Teesta River rises in the Pauhunri Mountain of Himalayas., UPSC.

Teesta hydel projects

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Context: A severe landslide in Sikkim has destroyed the Teesta-V hydropower station of the state-owned NHPC Limited.

Details

Particulars	Descriptions
Name	Teesta River
Length	414 km
Total Catchment Area	12,159 km²
Origin	Himalayas near Tso Lhamo Lake, Sikkim.
Source	Pahurni glacier, Khangse glacier, ChhoLhamo Lake.
River Basin	India: Major portion, Bangladesh: 17%.
Population in Basin	Sikkim: 2%, West Bengal: 27%, Bangladesh: 71%.
Tributary of	Right bank tributary of the Brahmaputra .
Major Tributaries	Left-bank: Lachung Chhu, Chakung Chhu, Dik Chhu, Rani Khola, Rangpo Chhu . Right-bank: Zemu Chhu, Rangyong Chhu, Rangit River.
Confluence	Joins the Brahmaputra (Jamuna in Bangladesh) and flows into the Bay of Bengal after meeting with the Ganges and Meghna.

Particulars	Descriptions
Name
Dams and Projects	Barrage: Gajoldobha (India), Duani (Bangladesh), Barakhata (Bangladesh) Major Dams: Teesta -V (510MW, Gangtok), Teesta III (1200 MW, Mangan) Teesta Low Dam III (132MW, Kalimpong), Teesta Low Dam IV (160MW, Kalimpong), Teesta VI (500MW, Gangtok) On Tributaries: Rangit III (60MW, Gyalshing), Gati Hydropower (110 MW, Pakyong), Dikchu Hydroelectric (96 MW, Gangtok), Madhya Bharat Power Corp. (96MW, Gangtok)
Water Sharing Conflict	Negotiations have been going on since 1983. 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. Both countries signed a water sharing treaty in 1996 which would look into water sharing between the two countries.

Major Hydro Power Plants in India

Name	Location	Configuration	Important Facts
Tehri Dam (3 Stages)	Uttarakhand	2400 MW	Tehri Dam Hudro Electric project is the highest Hydal project in India commissioned in 2006. Its construction started in 1978 with the technical collaboration from the USSR.
Koyna Hydroelectric Project (4 Stages)	Maharashtra	1960 MW	The Koyna Hydro electric project is the largest completed Hydal power project in India. The dam is constructed across Koyna river in Maharashtra.
Srisailam	Andhra Pradesh	1670 MW	Srisailam Dam is constructed on the Krishna River in the border districts between Andhra Pradesh and Telangana districts Kurnool and Mahabubnagar districts respectively. It is the second largest working hydro electric power project in India.
Nathpa Jhakri (6 Turbinesx25 MW)	Himachal Pradesh	1500 MW	The Nathpa Jhakri dam is concrete gravity dam constructed across Satluj River in Himachal Pradesh.
Sardar Sarovar Dam,	Navagam, Gujarat	1450 MW	The Sardar Sarovar Dam is the largest dam of Narmada Valley Project, is a concrete gravity dam on the Narmada river near Navagam in Gujarat.
Bhakra Nangal Dam (Gobind Sagar)	Sutlej River, Bilaspur - Himachal Pradesh	1325 MW	Bhakra Dam is a concrete gravity dam built across Sutlej River at Bhakra villege in Bilaspur District of Himachal Pradesh. The power generated here is shared between Himachal Pradesh and Punjab and most of the outflow water is used by Punjab and Haryana for irrigation.
Chamera I	Himachal Pradesh	1071 MW	Chamera Dam is a hydroelectric project on river Ravi, which is located near Dalhousie town in Chamba district of Himachal Pradesh.
Sharavathi Project	Karnataka	1035 MW	Sharavathi Dam, officially known as the Linganamakki Reservoir, is built across Sharavathi river, about 6 kilometers away from Jog Falls.
Indira Sagar Dam, Narmada River	Madhya Pradesh	1000 MW	The Indirasagar Dam is a multipurpose project of Madhya Pradesh on the Marmada river at Narmadanagar, Khandwa district of Madhya Pradesh.
Karcham Wangtoo Hydroelectric Plant	Himachal Pradesh	1000 MW	The Karcham Wangtoo Hydroelectric Plant is a 1200 MW run of the river power station on the Sutlej river in Kinnaur district of Himachal Pradesh.
Dehar (Pandoh) Power Project	Himachal Pradesh	990 MW	The Pandoh Dam is built across Beas river in Mandi district of Himachal Pradesh. It was commissioned in 1977 for the primary purpose of hydroelectric power generation.
Nagarjuna Sagar Dam Guntur	Andhra Pradesh	960 MW	Nagarjuna Sagar Dam Reservoir is created by NJ Sagar dam built across Krishna river, spread in the Nalgonda district of Telangana and Guntur district of Andhra Pradesh states. The dam was commissioned in 1967.
Purulia Pass	West bengal	900 MW	Purulia Pumped Storage Hydroelectric Power Plant of West Bengal State.
Idukki	Kerala	780 MW	Idukki Dam is built across Periyar River in Idukki district of Kerala. Commissioned in 1976, It is the largest source of electricity in the state
Salal I & II	Jammu & Kashmir	690 MW	Salal Hydroelectric Power Station Stage-I and Stage-II is constructed on Chenab river in Jammu and Kashmir.
Upper Indravati	Odisha	600 MW	Upper Indravati Dam is is a gravity dam on Indravati river.
Ranjit Sagar Dam	Punjab	600 MW	Ranjit Sagar Dam, also known as Thein Dam, is part of hydro electric cum irrigation purpose dam constructed by the govt of Punjab on the Ravi River in Punjab.
Omkareshwar	Madhya Pradesh	520MW	Omkareshwar Dam is a gravity dam on Narmada river in Khandwa district of Madhya Pradesh.
Balimela Dam	Odisha	510 MW	The Balimela Reservoir is constructed in Malkangiri district of Odisha on the river Sileru, a tributary of Godavari river. Balimela is a joint project of Andhra Pradesh and Orisha governments.
Teesta Dam	Sikkim	510 MW	Teesta-V is one of six hydropower projects in river Teesta in East Sikkim district with three turbines with a total installed capacity of 510 MW.

Major Hydro Power Plants Map

Impacts of Large-scale hydroelectric dams:

Environment Impact

Submergence of local vegetation.
Dams also disrupt the migration patterns of fish and other aquatic species.
It changes the concentration of nutrients downstream river, reducing water quality.
Dams affect the productivity and stability of estuaries, this led to a loss of habitat for aquatic life and a decline in ecotone and edge effect.

Other vulnerability

Displace local communities, affecting their livelihoods and cultural heritage.
The glacial lake outburst flood (GLOF) and massive landslides may led to the breaching of Hydro-Dams which ultimately led to flood in downstream.
Eg: 2023 Chungthang Hydro-Dam breaching, the latest landslide occurred in East Sikkim, flattening the Teesta Stage V hydroelectric project.
Unplanned construction, such as the numerous hydroelectric dams on Teesta, have led the river to become more flood-prone.

Alternatives to hydropower:

Micro hydro (100 kilowatts of electricity) systems are less expensive to build and maintain than large hydroelectric dams and have a smaller environmental footprint.
Micro hydro systems can be classified into two main types – run-of-river and storage systems. Run-of-river systems use the natural flow of water in a stream or river to generate electricity.
Storage systems use a reservoir to store water and release it as needed to generate electricity. So no flooding from reservoirs.
The solar industry: it will boost the shift from fossil fuel-based electricity and hydro electricity generation to solar power.