Teesta River is a 414 km (257 mi) long river that rises in the Pauhunri Mountain of eastern Himalayas, flows through the Indian states of Sikkim and West Bengal through Bangladesh and enters the Bay of Bengal.[1] It drains an area of 12,540 km² (4,840 sq mi).[2] In India, it flows through Mangan District, Gangtok District, Pakyong District, Kalimpong district, Darjeeling District, Jalpaiguri District, Cooch Behar districts and the cities of Rangpo, Jalpaiguri and Mekhliganj. It joins the Brahmaputra River at Phulchhari Upazila in Bangladesh. 305 km (190 mi) of the river lies in India and rest in Bangladesh. Teesta is the largest river of Sikkim and second largest river of West Bengal after the Ganges.

Teesta River
Teesta in Siliguri, West Bengal
Path of the Teesta
Source of Teesta river in Sikkim Show map of Sikkim Teesta River (India) Show map of India
Location
Country	India, Bangladesh
State	Sikkim, West Bengal, Rangpur Division
District	Kurigram District, Nilphamari District, Gangtok District, Pakyong District, Mangan District, Kalimpong district, Darjeeling district, Cooch Behar district and Jalpaiguri district
City	Singtam, Rangpo, Kalimpong, Jalpaiguri, Mekhliganj
Physical characteristics
Source	Pauhunri, Zemu Glacier, Gurudongmar Lake, Tso Lhamo Lake
• location	Sikkim, India
• elevation	7,128 m (23,386 ft)[1]
Mouth	Brahmaputra river
• location	Phulchhari Upazila, Gaibandha, Bangladesh
Length	414 km (257 mi)[1]
Basin size	12,540 km2 (4,840 sq mi)[2]
Basin features
Tributaries
• left	Rangpo River, Lachung River, Ranikhola, Relli River, Talung River, Dik Chhu, Lang Lang Chu
• right	Rangeet River, Ringyong Chhu, Ranghap Chhu

Course

The Teesta River originates from Teesta Khangtse Glacier, west of Pahunri (or Teesta Kangse) glacier above 5,400 m (17,700 ft), and flows southward through gorges and rapids in the Sikkim Himalaya.[3]

It is fed by rivulets arising in the Thangu, Yumthang, Dikchu and Donkha mountain ranges. The river then flows past the town of Singtam where Ranikhola joins and then descends towards Bardang, Majitar and reaches the city of Rangpo where Rangpo River, the second largest tributary of Teesta joins, and from there it forms the border between Sikkim and West Bengal up to Teesta Bazaar. Just before the Teesta Bridge, where the roads from Kalimpong and Darjeeling join, the river is met by its largest tributary, the Rangeet.[4]

At this point, it changes course southwards flowing into West Bengal. The river hits the plains at Sevoke, 22 kilometres (14 mi) northeast of Siliguri, where it is spanned by the Coronation Road Bridge and Sevoke Railway Bridge linking the northeast states to the rest of India. After crossing Sevoke, the river is fed by some small tributaries like Chel Khola, Neora Khola, Leesh Khola etc, and than reaches Gajoldoba where there is Teesta Barrage. The river then flows through Jalpaiguri City, where there are also Road and Railway bridges which links Northeastern States. The river flows further down through Mekhliganj and Haldibari in Cooch Behar district, where it is spanned by Joyee Setu Bridge, the longest roadway bridge of West Bengal. Here the river completes its journey in India and enters Bangladesh in Dahagram, Rangpur Division, further it flows towards Lalmonirhat town in Nilphamari District and joins River Brahmaputra at Gaibandha, Fulchhari in Kurigram District of Bangladesh.[5]

Geography

Through its course, the Teesta river has carved out ravines and gorges in Sikkim meandering through the hills with the hill station of Kalimpong lying just off the river and the city of Siliguri at the foothills of Himalaya. Variegated vegetation can be seen along this route. At lower elevations, tropical deciduous trees and shrubs cover the surrounding hills; alpine vegetation is seen at the upper altitudes. The river is flanked by white sand which is used by the construction industry in the region. Large boulders in and around the waters make it ideal for rafting enthusiasts.

Between Rangpo town and the railway bridge (popularly called Lohapul or iron bridge) on it as it enters the plains at Sevoke, the Teesta flows with a very strong current, ideal for white river rafting. Towns like Teesta Bazaar and Melli have facilities for group rafting. Though the river looks innocuous, the underlying current is very strong. In 1915, G.P. Robertson, the then Municipal Engineer of Darjeeling, drowned after losing control of the boat in the turbulence while surveying the river. The boat struck a partially hidden boulder and was sucked in by a whirlpool, leaving no trace of the occupants.

During the monsoons, Teesta river distends its banks; both in size and turbulence. Landslides in this region often dam up parts of the river in this season. It has also caused severe flooding, multiple times during monsoon in Bangladesh.[6][7]

Changes in course of rivers

In the past, the Teesta flowed south from Jalpaiguri in three channels: the Punarbhaba, Atrai and Karatoya rivers. The Teesta changed course as a result of the flooding of 1787, turning southeast to become part of the Brahmaputra.[8] During the 1700s, James Rennell made maps that showed the origins of the Teesta River.[9]

Hydroelectric projects and barrages

Hydel project on the Dikchu, a tributary of Teesta.

The Teesta Barrage is a major irrigation project in Bangladesh, in Lalmonirhat District. Construction started 1979 and was completed in 1997–98.[10]

India has an estimated total hydroelectric power potential of 84 GW (at 60% load factor). Of this, Sikkim's potential share is 2.9%, or about 4.29 GW. As of 2010, 13.9% (594 MW) of Sikkim's potential had been implemented and was under operation, 44.8% is under implementation (1919 MW), and another 41.3% (1773 MW) is yet to be examined from environment and engineering design perspective.[11]

The successfully completed major projects and dams are:

1. Teesta -V dam, the largest project so far, was completed in 2007 on Teesta in Dikchu, East Sikkim district. Its height is 87 metres (285 ft) and its length is 176 metres (577 ft). It generates 510 MW hydroelectric power and assists flood control.[12]
2. Rangit III hydroelectric project was completed in 2000 on Greater Rangit River which is a tributary of Teesta River. The catchment area of Rangit III dam is 979 square kilometres (378 sq mi) and the dam is 47 metres (154 ft) high. The project has 60 MW generation capacity, and is already online.[13]

The other three completed projects are significantly smaller and minor—Lower Lagyap, Upper Rongni Chhu and Mayang Chhu projects.[11]

Water sharing challenge

Disputes over the appropriate allocation and development of the water resources of the river have remained a subject of conflict between India and Bangladesh for almost 35 years, with several bilateral agreements and rounds of talks failing to produce results.[14][15][16]

Negotiations have been going on since 1983.[17][18][19] In 1983, a temporary solution had been worked out— Bangladesh would get 36%, India would get 39% while the rest of the water remained unallocated.[18] Both countries signed a water sharing treaty in 1996 which would look into water sharing between the two countries in general following the Ganges water dispute.[18] The water sharing remains a challenge.[18]

Seismic concerns

Teesta river area is in the seismically active Zone-V and has experienced micro-seismic activity. According to India's Ministry of Environment & Forests, the Teesta river dam projects have been approved with the requirement that they adopt suitable seismic coefficient in the design for the dam, tunnel, surge shaft and power house. The projects are cascaded over the length of the river, do not store large amounts water, have small reservoirs, and therefore the projects are expected to have very low risk from the reservoir induced seismicity in the area.[11]

Climate and tectonics

The Teesta river has preserved good imprints of climatic and tectonics along its valleys and catchments. The interrelationship between climate, erosion, deposition and tectonic activities is not properly understood to date. These are being studied.[3][20][21]

See also

• Talung River

References

External links

Wikimedia Commons has media related to Teesta River.

• Tista River at GEOnet Names Server
• Mesbah-us-Saleheen (2012), "Tista River", in Sirajul Islam and Ahmed A. Jamal (ed.), Banglapedia: National Encyclopedia of Bangladesh (Second ed.), Asiatic Society of Bangladesh

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