CES Technical Report XXM
Energy & Wetland Research Group
Centre for Ecological Sciences,
Indian Institute of Science,
Bangalore - 560012, INDIA
ENV IRONMENT AL IMPACT AS S ES S MENT OF T HE
NAT IONAL LARGE S OLAR T ELES COPE PROJ ECT
AND IT ’S ECOLOGICAL IMPACT IN MERAK AREA
Harish R. Bhat
Durga Madhab Mahapatra
K. Sankara Rao
Environmental Impact Assessment of the National Large Solar
Telescope Project and its ecological impact in Merak area
1 Executive Summary
2 Project Description 5
3 Site survey, selection criteria and reasons for selecting the proposed site
at Pangong Lake:
4 Consideration and evaluation of project alternatives 9
5 Methods used to identify, predict and assess impacts 12
6 Description of the Baseline Environment 12
7 Historic records indicative of the sequence in changes of Pangong lake
8 Study Area: Pangong tso (Site with 10km buffer) 28
9 Land cover Analysis 34
10 Flora 37
11 Fauna: Avian distribution 45
12 Fauna: Mammals, Reptiles... 58
13 Bird Migration 67
14 Impact of the proposed activity on migrant avian population and
15 Water quality 78
16 Environmental Impacts 80
17 EMP: Environment Management Plan 81
18 References 84
Environmental Impact Assessment of the National Large Solar
Telescope Project and its ecological impact in Merak area
A 2-m state-of-the-art telescope (National Large Solar Telescope - NLST) aimed at
understanding the fundamental processes taking place on the Sun has been proposed at Pangong
lake site at Merak due to the optimum atmospheric properties (the number of sunshine hours, sky
brightness and good atmospheric window enabling observations over long periods). This unique
facility with the innovative design and backend instruments will enable observations with an
unprecedented high spatial resolution that will provide crucial information on the nature of
magnetic fields in the solar atmosphere and also night-time astronomy. This being a multi-
purpose telescope, with state of the art post-focus instruments will permit Indian scientists to
carry out cutting edge research towards understanding the fundamental processes taking place on
The proposed NLST would involve the construction and operation of a modified reflecting
Gregorian-type telescope that would deliver images of small part of the sun (300” ×300”) onto
instrument stations mounted on the telescope and on a rotating platform located below the
telescope. The facilities would include: the observatory facility, which includes the telescope
(kept at a height of nearly 26 m), its pier, and the rotating instrument platform, the telescope
enclosure, the telescope building with a diameter of approximately 15 m and an aluminizing
chamber at a separate location sufficiently far off from the site.
Constitution of the team: The current study was undertaken by a multidisciplinary team of
scientists and engineers that comprised of ecologists, environmental engineers, , GIS and remote
sensing experts, botanists, zoologists, soil and water scientists, and wildlife experts. The team
visited the site and carried out field work during 25-28th September 2010.
Aspects/Facets of the study:
Environmental Impact Assessment of the National Large Solar Telescope Project and
its ecological impact in Merak area. This involves land use analysis and investigations
of flora and fauna
Landscape: Land use, Land cover analyses; Biodiversity; Aquatic ecosystem: Soil,
water and sediment characterization, impacts of the proposed work, proposed
environment management plan to mitigate the likely impacts
Study Area: The proposed location for commissioning a 2 m state-of-the-art telescope class
telescope (National Large Solar Telescope (NLST) is at Merak, close to the Pangong Tso Lake
and inside the Changthang Wildlife Sanctuary. Changthang Wildlife Sanctuary is a habitat for
endemic, endangered species, vulnerable, and near threatened species. The area is of adequate
ecological, faunal, floral, geomorphological and natural significance, and also link one protected
area with another. The area of Pangong Tso Wetland is one of the Wet-site of the Changthang
Wildlife Sanctuary. The area of 4000 Sq.Kms stands notified as Wildlife Sanetnary since 19-03-
1987. The same wet-site is protected under the overview of J&K Wildlife Protection Act 1978.
• Land use analysis: Remote sensing data along with collateral data
Ecology and Biodiversity: Field visit, consultation with the local forest
department officials and published literature
a) Documentation of the existing flora in the proposed corridor
b) Documentation of animal paths (bird migratory paths, if any)
c) Documentation of endemic species
d) Assessing the Environmental Impacts
e) Arriving at environmental management plan to achieve the least
disturbance to the existing flora and fauna
Development of Environment Management Plan: This is based on the
understanding of ecological and environmental impacts (if any) –
quantification was done based on the detailed field visit.
1. The Pangong Tso wetland (at elevation of 4258 m), is the longest lake in Ladakh, with
about 50 km stretch within Indian territory and over 100 km long stretch in the Tibetan
plateau of neighbouring China. It is fed by glacial waters and is well known for its deep
blue colour. Over the years, the outflows got blocked and the lake became mildly
brackish. Therefore, except for the locations of fresh glacial waters, the lake does support
marine life evident from under-water plants and algae. The lake is said to be in a
seismically safe zone. It runs between two mountain ranges in the NW to SE direction
which steadily widen towards south of south-east, before bending eastward into China
2. The Pangong Tso Wetland is home to a wide range of fauna ranging from migratory birds
to mammals of various species. The black-necked Siberian crane, bar-headed geese and
waterfowl are recorded at the lake. Many cranes sp. (i.e. species) such as red crowned
crane, bar headed goose and the high souring raptors cross high ranges to enter India and
finally leave towards Africa during the winter. The Siberian birds do also enter the
country through the north eastern Himalayan ranges and traverses through the Western
Ghats and southern parts of India before leading to Africa.
3. During the construction phase, there is likelihood of local disturbance on the silent and
pristine ecosystem. Movement of vehicles and the transfer of raw materials and
consequent noise and vibration would disrupt the local fauna habitat. The salinity of the
water is around 10, 000 mg/l. Special care should be taken for the metals like Fe and Cu,
which have ample chances of a very high corrosion.
4. Earlier studies indicate of increasing water levels and there is gradual submersion of
some elevated regions along the beaches of the lake. The proposed site (incursions into
the lake) has mixed origins which are parts of sedimentary deposits. These necessitate
appropriate structure through geotechnical investigations.
5. During the operation of the telescope, highly focused and concentrated reflected light
attract the birds. The very reflection and glare might disturb the birds passing by the
region. This excessive or obtrusive artificial light which hinders the movement of
organisms is referred as photo pollution or luminous pollution. This reflected light from
the mirror can confuse animal navigation and cause physiological harm. Birds have
tendency to get attracted to the intense light energy, and hit the mirror which might even
damage the mirror.
6. The field investigations and subsequent synthesis of field data indicate that the proposed
project has minimal impact on the environment and appropriate mitigation measures
would help in addressing these impacts.
Environment Management Plan:
ü Suppression of dust during the movement of vehicles –operation phase
ü Construction work and movement of vehicles only during the day time so that the fauna
are not affected during the night.
ü Shadow plate covering the primary mirror protects it from the vision of birds.
ü The mitigation measure involves change in angle to 30 degrees at the heat stop so that the
reflection from the heat stop is diffused and directed towards a far off point in the ground
and hence flying bird/birds are insulated from any reflections.
ü Use of low energy ultrasound transmitters to ward off the birds around the telescope in an
area of around half an acre.
ü Planting of native species of flora would aid as heat sinks
ü Setting up science centre and primary health centre for the employees and local public
(part of the social commitment)
Merak near Pangong lake is the most suitable site for commissioning and operation of National
Large Solar Telescope. The activities will involve minimal environmental impacts. Setting up of
NLST would boost the region as it would provide employment opportunities, and associate
benefits (like medical facilities, education, etc.) to the local people. This also gives visibility to
the region in the global perspective and might prevent further land encroachments. Bird’s death
is reported in migratory path sue to Sky scrapers which are constantly lit (high intensity
Reports reveal that about five million birds, representing about 250 species (most of them are
nocturnal migrants), fly through Chicago twice a year get confused with the night time lights of
high rise buildings. These birds either crash into high intensity reflection of these buildings or get
disoriented causing them to circle around and around, finally setting exhausted in a street tree or
bush. These birds tend to fly into glass windows as they fly towards a reflection. Mitigation
measures adopted by local residents are to dim or turn off decorative lighting late at night and to
minimize the use of bright interior lights during migration season.
In this context, considering the proposed building height of NLST building and implementation
of the suggested mitigation measures (- Shadow plate covering the primary mirror protects it
from the vision of birds; change in angle to 30 degrees at the heat stop so that the reflection from
the heat stop is diffused and directed towards a far off point in the ground and hence flying
bird/birds are insulated from any reflections and use of low energy ultrasound transmitters to
ward off the birds around the telescope in an area of around half an acre) would minimise the
impact on birds.
II Project Description
Description of project rationale: A 2-m state-of-the-art multi-purpose National Large
Solar Telescope (NLST) at Merak with state of the art post-focus instruments has been proposed
to carry out cutting edge research with an aim to understand the fundamental processes taking
place on the Sun. It’s innovative design and backend instruments will enable observations with
an unprecedented high spatial resolution that will provide crucial information on the nature of
magnetic fields in the solar atmosphere. This would be the largest solar telescope in the world
and fills the longitude gap between Japan and Europe. NLST will be a telescope, which will be
equipped. This would represent a continuation and extension of the tradition of solar studies
established at Kodaikanal more than a century ago.
The selection of a site with optimum atmospheric properties, such as the number of sunshine
hours and good “seeing” over long periods are critical to the successful implementation of
NLST. In this regard site characterization has been conducted at locations such as Hanle, Merak
and Devasthal. The data obtained so far suggest that the Pangong lake site at Merak has excellent
“seeing” conditions suited for a 2-m class solar telescope.
Site survey, selection criteria and reasons for selecting the proposed site at
Pangong Lake: Critical to the successful implementation of NLST is the selection of a site
with optimum atmospheric properties. Absence of clouds is one of the primary criteria. Another
is the presence of good seeing over long periods of time with clear skies. The diffraction limit of
a 2 meter solar telescope at 500 nanometers is 0.06 arc sec which corresponds to about 40 km on
the solar surface. With the use of adaptive optics, features on the sun can be resolved nearly up to
the above limit provided the atmospheric ‘seeing’ conditions of the site where the telescope is
located are very good, say in the range of 1” or better for significant periods of time. This forms
a major requirement for the site. Reconnaissance surveys were carried out in Ladakh. Hanle was
chosen for evaluation due to the advantage of logistics of already existing stellar observatory
Among the lake sites, the Pangong lake appeared more promising than Tso Morari or other major
lakes in Ladakh, due to the following advantages; its 30 km stretch within India, the several land
incursions into the lake, the almost east – west elongation, the wind ducting from east to west,
and the large flat land at the southern shore allowing good access to the southern declination,
necessary for solar observations at this latitude of about 34 degree north. The essential
parameters monitored were total annual sunshine hours, sky brightness, atmospheric seeing at
various heights of up to tens of meters above ground, micro thermal conditions, meteorological
parameters such as precipitation, wind speed, wind direction, humidity, irradiance, temperature
range, aerosol distribution at site and etc. Regular observations of seeing and other related
parameters were carried out by IIA at Hanle for over two years, at Merak for over one year.
The Pangong lake site at Merak appears to be very promising - it provides excellent spells of
continuous sub arc second periods of seeing (Figure 1). The wind speeds of a few meters per
second for most part of days help to stabilize the thermals. The total annual sunshine hour is
comparable to Hanle, being in the range of 1700 hours. However the afternoons in Hanle have
periods of strong winds.
Figure 1: Intensities of solar radiations at Merak
Need for a 2 m Telescope: A 2-m class telescope with a sufficiently large aperture, is required
to observe processes occurring on spatial scales of tens of kilometers (as crucial physical
processes like vortex flows, dissipation of magnetic fields and the generation of MHD waves can
occur efficiently on length scales even as small as 10 km). Telescope operating at its diffraction
limit is required in order to resolve structures with sub-arc sec resolution in the solar atmosphere
as well as to carry out spectropolarimetry. Good angular resolution with a high photon
throughput is necessary for spectropolarimetric observations to accurately measure vector
magnetic fields in the solar atmosphere with a good signal to noise ratio. In order to resolve
structures with sub-arc sec resolution in the solar atmosphere as well as to carry out
spectropolarimetry, a sufficiently large aperture telescope is required. Resolving structures
observationally is of utmost importance to study and improve our understanding of the different
physical processes involved. This helps in understanding the interaction of magnetic fields with
plasma for interpreting various processes in the atmosphere of the Sun. Unfortunately apertures
needed to resolve solar features to this level at visible wavelengths limit even the largest current
solar telescopes. Presently, the best spatial resolution that the existing generation of solar
telescopes can attain during moments of good seeing and using adaptive optics is limited to
about 0.13 arc sec corresponding to nearly 90 kms on Sun. NLST would provide a superior
platform for performing high quality solar research and aid as an unique research tool for several
talented solar astronomers and is expected to bring in enormous growth in scientific development
for the local region and the state. This would demand great technological challenges, give several
spin-offs both direct and indirect to the country.
NLST is a 3-mirror, Gregorian on-axis telescope with a 2-m aperture primary mirror and a final
f/40 focal ratio. NLST has a high throughput, which is highly desirable for polarimetry and
speckle interferometry. The telescope has a high-order adaptive optics (AO) system to ensure
diffraction limited performance. A 2-m parabolic primary mirror M1 (f/1.75) forms an image of
the solar disk with a diameter of 33 mm at the prime focus F1. Here a cooled heat stop rejects
and dissipates all the energy which does not pass through the stop. The primary mirror is cooled
from below to keep it close to the ambient temperature. A beam, providing total field of view
(FOV), passes through the centre hole with 3.4 mm diameter. An elliptical mirror M2 creates
f/7.7 beam and forms a secondary focus F2 at a distance of ~600mm in front of M1 and about
200 mm above the elevation axis. Here a FOV of 200 arc sec corresponds to a scale of 15 mm.
The modulation and calibration of the polarimetric package is kept here to exploit the symmetry
property. A weak negative field lens is also situated here (see Fig. 2). The F2 image is sent to
another elliptical mirror M3 which changes the f-ratio to f/40 in the beam that produces a final
image at F3 where we have the desired image scale of 2.5 arc sec mm-1. Additional specifications
are listed in Table 1.
Figure 2: Optical layout of NLST
M4 is a flat mirror with a central hole that reflects the beam into the elevation axis. The mirror
group M5/M6 reflects the beam into the azimuth axis which in our design is by the side of the
primary mirror. By means of the field lens in F2, the pupil is imaged on M6 which can serve as
the tip tilt mirror of the AO. M5 is a deformable mirror. F3 is about 6200 mm below the
elevation axis which allows for convenient access of the focus points in the building. A
mechanical turntable behind the telescope moves the whole post focus assembly which
compensates for the rotation of the image due to the alt-azimuth telescope system. NLST has a
mounting which is optimized for natural air flush in order to minimize mirror seeing. Heat near
the primary focus is taken out of the system with a heat stop.
NLST is housed in a building which is optimized aerodynamically in order to minimize
turbulence above the telescope. The telescope has an open design with a simple retractable dome
that will cover the telescope during the period when there are no observations.
Solar constant outside atmosphere: 1360 W/m2
Solar radiation at surface is given by the following equation:
Precautions have been taken to mitigate the likely impacts of reflection from the mirror and
likely impacts on birds. These include:
• Shadow plate covering the primary mirror protects it from the vision of birds.
• Change in angle to 30 degrees at the heat stop so that the reflection from the heat stop is
diffused and directed towards a far off point in the ground and hence flying bird/birds are
insulated from any reflections (figure 3).
• Use of low energy ultrasound transmitters to ward off the birds around the telescope in an
area of around half an acre.
Figure 3: Beam Geometry
The Merak site at Pangong lake has sky conditions which are comparable to that of the Big Bear
Solar Observatory lake site, combined with the advantages of the high altitude desert. It certainly
appears to be well suited for locating a two meter or even a larger solar telescope for optical and
near infra red observations. The following major criteria were used for preliminary selection:
sincos cos cosh)
• Annual number of clear sunshine hours (in the range of 2000),
• Significant number of 1 hour spells with median Fried parameter (r0) of 7 cm or
better and 30 min spells of r0 better than 10 cm,
• High altitude for excellent transparency & dry conditions for NIR observations, &
• Lake sites with winds of 4 to 8 mps, as they are known to be good for day skies.
Table 1: Optical Specifications:
Aperture ( primary mirror M1 ) : 2 metre
Focal length : 4 metre
Optical configuration : 3 mirror, Gregorian on axis
Aberration free Field of view : 200 arc sec
Final focal ratio of the system : f / 40
Image scale : 2.58 arc sec mm-1
Optical quality : 80 % of energy to be within circle of 0.1 arc sec
or less over the entire field of view of nearly
3 arc min diameter at 5000 Å.
Wavelength of operation : 3800 Å to 2.5 microns
Polarization accuracy : better than 1 part in 10,000
Scattered light level within telescope : < 1 %
Active and Adaptive optics : to realize near diffraction limited performance;
Strehl ratio >0.5 within Isoplanatic patch
Spatial resolution : < 0.1 arcsec at 5000 Å.
Consideration and evaluation of project alternatives: The exploratory surveys were
carried out in Hanle, Devasthal and Pangong Tso (Figure 4). The mountain desert conditions of
Ladakh provide good number of sunshine hours with minimal precipitation and have the
additional advantages of high altitude desert, such as excellent transparency and low humidity.
Therefore, Hanle, at an altitude of 4500 m in the Great Himalayan range in Ladakh, with
demonstrated good conditions for astronomical seeing for the night sky, having median of 1.07
arc sec, which was selected through a survey of the region during 1995-2000, was chosen as one
of the sites for evaluation.
Similarly, Devasthal, at an altitude of 2540 m in the Shivalik Hills of the Central Himalayan
range and has been shown, through a survey during 1980-1990, to have good night sky
conditions with medians of 1.1 to 1.4 arc sec (Sagar et al 2000), was chosen for detailed
evaluation since it provided an alternative topographical environment in the Himalayan range.
Besides, these two sites would have the advantage of the logistics available in an existing
Figure 4: Locations of the three probable sites, Hanle, Devasthal, & Merak
Several lakes in Ladakh were examined for prospective sites. Tso Morari, Pangong Tso, Tso Kar,
and Twin lake, in the altitude range of 4200 to 5000 m, were considered. The Pangong Tso lake,
with a long stretch of about 50 km, was readily recognized to be the most promising lake site for
detailed evaluation. The desirable land protrusion into the lake, the steady wind flowing over the
water body for most part of the day, and the clear access to the southern sky, were found to be
most favourable at a site along the shore near village Merak. This site was selected for detailed
Description of the sites selected: Three sites Hanle, Devasthal and Merak were identified
for the detailed investigations.
Hanle: This site was selected to be most prospective for night time astronomy, based on a
detailed study of meteorological data, satellite imagery, and site reconnaissance trips to six high-
altitude sites in the Great Himalayan Ranges. Site characterization starting 1995 proved that
Hanle in the high altitude cold desert of south eastern Ladakh is among the best high altitude
sites in the world for astronomical observations. A 2 m optical telescope, with remote operational
facility from near Bangalore, started functioning in the year 2000 (Figure 5). A site adjoining the
2 m optical telescope, at 32° 46' 47" N, 78° 57' 50" E, and at an altitude of 4486 m, was selected
for detailed study of the day time conditions.
Figure 5: NSO S-DIMM at Hanle
Devasthal: After a preliminary survey, carried out during 1982-91 and Devasthal turned out to
be the choice in terms of the prevailing night time seeing, meteorological conditions, and also the
logistics involved. A 1.3 m optical telescope has become operational in 2010, while a 3.6 m
optical telescope, in collaboration with TIFR, Mumbai, is in an advanced stage of procurement.
Both the telescopes are to be used for night time astronomy.
Figure 6. Devasthal site with instruments on towers and the observation hut.
Merak: The picturesque Pangong lake, at an elevation of 4258 m, is well known for the deep
blue colour of its water body. It is the longest lake in Ladakh, with about 50 km stretch within
Indian territory and over 100 km long stretch in the Tibetan plateau of neighbouring China. Fed
by glacial waters, the lake once drained into the Tangshe river. Over the years, the outflows got
blocked and the lake became mildly brackish. Therefore, except for the locations of fresh glacial
waters, the lake does support marine life. The lake is said to be in a seismically safe zone. It runs
between two mountain ranges in the NW to SE direction which steadily widen towards south of
south-east, before bending eastward into China
Figure 7: The Merak site with the lake. Cluster of towers & instruments, and the observing hut
The western shore of the lake has two villages, Spangmik and Merak. Following a survey of the
entire shore, the land protrusion near Merak at 33° 47' 42" N, 78° 37' 08" E, was selected for
implementing NLST. The prevailing wind is channeled over the water body for most part of the
day, at a steady speed of a few mps, and this was readily recognized to be a major advantage of
the site. The lake is well connected by road up to its starting point at Lukung, which is five hours
drive from Leh via Chang La pass. A motorable mud road further connects Spangmik, Merak,
Methods used to identify, predict and assess impacts
• Land use analysis: Remote sensing data along with collateral data
• Ecology and Biodiversity: Field visit, consultation with the local forest department
officials and published literature
a) Documentation of the existing flora in the proposed corridor
b) Documentation of animal paths (bird migratory paths, if any)
c) Documentation of endemic species
d) Assessing the Environmental Impacts
e) Arriving at environmental management plan to achieve the least disturbance to the
existing flora and fauna
• Development of Environment Management Plan: This is based on the understanding
of ecological and environmental impacts (if any) – quantification would be done based on
detailed field visit.
III Description of the Baseline Environment
The land protrusion near Merak at 33° 47' 42" N, 78° 37' 08" E, close to the Pangong Tso Lake
and inside the Changthang Wildlife Sanctuary was selected for commissioning a 2 m state-of-
the-art telescope (National Large Solar Telescope - NLST). Changthang Wildlife Sanctuary is a
habitat for endemic, endangered species, vulnerable, and near threatened species. The area is of
adequate ecological, faunal, floral, geomorphological and natural significance, and also link one
protected area with another. The area of Pangong Tso Wetland is one of the Wet-site of the
Changthang Wildlife Sanctuary. The area of 4000 Sq.Kms stands notified as Wildlife Sanctuary
since 19-03-1987. The same wet-site is protected under the overview of J&K Wildlife Protection
Act 1978. its 30 km stretch within India, the several land incursions into the lake, the almost east
– west elongation, the wind ducting from east to west, and the large flat land at the southern
shore allowing good access to the southern declination, necessary for solar observations at this
latitude of about 34 degree north. The essential parameters monitored were total annual sunshine
hours, sky brightness, atmospheric seeing at various heights of up to tens of meters above
ground, micro thermal conditions, meteorological parameters such as precipitation, wind speed,
wind direction, humidity, irradiance, temperature range, aerosol distribution at site and etc. The
next sections will discuss of Himalaya (geological aspects, evolution), origin of lake as the
proposed site is land incursion into the lake
Being the highest mountain range in the world the Himalayas extends along the northern
frontiers of Pakistan, India, Nepal, Bhutan, and Burma. Its origin was geologically driven as a
result of the collision of the Indian subcontinent with Asia. This process of plate tectonics is
ongoing, and the gradual northward drift of the Indian subcontinent still causes earthquakes.
Lesser mountain ranges proceed southward from the main body of the Himalayas at both the
eastern and western ends. The Himalayan system spanning about 2,400 kilometers in length and
varying in width from 240 to 330 kilometers, is made up of three parallel ranges i.e. the Greater
Himalayas, the Lesser Himalayas, and the Outer Himalayas and are sometimes collectively
called the Great Himalayan Range.
The Greater Himalayas, or northern range, average approximately 6,000 meters in height and
contain the three highest mountains on earth: Mount Everest (8,796 meters) on the China-Nepal
border; K2 (8,611 meters, also known as Mount Godwin-Austen, and in China as Qogir Feng) in
an area claimed by India, Pakistan, and China; and Kanchenjunga (8,598 meters) on the India-
Nepal border. Many major mountains are located entirely within India, such as Nanda Devi
(7,817 meters) in the state of Uttar Pradesh. The snow line averages 4,500 to 6,000 meters on the
southern side of the Greater Himalayas and 5,500 to 6,000 on the northern side. Because of
climatic conditions, the snow line in the eastern Himalayas averages 4,300 meters, while in the
western Himalayas it averages 5,800 meters.
The Lesser Himalayas range from 1,500 to 5,000 meters in height and are located in
northwestern India in the states of Himachal Pradesh and Uttar Pradesh, in north-central India in
the state of Sikkim, and in northeastern India in the state of Arunachal Pradesh. Shimla (Simla)
and Darjiling (Darjeeling) are the hill stations located in the Lesser Himalayas. It is in this
transitional vegetation zone that the contrasts between the bare southern slopes and the forested
northern slopes become most noticeable. The Outer or Southern Himalayas, averaging 900 to
1,200 meters in elevation, lie between the Lesser Himalayas and the Indo-Gangetic Plain. In
Himachal Pradesh and Uttar Pradesh, this southernmost range is often referred to as the Siwalik
Hills. The northernmost range, known as the Trans-Himalaya and is located entirely on the
Qinghai-Xizang Plateau, north of the great west-to-east trending valley of the Yarlung Zangbo
river. Although the Trans-Himalaya Range is divided from the Great Himalayan Range for most
of its length, it merges with the Great Himalayan Range in the western section as the
“Karakoram Range” where India, Pakistan, and China congregate. The southern slopes of each
of the Himalayan ranges are too steep to accumulate snow or support much tree life; the northern
slopes generally are forested below the snow line. Between the ranges are extensive high
plateaus, deep gorges, and fertile valleys, such as the vales of Kashmir and Kulu. The Himalayas
serve a very important purpose as they provide a physical screen within which the monsoon
system operates and are the source of the great river systems that water the alluvial plains below.
As a result of erosion, the rivers coming from the mountains carry enormous quantities of silt
that enrich the plains. The area of northeastern India adjacent to Burma and Bangladesh consists
of numerous hill tracts, averaging between 1,000 and 2,000 meters in elevation, that are not
associated with the eastern part of the Himalayas in Arunachal Pradesh. The Naga Hills, rising to
heights of more than 3,000 meters, form the watershed between India and Burma. The Mizo
Hills are the southern part of the northeastern ranges in India. The Garo, Khasi, and Jaintia hills
are centered in the state of Meghalaya and, isolated from the northeastern ranges, divide the
Assam Valley from Bangladesh to the south and west.
Evolution of Himalaya:
It is now widely accepted that the collision between the Indian Plate and the collage of
previously sutured micro-continental plates of Central Asia occurred during the mid to late
Eocene, at approximately 50-45 Ma (Million yrs. Ago) (Alleigre et al., 1984; Searle et al., I987).
The timing of terminal collision of the two plates is deduced from (i) the ending of marine
sedimentation in the Indus Suture Zone (ISZ), (ii) the beginning of continental molasse
sedimentation along the suture zone, (iii) the ending of Andean-type calc-alkaline magmatism
along the Trans-Himalayan (Ladakh-Kohistan-Gangdese) batholith and (iv) the initiation of the
major collision-related thrust systems in the Himalayan Ranges. Palaeo-magnetic data indicate
that over 2000-2500 km of southern (Neo) Tethys separated 55 Ma (Klootwijk, I979) and
terminal collision at about 40 Ma (Molnar & Tapponnier 1975; Klootwijk &
Radhakrishnamurthy, 198I). The northward relative motion of the Indian Plate decreased
threefold at 40 Ma from average rates of 14.9 + 4.5 cm/a to 5.2 + 0.8 cm/a (Pierce, 1978).
Seafloor spreading rates in the Indian Ocean also decreased drastically at anomaly 22 (given in
the fig. below), which corresponds in time to ca. 50 Ma (Sclater & Fisher 1974; Johnson et al.
1976). Major directional shifts in the relative motion of the Indian Plate at anomalies 22 and 21
(given in the fig. below) (50-48 Ma) are also thought to indicate the onset of collision (Patriat &
Achache, 1984). Another major shift occurred at anomaly 13 (36 Ma) after which India resumed
stable northwards convergence with a constant rate of 5 cm a-' (Patriat & Achache, I984).
The post-collision crustal shortening in the Indian Plate can only be deduced from the restoration
of balanced cross sections across the Himalaya. It is widely recognized that in general terms,
southward-propagating thrust stacking had occurred across the Himalaya since the mid-Eocene
collision and suturing (Molnar 1984; Mattauer 1986; Searle et al., 1987). The climax of crustal
shortening and thrust stacking occurred during the mid-Tertiary in the High Himalaya and
Zanskar Ranges, with thrusts propagating southwestwards from the Main Central Thrust (MCT)
system to the Lesser Himalaya and the late Tertiary Main Boundary Thrust (MBT) system
(Figure 8). The youngest thrusts occur along the southern boundary of the Himalaya, in the
Siwalik molasse deposits of the Indian foreland basin, where the Main Frontal Thrust (MFT)
terminates at tip lines below the Indo-Gangetic plains. Four major tectonic zones constitute the
Ladakh-Zanskar Himalaya. These are, from north to south, the Ladakh (Transhimalayan)
batholith, the Indus Suture Zone, the Tibetan-Tethys (Zanskar shelf) Zone, and the High
Himalaya. A generalized geological map depicting these zones is shown in figure 2. Figure 3
shows a late Cretaceous and Tertiary time chart for the Ladakh-Zanskar Himalaya (after Searle
1983, 1986) updated with all radiometric ages and stratigraphic time spans for the four tectonic
Ladakh Batholith: Batholiths are large emplacement of igneous intrusive (also called plutonic)
rock that forms from cooled magma deep in the earth's crust. Batholiths are almost always made
mostly of felsic or intermediate rock-types, such as granite, quartz monzonite, or diorite. The
Ladakh batholith, a part of the 2000 km long Transhimalayan batholith, is situated to the north
of the ISZ (Indus Srture Zone) in the Ladakh Ranges (figure 9). The Transhimalayan belt
Figure 8. Geological map of Ladakh-Zanskar (After Searle 1983, 1986)
continues westward to include the Kohistan batholith in northern Pakistan (Petterson & Windley,
I985) and eastward to include the Gangdese batholith in south Tibet (Alleigre et al., 1984;
Tapponnier et al. 1981). The Ladakh batholith ranges in composition from olivine-norite (types
of rocks) to leucogranites with grandiorites dominating (Thakur, 1981; Honegger et al., 1982).
Olivine-orthopyroxene-bearing norites, gabbros, diorites, granodiorites, granites and
leucogranites are all represented and collectively represent a continental, subduction-related
batholith (Honegger et al. i982). The presence of granitic gneisses and meta-sedimentary
sequences in the Ladakh Range provides evidence for the existence of precursory continental
crust (Honegger & Raz, 1985). Furthermore, a substantial component of inherited lead in
zircons extracted from samples of the batholith implies involvement of continental crust during
‘petrogenesis (Scharer et al., 1984).
Figure 9: Origin and changes in High Himalayan Leucogranites
Initial 87Sr/86Sr ratios of around 0.704 (Scharer et al., 1984) and 0.705 (Honegger et al., 1982)
are un-enriched, inferring a primary mantle that is a derivation of the magmas. The amount of
isotopic enrichment due to the envisaged crustal component remains to be quantified. Available
geo-chronological determinations indicate that the Ladakh batholith is composite and dominated
by pre-collisional magmatic events. U-Pb zircon ages of 103+3 Ma (Honegger et al., 1982) and
101+2 Ma (Scharer et alt., 1984) from samples collected near Kargil refer to important mid-
Cretaceous magmatism. A second U-Pb determination of monazite/allanite from a biotite-granite
near Leh gave an age of 60.7+0.4 Ma, whereas a Rb-Sr isochron age of 73+2.4 Ma (Scharer
et at. 1984) and a 39Ar/40Ar age of 82 + 6 Ma (Sckirer & Allbgre, 1982) may indicate a
continuity of magmatic activity for some 40 Ma, finally terminating with continent-continent
collision (figure 10). Likewise, a span of K-Ar mineral ages of 50-40 Ma is considered to reflect
a cooling period associated with uplift.
The termination of granitic magmatism in the Ladakh batholith is at the same time with the
closing of Neo-Tethys along the ISZ and the change from marine to continental
sedimentation. Clasts of granites, andesites and rhyolites are particularly widespread in the
conglomerates of the Chogdo, Nurla and Hemis Formations of the Indus Group molasse, which
unconformably, overlies the batholith. Volcanic rocks overlying the Ladakh batholith include
andesites and rhyolites (Srimal et al., 1987). Late-stage garnet-muscovite leucogranitic dykes
intrude the granite and may reflect a final phase of intracrustal melting after the 50 Ma
collision along the ISZ. Granitoids of the Ladakh batholith intrude the Dras island arc volcanics
and rocks of the suture zone around Kargil. This provides strong evidence that the Dras island
arc was accreted to the Karakoram-Lhasa Blocks by the mid-Cretaceous and that the Shyok
(Northern) Suture between the Ladakh and Karakoram terranes closed in the mid-Cretaceous
(Coward et al., 1986; Pudsey, 1986; Searle et al., 1988) and not in the late Tertiary (Thakur,
1981, 1987). The Ladakh batholith has undergone an unknown amount of post-collision
shortening evidenced by thrusting within the granitoids. Near Kargil, a number of late stage
shear zones with mylonitized amphibolites and greenschists cut intrusive rocks of the batholith
Figure 10. Tectonic map of Himalayas and its adjoining regions showing the major fault zones
and lithotectonic regions (Gansser, 1964)
Indus Suture Zone (ISZ): The Indus Suture Zone (ISZ) defines the zone of the collision
between the Indian Plate and the Karakoram-Lhasa Block to the north (Gansser, 1964, 1977;
Allegre et al., 1984; Searle et al. 1987) and can be traced for over 2000 km from Kohistan and
Ladakh in the east right across southern Tibet to the NE Frontier region of India-Burma. In Tibet
it is commonly referred to as the Yarlung-Tsangpo Suture; in the western Himalaya it is the
Indus Suture Zone. To the west of Ladakh, the ISZ is folded around the giant Nanga Parbat fold,
a 35 km wavelength, upright anticlinorium that exposes Indian Plate gneisses equivalent to the
Central Crystalline Complex in its core (figure 11). The ISZ has been offset by the late Tertiary
culmination of Nanga Parbat and downfaulted west of Nanga Parbat along the Rakhiot Fault
zone. It continues westwards as the Main Mantle Thrust (MMT) across southern Kohistan
(Tahirkheli & Jan, 1979). In Ladakh, the Indus Suture is bounded to the south by the backthrust
shelf sediments of the Zanskar Supergroup and the Tso Morari crystalline complex, and to the
north by the Ladakh batholith. The geology of the ISZ has been described by Gupta & Kumar
(1975), Shah et al. (1976), Andrieux et al. (1981), Fuchs (1977, 1979), Bassoullet et al. (1978,
1981), Frank et al. (1977), Baud et al. (1982), Brookfield & Andrews-Speed (1984a, b), Thakur
(1981, 1987) and Searle (1983, 1986). The Indus Suture Zone in Ladakh consists essentially of
three major linear thrust belts, the Lamayuru complex, the Nindam-Dras Volcanic Group and the
Indus Group molasse. They are separated by major fault zones or ophiolitic melange belts (figure
7 a, plate 1). Figure 4 is a palaeogeographic reconstruction of the Neo-Tethyan basin showing
the pre-Eocene stratigraphy of the rocks now preserved in the ISZ in Ladakh.
Indus Group molasses: The term “molasses” refers to the sandstones, shales and conglomerates
formed as terrestrial or shallow marine deposits in front of rising mountain chains. A continental
clastic sequence approximately 2000 m in thickness, comprising alluvial fan, braided stream and
fluvio-lacustrine sediments, constitutes the Indus Group (Brookfield & Andrews-Speed, 1984
a,b; Van Haver, 1984). Clasts in the conglomerates were derived mainly from the uplifted and
eroded Ladakh batholith to the north, but also from the suture zone itself (cherts, limestones,
serpentinised peridotites) and from the Zanskar shelf carbonates to the south. Palaeo-currents
show dominantly east to west basin axis-parallel sediment transport paths (Pickering et al., I987).
Near Kargil the Indus molasse unconformably rests on the Ladakh granitoids along the northern
margin of the ISZ. The collision of India with the Karakoram and Lhasa Blocks and the closing
of Tethys at 50 Ma mark the initiation of Indus Group molasse sedimentation (Searle et al.,
1987). The Chogdo Formation at the base of the molasse rests stratigraphically above late
Figure 11: Structural section along the Zanskar River between Chilling and Nimu about 40 km
west of Leh.
Tectonic Origin of the Himalayas: The magnificent heights to which the Himalayas have been
uplifted is as a result of several orogenic movements. The tectonic history of the Himalayas is a
much debated subject. Some workers have recognized five phases of deformation on the basis of
small scale shortening structures. Others have deciphered four major tectonic movements, the
earliest dating back to the Precambrian or Lower Paleozoic, while the other three postdating the
Permian. A few workers however, recognise only three episodes of orogenic activity, post-dating
The first phase of Himalayan orogeny-the Daling event (Precambrian or Lower Paleozoic) is
marked by medium grade metamorphism but intense deformation accompanied by both acid and
basic igneous intrusives. The second phase of orogeny known as the Ladakh phase involved the
beginning of earth movements which were responsible for the major uplift of the Himalayas. It is
during this phase that the Indian plate is believed to have collided with the Asian plate. This
caused a shallowing of seas, emplacement of ophiolites along the Indus Suture zone, granitic
intrusions, palingenesis, and granitization. Patches of Eocene rocks over the Tal (Jurassic), Krols
(Permo-Trias), Simla Slates (Paleozoic), and Deoban rocks (Paleozoic) indicate folding and
erosion of these sedimentary basins before transgression of the sea in Eocene period, and
subsequent deposition of Eocene sediments. This phase of the Himalayan orogeny was active
from Late Cretaceous to early Eocene times.
The third and most vigorous of all orogenic movements is termed the Dharamsala phase which
culminated in the Middle Miocene. The consequent compression due to under-thrusting of the
Indian plate beneath the Tibetan (=Asian) plate caused large scale isoclinal and recumbent
folding of the Precambrian crystalline rocks. This resulted in the thrusting of huge blocks of
these rocks that moved southwards, and came to rest upon the younger sedimentaries. Most of
the thrust sheets of the Lesser Himalayas and widespread regional metamorphism and acid
igneous activity are associated with this phase. Due to the great uplifting, a foredeep was created
in front of the rising Himalayas into which the Siwalik molasse sediments were deposited.
The fourth phase of Himalayasn orogeny is the Siwalik phase. This phase was very active from
the Late Pliocene to Middle Pliestocene period. Most of the present structures of the Himalayas
developed during this phase. The Siwalik sediments were also uplifted. Tectonic creep along
some of the thrust faults of the Himalayas, translation of upper Siwalik rocks over the subrecent
gravel beds, and seismicity in the region strongly suggest that this phase has not yet ceased.
Increase in the level of Indo-Tibetian Highland lakes assosciated with Climatic changes:
The earlier visits to Tibetan high altitude lakes (Figure 12) by Godwin Austen in 1866 recorded
and evidenced the Ice Age, which out shed the attention of the important processes like erosive
and bathymetric evidences of recent climatic oscillatory changes. In 1905 Huntington E observed
Pangong Tso showing a set of benches and beach lines which lie lower than any of the older
terraces surrounding the lake. During summer 1932 Terra and Hutchinson visited several lakes
like Pangong, Pongur, Mirpa, Morari and Kar in eastern ladakh along Kashmir-Tibetian
Boundary. The investigations have provided new informations regarding changes of depth, of
shore features, and related phenomena attributed to regional climatic oscillations. The reasons for
the recent changes of the high altitude lake-levels were attributed to topographic, physiographic
and hydrographic alterations.
Figure 12: The topto map showing the Pangong Tso lake and other high altitude Indo-Tibetian
The Pangong Tso, being the largest mountain lake north of the Himalaya (13, 915 feet above sea-
level), gave the first evidence of recent topographic changes. Terra and Hutchinson (1932)
noticed the base of the cliffs near northern shore between Churtse and Lukung were flooded and
observed the earlier path for traveling could be seen to lead into the lake, where the path
continued 5 feet below the water and around the cliff. Two drowned beaches at 3 and 5 feet
which may also be recognized on Figure 13.1).
According to Hutchinson the landmark a rocky islet (1/4 th of a mile from the shore at Yaktil)
had been marked as lying 5 feet above the lake-level on the old survey sheet does not exist
during the visit. As the shallowest water was 13.1 feet at the spot where the islets had been in
1861. Thus the lake had risen since then at-least 18 feet.
Along the Southern part of Pangong Lake from Lukung to Man and Takkung further
strengthened the rising levels of the lake by strong physiographic evidences. The fan formation
making the lake front is seen to be superimposed on the pleistocene deposits and is therefore of
post-glacial origin. At the slope of a cliff between Yaktil and Spangmik two distinct beach lines
were recorded at 3 and 5 feet above the water, and a third could be seen in the clear water 2
to 3 feet below the level of the lake. Shortly before reaching this spot the path makes a detour
around the advancing water of a shallow bay. In some of the shallower flood channels a more
recent heavy accumulation of gravel had taken place.
Twelve miles south-east of Takkung the underwater beaches were seen to follow the contours of
an old shore-line (Fig. 13.3). A small delta had here been built into the lake, and as the
underwater beaches broke abruptly off along the drowned shallow flood-channel of the rivulet
it is evident that the beach preceded the delta. Larger bushes could still be seen clinging to the
upper beaches while others had already become uprooted and were tossed about by the waves.
The rising lake water had then flooded these shore features until the lake is now cutting
into the front of the older fan.
Figure 13.1 ). Under water beaches of an old-shore line near Pangong Tso- South
Another interesting and important physiographic change connected with the rise of the Pangong
is the formation of small lagoons. They appear in parallel rows along the shore and in one place
two could be seen at distances of 3 and 10 feet from the shore. Fig. 13.2) illustrates how their
peculiar arrangement can be explained by a progressive rise of the lake-level. Their formation is
greatly assisted by preceding shore-ice action. The accumulation of gravel and sand in the
form of ridges is a common feature along Tibetan lakes (Figure 13.4.). Owing to the
severity of the frost, which keeps the lakes solidly icebound during four or five months of
the year, shore-ice is a much greater factor of accumulation than around lowland lakes in
middle latitudes. Most lagoons on Pangong can be traced back to the same process;
particularly where low terraced fans have become inundated, this indicates a recent rise of
Figure 13.2).The lagoon formations as a result of water level rise
Figure 13.3). Pangong Tso drowned beaches 13.4). Pangong Tso accumulated Gravel and sand.
Historic records indicative of the sequence in changes of Pangong
lake water level:
Figure 13.5 documents the changes in water level in Pangong lake.
1. W. Moorcroft and G. Trebeck in 1831 gave the first account of Pangong Tso and mention
the lack of a road along the northern shore in 1821.
2. H. Strachey who visited the lake in 1848, remarks on the outflow of the eastern Pangong at
Ot. They said that the lake had perceptibly receded in the last twenty-seven years.
3. H. von Schlagintweit relates native information according to which higher lake-levels in
connection with good harvests were frequent before 1841. In 1856 soundings were made but
no rock islet is mentioned.
4. H. H. Godwin Austen surveyed the rock islet in 1863 which appeared in 1859 above the
lake-level. Shore roads were passable. He observed five to six beach-lines, 1 foot distant
from each other, and also a submerged lake terrace, 10 feet below the 1863 level. From these
phenomena they inferred climatic oscillations.
5. In 1869 F. Drew observed pictures of the islet and mentions a total seasonal rise and fall of
the lake by 3 feet.
6. M. S. Wellby in 1898, had the choice to use either the shore route or the longer but safer one
across the Poranda La.
7. Sven Hedin gives soundings of 1900 and comments on the condition of the northern shore
route which was inundated, but the river at Ot was fordable. The existence of an older road,
10 m.above the path which he followed, makes him believe that his road of 1900 was once
8. E. Huntington observed in 1905 three to four small drowned beaches 10 to 12 feet below the
level, and gives native information according to which the lake was 10 to 12 feet lower
during I875-85. Although he recognized that oscillations were recent he attempted to couple
them with the formation of clay and gravel deposits near Man which Godwin Austen in 1866
had rightly interpreted to be of glacial and interglacial origin.
Figure 13.5). History of rising levels of Pangong Tso lake
Ladakh Region: Ladakh is situated between 30° to 36° E latitude and 76° to 79° N
longitude. It is part of the state of Jammu and Kashmir, has an area of 96,701 sq. km and
comprising a population of 200,000 habitants. Ladakh is bounded on the north by the eastern
range of the Karakoram Mountains and the Tibetan Plateau. Across the Kashmir Valley and over
the famous Zoji La pass (Zozi La pass) lies Ladakh – “the Land of High Passes”. It is a magical
land, so completely different from the green landscape of some other parts of the Himalayas. It is
nature at its extreme. A land of freezing winds and burning hot sunlight, Ladakh is a cold desert
lying in the rain shadow of the Great Himalayas and other smaller ranges. Little rain and snow
reaches this dry area, where the natural forces have created a fantastic landscape. Parts of Ladakh
are under the illegal occupation of Pakistan and China, respectively. The border of Ladakh
touches those of Afghanistan, Pakistan, China, the Kashmir Valley (India) and Himachal Pradesh
Figure 14: Indian vegetation with biogeographic regions
Ladakh has an average elevation of 2,700 m to 4,200 m. The aridity of this region is due to its
location in the rain shadow area of the Great Himalayas, elevation and radiation of heat from the
bare soil. The great Himalaya mountain, lying to the south, forms a barrier to monsoon in this
area. The most striking physical feature of Ladakh, however, is the parallelism of its mountain
ranges. The region is extremely dry, with rainfall as low as 10 cm each year. . It has many lakes
and springs, the famous springs are the sulphar springs of Panamic (Nobra), Chumathang and
Puga of Changthang, which are famous for early curing of joints/ rheumatic diseases. Many
mineral springs are also found in some remote parts of Ladakh. People of region use the spring
water as medicine to prevent and cure themselves from many diseases. In Ladakh, large rivers
and their tributaries have carved deep gorges far below their steep banks. However, their water is
not of much use as the terraced fields (Figure 15.1) lie high above the gorges.
Figure 15.1. The terrace type of cultivation in the cold arid deserts of Leh, Ladakh.
Earlier Ladakh could only be reached over high passes (Figure 15.2). The Zoji La pass
connecting Ladakh to Kashmir is at 14,000 ft and is the lowest approach from the west. The
south east approach has to cross the 18,200 ft high Tanglang La. And to the north lie the Saser
La and Karakoram passes, gateways to Central Asia from where trading caravans used to come
for many centuries. The altitude ranges from 3000 m (lower Indus and Nubra valleys) to 7600 m
(Zanskar and Karakoram ranges) (Gujja et al., 2003). The region of Ladakh normally remains
land locked between November to June every year as Srinagar-Ladakh and Ladakh - Manali
highways, which connect Ladakh with the other parts of the country, remain closed during this
period because of snow and rigorous winter. Due to this region Ladakh is an isolated cold desert
region. Figure 15.3 gives the glimpse the dry vegetation mostly Poplar and Willow at Leh,
Figure 15.2. The Changla pass on the way to Pangong Tso.
Figure 15.3: The dry vegetation mostly Poplar and Willow at Leh, Ladakh.
There are two districts in the Ladakh region, Leh and Kargil, with Leh as the administrative
capital. The 21,000 sq.km Changthang sub-division is part of Leh district, with high mountains,
wide-open valleys, natural grasslands, and snow-fed streams (jammukashmir.nic.in).
The State Government intends to declare an area of 4000 sq.km in eastern Ladakh at Changthang
as a sanctuary (Fig. 16). This area is a barren cold desert sparsely wooded and experiences the
severe cold in the region. Thus named as High altitude cold desert Changthang Wildlife
Sanctuary. It is located in the North-east of Leh and constitutes the eastern parts of the Ladakh
region, at a distance of about 130 km from Leh. The area falls at 34 – 79 degree north longitude
and 33 – 79 degree east latitude. This sanctuary includes the water catchment of the Indus River,
Hanlay, and Pangong Tso enrooting south-eastern catchment up to China border.The boundaries
of Changthang Wildlife Sanctuary are as follows: (i) North – Chilam and Lukoong (ii) South –
Kaigar – Tso and Hanlay (iii) East – International boundary of China. And (iv) West – Spanger –
Tso and Spangong – Tso.
Figure 16:. Changthang Wildlife Sanctuary.
Study Area: Pangong tso
Pangong Tso is a part of the protected area (Figure 17). It has been proposed for Ramsar site due
to its biological cultural and geological values (Chatterjee et al., 2002). The Ministry of
Environment and Forest, Government of India has identified Pangong Tso under the Wetland
conservation Programme (Islam & Rahmani, 2008). The Salim Ali Centre for Ornithology and
Natural History, Coimbatore has recommended it to be declared as a Ramsar Site (Prasad et al.,
Pangong Tso represents unique brackish ecosystem example of the highest (4300 m) and largest
(50 x 6 km) in India side and remain 75 x 6 km in Tibetan (Chinese) side wetland of the Trans-
Himalayan biogeographic Zone of the Indian sub-continent. The adjoining areas of the wet-side
abodes high diversity of endemic, rare, and vulnerable species. Pangong Tso is an important
breeding area for Ruddy Shelduck and Bar-headed Goose. This lake acts as a stagging and
foraging ground for birds, especially on the marshes on the fringe of this Lake (Pfister, 2005;
Chandan et al., 2005). Local people graze their livestock in the marshes and meadows, and
harvest the grasses for fodder very close to the nesting birds is a conservation issues (Islam &
The tourists have been seen in Pangong Tso during summer months, from the year 1993, with the
opening of the Changthang Wilderness area to the outsiders. The adjacent areas of the Pangong
Tso- Wetland having steppe cold desert ecosystem is bestowed with many types of floral species.
These provide ample grounds to the “Changpa” pastoral-nomads who take advantage of these
grounds on seasonal basis. Since, all the adjacent village-folk are dependent on the raring of the
“Pashmina goat”. The wetland invariably helping the economy of the local people.
Pangong Tso- is one of the Wet-site of Changthang Cold desert Wild life sanctuary. The area
remained notified as Wildlife Protected area under SRO no. 155 dt. 19-03-1987 issued under the
purview- of the J&K Wildlife protection Act (1978) section 17. The ownership of the wet-site
remains with the Department of Wildlife Protection J&K State Leh Division” However, some of
the surrounding areas of Spangmik, Man, Merak, Chushul are belonging of the local Pangong
Tso, at Man-Merak is owned by Indian Astronomical Observation to understand the fundamental
processes taking place on the Sun. The current proposal is to construct a 2 m state-of-the-art
telescope class telescope (National Large Solar Telescope (NLST)) at this site (Fig. 17 and 18).
The proposed site is very close to the Pangong Tso Lake and inside the Changthang Wildlife
Sanctuary, which has endemic, endangered species.
Figure 17. Pangong lake; proposed site and 10 km radius (regional investigations)
Figure 18. Merak Observatory
The area is of adequate ecological, faunal, floral, geomorphological or natural significance, for
the purpose of protecting, propagating or developing wildlife or its environment, including areas
adjacent to national parks and those which link one protected area with another. One of the most
spectacular lakes in Ladakh is the Pangong Tso, which lies across the Changla Pass from Leh. At
an altitude of almost 4,500 metres, the Pangong Tso is only 8 km wide at its broadest point, but
is an amazing 134km long. The Pangong is considered to be the longest lake in Ladakh. It is a
saltwater lake formed in much the same way as the Tso Morari lake during the Ice Age.
It is a lake situated far away in barren land in Ladakh. This lake is known for its calm, clear and
unending expanse. It is the one of biggest lake in Asia. Its area falls under both India and China.
One third of it is in India and remaining in China. It is 130 km long and 7 km wide. It is located
on the Changtang plateau in eastern Ladakh, around 140 km South-east of Leh, at an altitude of
over 14000 feet. Pangong Tso is also known as hollow lake. It is clear symbol of natures
craftsmanship. Its brackish water plays with sun light to produce different colour effect. This
area falls under army control and requires pass from deputy commissioner of Leh. To reach this
lake one has to travel 30 km down the Manali-leh highway to reach karu. From where the road
splits, one goes to Manali and one 113 km long to Pangong tso. After the verification of paper at
karu, one moves ahead through a green lush valley. This is very uncommon to see a green valley
at this height. There are total five army check posts are on the road to Pangong Tso. The second
check post is at Zingral (15,500 ft). Here army keeps a copy of the permit. This is rocky area and
porn for land slide.
This rocky terrain leads to Chang La (at 17,350 ft), the third-highest motor able pass in the
world. Traces of snow along the road welcome us. One crosses the valley on the sinking road.
The mountains appeared to be painted in hue of green, violet and brown. A school of
mountaineering is situated here, which imparts training in various degree of rock climbing Soon
we found our self in pasture which is filled with yaks, mountain cows. The rocky mountain
changes into sandy area. The road is full of causeway due water on the road.
Pangong appears suddenly while passing through this area. Just two km short of lake one passes
through the gravelly terrain, which is open on the left side. After crossing Lukung, the lake
emerges out of its veil in right. This land lock lake stretches through the whole length of Ruthog
region towards neighboring Chushul. Stretched towards indo-china border, it enters into china.
Most of the fresh water inlets that feed the lake are in Tibet. It is 100 metres deep at certain
The sun plays a unique role in displaying the different colours in lake. Its crystal clear water
plays with sun light to display the bands of blue, green, purple, violet, orange and red on the
surface, like a rainbow. This presents a very beautiful seeing. The lake looks like canvas painted
in the different colours of nature. With no outlet, Lake Basin has deposited wealth of mineral, by
the melting of snow. The lake is home to a wide range of fauna ranging from migratory birds to
mammals of various species. The black-necked Siberian crane, bar-headed geese and waterfowl
can be spotted at the lake.
Pangong Tso Wetland Reserve: Pangong Tso – Tsogul Tso wetland situated on the “North
East” of Leh city, is 150 kms away from it. The Leh district administrative district. The
population of the Leh town as per 1991 census was 11000. The Tangtse town falling on the
North – west of the wet-site is 110 kms from it and the nearest Centre/ village of the wetland is
Spangmik on its Southern side just near the shore of lake. The jurisdiction of the wetland rests
with the Govt of Jammu and Kashmir State (India) and the functional Jurisdiction of the wetland
lies with the Deptt . Of Wildlife Protection, J&K State and its Divisional Wing, Wildlife
Division, Leh Ladakh.
The population of the Centre/ village Spangmik, Man, Merak and Chushul with its cattle-head
1993-1994 was: 111 families and 219 persons. Livestock details are given in Table 2.
Table 2: Livestock
Cow Sheep Goat Horse Yalk/Demo Donkey Dzo/zomo Total
290 3396 9126 337 816 15 7 13987
Hydrologicl values: Due to high velocity and frost actions around the wet-site on regular basis,
plays a major role in rock denudation and its transportation. Huge quantities of sand segments
are deposited in the Wetland.
Ecological features: The lake shows monomictic and oligotrophic to ultra -oligiotrophic status.
The deeper parts of the lake are devoid off of any vegetation. However, the vegetation appear
near the margins of the wetland, on the steppe mounts, wet meadows and the bogs have abundant
plant life. The steppe vegetation includes, Herbs/Legumes, like,
1. Pedicularis longifolia.
2. Polygonium spp.
3. Parmassia cabuilica.
4. Gentiana leucomeleana.
5. Oxytropis microphylla.
6. Potentila aniserina.
7. Leontopodium spp.
8. Astragalus confertus.
9. Juncus spp.
Towards the northern and eastern side of the wetland, some sedge and grass species dominate the
area. They are:
• Carex steaophylla.
• Heontopodium spp. Or Trigolochin pulustoel.
• Caragana brivifolia.
• Dracocepholium spp.
Besides, this Caragana spp. dominate the northern end had played major role in sand trapping.
Among macrophytes, Potamageton pectinatius is the dominating species, whereas zooplanktons
are more varied than the Phytoplanktons, they are:
• Keratella spp.
• Alona spp.
• Daphnia spp.
• Gammarus spp.
• Cyclops spp.
Besides this algal species oocystis species can be seen in this area. The people of the Spangmech,
Man, Merak developed some crops vegetation of Barley (Hordeum spp.); Goosbery (Ribes);
towards southern area of the wetland.
Noteworthy flora: The flora including sonme wild legumes, macrophytes, grasses, sedges and
some other above mentioned plants are all representatives of the steppe vegetation of the Trans-
Himalayas ecosystem and thus all play their vital role in the system.
Social and cultural values: With the opening of the Changthang Wilderness area to the
outsiders from the year 1993 tremendous influx of the tourist have been seen in Pangong Tso.
Tourist approach the area in thousands during summer months. The nmber is mainly of
foreigners who approach the area from Leh. All the tourists are being accompanied by the local
tour operator and travel agents leading in-direct ecological benefits to the Spangmik, Mulbek
The adjacent areas of the Pangong Tso Wetland having steppe cold desert ecosystem bestowed
with many types of floral species. These provide ample grounds to the “Changpa” pastoral-
nomads who take advantage of these grounds on seasonal basis. Since, all the adjacent village-
folk are dependent on the raring of the Pashmina goat. The wetland invariably helps the economy
of the local people.
Cultural land use: The human activities inside the proposed Ramsar site ie. Pangong Tso
wetlands are nil. However the adjacent areas of the wetland are mainly used by the local people.
All the village-folk around or outside the wet-site area are dependent on the rearing of the
Pashmina Goat and are mostly living Pastoral-nomadic life. They are solely dependent upon the
availability of the floral species existing around the steppe-mounts of the wetland. Since 1994.
Tourism trade helped a little to the people of the village falling around wetland Agricultural
practices are being exercised by the local people of Spangmik, Man, Merak on the southern
steppe side of the lake. They grow Millets, Barley and local pea species.
Factors past present or potential adversely affecting the sites ecological character including
changes in land use and development projects: The regular speedy winds transport large
amount of sand into the wetland. Besides it huge soil erosion took place during summer. Months
due to glaciations from the surrounding mounts. The ice melting water straight way merge into
the wetland through five perennial and three small streams. All these natural calamities bring
large amount of sand and soil reducing the wetland size helping in its shrinkage.
Overgrazing of the area by the Live-Stock Changpa Pastrol and nomads who are dependent on
rearing of "Pashmina" goats have posed adverse impact on the biodiversity on the wetland. As
overgrazing results in pasture degradation increased soil erosion it also leads to the less
availability of grasses for wild herbivore and indirectly the Carnivores are invading the Cattle-
pens rendering heavy loss to the nomads.
The area of Pangong Tso Wetland is one of the Wet-site of the Changthang Wildlife Sanctuary.
The area of 4000 Sq.Kms stands notified as Wildlife Sanetnary since 19-03-1987. The same wet-
site is protected under the overview of J&K Wildlife Protection Act 1978. Since the people
living around Pangollg Tso are fond of Wildlife, cases of hunting/poaching are almost zero. Any
kind of developmental activities would not be carried out without the cognizance of the Wildlife
Protection Department, as all the powers about the wetland vests with the Department. With the
opening of the Pangong Tso Wetland to tourist in 1994 the influx of the tourist especially from
Western Countries like France, Belgium, Sweden, Germany, and asian country like Israel, has
increased exponentially. The tourist who made their way through Leh (J&K) and Delhi are being
attracted by the wetlands remoteness it is variegated and unique flora fauna pristine high desert
landscapes, culture tradition of Buddhist and age old Monastery of "Tangtse". These tourists are
being allowed to enter in the wetland only after obtaining a “Inner Line Permission" from the
Deputy Commissioner Leh.
Environmental Impact Assessment of the National Large Solar
Telescope Project and its ecological impact in Merak area
Land cover Analysis: Land cover refers to the physical status of the Earth’ surface and relates to
the type of features present on the surface of the Earth like forest, water body, soil, etc. Land use
refers to the way in which land is being employed by humans for various purposes. It relates the
functional utility of land to the economic activities. Land use/land cover pattern of a region is an
outcome of the natural and socio-economic factors and their utilization by man in time and
space. Demographic pressure has led to continuous exploitation of natural resources. There are
only a few landforms left on the Earth that are in their natural state. Due to anthropogenic
activities Earth surface is continuously being modified and the way land has been used has
significant effect upon the natural environment thus resulting into an observable land use/land
cover pattern over the time. Thus land use land cover change analysis has become a central
component is current strategies for managing natural resources. Temporal data aids in a process
of identifying differences in the state of an object or phenomenon by observing it at different
times. It forms an important parameter in monitoring and managing natural resources as it
provides quantitative assessment of the features of interest.
The spatial extent is about 31468 hectares, extended from north: 3751574.007 till south:
3731302.585 and east: 288642.589 till west: 268639.999 (Figure 19).
Figure 19: Study area - Pangong Tso
Data: Landsat TM of 1989, 2006, 2010 [downloaded from http://glcf.umiacs.umd.edu/data/]
Google Earth image (http://earth.google.com) served in pre and post classification process and
validation of the results. Spatial and spectral details of the data used for land cover analysis is
given in Table 3.
Table 3: Spatial and spectral details of the remote sensing data used for analysis
Satellite Bands Spectral Range Spatial Res. Year
Landsat TM 1
0.45 – 0.52
0.52 – 0.60
0.63 – 0.69
0.76 – 0.90
1.55 – 1.75
2.08 – 2.35
Methodology: Maximum Likelihood classifier (MLC), Which is based on the Gaussian
algorithm was used to classify temporal RS data into 5 LC classes – Vegetation, Water, Snow,
Open Sand area and Rocks. This is done using the signatures generated with the training data.
MLC is a parametric classifier that can be used to train a huge number of datasets. This
algorithm is Popular and widespread in RS because of its robustness (Hester et al., 2008). Due to
absence of historical data, training pixels were collected from the false color composite of the
respective bands (for the year 1989, 2006 and 2010). The data were processed using open source
software for analyzing geographical resources called GRASS. The accuracy of the classified
images on an average was 85 %. The Entire Procedure has been depicted in Figure 20.
Figure 20: Remote sensing data analysis schematic diagram
Figure 21 shows the classified image of 1989, 2006, 2010 obtained with five land use categories
(Vegetation, Water, Snow, Open Sand area and Rocks). Table 4 gives the details of the classified
images. The analysis shows that only 0.08% is under vegetation, 23% under water and the
Figure 21 . Classified images of 1989(a), 2006(b), 2010(c).
Table 4: Land use statistics of study area – Pangong Tso.
Open Sand area
The high floral diversity of Ladakh could also be attributed to its location at the junction of three
of the six bibliographical zones of the world. The climate is influenced to a large extent by the
Greater Himalaya to the south. There is minimal precipitation in the region due to the rain
shadow effect of the Himalayan crest. Thus, the plant production is low, and vegetation of the
region is characterized by alpine steppe, where the cover hardly crosses 20%. Despite such poor
primary productivity, there is a diverse assemblage of fauna that thrived for millenia. Situated in
the valley of Changthang, the lake Pangong tso and its surroundings provide a unique habitat for
life. It is largely an exposed barren landscape, the cold desert with sparse vegetation exhibiting
characteristic adaptations to withstand the adverse ecoclimatic conditions. Nevertheless many
wetlands that exist in the valley support extensive pastures. The vegetation in the pastures is
largely cold hardy grasses and sedge species. The vegetation in the other places is largely of
scattered shrub. Tree cover is almost completely absent. Diversity here is to the minimum, the
same species being repeated throughout. These species are not different from those inhabiting
rest of the areas in Changthang.
The soil in the valley, particularly that in the vicinity of the lakes is sandy and gravelly, lacks
organic matter and understandably a poor substratum to support plant growth. The water of
Pangong tso is brackish. The vegetation along the lake is particularly scanty, one species of grass
being predominant. The habitat does not appear to be a hotspot area for plant species. The
Pangong lake however seems to be teamed with an array of algal species.
The region lack vegetation in the deeper parts of the lake, but at the margins and marshy areas,
sedges and grasses are found towards the northern and eastern sides. The surrounding plateau
and hills support low thorn scrub and perennial herbs (Islam and Rahmani, 2008). The two
biotopes of the Changthang Wildlife Sanctuary via riverine contains Salix sp. and Myricaria
germanica, and Caragana scrub contains Caragana pyomea.
Seabuckthorn (Ladakhi:Tsermang): This shrub which is found in large parts of Ladakh is
known for its delicious berries. These fruits have a high content of Vitamin C and are known for
the anti-aging properties they are said to possess. Some of the varieties of Seabuckthorn are high
in Vitamin A and other oils. Over 200 products can be commercially made from this plant, which
is very important for the local people too as fuel wood and construction material.
The following flowering plant species (Figure 24-35) are noticed within the 50 sq.km of the
proposed site for solar telescope by the side of Pangong tso:
1) Nepeta longibracteata (Lamiaceae)
2) Arnebia guttata (Boraginaceae)
3) Taraxacum officinale (Asteraceae)
4) Echinops cornigerus (Asteraceae)
5) Tanacetum tibeticum (Asteraceae)
6) Aconitum sp. (Ranunculaceae)
7) Silene nigrescens (Caryophyllaceae) - Near Changla pass
8) Potentilla sp. (Rosaceae)
9) Crepis flexuosa (Asteraceae)
10) Nepeta podostachys (Lamiaceae)
11) Cirsium sp. (Asteraceae)
12) Anaphalis triplinervis (Asteraceae)
13) Christolea crassifolia (Brassicaceae)
14) Saxifraga sp. (Saxifragaceae) – An alpine grassland species
15) Rhodiola imbricata (Crassulaceae)
16) Sibbaldia sp. (Rosaceae)
17) Scorzonera virgata (Asteraceae)
18) Sassurea bracteata (Asteraceae)
Figure 22: Seabuckthorn shrub
Ephedra gerardiana, a gymnosperm that is found towards Henle could not be sited in Changthang
valley, particularly around Pangong tso. Also, natural populations of Hippophae rhamnoides
(Elaeagnaceae) which are almost everywhere in Ladakh and predominant towards Leh are
strikingly absent here.
The dominant and widespread among the above listed flowering species are:
1) Tanacetum tibeticum
2) Echinops cornigerus (Asteraceae)
3) Crepis flexuosa
4) Cirsium sp.
Other flowering taxa exist here in small numbers which could not be identified as they were not
in their flowering/fruiting stage at the time of our visit.
Figure 24. Clematis sp.
Figure 25. Cristolea crassifolia
6. Gentiana s
7. Rosa sp.
Figure 28. Tanacetum gracile
Figure 29. Taraxacum officinale
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Environmental Impact Assessment of the National Large Solar
Telescope Project and its ecological impact in Merak area
FAUNA distribution in the study area
1. Avian distribution in the Pangong wetland Area:
Avifauna of Ladakh was first studied by Ferdinand Stoliczka, an Austrian- Czech
palaeontologist, who carried out a massive expedition in the region in the 1870s. Ladakh has
a great diversity of birds — a total of 225 species have been recorded. The digital
documentation of birds during the field work is given in Figures 37 to 53, which
demonstrates the richness. Many species of finches, robins, redstarts (like the Black Redstart
that migrates to the south), and the Hoopoe are common in summer. The Brown-headed Gull
is seen in summer on the river Indus and on some lakes like the Changthang and Pangong
Lake. The Pangong lake acts as an important breeding ground for a variety of birds including
a number of migratory birds. During summer, the Bar-headed goose and Brahmini ducks are
commonly seen here. Formerly, Pangong Tso had an outlet to Shyok River, a tributary of
Indus River, but it was closed off due to natural damming. Two streams feed the lake from
the Indian side, forming marshes and wetlands at the edges. Resident water-birds include the
Brahminy duck also known as the Ruddy Sheldrake and the Bar-headed Goose. These ducks
migrates to South India in winter to escape the extreme cold temperature and return to
Ladakh in Mid May. Other birds include the Raven, Red-billed Chough, Tibetan Snowcock,
and Chukar. The endangered Black-necked Crane (Grus nigricollis), being the state bird of
Jammu and Kashmir are found scattered in the Tibetan plateau, is also found in parts of
Ladakh. There are about 36 individuals sighted and reported by the wildlife department along
with other research institution. The recent team visit for present study could list out 50
species (Table 5) of birds in quite limited time and also spot 26 Black-necked Cranes at
various wetland locations between Merak and Hanle. Their distribution is very much
restricted to wetlands, marshy areas, even closer to village hamlets. The Lammergeier,
Upland Buzzard, Golden Eagle and some other quite interesting raptors are spotted at sereval
regions of Ladakh, especially Leh, Merak, Chumatang and Hanle. The Brown-headed Gull
breeds at Ladakh region, migrates to Sea coast during winter till summer. Pangong lake,
though brakish water quality harboured several Brown headed-gulls at the centre and at the
peripheral region brahminy ducks, Bar-headed geese along with other birds. The presence of
Brown headed-gull at the upland wetland is quite interesting as they are usually seen only at
sea coast. Wagtails like the White wagtail, Citrine wagtail, and Yellow wagtail were observed
thriving in great numbers all throughout Ladakh region. These birds breed in Ladakh,
migrates to south to warmer parts during winter. The avian diversity of this high altitude
wetland proves quite rich, attributing to the landscape, food availability and the climatic
Table 5: List of birds observed during present study at Ladakh.
1 Bar-headed Goose
Common name Scientific Name Location Ind. M S
Pangong Lake, Hanle,
Phoenicurus ochruros Leh, She, Changla Pas
LC Leh, Merak, She, Hanle,
Pangong Lake, Chushul,
Indus river, Merak, Loma,
Chushul, Loma, Hanle
4 Black-headed Gull
Blue Rock Pigeon
Brown Wood Owl
Leh, Merak, Hanle
Pangong Lake, Chushul,
Indus river, Merak, Loma,
Chushul, Loma, Merak,
Changla Pas, Hanle
Chushul, Loma, ,Indus
Loma, She, Hanle
10 Chestnut-eared Bunting
16 Common Raven
17 Common Redstart
Common Wood Pigeon
Pangong Lake, Merak
Leh, Merak, Hanle,
22 Cotton Pygmy Goose
3 * LC
Leh, Changla Pas
25 Eurasian Tree Sparrow
Leh, Merak, Hanle, She,
Leh, Changla Pas
Pangong Lake, Tangste
Leh, Changla Pas, Tangste
Pangong Lake, Merak,
Changla Pas, Hanle
Great Crested Grebe
31 Green Sandpiper
32 Himalayan Snowcock
33 Horned Lark Leh, Merak, Chushul,
Changla Pas, Hanle,
Pangong Lake, Tangste,
Lesser Spotted Eagle
Palla's Fish Eagle
Haliaeetus leucoryphus Hanle
Leh, Merak, She, Hanle,
Pangong Lake, Loma,
Pangong Lake, Chushul,
Indus river, Merak, Loma,
Tetraogallus tibetanus Changla Pas, Hanle
Hanle, Chushul, Merak,
Leh, Changla Pas,
Chushul, She, Loma,
Hanle, Pangong Lake,
49 White Wagtail ssp.
2 * LC
48 Download full-text
Leh, Changla Pas,
Tangste, Merak, Hanle
Note: M – Migratory, S – IUCN status, V – Vulnearable, LC – Least Concern, NT – Near
The BNHS and BirdLife International have listed Pangong Tso as an Important Bird
Areas (IBA) criteria A1 (Islam and Rahmani, 2004).
A1 (Globally threatened species), Criterion: The site is known or thought regularly to
hold significant numbers of a globally threatened species, or other species of global
conservation concern.The site qualifies if it is known, estimated or thought to hold a
population of a species categorized by the IUCN Red List as Critically Endangered,
Endangered or Vulnerable. In general, the regular presence of a Critical or Endangered
species, irrespective of population size, at a site may be sufficient for a site to qualify as
an IBA. For Vulnerable species, the presence of more than threshold numbers at a site is
necessary to trigger selection. Thresholds are set regionally, often on a species by species
basis. The site may also qualify if holds more than threshold numbers of other species of
global conservation concern in the Near Threatened, Data Deficient and, formerly, in the
no-longer recognized Conservation Dependent categories. Again, thresholds are set
Black-necked Crane: Black-necked Crane (Grus nigricollis) is classified as Vulnerable
under the IUCN Red List of threatened Animals (figure 36), because it has a single small
population that is declining owing to the loss and degradation of wetlands, and changing
agricultural practices in both its breeding and wintering grounds. However, the population
has apparently increased in recent years. It breeds on the Qinghai-Tibetan plateau, China,
with a small population in adjacent Ladakh, India. Sighting of Black-necked Cranes in the
study area is given in Figure 37.Six wintering areas have been identified at lower altitudes on
the Qinghai-Tibet and Yunnan-Guizhou plateaus, China, including counts of 3,562 birds in
Yunnan and western Guizhou in winter 2003 and, in Tibet, 4,277 in 1999 increasing to 6,940
in 2007. It also winters in Bhutan (500 individuals), and Arunachal Pradesh, India (10
individuals) and small numbers have been recorded in Vietnam. These figures imply a total
world population of approximately 11,000 individuals, although it is estimated that the
number of mature individuals is perhaps 8,800. Major threats to this species are Intensive
grazing, pesticide, planting high yield winter wheat rather than traditional crops, drying-up of
marshes and desertification as a result of surrounding development and agriculture, dam,
habitat degradation and climate change (BirdLife International, 2009).
Golden Eagle: Golden Eagle (Aquila clanga) has a small population which appears to be
declining owing to extensive habitat loss and persistent persecution. It is therefore listed as
Yellow Wagtail 1 * LC