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Teesta River

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The Teesta River is a major waterway in South Asia.

It begins in the Pauhunri Mountain of the eastern Himalayas. The river originates from the Teesta Khangtse Glacier. This glacier sits west of the Pahunri glacier. From these high altitudes, the river flows southward through the Sikkim Himalaya. It moves through deep gorges and fast rapids. The Teesta is the largest river in Sikkim. In West Bengal, it is the second largest river after the Ganges. It eventually flows into Bangladesh and joins the Jamuna River. This large river system eventually empties into the Bay of Bengal.

Many different sources feed the Teesta as it moves downhill. It receives water from streams at Tso Lhamo Lake and Gurudongmar Lake. Rivulets from the Thangu Valley and Yumthang Valley of Flowers also provide water. The river is fed by the Dikchu and Donkha mountain ranges. As it travels, several major tributaries join the main flow. The Kanaka River is one such tributary. Later, the Ranikhola joins the river near Singtam. The Rangpo River is the second largest tributary. Just before the Teesta Bridge, the Rangeet River joins as the largest tributary. These additions increase the volume of water as the river descends.

Teestavalley
Teestavalley

The landscape around the river changes based on elevation. At high altitudes, the river is surrounded by alpine vegetation. At lower elevations, tropical deciduous trees and shrubs cover the hills. The river has carved out many ravines and gorges in Sikkim. Along its banks, you can find white sand used by the construction industry. Large boulders in the water make the river ideal for rafting. During the monsoon season, the river changes significantly. It distends its banks and becomes much more turbulent. Landslides in the mountains can even dam up parts of the river during this time.

1776 Rennell - Dury Wall Map of Bihar and Bengal, India - Geographicus - BaharBengal-dury-1776
1776 Rennell - Dury Wall Map of Bihar and Bengal, India - Geographicus - BaharBengal-dury-1776

The path of the Teesta has changed over many centuries. A map from 1776 by James Rennell shows an earlier flow. In the past, the river flowed south from Jalpaiguri in three separate channels. These channels were named the Punarbhaba, Atrai, and Karatoya Rivers. A devastating flood occurred in 1787. This event changed the course of the river forever. The Teesta turned southeast to become part of the Brahmaputra River system instead of meeting the Ganges.

Gajoldoba Barrage on Teesta river in Gajoldoba 13
Gajoldoba Barrage on Teesta river in Gajoldoba 13

Humans use the Teesta to generate hydroelectric power. This is electricity made from moving water. Many dams and barrages have been built along its course. The Teesta III Dam in Mangan District can produce 1200 MW of power. The Teesta V Dam in Gangtok District produces 510 MW. Other projects include the Teesta Low Dam IV and the Teesta VI Dam. There is also a barrage at Gajoldoba in West Bengal. However, these projects face risks from nature. In October 2023, heavy rains caused a glacial lake outburst flood. This flood destroyed the Teesta III Dam in minutes.

Managing the water is a complex task for India and Bangladesh. These two countries have discussed water sharing for almost 35 years. Negotiations have been ongoing since 1983. In 1983, a temporary arrangement was made for the water. India was allocated 39% and Bangladesh was allocated 36%. A water sharing treaty was signed in 1996. Despite these efforts, the water sharing remains a significant challenge. Both nations must work together to follow international water-sharing principles. Success in these talks is important for the relationship between the two countries.

The Teesta River area is also located in a seismically active zone. This means the ground is prone to earthquakes. The region is classified as Zone-V, which is a high-activity area. Because of this, engineers must use specific seismic coefficients in their designs. These designs help protect dams, tunnels, and power houses from tremors. Scientists are also studying how climate and tectonics affect the river. They want to understand the link between climate, erosion, and tectonic activities. This research helps us understand how the river valleys and catchments continue to change.

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🖼️ Images & Media (4)
File:Teesta river near Gangtok.jpg
Teesta river near Gangtok.jpg
File:Teestavalley.jpg
Teestavalley.jpg
File:Gajoldoba Barrage on Teesta river in Gajoldoba 13.jpg
Gajoldoba Barrage on Teesta river in...
File:1776 Rennell - Dury Wall Map of Bihar and Bengal, India - Geographicus - BaharBengal-dury-1776.jpg
1776 Rennell - Dury Wall Map of Bihar and...
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