Which Dam is Built on Ganga River?
Tehri Dam built on Bhagirathi – a tributary of Ganges, is a rock and earth filled embankment dam. It is located in the North Western state of Uttrakhand (initially known as Uttaranchal) and is the highest dam in India and also ranks eighth in the world on same parameter. The dam serves various purposes like- electricity generation, providing water for irrigation, for drinking and for containing floods.
In the past the dam has proved its mettle in containing the flood waters of Bhagirathi thereby saving lives of millions and preventing villages from being submerged under water. Despite its usefulness, the dam and its construction have always remained controversial due to some social as well as environmental issues.
There have been many protests in the past against the construction of the dam because of inadequate resettlement benefits provided to the people affected and also because of the fact that the dam is located on an active seismic zone or a geological fault zone.
Location of Tehri Dam
Tehri Dam is constructed on one of the tributaries of Ganges – Bhagirathi. It is build at Tehri town nearly 1.5 kms downstream from the confluence of Bhagirathi and Bhilangna rivers. The dam is located around 90 Kms from the religious town of Rishikesh (Uttrakhand) via Chamba and New Tehri town.
History of Tehri Dam
Tehri Dam is a rock-earth filled embankment dam which means that it is basically made by the compaction of earth and rocks. Compaction is a process in which the earth is compressed resulting in the densification of soil as the air is removed from the pores making the structure stronger and spill proof. The survey for the construction of Tehri Dam started during 1961 but design for the construction was completed in the year 1972 with total proposed generation capacity of 600 MW.
The construction began in 1978 but was intermittent due to financial as well as political restraints. During 1986 Russian government provided technical and financial support for the construction of Tehri dam but again this was interrupted due to political unrest in India and the project went into the total control of the Department of Irrigation, Government of Uttar Pradesh.
Major breakthrough in the construction of the dam came in July 1988 with the formation of ‘Tehri Hydro Development Corporation’; which is a joint venture of the Government of India and the state government of Uttar Pradesh. The finances were agreed to be shared in ratio of 75:25; with the Government of India providing 75% of the financial need while government of Uttar Pradesh providing for remaining 25%. Also the state government of Uttar Pradesh was to finance all the agriculture aspects of the project on its own.
The total construction cost of the Tehri Dam project is nearly INR 8000 crore.
Structural and Technical Details of Tehri Dam
Tehri Dam is a massive structure, the huge size of which can mesmerize anyone who views it. The dam along with its huge lake is an awesome view and a memory to reckon with. The remains of old Tehri town which got submerged under the huge reservoir are visible during low water level. The length of the dam is 575 Mtrs and it has a height of 260.5 Mtrs which makes it the highest dam in India. The base and crest widths of the dam are 1128 Mtrs and 20 Mtrs respectively. The reservoir which the dam creates is huge with a total capacity of 3200000 acre-feet and a total surface area of 52 sq Kms.
The dam houses one chute spillway and four shaft spillways with a total spill way capacity of 15540 cubic meters/second. A chute spillway is a kind of slope constructed to smoothly release the higher level water to a lower level downstream of a river. A shaft spill way on the other hand is a vertical shaft into which the water spills and is further conveyed with networks of tunnels.
As on today the main structure of dam has 11 floors including those under and above water. The main power house of the dam has four turbines with a capacity of 250 MW each, making the dam’s total installed capacity of 1000 MW.
The dam’s pumped storage Hydroelectric Unit with a generation capacity of 1000 MW is expected to be completed in 2018. The Pumped Storage Hydroelectric Unit is located between Tehri Dam and Koteshwar Dam. The Koteshwar Dam is 97.5 Mtrs high and has a reservoir capacity of 72072 acre-feet and is located 22 Kmtrs downstream of the Tehri Dam.
The Tehri Hydroelectric Project of 2400 MW is divided into three important sections-
- Tehri Dam and hydro power plant- 1000 MW (completed)
- The TPS (Tehri Pumped Storage ) plant- 1000 MW (under construction)
- The Koteshwar Dam power plant- 400 MW (completed)
Advantages of Tehri Hydroelectric Project
The Tehri Hydroelectric Project serves many purposes like electricity generation, Irrigation and containment of flood. We will briefly go through some of the major advantages of the project.
a) Electricity Generation and Distribution
The electricity generated by the two completely functional sections of the Tehri Hydroelectric Project i.e. Tehri Dam Hydro power plant and Koteshwar Dam power plant; is distributed to seven states of North and North West India – Uttar Pradesh, Uttrakhand, Himanchal Pradesh, Haryana, Punjab, Rajasthan, Jammu and Kashmir and to the Union Territories of Delhi and Chandigarh.
b) Agriculture
The Tehri project supports the irrigation on 270000 hectares of land in Uttarakhand, Uttar Pradesh and Delhi along with providing clean drinking water to nearly 70 lakh people of Delhi and Uttar Pradesh as well as Uttarakhand.
c) Promotes Tourism
The Tehri Dam with its massive build and the beautiful landscape surrounding it attracts thousands of domestic tourists every year making itself a tourism hot spot in Uttarakhand with many recreational activities.
d) Revenue Generation
The project provides a total annual revenue of 2400 Crore to the central government and nearly 800 crore to the state government of Uttar Pradesh.
e) Containment of Flood
During the Uttarakhand floods of 2013 when both Alakhnanda and Bhagirathi were swelling with flood waters the Tehri Dam helped containing furious Bhagirathi thereby saving lives of millions and keeping hundreds of settlements from being submerged completely.
f) Better Quality of Life and Employment Opportunities
Needless to say that along with the electricity generation and supporting agriculture the project provides various employment opportunities to skilled or unskilled local residents resulting in their higher standard of living.
Controversies
Despite its numerous advantages and the financial revenue that the dam provides to the central as well as the state government, the dam since its construction has been a reason for protests and controversies. The construction of the dam has been opposed by many due to its social and geological impacts. Below we will discuss some of the major factors giving rise to the controversy.
a) Seismic Fault Zone
The Tehri Dam is located in a Seismic fault zone in the central Himalayas which is more prone to the occurrence of earthquakes also the pressure of the huge structure of dam and reservoir water is only adding to the fault. The epicenter of the last earthquake in Oct 1991 was just 53 Kmtrs from the dam and had a magnitude of 6.8 on Richter scale.
The officials claim that the structure is constructed to withstand an earthquake of Richter 8.5 magnitude, a claim disbelieved by many and yet to be proved. If an earthquake of such magnitude occurs in the dam’s vicinity and damages it then the wrath which the reservoir water will unleash upon human settlements is unimaginable; submerging hundreds of villages completely under water within minutes and killing nearly half a million people instantly.
b) Settlement Destruction
The construction of the dam has been a reason for various protests and agitations because of the large number of destruction of houses and poor compensation provided often resulting in long legal battles between the displaced and the government. People fighting with the government for their settlement rights and adequate compensation have also resulted in the delay of the project.
Around 110 villages were affected by the construction and almost one Lakh people were rehabilitated. As early as 1990 the villagers had organized a ‘Tehri Bandh Virodhi Sangharsh Samiti’ which is loosely translated in English as- ‘Anti Tehri Dam Movement’, fighting for their displacement rights and environmental factors.
c) Religious Factor
The construction of Tehri Dam has always been an object of protest by Hindus since the construction of dam has curtailed the flow of Bhagirathi; which is, a most revered river and a major tributary of the Ganges. Since the constriction of the dam, the flow of Bhagirathi has dropped from 1000 cubic feets/sec to 200 cubic feet/sec. This infuriated many Hindu believers as the Bhagirathi is considered sacred by Hindus.
FAQs on Tehri Dam (Highest Dam in India)
Q1) Where and in which state is the Tehri Dam located?
Ans – The Tehri Dam is located in New Tehri town in the state of Uttakhand.
Q2) On which river is the Tehri Dam built?
Ans – The Tehri Dam is built on Bhagirathi, a major tributary of Ganges; 1.5 kms downstream from the confluence of Bhagirathi and Bhailangna.
Q3) Is the dam located in old Tehri or new Tehri town?
Ans –The dam is located in New Tehri town as the Old Tehri is submerged under water of the reservoir.
Q4) Is Tehri Dam the highest/tallest dam in India?
Ans – Yes, it is the tallest in India and eighth highest in the world.
Q5) What is the height of Tehri Dam?
Ans – The height of Tehri Dam is 260.5 Mtrs.
Q6) What is total length of Tehri Dam?
Ans – Total length of the Tehri Dam is 575 Meters.
Q7) What type of dam is Tehri Dam?
Ans – It is Earth rock filled Embankment type of dam.
Q8) What is the Opening date of Tehri Dam hydroelectric project?
Ans – All the four units of Tehri power station were commissioned in 2006-07.
Q9) What is the overall construction cost of the project?
Ans – The overall construction cost of the project is INR 8000 Crores.
Q10) What is the name of the Tehri Dam project?
Ans – Tehri Dam Hydro Power complex- 2400 MW.
Q11) Which company looks after the functioning of the dam?
Ans – ‘Tehri Hydro Development Corporation’ formed in 1988.
Q12) When was initial survey for the project completed?
Ans – Initial survey for the construction of dam was completed in 1961.
Q13) When did the construction work started?
Ans – The construction started in 1978.
Q14) What is the total reservoir capacity of the dam?
Ans – The reservoir has a total capacity of 3200000 acre-feet.
Q15) What is annual water level of the Tehri Dam?
Ans –Water level on the reservoir side of the dam goes up to 800 meters during rains.
Q16) Was any foreign aid provided for the project?
Ans – In 1986 USSR provided technical and financial assistance to the project.
Q17) How much equity is shared between the central and state governments?
Ans – Equity is shared between the central government and the state government of Uttar Pradesh in a ratio of 75:25 respectively.
Q18) Which government was given the responsibility of all the agricultural aspects of the project?
Ans – State government of Uttar Pradesh.
Q19) How many spillways do the dam houses?
Ans – The dam houses five spillways – One chute spillway and four shaft spillways.
Q20) How many floors do the main structure of the dam has?
Ans – Eleven floors with most of them housing huge machineries.
Q21) Which projects are parts of the Tehri Dam Hydroelectric Project?
Ans –
- Tehri Dam and Hydro Power Plant- 1000 MW (completed)
- The TPS (Tehri Pumped Storage ) Plant- 1000 MW (under construction)
- The Koteshwar Dam Power Plant- 400 MW (completed)
Q22) Is the Koteshwar Dam Power Plant functional?
Ans – Yes, All the four units have been fully commissioned since March 2012.
Q23) Where is the Koteshwar Dam Power plant located?
Ans – 22 Kilometers downstream of Tehri Dam.
Q24) What is the total capacity of Koteshwar Dam Power plant?
Ans- 400 MW
Q25) Is the Tehri Pumped Storage Plant functional?
Ans – No, It is still under construction.
Q26) What is the planned generation from TPS Plant?
Ans – The Tehri Pumped storage Plant is designed to generate 1000 MW.
Q27) In how much area does the project supports agriculture?
Ans – 270000 hectares of land in Uttar Pradesh, Uttarakahnd and Delhi.
Q28) To which Indian states/UTs does the dam provide clean drinking water?
Ans – Uttrakhand, Uttar Pradesh and Delhi.
Q29) Which states/UTs are directly utilizing the water or electricity produced by the project?
Ans – Uttrakhand, Uttar Pradesh, Jammu and Kashmir, Himachal Pradesh, Rajasthan, Punjab, Haryana, Delhi and Chandigarh.
Q30) What is the geological concern for the location of the dam?
Ans – Located on a geological fault zone prone to the occurrence of earthquakes.
Q31) How many villages were destructed due to the dam’s construction?
Ans – Nearly 110 villages were destructed to make way for the construction.
Q32) How many people were relocated?
Ans – Nearly 100000 people were rehabilitated.
Q33) What is ‘Tehri Dam Andolan’?
Ans – It is a protest opposing the construction of the dam because of its environmental effects and inadequate compensation for those rehabilitated.
Q34) Name some leaders of Tehri Dam Andolan.
Ans – V.D. Saklani and Sunder Lal Bahuguna.
Q35) Why the dam’s construction is opposed by Hindus?
Ans – The dam’s construction reduced the flow of Bhagirathi which is a sacred river for Hindus and a major tributary of the Ganges.