545
the Okavango River reaches a tectonic trough
in the central part of the endorheic basin of the
Kalahari. The Okavango is produced by seasonal fl ooding. This habitat attracts animals
from kilometres around and creating one of
Africa’s greatest concentrations of wildlife.
The delta is very fl at, with <2 m variation in
height across its 15,000 km
2 . Every year,
approx. 60 % of the water is transpired by
plants and 36 % by evaporation, 2 % percolates into the aquifer system and 2 % fl ows
into Lake Ngami. The delta’s profuse greenery is not the result of a tropical climate.
Rather, it is an oasis in an arid country. The
Okavango Delta is both a permanent and seasonal home to a wide variety of wildlife. The
most populous large mammal is the lechwe
antelope. The Okavango Delta is home to 71
fi sh species including tigerfi sh, tilapia and catfi sh. They range from 1.4 m (sharptooth catfi sh) to 3.2 cm (Sickle-fi n Barb). Papyrus and
reed rafts make up a large part of the
Okavango’s vegetation. The inhabitants of
Okavango Delta consist of fi ve ethnic groups,
each with its own ethnic identity and
language.
5. The Wetlands of East Africa include the signifi cant Lake Naivasha (Kenya). Lake
Naivasha lies at 1,884 m MSL. It is an FW
lake lying NW of Nairobi in Kenya. The lake
is fed by the perennial Malewa and Gilgil rivers. Lake Naivasha has been further dealt with
in Chap. 6 .
6. In Sudan , Lake Nubia is a part of Lake Nasser
and has much fi shery potential. Thirty species
of fi shes were recorded from Lake Nubia.
7. In Ethiopia , Lake Hayq is an Ethiopian highland lake with an area of 23 km
2 and a maximum depth of well over 80 m. The lake is a
typical fairly African class II lake, but it
differs from other Ethiopian lakes of this class
in the remarkable transparency of its water.
8. In Zimbabwe , Lake McIlwaine is one of the
largest water conservation reservoirs in south
and central African region. Three types of AM
communities are found in the lake, namely,
Phragmitis , Typha and Aponogeton . However,
in areas not directly exposed to wave action,
belts of Typha and Aponogeton become separated by large beds of water lily, namely,
Nymphaea sp., which may fi nd anchorage in
depths as great as 4 m. The bottom deposits
are generally relatively constant throughout
the lake.
Further, the Afram arm of Volta Lake is
shallow. It receives frequent winds, which,
together with the fl oods of the June to
September, create near-isothermal conditions. The upper 10 m is well oxygenated.
Frequent algal blooms of Oscillatoria curviceps , Microcystis aeruginosa , etc., usually occur.
Suggested Readings
Abu Gideiri YB, Ali MT (1973) Preliminary biological
survey of Lake Nubia. Hydrobiologia 46(4):535–541
Amrithalingam C (1965) A guide to the common freshwater fi shes of Sudan. Govt Printing Press, Khartoum
Barning K, Bason J (1969) Possible sedimentation and
seismic effects on the Volta Lake. In: Obeng L (ed)
International symposium on man-made lakes, Accra
Baxter RM, Golobitsh DL (1970) A note on the limnology of Lake Hayq, Ethiopia. Limnol Oceanogr
15:144–149
Mackereth JFH (1963) Some methods of water analysis
for Limnologists. Freshwater Biology Association
Publication no. 21
Munro JL (1966) Limnological survey of Lake McIlwaine,
Rhodesia. Hydrobiologia 55:281–308
Obeng EK (1977) A limnological study of the Afram arm
of Volta Lake. Hydrobiologia 55(3):257–264
Suggested Readings
the Okavango River reaches a tectonic trough
in the central part of the endorheic basin of the
Kalahari. The Okavango is produced by seasonal fl ooding. This habitat attracts animals
from kilometres around and creating one of
Africa’s greatest concentrations of wildlife.
The delta is very fl at, with <2 m variation in
height across its 15,000 km
2 . Every year,
approx. 60 % of the water is transpired by
plants and 36 % by evaporation, 2 % percolates into the aquifer system and 2 % fl ows
into Lake Ngami. The delta’s profuse greenery is not the result of a tropical climate.
Rather, it is an oasis in an arid country. The
Okavango Delta is both a permanent and seasonal home to a wide variety of wildlife. The
most populous large mammal is the lechwe
antelope. The Okavango Delta is home to 71
fi sh species including tigerfi sh, tilapia and catfi sh. They range from 1.4 m (sharptooth catfi sh) to 3.2 cm (Sickle-fi n Barb). Papyrus and
reed rafts make up a large part of the
Okavango’s vegetation. The inhabitants of
Okavango Delta consist of fi ve ethnic groups,
each with its own ethnic identity and
language.
5. The Wetlands of East Africa include the signifi cant Lake Naivasha (Kenya). Lake
Naivasha lies at 1,884 m MSL. It is an FW
lake lying NW of Nairobi in Kenya. The lake
is fed by the perennial Malewa and Gilgil rivers. Lake Naivasha has been further dealt with
in Chap. 6 .
6. In Sudan , Lake Nubia is a part of Lake Nasser
and has much fi shery potential. Thirty species
of fi shes were recorded from Lake Nubia.
7. In Ethiopia , Lake Hayq is an Ethiopian highland lake with an area of 23 km
2 and a maximum depth of well over 80 m. The lake is a
typical fairly African class II lake, but it
differs from other Ethiopian lakes of this class
in the remarkable transparency of its water.
8. In Zimbabwe , Lake McIlwaine is one of the
largest water conservation reservoirs in south
and central African region. Three types of AM
communities are found in the lake, namely,
Phragmitis , Typha and Aponogeton . However,
in areas not directly exposed to wave action,
belts of Typha and Aponogeton become separated by large beds of water lily, namely,
Nymphaea sp., which may fi nd anchorage in
depths as great as 4 m. The bottom deposits
are generally relatively constant throughout
the lake.
Further, the Afram arm of Volta Lake is
shallow. It receives frequent winds, which,
together with the fl oods of the June to
September, create near-isothermal conditions. The upper 10 m is well oxygenated.
Frequent algal blooms of Oscillatoria curviceps , Microcystis aeruginosa , etc., usually occur.
Suggested Readings
Abu Gideiri YB, Ali MT (1973) Preliminary biological
survey of Lake Nubia. Hydrobiologia 46(4):535–541
Amrithalingam C (1965) A guide to the common freshwater fi shes of Sudan. Govt Printing Press, Khartoum
Barning K, Bason J (1969) Possible sedimentation and
seismic effects on the Volta Lake. In: Obeng L (ed)
International symposium on man-made lakes, Accra
Baxter RM, Golobitsh DL (1970) A note on the limnology of Lake Hayq, Ethiopia. Limnol Oceanogr
15:144–149
Mackereth JFH (1963) Some methods of water analysis
for Limnologists. Freshwater Biology Association
Publication no. 21
Munro JL (1966) Limnological survey of Lake McIlwaine,
Rhodesia. Hydrobiologia 55:281–308
Obeng EK (1977) A limnological study of the Afram arm
of Volta Lake. Hydrobiologia 55(3):257–264
Suggested Readings