(Last Updated on : 14/03/2012)
The two major dams of Uttarakhand
namely the Tehri Dam and the Dhauliganga Dam have been constructed with the purpose of flood control and generation of hydroelectric power. The dams have been built on the Bhagirathi River
which is a tributary of Ganga River
The Tehri Development Project begun as the Tehri Dam which is a major hydroelectric project centered near the Tehri Town in the state of Uttarakhand. The dam measures 855 feet in height and is believed to be the fifth tallest dam in the entire world. The Tehri dam is located in the Seismic Gap of the Central Himalayas. The area of its location is also known as a major geologic fault zone. As a result the region is highly earthquake prone but the founders of the dam claim that it can withstand an earthquake of magnitude 7.2 in the Richter scale.
The main purpose of the Tehri Dam was power generation of a capacity 2400 MW. It also caters to the irrigation requirements of an area of 270,000 hectares. Supplying 270 million gallons of drinking water per day to the industrialized areas of Delhi,
Uttar Pradesh and Uttarakhand is another major function of the dam. Koteshwar, a part of the TDP hydroelectric plan is another smaller dam, constructed 14 km downstream. It produces around 400 MW of electricity. An estimated amount of 1 billion US dollars has been spent on the construction of the Tehri Dam. Presently the Tehri Dam has been the issue of active protests by ecological organisations and the localities. More than 100,000 people from dam the area were relocated to various other places. As a result the project was completed quite late.
The Dhauliganga Dam is another dam in the state of Uttarakhand. It is built under the Dhauliganga Power Plant Project and has been constructed in the border triangle between India, Nepal and China of the Indian Himalayas. The dam is raised to a height of about 56 meters and is a concrete-faced rock filled dam. The crown length of this dam is 270 m. The cut-off wall of Dhauliganga Dam is located at the upstream toe of the dam and it is built in the diaphragm walling process. The thickness of the dam is 1 meter and water reaches at a depth of about 70 meter with a total area of 8000 mÂ². The construction and functioning of the dam is supervised by a joint venture of Kajima Corporation (Japan) and Daewoo Corporation (Republic of Korea).
The dam axis is sited at a V-type valley with very steep side slopes. The rock layer is formed of biotite gneiss and augen gneiss with streaks of mica schists. The valley deposits are mainly fluvial deposits formed of sand and gravel with some streaks of marl type layers. The main characteristics of the bedrock of this Dhauliganga Dam is however the presence of boulders throughout the whole valley section. The boulders are found at various depths with a size ranging from 20 centimeters to several meters.