Previous Year Question
With reference to river Teesta, consider the following statements:
The source of river Teesta is the same as that of Brahmaputra but it flows through Sikkim.
River Rangeet originates in Sikkim and it is a tributary of river Teesta.
River Teesta flows into Bay of Bengal on the borders of India and Bangladesh.
Which of the statements given above is/are correct?
1 and 3
Only 2
2 and 3
1, 2 and 3
Correct Answer: B
Detailed Solution
Only Statement 2 is correct. The Teesta and Brahmaputra have different sources, and the Teesta does not directly enter the Bay of Bengal at the India-Bangladesh border.
Statement 1: Incorrect
The Teesta and Brahmaputra do not have the same source.
Source of the Teesta
The upper headwaters of the Teesta originate from the Tso Lhamo Lake and Teesta Khangse Glacier region in North Sikkim.
This region lies near Pauhunri Mountain in the Eastern Himalayas.
Mountain streams such as the Lachen Chu and Lachung Chu subsequently contribute to the Teesta river system.
The Teesta flows southward through deep valleys and steep gradients in Sikkim.
It subsequently flows through the Darjeeling and Jalpaiguri regions of West Bengal before entering Bangladesh.
Source of the Brahmaputra
The Brahmaputra originates from glaciers situated in Tibet near the Kailash-Mansarovar region.
It is known as the Yarlung Tsangpo in Tibet.
It flows eastward across the Tibetan Plateau to the north of the Himalayas.
Near Namcha Barwa, it forms a deep gorge and turns towards the south.
After entering Arunachal Pradesh, it is known as the Siang or Dihang.
It becomes known as the Brahmaputra after being joined by the Dibang and Lohit rivers.
Therefore, the two rivers have different source regions, making Statement 1 incorrect.
Statement 2: Correct
The Rangeet originates in Sikkim and is a tributary of the Teesta.
The Rangeet or Rangit originates in the Himalayan region of western Sikkim.
Its upper headwaters are associated with the Rathong Glacier and the Kangchenjunga mountain region.
It flows generally towards the south and south-east.
The Rangeet joins the Teesta near the Teesta Bazaar region, close to the Sikkim-West Bengal boundary.
It is one of the most important tributaries of the Teesta.
Its steep gradient provides favourable conditions for hydropower generation, and the Rangit Hydroelectric Project has been developed on the river.
Therefore, Statement 2 is correct.
Statement 3: Incorrect
The Teesta does not directly enter the Bay of Bengal at the India-Bangladesh border.
The Teesta enters Bangladesh from West Bengal.
It subsequently joins the Jamuna or Brahmaputra River in Bangladesh.
The combined Brahmaputra flow then reaches the Bay of Bengal through the Ganga-Padma and Meghna river system.
The Teesta is therefore a tributary of the Brahmaputra, not an independent river directly entering the Bay of Bengal.
The Teesta does not meet the Bay of Bengal at the international boundary; the coast lies far to the south.
Course of the Teesta
North Sikkim → mountain valleys of Sikkim → West Bengal → Bangladesh → Jamuna/Brahmaputra → Padma-Meghna system → Bay of Bengal
Historical change in course
Historically, some channels of the Teesta flowed towards the Ganga river system.
Following a major flood in 1787, its principal course shifted eastward and became connected with the Brahmaputra system.
This is an important example of river-course change and river capture.