Rishikesh: 24 th Sept, 2021 proved to be remarkable day in the history of Tehri Dam Project as Tehri reservoir has touched the level of 830m,
its Full Reservoir Level, for the first time. Though the Project has been providing much needed 1000 MW peaking power and other benefits such as
drinking and irrigation water, flood moderation, fishing, tourism etc. for the past 15 years, yet its full potential remained untapped. Tehri reservoir could
not be raised to Full Reservoir Level (FRL), of EL 830m. However, with the active support of Ministry of Power, Govt. of India and Govt. of
Uttarakhand, this mammoth task could be achieved after the pending rehabilitation issues of the Project were resolved by THDC with a very liberal view.
Thereafter, Hon’ble Chief Minister of Uttarakhand, Sh. Pushkar Singh Dhami considered the larger interests of the public and permitted to raise Tehri
reservoir level to EL 830m on 25 th August, 2021. Prior to this permission, dam authorities were not allowed to raise Tehri reservoir to full level and full
potential of the Project in respect of water and power was not getting fully utilized.
Tehri Dam Project is a multipurpose hydro power scheme on river Bhagirathi and is the 3 rd highest among earth fill dams and 10 th highest
among all dams of the World. The project consists of 260.5 M high Earth and Rock fill Dam, and 4 Machines of 250 MW each in an underground power
house. Tehri dam project has a capacity to store about 2615 MCM of surplus flood water during monsoon. Post monsoon, the stored water provides
irrigation support to 8.74 Lac hectares land in the Gangetic plains of Uttar Pradesh; and also provides around 300 cusecs of drinking water to New Delhi
for about 40 Lacs population and 200 cusecs to UP for about 30 Lacs population. Tehri project in fact has quenched the thirst of Delhi and Agra in real
sense. Project has also enabled the farmers of Tehri command area to take even upto 3 crops in a year.
It ensures sufficient discharge by releasing additional water in river Ganges during lean period for different “holy Snans” and “Parvas” at Haridwar and
Prayagraj. It also ensures sufficient water discharges in rives Ganges by additional releases during “Kumbh Mela” for whole season on the demand of
Govt. of Uttarakhand and Govt. of UP. Tehri power plant provides 1000MW of peaking power and more than 3000Million Units of energy annually to the
northern grid, of which 12% goes to Uttarakhand state free of cost. Thus, Tehri project has been a boon for the people of society and these benefits are
now likely to increase further with the Hon’ble Chief Minister’s decision to raise Tehri reservoir to full level.
Tehri dam project was conceived in the year 1949 and it was cleared by the Govt. of India in the year 1986 as a Joint Venture Company of Govt. of India
and Govt. of Uttar Pradesh. A bilateral techno-economic agreement between India and Russia was signed in 1986. THDC India Ltd. (formerly Tehri
Hydro Development Corporation) was incorporated to implement the scheme in 1988. Safety of the dam and its impact on quality of water and
environment had also been contentious issues. Several government departments and panels of eminent scientists and experts were constituted to deliberate
these issues and after their recommendations, construction of main dam started in 1990 with raising of the upstream coffer dam. Seismic safety of the dam
was again reviewed by the Indian and Russian experts. Govt. of India approved the implementation of the project in 1994 and actual construction of dam
works started in 1995. The construction of project structures continued with intermittent protests and could finally be completed in 2005. The
commissioning of the project could start in Oct’ 2005 when the Honorable High Court of Uttarakhand allowed closure of last diversion tunnel (T-2) to
start filling of the Tehri reservoir. Subsequent to commencement of initial filling of the reservoir in Oct’ 2005, commissioning of the 4 units of the power
house also started, one by one and project was fully commissioned in July’ 2007.
The initial filling of the Tehri reservoir was a challenge as Tehri dam was the 1 st earth and rock fill dam of such a height in India. THDCIL took every
precaution, reviewed available literature about the initial filling of high dams worldwide and consulted eminent hydro project experts to frame the dam
filling program along with the program of regular monitoring of the structures through instruments installed and geodetic observations.
After closure of last Tunnel T-2 in Oct’ 2005, reservoir gradually filled above EL (+) 638m up to EL (+) 785m by Oct’ 2006 i.e. till completion of 1 st
filling season. Thereafter, from Nov’ 2006 to June’ 2007, the reservoir depleted back to EL 740m.
Till the years 2020, the reservoir was filled up to EL 828m, as GoUK permitted THDCIL to raise the reservoir level upto 828m only. Permission for
filling up to EL 830m was granted by the State Government this year in Aug’ 2021. The reservoir touched EL 828m on 11 th Sep’ and thereafter filling
done @ 0.30m in 48 hrs to reach EL (+) 830 m on 24 th Sep’ 2021.
24th Sep’ 2021 has become a historical date in the history of Tehri dam project being the date of achieving full potential of the project in all respects
which was conceived many years back. 24th Sep’ 2021 shall be remembered as beginning of new era in the history of Tehri dam project from where it
started delivering the maximum intended benefits to the society fully. Most of the credit to this feat goes to the current political leadership of the state
under the guidance of Hon’ble Chief Minister, Shri Pushker Singh Dhami and Irrigation Minister, Shri Satpal Maharaj, who acknowledged the situation of
wastage of national resource in view of restricted impoundment of reservoir and grated the permission to fill the reservoir to its full capacity. The strong
pursuance of the Ministry of Power, Government of India has been another push to achieve this historical milestone. Management of THDCIL led by its
CMD, Mr. R.K. Vishnoi has thanked the state leadership and congratulated the people of the state in achieving this much awaited goal. He further
mentioned that the commitments made by THDC to Hon’ble CM and Sh. Satpal Maharaj, Hon’ble Minister of Irrigation, GoUK regarding project affected
people shall be fulfilled instantly after reviewing the verified list of beneficiaries from Distt. Administration.
Tehri Dam achieved its full reservoir Level, for the first time
