Tehri Dam: Touching the Sky — India’s Highest Engineering Marvel
Key Takeaways
- Tehri Dam is the highest dam in India and South Asia (260.5 m / 855 ft) and ranks among the top 10 highest dams in the world. It is an earth and rock-fill dam (with clay core), not a concrete gravity dam like Bhakra Nangal.
- Built on the Bhagirathi River (principal tributary of the Ganga) in Tehri district, Uttarakhand. The reservoir is called Swami Ramtirth Sagar (Tehri Lake) with a surface area of ~52 sq km.
- The Tehri Hydropower Complex has a total planned capacity of 2,400 MW:
• Tehri HPP: 1,000 MW
• Koteshwar HEP (22 km downstream): 400 MW (balancing reservoir)
• Tehri Pumped Storage Plant (PSP): 1,000 MW - Multipurpose benefits: Irrigation for ~270,000 ha in Uttarakhand & western UP; 270 million gallons/day drinking water to Delhi, UP & Uttarakhand; power to multiple northern states.
- Located in Seismic Zone V (Central Himalayan Seismic Gap). Designed as a flexible rock-fill structure to withstand earthquakes up to 9.0 on the Richter scale.
- Controversial project: Led to submergence of Old Tehri Town and 112 villages. Over 100,000 people were resettled. The Anti-Tehri Dam Movement was led by environmentalist Sunderlal Bahuguna (Chipko Movement leader).
Introduction & Strategic Significance
Tehri Dam stands as India’s tallest dam and one of the most ambitious hydroelectric projects in the Himalayan region. Located on the Bhagirathi River in Uttarakhand, it is not just an engineering marvel but also a symbol of the complex trade-offs between development, ecology, seismicity, and social displacement in the fragile Himalayan ecosystem.
For competitive exams, Tehri is a high-yield topic because it combines multiple themes: highest dam in India, pumped storage technology, seismic design in Zone V, the Anti-Tehri movement led by Sunderlal Bahuguna, and the rehabilitation of an entire town (Old Tehri).
Tehri is frequently asked under “Highest dam in India”, “Pumped Storage Plants”, “Seismic Zone V projects”, “Chipko & Anti-Tehri movements”, and “Ganga tributary projects”.
Location, River & Himalayan Setting
The dam is located in Tehri district, Uttarakhand, on the Bhagirathi River — one of the two headstreams of the Ganga (the other being Alaknanda). The Bhagirathi originates from the Gangotri Glacier.
The project is situated in a deep Himalayan valley. The reservoir, officially named Swami Ramtirth Sagar (commonly called Tehri Lake), has a surface area of approximately 52 square kilometres.
“Tehri = Touching the Sky (260.5 m) on Bhagirathi (Ganga’s headstream) in Seismic Zone V”. It is the only major dam in India that is both the highest and located in the most seismically sensitive zone.
Physical Specifications & Rock-Fill Design
Unlike many large Indian dams (Bhakra, Nagarjuna Sagar, Sardar Sarovar) which are concrete gravity or masonry dams, Tehri is an earth and rock-fill dam with a central clay core. This flexible design was chosen specifically to withstand high seismic activity.
Base Width: 1,128 metres (3,701 ft). The dam uses a clay core surrounded by zones of rock and earth fill, making it flexible enough to absorb seismic shocks.
Power Generation Complex (2,400 MW)
The Tehri Hydropower Complex is designed with three integrated components for a total planned capacity of 2,400 MW:
- Tehri Dam & Hydropower Plant (HPP): 1,000 MW (4 × 250 MW units) — Variable speed units.
- Koteshwar Hydroelectric Project: 400 MW (4 × 100 MW units), located 22 km downstream. It acts as a balancing reservoir for the pumped storage operation.
- Tehri Pumped Storage Plant (PSP): 1,000 MW (4 × 250 MW units) — One of the largest pumped storage facilities in India. It pumps water from Koteshwar back to Tehri during off-peak hours and generates power during peak demand.
Remember the breakup: Tehri HPP 1,000 MW + PSP 1,000 MW + Koteshwar 400 MW = 2,400 MW total complex. PSP is key for peak power management in the Northern Grid.
Multipurpose Objectives & Beneficiary States
Besides power, the project was built to serve irrigation and drinking water needs across North India:
- Irrigation: Provides water to irrigate approximately 270,000 hectares in Uttarakhand and western Uttar Pradesh.
- Drinking Water: Supplies 270 million gallons per day of clean drinking water to New Delhi, Uttar Pradesh, and Uttarakhand.
- Power Beneficiary States: Uttarakhand, Uttar Pradesh, Delhi, Punjab, Haryana, Jammu & Kashmir, Chandigarh, Rajasthan, and Himachal Pradesh.
Historical Timeline
- 1961 — Preliminary investigations and feasibility studies completed.
- 1972 — Planning Commission of India officially approves the project.
- 1978 — Physical construction begins under the Irrigation Department of Uttar Pradesh.
- 1988 — Tehri Hydro Development Corporation (THDC) is formed to expedite construction.
- 2006 — First unit of the 1,000 MW Hydropower Plant is commissioned; major operations begin.
Seismic, Environmental & Social Controversies
A. The Seismic Threat (Central Himalayan Seismic Gap)
Tehri Dam is located in Seismic Zone V (highest risk zone in India) within the Central Himalayan Seismic Gap. Environmentalists raised serious concerns that a major earthquake (magnitude 8.0+) could cause catastrophic failure, endangering downstream holy towns like Rishikesh and Haridwar.
Engineering Response: Designers chose a flexible earth and rock-fill structure (instead of rigid concrete) capable of absorbing seismic shocks up to 9.0 on the Richter scale.
B. Anti-Tehri Dam Movement
The project faced prolonged protests led by legendary environmentalist Sunderlal Bahuguna (leader of the Chipko Movement). He undertook several hunger strikes (notably in 1995 and 2001) against the dam.
Main Arguments:
- Submergence of pristine Himalayan forests
- Interruption of the natural flow and self-purifying capacity of the holy Bhagirathi/Ganga
- Trapping of nutrient-rich silt behind the dam
C. Rehabilitation & Resettlement
The reservoir completely submerged Old Tehri Town and partially or fully submerged 112 villages. Over 100,000 people had to be relocated — one of the largest human resettlement projects in the Indian Himalayas. Most were shifted to the newly created township of New Tehri at a higher elevation.
Tehri is the highest dam in India (260.5 m), but not the longest (Hirakud is the longest at 25.8 km) and not a concrete gravity dam (it is earth & rock-fill). Bhakra (226 m) is the highest concrete gravity dam.
Tehri Dam vs Other Major Indian Dams (Quick Exam Checklist)
| Parameter | Dam | Key Fact |
|---|---|---|
| Highest Dam in India | Tehri Dam | 260.5 m (Earth & Rock-fill) on Bhagirathi |
| Longest Dam in India | Hirakud Dam (Odisha) | 25.8 km on Mahanadi |
| Highest Concrete Gravity Dam | Bhakra Nangal | 226 m on Sutlej (Himachal) |
| Largest Reservoir by Volume | Indira Sagar (MP) | Narmada River |
| World’s Largest Masonry Dam | Nagarjuna Sagar | 124 m on Krishna |
Quick Revision One-Liners for Exams
- Tehri Dam — Highest dam in India (260.5 m) and South Asia; 8th highest in the world. Earth & rock-fill dam on Bhagirathi River (Uttarakhand).
- Dimensions — Height 260.5 m, Length 575 m, Base width 1,128 m. Reservoir: Swami Ramtirth Sagar (~52 sq km).
- Power Complex — Total 2,400 MW: Tehri HPP 1,000 MW + PSP 1,000 MW + Koteshwar 400 MW (22 km downstream).
- Benefits — Irrigation for 270,000 ha; 270 million gallons/day drinking water to Delhi, UP & Uttarakhand.
- Seismic Design — Located in Seismic Zone V. Flexible rock-fill structure designed to withstand up to 9.0 Richter scale.
- Anti-Tehri Movement — Led by Sunderlal Bahuguna (Chipko leader) with multiple hunger strikes against submergence and ecological damage.
- Rehabilitation — Old Tehri Town + 112 villages submerged. Over 100,000 people resettled to New Tehri.
- Timeline — Approved 1972; Construction began 1978; THDC formed 1988; First power 2006.
- Unique Feature — One of India’s largest pumped storage plants integrated with a balancing reservoir (Koteshwar).
- Quick Comparison — Highest Dam: Tehri (260.5 m) | Longest Dam: Hirakud | Highest Gravity Dam: Bhakra (226 m).
Frequently Asked Questions
What is the height of Tehri Dam and why is it significant?
What is the total power generation capacity of the Tehri complex?
Why was the Tehri Dam designed as an earth and rock-fill dam instead of concrete?
Who led the Anti-Tehri Dam Movement and what were the main concerns?
How many people were displaced by the Tehri Dam?
What are the irrigation and drinking water benefits of Tehri Dam?
What is the difference between Tehri Dam and Koteshwar Project?
Geography Quiz Time
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🎯 Practice Questions: Test Yourself for RRB, SSC & UPSC
Attempt these 10 exam-style MCQs based strictly on this article, then reveal each answer.
Q1. What is the height of Tehri Dam, the highest dam in India?
A) 226 m B) 260.5 m C) 275 m D) 310.5 m
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Q2. Tehri Dam is built on which river?
A) Alaknanda B) Mandakini C) Bhagirathi D) Yamuna
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Q3. The reservoir of Tehri Dam is officially named:
A) Gobind Sagar B) Swami Ramtirth Sagar C) Indira Sagar D) Rana Pratap Sagar
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Q4. What is the total planned capacity of the Tehri Hydropower Complex?
A) 1,000 MW B) 1,400 MW C) 2,000 MW D) 2,400 MW
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Q5. The Koteshwar Hydroelectric Project, the balancing reservoir for Tehri PSP, has a capacity of:
A) 400 MW, 22 km downstream B) 600 MW, 10 km upstream C) 250 MW, 30 km downstream D) 1,000 MW, 22 km upstream
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Q6. Tehri Dam is structurally which type of dam?
A) Concrete gravity B) Masonry C) Earth & rock-fill with clay core D) Arch dam
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Q7. Tehri Dam lies in which seismic zone, and up to what earthquake magnitude is it designed?
A) Zone III, 7.0 B) Zone IV, 8.0 C) Zone V, 9.0 D) Zone II, 6.5
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Q8. Who led the Anti-Tehri Dam Movement?
A) Medha Patkar B) Sunderlal Bahuguna C) Chandi Prasad Bhatt D) Baba Amte
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Q9. How many villages were fully or partially submerged by the Tehri reservoir?
A) 52 B) 87 C) 112 D) 150
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Q10. Tehri Hydro Development Corporation (THDC) was formed in which year?
A) 1972 B) 1978 C) 1988 D) 2006
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260 m Rock-Fill, Bhagirathi, Seismic Gap
Tehri is tallest-dam-plus-seismic-gap. Sit a full mock, then use PYQs for the Bhagirathi location and the anti-dam movement name.
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