International Journal of Scientific & Engineering Research, Volume 4, Issue 9, September-2013 1560

ISSN 2229-5518

Glaciers in Ganges basin: an assessment of their dimensions through inventories

Nathaniel B. Dkhar and Shresth Tayal

Abstract— The objective of this paper is to analyse the data available in the glacier inventories published by Geological Survey of India and International Centre for Integrated Mountain Development and make a comparative assessment of the distribution and extent of Himalayan glaciers in the Ganges river system of Indian and Nepal Himalaya.Some interesting conclusions for this assessment were that majority of the estimated glacial ice volume towards the Ganges river system was from the Nepal Himalayas. Also, it was found that smaller glaciers have a larger representation than large glaciers in the Ganges basin.

Index Terms— Ganges, Gangotri, Glaciers, Indian Himalaya, Nepal Himalaya

——————————  ——————————

1 INTRODUCTION

he higher altitude range of Himalayas consists of a num- ber of small and large glaciers. Their occurrence is con- trolled by climatic conditions, which are responsible for accumulation of snow and ablation. The Himalaya has one of the largest concentrations of glaciers outside the Polar Regions
and is often referred to as the Third Pole.
The Ganges River system remains the main source of
freshwater for about half the population of India and Bangla-
desh and nearly the entire population of Nepal. The Ganges
River originates from the central Himalayas and flows around
2,500 kilometres to the Bay of Bengal. [1]
The Himalayan mountain range spans 2500 km east to west
and includes diverse cultures of five countries (Afghanistan, Pakistan, India, Nepal, and Bhutan). [2] The snow and ice pre- sent in the Himalaya acts as a huge reservoir for freshwater which makes it a very precious resource. The cryosphere in
the Himalayan region are continuously undergoing natural changes. These changes are accelerated by the increasing pop- ulation, industrialisation, and rising levels of urbanisa- tion.Green House Gas led global warming and related climate change impacts also lead to the enhanced melting of the glaci- ers. The deglaciation of Himalayan glaciers can be attributed principally to the increasing temperatures linked to global warming due to increase in anthropogenic emission of green- house gases. The relatively high population density near the Himalayan glaciers and consequent deforestation and land- use changes has also adversely affected these glaciers. [3] Glacier changes are recognized as high-confident climate indi- cator and as a valuable constituent in early detection strategies within the international climate monitoring programmes. Fluctuations of a glacier, which is not influenced by thick de- bris covers, calving or surge instabilities, are a reaction to cli- matic forcing. Thereby, the glacier length change (i.e., the ad- vance or retreat) is the indirect, delayed, filtered but also en-

————————————————

• Nathaniel B. Dkhar is currently pursuing Ph.D. program, from the De- partment of Natural Resource, TERI University, New Delhi, India.

PH-01124682100. E-mail: nathaniel.dkhar@teri.res.in

• Dr. Shresth Tayal is the Area Convenor and Fellow in Water Resource Division, TERI, New Delhi, India. PH-01124682100. E-mail: stayal @teri.res.in

hanced signal to a change in climate, whereas the glacier mass balance (i.e., the change in thickness/volume) is the direct and un-delayed response to the annual atmosphere conditions. [4] The high rate of deglaciation of the Himalayan glaciers is a cause for concern as they form an integral part of the water supply for the downstream areas and its melt water guaran- tees the perennial supply of water to the rivers. Melting glaci- ers provide a key source of water for the region in the summer months and as much as 70 percent of the summer flow in the Ganges is contributed by the Himalayan Cryosphere. [5], [6] However the rapid deglaciation of the Himalayan glaciers
could subsequently lead to water‐related hazards, such as wa-
ter stress, due to the expected decline in fresh water supplies
especially during the dry season and also increase in number
of hazardous events like Glacier Lake Outburst Floods
(GLOFs). [7]

2 OBJECTIVE

The aim is to make a comparative assessment of the distribu- tion and extent of Himalayan glaciers in Ganges river system of Indian and Nepal Himalaya.

3 MATERIALS & METHODS

Geological Survey India had undertaken the task of compila- tion of glacier inventory in 1977, immediately after the consti- tution of the world glacier inventory body at Zurich. GSI's inventory is based on the guidelines provided by the Tempo- rary Technical Secretary (TTS) for the World GlacierInventory (WGI) of the Swiss Federal Institute of Technology (ETH), Zurich.
Geological Survey of India published an inventory of Him- alayan glaciers in 2009, which is an updated version of GSI's earlier publication - 'Inventory of the Himalayan Glaciers' (Secial. Publication No. 34) published in 1999. This inventory gives information about the glaciers in Himalaya, specifically for their location, orientation, elevation, length, area and vol- ume, as compiled from the survey of India toposheets of 1960s and 1970s (of scale 1:50,000 and 1:250,000). The compilation of data was also aided by study of aerial photographs and satel-

International Journal of Scientific & Engineering Research, Volume 4, Issue 9, September-2013 1561

ISSN 2229-5518

lite images wherever available, along with field and compila- tion work of the officers of GSI. On spot monitoring and anal- ysis for most of the descriptive parameters, which are dynamic in space and time was seen as a requirement for higher accu- racy. To accomplish this, regular field checks in various ter- rains, selected basins, continuous monitoring of different ba- sins with a number of glaciers as a reference base were con- ducted. [8]
The “Geological Survey of India: Inventory of the Himalayan Glaciers, Special Publication No. 34, 2009” is a reference re- source on Indian Himalayan glaciers.
The Inventory of Glaciers, Glacial Lakes and Glacial Lake Outburst Floods: Monitoring and Early Warning Systems in the Hindu Kush-Himalayan Region - Nepal (2001) published by ICIMOD has information on the glaciers of Nepal. ICIMOD used geographic information systems (GIS) to create a com- prehensive inventory and GIS database of glaciers and glacial lakes in Nepal using available maps, satellite images, aerial photographs, reports, and field data on different scales.ICIMOD’s inventory is also based on the guidelines provided by the Temporary Technical Secretary (TTS) for the World GlacierInventory (WGI) of the Swiss Federal Institute of Technology (ETH), Zurich. [9]
The data presented in the Geological Survey of India inven- tory and ICIMOD Inventory of glaciers was analysed to make a comparative assessment of the distribution of Indian Hima- layan glaciers in the river systems of Ganges, and also to ana- lyse the dimension of Indian Himalayan glaciers.

4. RESULTS

It was estimated that 33,200 sq. km of the Himalaya is glaciat- ed6 and glaciers occupy about 17 percent of the total moun- tainous area of the Himalaya. [12] As per the survey by Geo- logical Survey of India, Indian Himalaya has a total of 9575 glaciers. Out of these, information related to their length, area and volume are available for 9040 glaciers, which occupy an area of 18527.79 km2 and have a volume of 1306.1 km3. Out of these, 94.09 percent of glaciers are smaller than 5 km in length and 92.8 percent of glaciers are smaller than 5 km2 in area. [8]
In total Indian Himalaya glaciers occupy more than 55.81 per- cent of the entire glaciated area of the Himalaya.
divided into four major river basins i.e. Yamuna, Bhagirathi, Alaknanda and Ghaghara River Basins. These basins originate from the higher reaches of Uttarakhand.
River Ganga is fed by 10.1 percent of all the glaciers in Indian
Himalaya, totaling 968 glaciers which are distributed among
18 sub-basins. 87.7 percent of these glaciers are smaller than 5
km in length and 86.57 percent are small to very small in size
ranging from 5.0 km2 to 0.03 km2.
Glacial depth is normally related to its area and usually small
glaciers have comparatively lesser depth. As glacier response
time is relative to its depth it could vary between 4 and 60
years, depending upon glacial size. This could be the funda- mental reason for large retreat of small glaciers. [10] The cur- rent trend of fragmentation of glaciers to smaller glaciers and separation from glacier to form dead ice will also increase the
rates of deglaciation thereby enhancing the impacts of global warming.
The glaciers with a smaller area are more threatened by de- glaciation than large glaciers. Loss in glaciated area for large glaciers [area more than 10 km2] was 12 percent compared to
38 percent for small glaciers [area less than 1 km2]. A loss of 29 percent and 27 percent of area was also observed for glaciers of the size range of 1-5 km2 and 5-10 km2 respectively between
1962 and 2001. [10]
It can also be noted that even though the network of lower
latitude small glaciers and ice caps, make up for only about
four percent of the total land ice area or about 760,000 km2,
they may have provided as much as 60 percent of the total

glacier contribution to sea level change since 1990s. [11]

Fig. 2. Ganges Basin: Number of glaciers in Indian Himalaya [8]

Fig. 1. Indian Himalayan Glaciers [8]

The Ganges River system in the Indian Himalayas can be

Fig. 3. Ganges Basin: Indian Himalaya Glaciated Area km2 [8]

International Journal of Scientific & Engineering Research, Volume 4, Issue 9, September-2013 1562

ISSN 2229-5518

Fig. 4. Ganges Basin: Indian Himalaya Volume km3 [8]

Fig. 7. Ganges Basin: Nepal Himalaya Volume km3 [9]

River flow in Ganga is also supported by 3252 glaciers of Nepal Himalaya with a glacierised area of 5322 km2 and ice volume of 481 km3. The Nepal Himalayas area can be divided into four major river basins namely Koshi, Gandaki, Karnali and Mahakali River Basins. It can be noted that even though Karnali basin has more number of glaciers than Gandaki ba- sin, Gandaki basin has a larger glacierised area due to the presence of larger glaciers.
Accordingly, Nepal Himalaya has 77 percent of the total number of glaciers in the Ganga basin, 65 percent of glaciated area and 69 percent of total ice volume contributing to River Ganga.

4.1 Gangotri Glacier

Gangotri glacier is the largest glacier of Ganga basin cover- ing 5percent of the total glaciated area and 13 percent of total ice volume in the Indian Himalayan part of the basin. Fur- thermore, as many as 40 glaciers have a significant ice volume of more than 1km3, but concentrated mostly in 5 of the 18 sub basins of Indian Himalayas. Out of the 40 glaciers, only 6 have an ice volume of more than 5 km3 but they account for 26.82 percent of the ice volume.
However when compared with contributions from Nepal Himalayas, Gangotri glacier occupies 2 percent of the total glaciated area of the basin. Gangotri glacier has an estimated ice volume of 28.72 km3 accounting for 4 percent of the total ice reserves in the Ganges River Basin.

Fig. 5. Ganges Basin: Number of glaciers in Nepal Himalaya [9]

Fig. 6. Ganges Basin: Nepal Himalaya Glaciated Area sq. km2

[9]

Fig. 8. Ganges River System: Comparison of Area and Volume

[8], [9]

International Journal of Scientific & Engineering Research, Volume 4, Issue 9, September-2013 1563

ISSN 2229-5518

5 CONCLUSION

Majority of glaciers in Indian Himalayas, and Ganges Basin are smaller in size. Furthermore, smaller glaciers are more susceptible to melting, and hence vulnerable to global warm- ing. Additionally, the bulk of ice volume contributing to the Ganges river system is located in Nepal Himalayas. Therefore,
there is an urgent need for cross‐border co‐operation to devel-
op a shared understanding of melting response of glaciers
contributing to Ganges basin.
The identification of mutual benefits is vital and it is a pre- requisite for successful regional cooperation. There is a need to share hydro-meteorological knowledge between India and Nepal and for collaborative efforts towards cryosphere preservation, flood forecasting and warning, and research studies on the effects of climate change in the Himalayan re- gion. Joint field expeditions and research programmes on In- dian and Nepal Himalayan glaciers should be developed with the collaborative efforts of researchers from the two sides.
Few studies have been done on glaciers other than the Gangotri glacier. Therefore it is also necessary to study the impacts on smaller glaciers which have larger representation, and face the maximum possible risks due to climate change effects.
Long term studies on glacier dynamics and mass balance are needed to understand the behavior of the Himalayan glac- iers and climate change impacts.

ACKNOWLEDGEMENT

Authors are thankful to The Energy Resources Institute (TERI), for initiating the Glacier Research Programme and extending an opportunity to work in it.

laya, India”, Current Science, vol. 92, no. 3, pp. 376–382, 2007

[7] M.B. Karki and R. Vaidya, “Adaptation to Climate Change Impacts and Regional Cooperation on Water and Hazards in the Himalayan Region”, International Centre for Integrated Mountain Development (ICIMOD), 2008

[8] Inventory of the Himalayan Glaciers, Geological Survey of India, C.V.

Sangewqar and S.P. Shukla. Eds., Special Publication No. 34, 2009

[9] Mool, P.K.,Bajracharya, S. R., Joshi, S. P., 2001, Inventory of Glaciers, Glacial Lakes and Glacial Lake Outburst Floods: Monitoring and Ear- ly Warning Systems in the Hindu Kush-Himalayan Region - Nepal, ICIMOD

[10] A.V Kulkarni, I.M. Bahuguna, B.P. Rathore, S.K. Singh, Randhawa S.

S., Sood R. K. and Sunil Dhar, 2007, Glacial retreat in Himalaya using

Indian Remote Sensing Satellite Data, Current Science 92(1), 69-74. [11] Mark F. Meier, Dyurgerov M. B., Rick U. K., O'neel S., Pfeffer W. T.,

Anderson R.S., Anderson S.P., and Glazovsky A.F., 2007, Glaciers

Dominate Eustatic Sea-Level Rise in the 21st Century, Science 317,

1064

[12] R. F Flint. Glacial and Quaternary Geology. Wiley. Xiv, pdp. 892,

1971.

REFERENCES

[1] H.Er. Rashid, B. Kabir, “Water Resources and Population Pressures in the Ganges River Basin” Water and Population Dynamics: Case Studies and Policy Implications, Alex de Sherbinin and Victoria Dompka, eds., Report of a Work- shop October 1996 Montreal, Canada http://www.aaas.org/international/ehn/waterpop/bang.htm

[2] S. Tayal, S.I. Hasnain, “Role of sub-regional variations on melting Response of Indian-Himalayan Glaciers” American Geophysical Union, Fall Meeting, 2010

[3] IPCC Fourth Assessment Report: Climate Change 2007: Working

Group II: Impacts, Adaptation and Vulnerability“The Himalayan glaciers”

[4] W. Haeberli, M. Hoelzle, “Application of inventory data for estimat- ing characteristics of and regional climate-change effects on moun- tain glaciers: a pilot study with the European Alps” Annals of Glaciol- ogy, Vol. 21, pp. 206-212, 1995.

[5] T.P. Barnett, J.C. Adam & D.P. Lettenmaier, Potential impacts of a warming climate on water availability in snow-dominated regions, Nature vol. 438, pp. 303-309, 2005

[6] R.J. Thayyen, J.T. Gergan, and D.P. Dobhal, “Role of glaciers and snow cover on headwater river hydrology in monsoon regime: Micro scale study of Din Gad catchment (Dokriani Glacier), Garhwal Hima-