95
6.9.1 High Altitude (HA) Lentic
Bodies of India
HA lentic bodies depict typical ecological characteristics. In India, the HA lentic bodies are mostly
situated in the Himalayan region. The Himalayas
extend for about 2,500 km from west to east and
are drained by 19 major (and many minor) rivers,
which have a close relation (of different types)
with the HA lakes. Thus, most of the HA lakes of
India cannot be studied completely in isolation
with the Himalayan rivers. As such, a brief account
of the Himalayan rivers is appended here. Out of
the Himalayan rivers, the Ganges, the Brahmaputra
and the Indus are amongst some of the largest rivers in the world, each having a mountain catchment of about 160,000 km
2
. Of the remaining
rivers, 5 belong to the Indus system, of which the
Beas and the Sutlej have a total catchment area of
80,000 km
2
; 9 (Ganga, Yamuna, Ramganga, KaliSharda, Karnali, Rapti, Gandak, Bhagmati, Kosi)
belong to the Ganga system, draining nearly
150,000 km
2
; and about 12 (notably Tista, Raidak,
Manas, etc.) belong to the Brahmaputra system,
draining another 110,000 km
2
.
Further, the Ganga has fi ve source rivers, namely,
the Bhagirathi, the Mandakini, the Alaknanda, the
Dhauliganga and the Pindar. They join at different
‘Prayag’ to form the main ‘Ganga’, which emerges
from the mountains at Rishikesh and fl ows down
to Hardwar and to the northern plains of India.
The River Brahmaputra, on the other hand,
known as Yarlung Zangbo Jiang (Tsangpo) in
Tibet, enters India under the name Dihang in
Arunachal Pradesh. At its border with Assam, it is
joined by the Dibang and the Lohit, and from that
point, turning west, the river is known as the
Brahmaputra. The river carries clear water with
little silt in Tibet, but on its entry into India, the silt
load increases. The river causes heavy fl oods during the southwest monsoon season. River Barak is
also a signifi cant river in the Himalayan system.
The River Indus originates from the Himalayas
and greater part of it fl ows through Pakistan.
The Himalayas could be broadly classifi ed
into four divisions from south to north, namely,
(a) the Siwaliks, (b) the Lesser Himalayas, (c) the
Greater Himalayas and (d) the Trans-Himalayas.
Further, in the Himalayas, two other types of
zones could be distinguished on the basis of
other grounds, namely, (a) the rhithron zone ,
characterised by a monthly mean temperature of
17.3 °C, high DO (usually l0.l mg l
−1
), fast current
(0.9–1.8 m s
−1 ) and turbulent waters. The substratum is generally with bedrocks and boulders
and with occasional pools. The fi sh of this zone
are stenothermic, such as brown trout and snow
trout ( Schizothorax richardsonii , S. esocinus and
Schizothoraichthys progastus ). (b) The potamon
zone is bordered by the rhithron zone. This zone
usually has a higher mean water temperature of
22.1 °C, DO 8.0 mg l
−1 , current velocity 0.5–
0.7 m s
−1 and so on. The substratum consists of
boulders, cobbles, gravels, pools with occasional
patches of AM. The fi sh fauna is eurythermic or
warm- stenothermic ( Labeo dero , Tor putitora
and Garra gotyla ).
Further, in the physiography of the Himalayas,
the forest or vegetation cover forms an important
element. Subtropical, temperate and alpine zones
of vegetation are encountered as one moves from
sub-Himalayan tracts to the snowy ranges.
Lakes situated in Jammu and Kashmir ( J & K) ,
in Himachal Pradesh (HP), in Uttarakhand
(UKh) , Sikkim, Arunachal Pradesh, Meghalaya,
Mizoram, etc., are the major HA lakes in the
Himalayan region, and its extension.
6.9.1.1 Fish
The fi sh species distribution in the Himalayan
waterbodies, particularly streams, depends on
the fl ow rate, nature of substratum, water temperature and the availability of food. In torrential streams, Sehgal (1988) identifi ed a number
of zones on the basis of dominant fi sh species
and the hydrographical features: (i) headwater
zone inhabited by rheophilic species of loaches
and catfi shes ( Nemacheilus sp., and Glyptosternon
reticulatum ); (ii) large stream zone, formed by
the joining of headwater streams, inhabited by
Diptychus maculatus and Nemacheilus spp. In
the upper reaches or the most torrential reaches
of this zone, rheophilic species of the snow
trouts Schizothoraichthys esocinus , S. progastus ,
Schizothorax richardsonii and Schizopygopsis
stoliczkae occur. The intermediate reaches of
6.9 High Altitude (HA) Lentic Bodies
6.9.1 High Altitude (HA) Lentic
Bodies of India
HA lentic bodies depict typical ecological characteristics. In India, the HA lentic bodies are mostly
situated in the Himalayan region. The Himalayas
extend for about 2,500 km from west to east and
are drained by 19 major (and many minor) rivers,
which have a close relation (of different types)
with the HA lakes. Thus, most of the HA lakes of
India cannot be studied completely in isolation
with the Himalayan rivers. As such, a brief account
of the Himalayan rivers is appended here. Out of
the Himalayan rivers, the Ganges, the Brahmaputra
and the Indus are amongst some of the largest rivers in the world, each having a mountain catchment of about 160,000 km
2
. Of the remaining
rivers, 5 belong to the Indus system, of which the
Beas and the Sutlej have a total catchment area of
80,000 km
2
; 9 (Ganga, Yamuna, Ramganga, KaliSharda, Karnali, Rapti, Gandak, Bhagmati, Kosi)
belong to the Ganga system, draining nearly
150,000 km
2
; and about 12 (notably Tista, Raidak,
Manas, etc.) belong to the Brahmaputra system,
draining another 110,000 km
2
.
Further, the Ganga has fi ve source rivers, namely,
the Bhagirathi, the Mandakini, the Alaknanda, the
Dhauliganga and the Pindar. They join at different
‘Prayag’ to form the main ‘Ganga’, which emerges
from the mountains at Rishikesh and fl ows down
to Hardwar and to the northern plains of India.
The River Brahmaputra, on the other hand,
known as Yarlung Zangbo Jiang (Tsangpo) in
Tibet, enters India under the name Dihang in
Arunachal Pradesh. At its border with Assam, it is
joined by the Dibang and the Lohit, and from that
point, turning west, the river is known as the
Brahmaputra. The river carries clear water with
little silt in Tibet, but on its entry into India, the silt
load increases. The river causes heavy fl oods during the southwest monsoon season. River Barak is
also a signifi cant river in the Himalayan system.
The River Indus originates from the Himalayas
and greater part of it fl ows through Pakistan.
The Himalayas could be broadly classifi ed
into four divisions from south to north, namely,
(a) the Siwaliks, (b) the Lesser Himalayas, (c) the
Greater Himalayas and (d) the Trans-Himalayas.
Further, in the Himalayas, two other types of
zones could be distinguished on the basis of
other grounds, namely, (a) the rhithron zone ,
characterised by a monthly mean temperature of
17.3 °C, high DO (usually l0.l mg l
−1
), fast current
(0.9–1.8 m s
−1 ) and turbulent waters. The substratum is generally with bedrocks and boulders
and with occasional pools. The fi sh of this zone
are stenothermic, such as brown trout and snow
trout ( Schizothorax richardsonii , S. esocinus and
Schizothoraichthys progastus ). (b) The potamon
zone is bordered by the rhithron zone. This zone
usually has a higher mean water temperature of
22.1 °C, DO 8.0 mg l
−1 , current velocity 0.5–
0.7 m s
−1 and so on. The substratum consists of
boulders, cobbles, gravels, pools with occasional
patches of AM. The fi sh fauna is eurythermic or
warm- stenothermic ( Labeo dero , Tor putitora
and Garra gotyla ).
Further, in the physiography of the Himalayas,
the forest or vegetation cover forms an important
element. Subtropical, temperate and alpine zones
of vegetation are encountered as one moves from
sub-Himalayan tracts to the snowy ranges.
Lakes situated in Jammu and Kashmir ( J & K) ,
in Himachal Pradesh (HP), in Uttarakhand
(UKh) , Sikkim, Arunachal Pradesh, Meghalaya,
Mizoram, etc., are the major HA lakes in the
Himalayan region, and its extension.
6.9.1.1 Fish
The fi sh species distribution in the Himalayan
waterbodies, particularly streams, depends on
the fl ow rate, nature of substratum, water temperature and the availability of food. In torrential streams, Sehgal (1988) identifi ed a number
of zones on the basis of dominant fi sh species
and the hydrographical features: (i) headwater
zone inhabited by rheophilic species of loaches
and catfi shes ( Nemacheilus sp., and Glyptosternon
reticulatum ); (ii) large stream zone, formed by
the joining of headwater streams, inhabited by
Diptychus maculatus and Nemacheilus spp. In
the upper reaches or the most torrential reaches
of this zone, rheophilic species of the snow
trouts Schizothoraichthys esocinus , S. progastus ,
Schizothorax richardsonii and Schizopygopsis
stoliczkae occur. The intermediate reaches of
6.9 High Altitude (HA) Lentic Bodies