Tehri Dam: The Tallest Dam of India

Tehri Dam, located on Bhagirathi River close to Tehri region of Uttarakhand, India is a rock & earth-filled multipurpose embankment dam that started under a lot of controversies but has stood the test of time. Tehri is about 200 miles towards the northern frontier of East Delhi. Flaunting a massive height of 855 feet (260 meters), this dam has been dubbed as 5^th tallest dam in the entire world while bagging the crown of being the tallest one in India. The dam withholds a gigantic reservoir dedicated to purposes such as irrigation, water supply for municipality, as well as generation close to 1000 megawatts hydroelectricity which when converted equals to 1,300,000 hp.

Construction of Tehri Dam

The dam’s inception started back in 1978 while the first phase of the construction process was evidently completed by the year 2006. The overall construction cost for this dam scaled close to $1 Billion. The dam is owned by THDC India Ltd. The THDC or Tehri Hydro Development Corporation works as a joint endeavour that started between Uttaranchal State Government and Government of India. In the year 1986, the Indo-Soviet agreement fetched the Soviet expertise along with a financial aid that consisted of $416 Million for completion of the project. In the year 2001, Hermes, the export credit organization from Germany guaranteed a loan to be provided to Siemens Hydro for catering generating equipment designated for the Tehri Dam project.

The Tehri Development Project also comprised of the construction of Koteshwar Dam which is 97 meter in height located 14 miles towards the downstream of the Tehri Dam. The water holding capacity of the Koteshwar Dam has the potential to completely or at least partially submerge a minimum of 16 villages while generating 400 MW power and provides about 270 Million Gallons of fresh drinking water everyday to different locations spread all over Uttar Pradesh, Uttaranchal, and Delhi. Additionally, it also provides stabilization to the existing irrigation system for 600,00 hectares of land in the area.

Right from the day the idea of Tehri Dam was conceived, it has been actively opposed over environmental concerns as well as social impact. The dam is known for its unique ability for handling earthquake of any intensity without getting damaged. Not just this, the story behind Tehri Dam is nothing less than a good movie story with multiple cases of financial corruption.

History of Tehri Dam

It was back in 1961 when the preliminary investigations for construction of Tehri Dam Project was initiated. By 1972, the design for the dam was completed that started with 600 MW power plant capacity crafted after the initial study. Six years after the completion of the design, the construction started with delayed progress in 1978 due to social impacts, financial issues, and environment concerns. The year 1986 marked the event when financial as well as technical assistance was catered by USSR. However, this help was later interrupted due to the political instability in the country after which Indian government was left with no choice but to take lead of this project. Initially, the construction phase of Tehri Dam was diverted to be directed by Irrigation Department of Uttar Pradesh.

In the year 1988, Tehri Hydro Development Corporation or THDC was brought into existence to take lead and manage the project where 75 percent of the overall funding requirement was to be facilitated by federal government while the rest 25 percent was to be dispatched by state government. The irrigation faction of Tehri Dam project was to be financed by Uttar Pradesh. When the original idea didn’t seem as conceivable, the THDC in 1990, changed the design into what we see today with multi-purpose capabilities. By 2006, the construction phase of Tehri Dam got completed followed by the completion of its 2^nd part which was Koteshwar Dam in the year 2012.

Tehri Dam today serves as one of the major sources of water for Indian capital city, Delhi. However, the creation of this massive reservoir inundated a town named Old Tehri and 110+ villages that effectively displaced about 50,000-100,000 people. In order to provide a roof to some of the displaced population, a new city was constructed that goes by the name New Tehri. The people who were actually accustomed to the original long-established lifestyle alongside Bhilangna & Bhagirathi Rivers, now struggle to adapt to the new environment that is towards the other half of the local mountains that are directly connected with these rivers.

Technical Details of Tehri Dam

Tehri Dam flaunts an installed hydroelectric capacity of 1,000 MW paired with additional 1.000 MW for pumped storage of hydroelectricity. Koteshwar Dam located in the downstream serves as the lower faction of this reservoir designated for pumped-storage purposes. The dam is spread across a length of 1,886 feet with width of 66 feet and 3,701 feet of base. The spillway is gate controlled with capacity of 549,000 cu ft/s. Tehri Dam comprises of the Vertical Francis Turbines that supplies about 270 Million Gallons of regular drinking water everyday to industrialized factions of areas such as Uttar Pradesh, Delhi, and Uttarakhand.

The New Tehri Town

It’s a newly constructed and well-planned town that rests at the height of about 1,550 metres above the mammoth artificial lake as well as the Tehri dam which is built over the Bhilangana & Bhagirathi Rivers. This town has essentially taken over the post of Tehri Garhwal District Headquarters which was previously assigned to Old Tehri Town which was completely submerged post construction of Tehri Dam.

To add to the facts associated with Tehri Dam, the New Tehri Town is actually considered one among Asia’s highly comprehensive & successful rehabilitation programs. This township has been developed in the form of a beautiful hill resort. The nearest airport from New Tehri is located at Jollygrant which is 93 kilometres away. For access via railways, the closest one to this town is Rishikesh Railway Station which 76 kilometres.

THDC India Limited

THDC India Limited which was previously known as Tehri Hydro Development Corporation Limited serves as a company that is jointly promoted under the Indian Government and State Government of the state Uttar Pradesh. The equity between the two is shared via the ratio of 75:25 for power component of the dam. This conglomerate was incorporated back in 1988 in the month of July for the development, operation, and maintenance of 2400 MW Tehri Hydro Power Complex along with other projects associated with Tehri. THDC India Limited has been dubbed as the Mini Ratna Category-1 Enterprise.

Currently, the company heads 2 major power plants. The first being Tehri Dam at 1000 MV capacity while the ends being Koteshwar Dam at 400 MW capacity. This corporation slowly emerged as an organization that is capable of handling multiple projects in various states and even in the country Bhutan. THDICL currently hands 16 projects under its tutelage with an overall installed capacity totalling to a whopping 8796 MW.

Environmental Impact from Tehri Dam

Tehri Dam for years has been a constant object for protests initiated by the environmental organizations as well as local people belonging to the region. Post construction of these dam, this new structure has unfortunately resulted in the destruction of the houses belonging to thousands of locals living in the Old Tehri. Relocation of 100,000+ people in the area surely led to the protracted legal issues over the resettlement rights which ultimately led to delayed completion of the project.

Since the year 2005, this reservoir being filled has caused a reduced flow for the Bhagirathi river. Normally, the water flow in the area is close to 1000 cubic feet/second which has recently reduced to 200 cubic feet/second. This water level reduction has been one of the central issues that led to increase in the local protest that happened against the construction of the dam. Given the fact that Bhagirathi is a major part of holy River Ganges, the locals here consider that the waters belonging to these rivers are highly crucial to religious beliefs of Hindus.

It has been estimated that with such low water flow, at any point of the year, the tributaries might stop flowing which could lead to resentment among the Hindus living in the area. The locals also complain that the holy river has been unethically compromised for electricity generation. On the contrary, the officials confirm that nothing will happen to the flow of the river once the reservoirs have been completely filled to its brim, the river shall restore back to its original glory. However, the protests and concerns continue even today with operations going full-scale in the dam.

There are several impacts over the area surrounding the dam from the inclusion of this structure which include things such as:

• A change in overall chemistry of water has been observed which is especially true for the oxygen dissolved in the water as well as the water turbidity.
• Harmful impact over the biodiversity of this area.
• A study conducted over the reservoir stated that the rivers tend to carry lots of sediments that with time collect close to the wall of the dam resulting in the overall capacity of this dam being eaten away.
• There is a huge impact from the water being accumulated towards the dam upstream resulting in land inundation for the forest area.
• Issues with water-logging and high-salinity in the land area.

Measures taken for the Ecological Impacts due to Tehri Dam

• Afforestation for compensation

Forest land comprising of 4193.813 hectares were eventually diverted for the construction of this dam and the associated project. This total forest cover compensated to balance the loss included all the land that was used for Project construction, creation of new colonies, as well as the area used for filling the area.

• CAT (Catchment Area Treatment)

In an effort to reduce the soil erosion as well as the reduction of sedimentation around the reservoir. The project eventually completed CAT for the overall degraded catchment close to areas that have been termed among the “High Class” and “Very High-Class” erosion locales.

• Command Area Development

The high salinity & water-logging in the area has been monitored by the authorities with solutions implemented to counteract the same. The Command Area Development Plan was implemented by Irrigation Departments of State Governments belonging to U.P. and Uttarakhand. The authorities came up with the idea of creating network of drains and field channels for addressing the issue.

• Flora

Under the CAT implemented by the authorities of Tehri Dam, the species that were harmed from the construction of the dam as stated by BSI or Botanical Survey of India, were planted again to ensure the ecosystem is consistent. Not just that, a whole new Botanical Garden has been established in the area totalling 14.28 hectares with the plantations comprised of several species that were submerged has been re-implanted in order to preserve the flora of this region.

• Fauna

As per the study conducted by ZSI or Zoological Survey of India, the fauna that was affected after the formation of the reservoir didn’t include the mammals, Reptiles, Aves, Amphibians, or the fishes from fresh water. However, the only species affected from the same included Tor-Putitora which is also known as the Mahseer Fish.

• Quality Maintenance for Water

After the concerned authorities conducted a study on the overall quality of water in the area, it was concluded that there had been no such adverse effects from the impoundment on water quality. However, constant monitoring is being carried out for water quality at both downstream and upstream area of the river at 5 different monitoring stations to ensure no such issues surface up.

• Human Health Impact

Tehri Dam has also been involved in the issues related to health impacts of the local people living in the area. According to a joint study conducted by NMEP or National Malaria Eradication Program and the MRC (Malaria Research Centre) paired with detailed investigations for the area affected, a plan is under implementation for the prevention or mitigation of issues that can surface in future or the ones currently ailing the locals.

• Green Belt

A plan for creation of the green belt has been planned along the reservoir’s rim between the area which is 850 meters above the MSL as well as 1050 meters above the MSL. The main idea behind development of green belt was for keeping a check on the soil erosion or the resultant siltation at the reservoir. This idea will eventually protect and even regenerate the area’s vegetation for increasing the beauty of this landscape to the original point.

Benefits of Tehri Dam to the Nation

Tehri Dam has been a major project for the nation and even with so many controversies associated with the structure, the dam also brings a lot of benefits for the nation today. With 2400 MW peaking power, it will surely lead to agricultural and industrial growth in Northern Region. Additionally, the project dedicates about 12 percent of the overall power generated from the dam to the home state for free. This free power is additional to the original share given the fact that the project has been a cause of distress at this site.

An additional irrigation stabilization for 2.7 Lakhs Hectares of area apart from the already irrigated enclosure of 6 Lakhs Hectares. The project supplies about 162 Million Gallons/day water supply for Delhi which caters to the need of 4 million families in the area. About 108 Million Gallons/Day water supply is dedicated for UP state that caters to 3 Million population. Tehri Dam has initiated complete development of this area with better infrastructure as well as easy availability for electricity which is especially true for power requirement during peak time.

The project has also helped with flood moderation for monsoon seasons when there is excess water in the area. Tehri Dam takes up the extra water in its reservoirs leading to protection of the nearby area from unnecessary flooding. Also, the project led to development for pisciculture along with integrated development for catchment area.

Benefits to the nearby Regions

• Hill Station Development

The relocation of the residents of Old Tehri to New Tehri and the development of the area at the height ranging between 1550 to 1850 meters has led to creation of a hill station with modern amenities that are similar toMussorrie bringing in higher number of tourists to North.

• Clearer Road Network

Post development of the project, the roads located in the area were widened and even improved making communication comfortable and easier. The Rishikesh-Chamba-NTT roads are widened with improved geometry leading to overall reduction for journey time.

• Educational Benefits

Shifting the Old Tehri Town based institutes to the new location led to creation of modern facilities and larger buildings that were capable of accommodating more students with better scope for additional expansion for future requirements. Hostel facilities for 860+ students being introduced in the new location has resulted in more students taking admission for various courses with NTT as the nodal center dedicated for education. To compensate the college located in the Old Tehri, another degree college as well as a massive university campus was constructed at the area named Badshahithaulcapable of accommodating at least 400 students along with teaching staff.

• Health

As opposed to the 22-bed based hospital in Old Tehri, the new town saw the inclusion of a 75-bed capacity hospital with all the modern facilities for medical treatment. For catering hygienic conditions for the locals, the house dwellers are supplied with treated water. Also, a centrally located sewerage plant was constructed with properly designed sewer lines network for facilitation of proper drainage.

• Electrification

The area has been provided with 3 different 33 KV Sub-Stations for improvement of electricity distribution in rural areas with a well-aligned network comprised of the LT/HT electricity transmission lines.

• Facility for clean drinking water

A total of 54 schemes for drinking water have been implemented at the rural areas as well as New Tehri which is maintained by the respective agencies.

• District Head-Quarters Shifted

The District Head Quarters shifted from the Narendra Nagar all the way to New Tehri which has reduced a distance of 60 kilometres when it comes to transportation for the rural and urban population saving time for employees and public seeking access to the offices.

• New Industrial Setup

Non-pollutive industries have been setup at New Tehri leading to better communication facilities and great climatic conditions. More factories can take up the area in upcoming years leading to better industrialization of the area.

• Tourism

With modern facilities added to the NTT area, tourism is set to expand. Water sports could be a major attraction for the tourists given the creation of the lake caused of impoundment of reservoir at Tehri Dam. Wider roads along with improved communication has been adding to better business for tourism industry as well as the hotel industry. This will eventually lead to better scope for employment.

• More commercial centres

The market at NTT is developing rapidly for the adjoining villages and towns. Not just that, this market will serve as the nodal commercial infrastructure for the region given the vocational advantage along with better infrastructure and facilities such as telecommunication, roads, and artistically designed shopping centres. The shopping area is larger than before with better capacity for storage of goods.

How to Reach the Tehri Dam

• By Air

In order to get to Tehri Dam via airways, one can look for the Jolly Grant Airport which is well connected with major airports such as Chandigarh, Delhi, and Mumbai. The journey from Jolly Grant to New Tehri can be completed by covering 91 kilometres.

• By Rail

To reach New Tehri via railways, one needs to book a ticket with Indian Railways to Rishikesh which is well connected to major locations in the country. You can easily get a taxi or bus from Rishikesh in order to reach New Tehri located at a distance of 76.1 km via NH34.

• By Road

New Tehri can easily be accessed via motorable roads from major destinations in the northern periphery of India as well as Uttarakhand. Taxi or local bus can be a great option from places such as Mussoorie, Dehradun, Haridwar, Rishikesh, Srinagar, Devprayag, and many others.

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