Tehri Dam
Tehri Dam, multipurpose dam built on the Bhagirathi River in the Garhwal district of Uttarakhand state, India. At 855 feet (260.5 meters) high, it is the tallest dam in the country. Moreover, it is one of the largest hydroelectric power projects in the world. As such, it has raised environmental concerns and displaced about 100,000 people. Tehri Dam is managed by Tehri Hydro Development Corporation (THDC) India Limited, a subsidiary of the National Thermal Power Corporation (NTPC) Limited.
History and construction
The idea of building a dam to use the energy of the Bhagirathi River was first conceived in the 1940s, and preliminary investigations were completed in 1961. The project, sanctioned in 1972, was designed to be capable of generating 600 megawatts of power. Construction started in 1978, but significant delays were caused by fears about the dam’s environmental impact, the need to resettle local people who would lose their homes, and administrative issues. The project was revived in 1986 and was initially led by the Irrigation Department of Uttar Pradesh (Uttarakhand was a part of Uttar Pradesh until 2000, when it became a new state).
The THDC was formed in 1988 to carry forward the dam’s development. In 1990 the project was revised to a capacity of 2,400 megawatts, to be developed in three stages. The first stage, Tehri Dam itself, was completed in 2006. The second stage, Koteshwar Dam, 13.75 miles (22 km) downstream from Tehri Dam, was completed in 2012. As of 2025 the third stage, a pumped storage plant to lift water from Koteshwar Dam to Tehri Dam, is underway.
Tehri Dam is built in a region highly susceptible to seismic movements. To reduce the risk of damage from earthquakes, the dam was designed not as an unyielding homogeneous mass but rather as a flexible rock-filled structure with a gentle slope and a clay earth core. This structure enables the dam to absorb seismic energy and undergo plastic deformations without failing. Extensive testing was done to validate the dam’s design and its resistance to earthquakes.
In addition to generating electricity for multiple states in northern India, Tehri Dam enables irrigation of more than 1,977,000 acres (800,000 hectares) of land. Moreover, it provides drinking water for Uttarakhand and Uttar Pradesh as well as Delhi. The reservoir behind the dam has led to a tourism boost for the region.
Opposition to the dam
The construction of Tehri Dam was opposed on grounds of environmental impact, religious belief, and consequences for the local population. Concerns have been raised about the dam’s stability as well as its possible effects on the fragile ecosystem of the region, which is prone to floods and landslides as well as seismic activity.
Local opposition to the dam was mobilized into an organized protest led by the Tehri Bandh Virodhi Sangharsh Samiti (TBVSS), a group that was formed in 1978 to agitate against the dam, demand proper rehabilitation of displaced people, and push for sustainable development. The TBVSS’s protest was boosted when the Environmental Appraisal Committee of the Indian Ministry of Environment and Forests refused to clear the project in 1990 and a 6.1-magnitude earthquake hit the Garhwal region in 1991. In 2003, however, the Supreme Court of India concluded that construction of the dam had not violated environmental clearances, and it put the onus to track any future lapses on monitoring agencies.
Environmental activist Sunderlal Bahuguna was a prominent leader in the movement opposing the dam. Instead of large-scale dam projects, he pushed for micro-hydroelectric projects to meet local power requirements. Bahuguna undertook several fasts over the years to protest Tehri Dam, and his nonviolent methods drew widespread attention to the movement. Eventually, however, he was forced to relocate because of the rising waters of the Tehri reservoir. Thus, he became one of some 100,000 locals to lose their ancestral homes to the dam project.
Several Hindu right-wing religious and political groups, such as the Vishwa Hindu Parishad, also opposed the project, on the belief that damming the Bhagirathi River would dilute the water of the Ganges (Ganga) River, considered holy by Hindus. Even though the Bhagirathi is the smaller of the two main tributaries that form the Ganges at Devprayag (the Alaknanda River being the other), its reduced flow led to disquiet among devotees.