The Tehri Dam, one of the tallest dams in India, is constructed on the Bhagirathi River. Let's delve into the details below:

The Bhagirathi River:
The Bhagirathi River is one of the major tributaries of the Ganges River, flowing through the Indian state of Uttarakhand. It originates from the Gangotri Glacier in the Garhwal Himalayas and is considered sacred by Hindus. The river merges with the Alaknanda River at Devprayag to form the Ganges River.

Construction of the Tehri Dam:
The Tehri Dam is located on the Bhagirathi River in the town of Tehri in Uttarakhand. It is a multipurpose rock and earth-fill embankment dam that was constructed to generate hydroelectric power, provide irrigation, and control floods. The project was undertaken by the Tehri Hydro Development Corporation (THDC) and completed in the year 2006.

Key Features of the Tehri Dam:
1. Height: The Tehri Dam is one of the tallest dams in India, standing at a height of approximately 260 meters (853 feet). It is also one of the tallest dams in the world.
2. Reservoir: The dam forms the Tehri Reservoir, which has a capacity of around 2.6 billion cubic meters. The reservoir provides water for irrigation to the nearby agricultural areas.
3. Hydroelectric Power Generation: The Tehri Dam has a power generation capacity of 1,000 megawatts. It houses four generators, each with a capacity of 250 megawatts.
4. Environmental Impact: The construction of the Tehri Dam resulted in the displacement of numerous villages and people. However, efforts were made to rehabilitate the affected individuals and ensure their well-being.

Importance of the Tehri Dam:
1. Hydroelectric Power Generation: The dam plays a significant role in meeting the electricity needs of Uttarakhand and the surrounding regions. It contributes to the overall power generation capacity of the country.
2. Irrigation: The Tehri Reservoir provides water for irrigation purposes, benefiting the farmers in the region and enhancing agricultural productivity.
3. Flood Control: The dam helps in mitigating the impacts of floods by regulating the flow of water downstream. It reduces the risk of floods in the lower reaches of the Bhagirathi and Ganges rivers.

In conclusion, the Tehri Dam is constructed on the Bhagirathi River. It serves multiple purposes, including hydroelectric power generation, irrigation, and flood control. The dam's construction has had a significant impact on the region, both in terms of its benefits and the challenges it posed in terms of displacement and rehabilitation.