148
lake lying NW of Nairobi, outside the town of
Naivasha in Kenya. The town of Naivasha (formerly East Nakuru) lies on the northeast edge of
the lake. It is a part of the Great Rift Valley. The
name is derived from the local Maasai name
‘Nai’posha’, meaning ‘rough water’ because of
the sudden storms which generally arise. Further,
the lake is at the highest elevation of the Kenyan
Rift Valley at 1,890 m in a complex geological
combination of volcanic rocks and sedimentary
deposits from a larger lake of Pleistocene era.
The lake has a maximum depth, average and surface area of 30 m, 6 m and 139 km
2 , respectively.
It is surrounded by a swamp which covers an area
of 64 km
2 , but this can vary largely depending on
rainfall. The deepest area of the lake is at Crescent
Island. Apart from transient streams, the lake is
fed by the perennial Malewa and Gilgil rivers.
There is no visible outlet, but it is assumed to
have an underground outfl ow, since the lake
water is relatively fresh. Njorowa Gorge used to
form the lake’s outlet.
History
Between 1937 and 1950, the lake was used as a
landing place for fl ying boats of the Imperial
Airways passenger and mail service along a route
from Southampton in Britain to South Africa. It
linked Kisumu and Nairobi. Joy Adamson, the
author of Born Free, lived on the shores of the
lake in the mid-1960s. On the shores of the lake
is the Djinn Palace, which gained notoriety in the
Happy Valley days between the two world wars.
It now forms part of the Oserian fl ower farm. In
1999 the Lake Naivasha Riparian Association
received the Ramsar Wetland Conservation
Award for its conservation efforts regarding the
Lake Naivasha Ramsar site.
Ecology
The lake is home to a rich diversity of wildlife
including >400 different species of birds and a
sizeable population of hippos. The fi sh community in the lake has been highly variable over
time, infl uenced by changes in climate, fi shing
efforts and the introduction of invasive species.
The most recent shift in the fi sh population followed the accidental introduction of common
carp in 2001. However, in 2010, common carp
accounted for >90 % of the total weight of
fi shes caught from the lake. In addition to above,
there are two smaller lakes in the vicinity of
Lake Naivasha, namely, Lake Oloiden and Lake
Sonachi (a green crater lake). The Crater
Lake Game Sanctuary lies nearby, while the lake
shore is known for its population of European
immigrants and settlers.
Agriculture and Industry
Floriculture forms the main industry around the
lake. However, the largely unregulated use of
lake water for irrigation is reducing the level of
the lake and is the subject of concern in Kenya.
Incidentally, the lake had dried up almost completely in the 1890s. Having refi lled, water levels
are now dropping again. Nevertheless, fi shing in
the lake is also another source of earning livelihood for the local inhabitants. Further, in 1981,
the fi rst geothermal plant for Lake Naivasha was
commissioned. By 1985, a total of 45 MW of
electricity was generated in the area. In this connection, it may be noted here that the water level
of Lake Naivasha reached a low level of 0.6 m
(depth) in 1945. But the water level rose again,
with minor drops, to reach a maximum depth of
6 m (approx.) in 1968. There was another major
decline of the water level in 1987. This led to
increased concern in the future of geothermal
industry. It was speculated that Lake Naivasha
underground water might be feeding the geothermal reservoir at Olkaria. Hence, the decline in the
lake water might affect the future of the geothermal industry.
Okavango Delta in Botswana
The Okavango Delta (or Okavango Swamp ), in
Botswana, is a large inland Delta, formed where
the Okavango River reaches a tectonic trough in
the central part of the endorheic basin of the
Kalahari. This delta has been described in detail
in Chap. 24 .
6.9.2.11 High Altitude Lakes
in the USA
There are a number of HA lakes in the USA. An
account of some of these is given below.
6 Lakes of the World
lake lying NW of Nairobi, outside the town of
Naivasha in Kenya. The town of Naivasha (formerly East Nakuru) lies on the northeast edge of
the lake. It is a part of the Great Rift Valley. The
name is derived from the local Maasai name
‘Nai’posha’, meaning ‘rough water’ because of
the sudden storms which generally arise. Further,
the lake is at the highest elevation of the Kenyan
Rift Valley at 1,890 m in a complex geological
combination of volcanic rocks and sedimentary
deposits from a larger lake of Pleistocene era.
The lake has a maximum depth, average and surface area of 30 m, 6 m and 139 km
2 , respectively.
It is surrounded by a swamp which covers an area
of 64 km
2 , but this can vary largely depending on
rainfall. The deepest area of the lake is at Crescent
Island. Apart from transient streams, the lake is
fed by the perennial Malewa and Gilgil rivers.
There is no visible outlet, but it is assumed to
have an underground outfl ow, since the lake
water is relatively fresh. Njorowa Gorge used to
form the lake’s outlet.
History
Between 1937 and 1950, the lake was used as a
landing place for fl ying boats of the Imperial
Airways passenger and mail service along a route
from Southampton in Britain to South Africa. It
linked Kisumu and Nairobi. Joy Adamson, the
author of Born Free, lived on the shores of the
lake in the mid-1960s. On the shores of the lake
is the Djinn Palace, which gained notoriety in the
Happy Valley days between the two world wars.
It now forms part of the Oserian fl ower farm. In
1999 the Lake Naivasha Riparian Association
received the Ramsar Wetland Conservation
Award for its conservation efforts regarding the
Lake Naivasha Ramsar site.
Ecology
The lake is home to a rich diversity of wildlife
including >400 different species of birds and a
sizeable population of hippos. The fi sh community in the lake has been highly variable over
time, infl uenced by changes in climate, fi shing
efforts and the introduction of invasive species.
The most recent shift in the fi sh population followed the accidental introduction of common
carp in 2001. However, in 2010, common carp
accounted for >90 % of the total weight of
fi shes caught from the lake. In addition to above,
there are two smaller lakes in the vicinity of
Lake Naivasha, namely, Lake Oloiden and Lake
Sonachi (a green crater lake). The Crater
Lake Game Sanctuary lies nearby, while the lake
shore is known for its population of European
immigrants and settlers.
Agriculture and Industry
Floriculture forms the main industry around the
lake. However, the largely unregulated use of
lake water for irrigation is reducing the level of
the lake and is the subject of concern in Kenya.
Incidentally, the lake had dried up almost completely in the 1890s. Having refi lled, water levels
are now dropping again. Nevertheless, fi shing in
the lake is also another source of earning livelihood for the local inhabitants. Further, in 1981,
the fi rst geothermal plant for Lake Naivasha was
commissioned. By 1985, a total of 45 MW of
electricity was generated in the area. In this connection, it may be noted here that the water level
of Lake Naivasha reached a low level of 0.6 m
(depth) in 1945. But the water level rose again,
with minor drops, to reach a maximum depth of
6 m (approx.) in 1968. There was another major
decline of the water level in 1987. This led to
increased concern in the future of geothermal
industry. It was speculated that Lake Naivasha
underground water might be feeding the geothermal reservoir at Olkaria. Hence, the decline in the
lake water might affect the future of the geothermal industry.
Okavango Delta in Botswana
The Okavango Delta (or Okavango Swamp ), in
Botswana, is a large inland Delta, formed where
the Okavango River reaches a tectonic trough in
the central part of the endorheic basin of the
Kalahari. This delta has been described in detail
in Chap. 24 .
6.9.2.11 High Altitude Lakes
in the USA
There are a number of HA lakes in the USA. An
account of some of these is given below.
6 Lakes of the World