Various countries are building large dams on Himalayan rivers. Apart from local factors this often gets discussed in terms of the conflicting interests of various countries. In the process the wider reality of dams in Himalayan region being inherently risky ventures gets neglected. The wider reality is that many uncertainties and risks are involved in building and managing large dams in the Himalayan region, uncertainties which are increasing further in times of climate change.
Hence when one hears that China is planning to build such a huge structure in Medog on the part of the Brahmaputra river that flows in Tibet (where the river is known as Yarlung Tsangpo) that its planned hydro power is being estimated at more than 2.5 times the power generation capacity of the present day biggest dam of Three Gorges, then of course one must worry regarding its adverse, and in certain situations highly catastrophic impact on India, Bangladesh and Bhutan, but in addition one must also warn that the project is inherently too high risk a project to be feasible and should be given up at the outset.
The Himalayan region is characterized by two contradictary features. In engineering terms it has a very huge potential for producing hydro power. However in ecological and geological terms the building of dams and hydro-electricity projects involves very serious disruptions and safety risks in this inherently fragile region of high seismicity which in geological terms is still in its formation stage.
These contradictions came to the fore in the course of one of the most controversial and difficult dam projects —the 260.5m high Tehri Dam Project (TDP) in Uttarakhand state of India. As Y.K.Murthy, former Chairperson of Central Water Commission of India has stated, this dam was planned not just as one of the highest structures of its kind in a region of known high seismicity, it also called for tackling of “complex technical problems involved in a rockfill dam of such a height for which there was very little precedence available elsewhere in the world.”
The TDP faced much opposition, and in 1980 the then Prime Minister Mrs. Indira Gandhi ordered a review. The Experts’ Group which conducted the review asked for stopping the project. The project authorities managed to continue the project somehow. In 1990 the Environment Appraisal Committee(EAC) made an more more damning indictment of the project, denying it clearance on the ground of the very high risks to the dam structure in the event of an earthquake of high intensity likely to occur in this highly seismic zone, exposing millions of people and pilgrims in downstream areas ( including the most holy cities of Haridwar and Rishikesh) to unacceptably highly risks. The EAC also mentioned several other hazards, including reservoir induced seismicity and land sliding towards reservoir after impoundment of water and changes in its level.
In 1991 there was an earthquake in Uttarakhand. It was noticed that damage was particularly acute in the villages located close to hydro electricity projects, like Jamakh village close to Maneri Bhali project, upstream of TDP. This was attributed by local people to blasting work which had shaken up the fragile geological formations. In 2013, devastaing floods killed around 6000 people in Uttarakhand. An Experts Body appointed at the initiative of the Supreme Court, chaired by Dr. Ravi Chopra, pointed out that the damage had been particularly acute near hydro-electicity projects. Poor muck management and neglect of catchment area treatment came in for special criticism by these experts.Yet again at the time of destructive floods in 2021, hydro-electricity projects were blamed for aggravating the disaster.
The Experts Group of 2013 stated that it was not just a question of individual projects seen in isolation but also of the series of projects taken up at short distances on a river, disrupting the entire ecology and biodiversity of the river. Also there was the question of the saturation point or bearing capacity of a fragile region. The report pointed that in the western Himalayan state of Uttarakhand extensive hazards ,ecological and social disruptions had appeared already when 92 projects with a total installed capacity of 3624 MW had been completed, while the eventual planning was for 450 projects with 27039 MW installed capacity. In the eastern state of Arunachal Pradesh the potential of hydro electricity is stated to be even higher. Both states have a border with China, which has even more ambitious hydro-electricity plans.
In fact now a much bigger safety and ecological risk has appeared on the Chinese side of the eastern border where China has embarked on a biggest of them all mega project in Medog in Tibet Autonomous Region. The Brahmaputra river, life-line for a significant part of India and Bangladesh, originates in Tibet before flowing into Arunachal Pradesh and other states of India, flowing further to Bangladesh before merging into the Bay of Bengal.
China has already built some projects on the stretch of this river flowing in Tibet, where it is known as Yarlung Tsangpo, but its much bigger ambition is to tap the enormous potential at a place, close to the border, where the river has a 2000 meters drop. This mother of all such projects, it is claimed, will have an installed hydro power potential over 2.5 times that of the Three Gorges Dam, the highest capacity project at present.
Clearly a project of this scale, located very close to the Indian side of the border, can also be much more hazardous than previous Himalayan projects, and many risks will spill over first to India and further down to Bangladesh, while Bhutan too is affected. This can be in the form of flash floods, reservoir induced seismicity and other factors. At the same time the lean season flow may reduce, as also the deposition of fertile silt.
What is more, the relatively more free debate which allows the various risks to be exposed and discussed in India may not take place in China, particularly regarding the hazards to the Indian side. China may not share all relevant data with India, despite clams to the contrary.
Hence the risks and hazards of Himalayan dams and hydro-electricity projects are set to increase, despite all the warnings voiced by many concerned experts. To avoid catastrophic harm in future, voices for a more cautionary approach are much needed before it is too late.
While India is well-justified in raising its concerns with China relating to the planned largest dam project , at the same time India must also show much greater caution regarding the risks and adverse impacts of large dams in the Himalayan region. The same holds true for other countries like Nepal, Bhutan and Pakistan.
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The writer is author of several books/booklets on this issue, the latest being "Vimla and Sunderlal Bahuguna—Chipko Movement and the Struggle against Tehri Dam Project in Garhwal Himalaya". His other recent books include "Protecting Earth for Children", "Planet in Peril" and "Man over Machine-A Path to Peace". He is Honorary Convener, Campaign to Save Earth Now
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