Everything About Tehri Dam, The Highest Dam In India

The Tehri Dam is a multi-purpose rock and earth-fill embankment dam on the Bhagirathi River near Tehri in Uttarakhand, India. Tehri is situated 200 miles northeast of New Delhi. With a height of 260.5 meters, Tehri Dam is the tallest dam in India, the second tallest in Asia, and the eighth tallest in the world.

A true multipurpose dam, it holds a reservoir for irrigation, municipal water supply, and generation of 1000 Mega Watts of hydroelectricity, along with an additional 1000 MW of pumped-storage hydroelectricity. The Tehri Dam and the Tehri Pumped Storage Hydroelectric Power Plant are part of the Tehri Hydropower Complex.

History of Tehri Dam

A pilot investigation for the Tehri Dam Project was conducted in 1961. The design of the dam was completed in 1972.

• Based on the study, a 600 MW capacity power plant was approved. However, the construction began only in 1978 after the feasibility studies but got delayed due to financial, environmental, and social impacts.
• In 1986, the erstwhile USSR provided technical and financial assistance but was interrupted years later due to political instability in USSR. As a result, the Government of India placed the project under the direction of the Irrigation Department of Uttar Pradesh.

• In 1988, Tehri Hydro Development Corporation (THDC) was formed to manage the dam. 75% of the funding was provided by the Central Government and the remaining 25% was funded by the State Government of Uttar Pradesh, which also financed the entire irrigation portion of the project.
• In 1990, the project was reconsidered and the design of the dam was changed to its current multipurpose form. Construction of the Tehri Dam got completed in the year 2006 and the dam was dedicated to the nation.

Features of the Tehri Dam

• Standing tall at a staggering 260.5 meters, the Tehri Dam is India’s tallest Dam and the eighth tallest dam in the world. This rock and earth-fill embankment dam are 575 meters long with a crest width of 20 meters and the base width of 1,128 meters.
• The dam’s reservoir surface area is 52 km² (20 square miles ) with a total capacity of 4 km³ (3.2 million acre-ft). The dam has two gate-controlled spillways with a flowing capacity of 15,540 cubic meters per second.

Hydroelectricity generation and irrigation

Being a multipurpose dam, the Tehri dam supplies large amounts of electricity as well as drinking and irrigation water to the greater part of Northern India, including the country’s capital city of Delhi.

• The dam has Francis pump turbines with an installed capacity to produce 1000 MW of power with an additional 1000 MW of pumped-storage hydroelectricity.
• The Tehri Hydropower Complex also includes the 400 MW Koteshwar Dam. The maximum planned capacity of the Tehri dam is 2400 MW.
• The electricity produced from the dam is distributed to Uttar Pradesh, Uttarakhand, Punjab, Delhi, Haryana, Jammu & Kashmir, Chandigarh, Rajasthan, and Himachal Pradesh.
• The dam would also provide irrigation to an area of 670,000 hectares and supply 270 million imperial gallons of drinking water per day to the industrialized areas of Delhi, Uttar Pradesh, and Uttarakhand.

Construction expenditure of Tehri Dam

The cost of construction of the dam was the whopping US $ 1 billion. A cost-benefit analysis done by India National Trust For Art and Cultural Heritage (INTACH) concluded that the construction cost of the dam is twice the benefits of the project. The dam’s 1,000 MW variable-speed pumped-storage scheme is presently under construction with expected commissioning in 2025

The New Tehri

The old town of Tehri was the capital of the princely state of Tehri Garhwal in British India. With the construction of the Tehri dam, the old town of Tehri was completely submerged under its waters.

• The population of the old town was shifted to the town of New Tehri. The newly built town nestles at a height of 1550 meters overlooking the massive artificial lake and the Tehri dam.
• Today it is blossoming into a lovely hill spot attracting a lot of tourists. New Tehri is well connected by road to all the important cities in the Garhwal division like Mussorie, Dehradun, Rishikesh, Haridwar, etc.

Tehri Dam Tourism

“The Tallest dam in India” is a title sufficient enough to attract people from around the country, which it does. The construction of the Tehri dam created a huge water body as a reservoir. T

• he Tourism Department has developed this 52 km² artificial lake as a tourist spot. Arrangement of various water sports like jet skiing, canoeing, boating, snorkeling, kayaking, etc. has been made on the lake.
• There is a viewpoint near the Bhagirathpuram bus stop from where one can have an imposing view of the Tehri dam.
• Tourists also visit a botanical garden in New Tehri, that features a gamut of beautiful flowers.

Environmental concerns and protests

• Tehri dam attracted a lot of protests by local people and environmental organizations. Displacement of the inhabitants of the old Tehri town along with the dam’s environmental consequence on the fragile ecosystem of the Himalayas were the main concerns for the protest.
• Sunderlal Bahuguna, a renowned environmental activist, led the Anti-Tehri Dam protests from the 1980s till 2004. Protracted legal battles over resettlement rights of more than 100,000 residents caused a lot of delays in the project’s completion.
• The filling of the dam’s reservoir has also reduced the flow of the Bhagirathi river from a normal 1000 cusecs (cubic feet per second) to a mere 200 cusecs. This has caused resentment among the locals since Bhagirathi is considered a part of the river Ganges, which is a revered river for Hindus.
• Officials say that once the reservoir is filled to its maximum capacity, the river flow would return back to normal. Landslides are a prevalent problem as a result of deforestation and road construction.

Potential earthquake peril

Tehri dam is built on a major geological fault line in the Central Himalayan Seismic Gap, which experienced an earthquake of a magnitude of 6.5 on the Richter Scale in October 1991.

• It’s claimed by some dam exponents that the Tehri dam is designed to withstand an earthquake of 8.4 magnitudes, however, some seismologists say that an earthquake of a magnitude of 8.5 or more can occur in the region.
• If such a catastrophe were to happen, it could potentially damage the dam and submerge the areas downstream with a population of almost half a million.
• A major landslide into the reservoir could create a huge wave that could overtop the dam and cause massive damage downstream.

Management of the Dam

• Tehri Hydro Development Corporation India Limited, formerly called Tehri Hydro Development Corporation, is a corporation jointly promoted by the Government of India and the Government of Uttar Pradesh.
• Incorporated in the year 1988 to operate, manage and maintain the 2400 MW Tehri Hydro Power Complex, it is a Mini Ratna Category -1 enterprise. At present, the enterprise operates two power plants namely the Tehri Dam (1000 MW) and Koteshwar Dam (400 MW).
• The corporation has grown into a multi-project organization with projects spread over various states.

Also read- 10 Major Dams In India, A Barrier That Holds Water Or Underground Streams