the segregation of fish species.
The five lakes bordering the northern coast of Egypt, together represent 25% of the remaining wetland
habitat in the Mediterranean basin. Residents of these lakes traditionally exploited a wide variety of
resources. Today these lakes face a number of threats to their existence, including large-scale
reclamation and water pollution besides global warming and sea water level rise. Agricultural
authorities, engineers, fishery managers, and conservationists in Egypt and abroad debate about how
best to manage and develop the lake region's resources, but few of these groups understand or
communicate with one another, or with residents of the lake communities (Parmenter, 1991). To study
such an interacting system of drainage networks and lakes suffering from water quality deterioration,
the integrated watershed approach should be taken into consideration. This means that the Delta region
should be divided into several sub-watersheds contributing to the three main components of the Delta
region (Western-Middle-Eastern). These watersheds could be defined according to the outlet points
which are the northern lakes, which in turn are directly affected by upstream conditions. This means
that each sub-watershed should be managed as a complete system taking into consideration the
northern lakes affected by the drainage water discharged from the upstream catchments.
5.4.3.
Nile Delta Northern lakes Ecology
Vegetation
The northern lakes of the /Nile Delta are considered a rich aquatic environment. The Nile Delta was
once known for large papyrus (
Cyperus papyrus
) swamps, but papyrus is now almost absent from the
delta. Vegetation consists of
Phragmites australis, Typha capensis
, and
Juncus maritimus
, with some
small sedges. The Manzala, Burulus and Edko coastal lagoons supports beds of
Ceratophyllum
demersum, Potamogeton crispus
, and
P. pectinatus
around the southern shore as well as dense
phytoplankton. Other typical species found here are
Najas pectinata, Eichhornia crassipes
, and
Cyperus
and
Juncus
spp. that grow along lake shores. The salt tolerant
Halocnemum
spp. and
Nitraria
retusa
grow in marshes along the Mediterranean coast. Farther south along the Nile river, dense
swamp vegetation grows unchecked without the seasonal fluctuations of the river, held back by the
Aswan Dam.
Figure (5-3a,b,
c,d
)
shows the dominant types of vegetation in coastal lakes and Delta
wetlands.
Figure (5-3a): Ceratophyllum demersum Figure (5-3b):
Phragmites Australis
Search WWH ::
Custom Search