393
The tanks are water storage reservoirs. Some
of the signifi cant tanks are Heggeri tank, Naregal
tank, Jakkur tank, Lalbagh tank, Sankey tank,
Hebbal tank, Yelahanka tank, Tailur tank, Kandur
tank, Masoor tank, Gangibhavi tank near Saundatti
tank, Dhupdal tank, etc. Some of these tanks are
situated in and around Bengaluru City. Out of
these, the Heggeri tank and the Naregal tank are
situated near Haveri in Dharwad District. The former is a semi-permanent tank of 88 ha having a
maximum depth of 4 m. The water is circum-neutral with pH ranging from 6.9 to 7.0. There is a
prolifi c growth of AM. It was constructed in 1134
AD and is a bathing site for pilgrims on 14 January
every year. The tank is fed by two major inlets and
is used for irrigation purposes from May to
February. On the other hand, the Naregal tank is a
semi-permanent tank of 122 ha with a maximum
depth of 3 m. The wetland has extensive fl oating
and submerged AM. Water of the tanks is mostly
used for irrigation, domestic purposes, etc.
Some of the AM in the tanks are Ipomoea,
Hydrilla, Vallisneria, Nelumbo, Scirpus, etc.
Some of the tanks are stocked with fi shes and
fi shing is done. However, most of these tanks are
not very well protected except a few, like
Gangibhavi and Renuka Sagar tanks. As such,
there is unlawful hunting in some of the tanks.
Hence, some of them have been proposed for
welfare of wildlife. Many of the tanks are places
of pilgrimage and recreation.
Further, some of the tanks are habitats for resident and migratory waterfowls. Tailur tanks usually
harbour large number of waterfowls and accounted
for about 85 % of the total birds observed. Some of
the tanks also contain amphibians.
A brief account of important lentic bodies in
Karnataka is given below.
20.3.7.7 Tungabhadra Reservoir
It is a 37,843-ha reservoir around Hospet in
Karnataka. The qualitative studies of plankton
undertaken in here showed a seasonal variation
with distinct summer and winter peaks.
Zooplankton was relatively higher during summer
and phytoplankton during winter. Quantitative
studies of plankton by tow net hauls were also
comparable in their seasonal variation. This reservoir was found to show a trend towards increase
in plankton production during a year (commonly
termed ‘biological year’ by some authors). Studies
revealed that water transparency ranged between
20.2 and 125.0 cm. Surface water temperature
ranged from 23.9 to 30.9 °C, while the bottom
water temperature had varied from 22.6 to
29.4 °C. The water pH ranged from 7.61 to 8.36.
DO ranged from 4.38 to 7.85 mg/l; FCO 2 varied
from 1.65 to 2.4 mg/l. The reservoir exhibited an
almost clinograde oxygen curve (i.e. temperature
and DO showing a uniform variation at different
depths) during February to May and orthograde
oxygen distribution (i.e. no variation in temperature and DO at all depths) during September to
January. Further, phosphate and nitrate-rich rain
washings of SW monsoon seemed to show greater
impact on productivity of plankton than the NE
monsoon (Govind 1963 ). During stagnation
period, when DO often fully disappears, reduction of Fe(OH) 3 takes place with the liberation of
phosphorus. However, the DO was, perhaps,
never found to be fully absent at the bottom
throughout the year. As such, the only method by
which the absorbed nutrients which could be
brought in Free State again, is probably, by turbulent water movements in the lentic body.
Diatoms were found to predominate over other
phytoplankton. Diatomaceae formed c 25.6 % of
phytoplankton and 25.7 % of the food of Puntius
kolus and 18 % of the food of P. sarana. However,
amongst the cyanophytes, Anabaena was found
to be abundant. However, a uniform distribution
of phytoplankton was evident during the cold
season. Occasional phytoplankton scarce was,
probably, due to decrease in transparency. The
zooplankton consisted of Rotifera (10.6 %),
Cladocera (10 %), Copepoda (58 %) and
Ostracoda (being very rare) (Govind 1963 ).
20.3.7.8 Nuggikari Lake in Dharwar,
Mysore
It is a 20-acre freshwater wetland (commonly
called lake) situated on the eastern side, about
8 km away from Dharwar City, in Karnataka
(earlier Mysore) province. It is surrounded by
hillocks on all sides, so that the lake forms a deep
depression at the centre of the region. Three
20.3 Wetlands of Other Regions in India
The tanks are water storage reservoirs. Some
of the signifi cant tanks are Heggeri tank, Naregal
tank, Jakkur tank, Lalbagh tank, Sankey tank,
Hebbal tank, Yelahanka tank, Tailur tank, Kandur
tank, Masoor tank, Gangibhavi tank near Saundatti
tank, Dhupdal tank, etc. Some of these tanks are
situated in and around Bengaluru City. Out of
these, the Heggeri tank and the Naregal tank are
situated near Haveri in Dharwad District. The former is a semi-permanent tank of 88 ha having a
maximum depth of 4 m. The water is circum-neutral with pH ranging from 6.9 to 7.0. There is a
prolifi c growth of AM. It was constructed in 1134
AD and is a bathing site for pilgrims on 14 January
every year. The tank is fed by two major inlets and
is used for irrigation purposes from May to
February. On the other hand, the Naregal tank is a
semi-permanent tank of 122 ha with a maximum
depth of 3 m. The wetland has extensive fl oating
and submerged AM. Water of the tanks is mostly
used for irrigation, domestic purposes, etc.
Some of the AM in the tanks are Ipomoea,
Hydrilla, Vallisneria, Nelumbo, Scirpus, etc.
Some of the tanks are stocked with fi shes and
fi shing is done. However, most of these tanks are
not very well protected except a few, like
Gangibhavi and Renuka Sagar tanks. As such,
there is unlawful hunting in some of the tanks.
Hence, some of them have been proposed for
welfare of wildlife. Many of the tanks are places
of pilgrimage and recreation.
Further, some of the tanks are habitats for resident and migratory waterfowls. Tailur tanks usually
harbour large number of waterfowls and accounted
for about 85 % of the total birds observed. Some of
the tanks also contain amphibians.
A brief account of important lentic bodies in
Karnataka is given below.
20.3.7.7 Tungabhadra Reservoir
It is a 37,843-ha reservoir around Hospet in
Karnataka. The qualitative studies of plankton
undertaken in here showed a seasonal variation
with distinct summer and winter peaks.
Zooplankton was relatively higher during summer
and phytoplankton during winter. Quantitative
studies of plankton by tow net hauls were also
comparable in their seasonal variation. This reservoir was found to show a trend towards increase
in plankton production during a year (commonly
termed ‘biological year’ by some authors). Studies
revealed that water transparency ranged between
20.2 and 125.0 cm. Surface water temperature
ranged from 23.9 to 30.9 °C, while the bottom
water temperature had varied from 22.6 to
29.4 °C. The water pH ranged from 7.61 to 8.36.
DO ranged from 4.38 to 7.85 mg/l; FCO 2 varied
from 1.65 to 2.4 mg/l. The reservoir exhibited an
almost clinograde oxygen curve (i.e. temperature
and DO showing a uniform variation at different
depths) during February to May and orthograde
oxygen distribution (i.e. no variation in temperature and DO at all depths) during September to
January. Further, phosphate and nitrate-rich rain
washings of SW monsoon seemed to show greater
impact on productivity of plankton than the NE
monsoon (Govind 1963 ). During stagnation
period, when DO often fully disappears, reduction of Fe(OH) 3 takes place with the liberation of
phosphorus. However, the DO was, perhaps,
never found to be fully absent at the bottom
throughout the year. As such, the only method by
which the absorbed nutrients which could be
brought in Free State again, is probably, by turbulent water movements in the lentic body.
Diatoms were found to predominate over other
phytoplankton. Diatomaceae formed c 25.6 % of
phytoplankton and 25.7 % of the food of Puntius
kolus and 18 % of the food of P. sarana. However,
amongst the cyanophytes, Anabaena was found
to be abundant. However, a uniform distribution
of phytoplankton was evident during the cold
season. Occasional phytoplankton scarce was,
probably, due to decrease in transparency. The
zooplankton consisted of Rotifera (10.6 %),
Cladocera (10 %), Copepoda (58 %) and
Ostracoda (being very rare) (Govind 1963 ).
20.3.7.8 Nuggikari Lake in Dharwar,
Mysore
It is a 20-acre freshwater wetland (commonly
called lake) situated on the eastern side, about
8 km away from Dharwar City, in Karnataka
(earlier Mysore) province. It is surrounded by
hillocks on all sides, so that the lake forms a deep
depression at the centre of the region. Three
20.3 Wetlands of Other Regions in India