Hydroelectric Dams in the Himalayas – A Risk Not Worth Taking

Gopakumar Menon
The Himalayas - a sensitive zone to infrastructure development
Ramki Sreenivasan
Several hydroprojects are in the making in the Himalayas. However, studies have warned of more earthquakes in the Himalayas and urged development policies to be in sync with its geography.
How do glacial floods occur?
This video explains the causes and impacts of floods from glacial breaks.

On July 11th, 2020, Mint, an Indian business newspaper, carried a centrepiece titled, “The Big Himalayan Earthquake Is Coming”. This story quoted several scientific studies that warned of the risks posed to cities, towns, and hundreds of villages in the Himalayan region from a future earthquake that has been predicted with a high degree of certainty.  The seismological research supporting the key premise of this article is impeccable, has been subject to examination, validation, and peer-review, and therefore must be accepted on the tenet of the Precautionary Principle and the highly destructive possible consequences that could accrue from the event. While a number of these studies had been going on for years, the message – that development policy in the Himalayan arc must align to this reality – has acquired an urgent tone following the devastating Gorkha earthquake in Nepal in 2015, which has now been studied in detail with the latest technical tools accessible to seismologists. 

Yet, India’s energy policy continues to encourage the construction of new hydropower projects.  In Uttarakhand alone, 37 hydropower projects are operational, and 87 more projects are in different planning and construction stages.

The Science

The likelihood of a major, intense earthquake above 8Mw in the making has been endorsed by several experts including earth scientist Dr. C. P. Rajendran, Adjunct Professor, National Institute of Advanced Studies, Prof Dr. Roger Bilham, geo-scientist at the University of Colorado, Boulder, and Prof Luca Dal Zilio, a geophysicist at the California Institute of Technology (Caltech) in independent studies.

In August 2020, Prof Steven G Wesnousky, a professor of geology and seismology and director of the Center for Neotectonic Studies at the University of Nevada, US, published a paper in Seismological Research Letters titled ‘Great Pending Himalayan Earthquakes’. The principal conclusion of his paper is that geological, historical, and geophysical observations show that the entire Himalayan arc is poised to produce a sequence of great earthquakes, possibly similar to that which occurred in the twentieth century along the Aleutian subduction zone. He believes that the human catastrophe in the densely populated countries astride the arc is likely to be unprecedented when these earthquakes occur.  Seismologist Supriyo Mitra, a professor in the Department of Earth Sciences at the Indian Institute of Science Education and Research (IISER) Kolkata, noted that this research matches previous studies.

The highly damaging impact of such an earthquake on a mega-structure like a dam will be without precedence and will have horrific consequences for entire communities living alongside these structures and downstream from them, as well as for the environment.

Compounding this substantial risk is the increasing threat from glacial lakes, particularly as a consequence of climate change.  These lakes are formed in large depressions (that were earlier eroded by glacial activity).  Satellite imagery and ground-level observations have recorded those glaciers in the Himalayas are melting at an unprecedented rate, increasing the instances of glacial lake breaches or ‘outbursts’. Large scale destruction from glacial lake outburst floods (GLOFs) is already being witnessed: in 2013, for instance, over 100,000 people in Uttarakhand were impacted by a flood, which caused immense infrastructural damage and ravaged homes and livelihoods and glacial lake outburst has been cited as one of the possible causes of this disaster.

A research paper titled ‘Hazard from Himalayan glacier lake outburst floods’ by Georg Veh, Oliver Korup, and Ariane Walz has stated the dangers of such an event clearly. They note, with concern, that there are over five thousand glacier lakes in the Himalayas that could breach with disastrous consequences. A further study led by Prof Wolfgang Schwanghart, a geologist at the Institute of Earth and Environmental Sciences, University of Potsdam, Germany estimated that of the 177 hydropower projects located close to Himalayan glaciers, over a fifth – including many in India – could be under threat from floods caused by the outbursts of glacial lakes. Worryingly, many of these hydro projects are in the Eastern Himalayas, where the GLOF risks are the highest.

Risks from earthquakes and GLOFs are serious, worrisome, and real. Yet, there is an additional risk – one of random raining of debris from a relatively young Himalayan ecosystem that is now being modified at an unprecedented rate. As reported by the European Space Agency, “On 7 February 2021, the Chamoli district in the Uttarakhand region of India experienced a humanitarian tragedy when a large mass of rock and ice, around 27 million cubic metres, was released from the steep mountain flank of the Ronti peak. This collapse caused a flow of debris to barrel down the Ronti Gad, Rishiganga, and Dhauliganga river valleys, causing significant destruction along the route, killing more than 200 people and destroying two major hydropower facilities that were under construction……. the study provides satellite evidence that the disaster was caused by a large mass of ice and rock dislodged from the slopes of Ronti Peak, starting as a giant landslide that transformed into a mud and debris flow destroying its path.” The BBC reported, “To put this volume (of debris) in context, it’s about 10 times that of the Great Pyramid of Giza in Egypt.  When the mass hit the Ronti Gad valley floor, it released the energy equivalent to 15 Hiroshima atomic bombs.”

The Conclusion

The science and ground evidence has a clear and ominous message.  It is imperative to plan any development intervention – whether it be a hydropower project or a highway – with the Precautionary Principle and the safety of towns, people, and the environment as the supreme consideration.  When such risks are omnipresent, hydropower generation in the Himalayan ecosystem cannot be classified as ‘environment-friendly’, ‘people-friendly’ or ‘clean technology’ by any measure; on the contrary, such projects have added to the magnitude of likely future disasters arising out of earthquakes or glacial lake outburst floods. Hydropower projects in the Himalayan region are at serious risk from earthquakes and glacial lake outburst floods and pose a grave threat to tens of thousands of people.  This has been emphasised by a Supreme Court-appointed committee headed by Ravi Chopra, director of the People’s Science Institute, which submitted a detailed report. It warned that a glacial retreat in the state of Uttarakhand, coupled with structures built for hydroelectricity generation and dams, could lead to large-scale disasters downstream.

There are two important arguments in favour of hydropower in general that have been made:

  1. India’s power needs are likely to grow significantly in the next two decades; and
  2. Hydro acts as the ‘balancing’ force, providing power at night when solar power cannot function

While these were seemingly valid until recently, rapid – indeed, breath-taking – developments in solar energy and storage have dented those arguments.

The Institute for Energy Economics and Financial Analysis (IEEFA), in a commentary dated July 22nd, 2021, has reflected on the current utilisation and excess capacity and the scenario until 2030. July 2021 witnessed a record power demand of 200 GW in a single day, which translates to a compound annual growth rate (CAGR) of 4.5% in the last decade.  However, as IEEFA points out, “the Central Electricity Authority (CEA) forecasts much higher growth going forward, with peak electricity demand to touch ~340GW by the end of 2030. This implies a 6.9% CAGR, compared to 4.5% in the last decade. If India’s peak demand continues its strong growth trajectory of the last decade, it will remain in the range of 285-300GW by the end of this decade.” It may be noted that CEA has consistently over-estimated peak demand, resulting in some poor – and costly – decisions: India has too many coal plants today with an average capacity utilisation that is less than 60% in the last four years (and another 33 GW being built as we speak). 

Yet, solar energy capacity is rapidly growing: by 2030, it is likely to top 300 GW and is capable, with the battery capacity that is currently planned on a Gigafactory scale, of being the prime source of energy.  Such battery capacity is likely to render the ‘balancing power’ argument void as well.  In addition, innovation in new sources of energy like ‘green hydrogen’ is an exciting trend. In an article in the Mint in July 2021, two partners of McKinsey stated that “Green hydrogen is expected to speed up decarbonization of hard-to-abate sectors such as steel, heavy transport, and refining.  Energy storage will play an important role in stabilizing grids and reducing intermittence of renewables.”

It is not just the excess capacity of energy that will be disruptive; the price is likely to remain low, rendering hydropower hopelessly uncompetitive. Tim Buckley from IEEFA says that, by 2030, solar tariffs will touch Rs 1 per unit.  For hydropower to make meaningful returns to shareholders – and ensure that lenders receive their dues – tariffs need to be at least four times that (at today’s prices). 

Therefore, the two principal arguments stand entirely discredited and are unlikely to have their validity retrieved in the future.  In summary, this note makes a case for an immediate cessation of all hydropower projects in the Himalayan arc and the gradual decommissioning of existing projects, with emphasis on ecological restoration of the project sites.  This is the only way to ensure that India will be prepared for the disasters caused by earthquakes and GLOFs when they happen. 


  1. The Mint article notes, “With a moment magnitude (Mw) of 7.8, it was a major trembler. In Nepal, it killed nearly 9,000 people and injured some 22,000……And yet, it wasn’t a big earthquake, over Mw8 monsters that can turn the ground into mud. If anything, the 2015 earthquake set the ground conditions that make a far larger earthquake more favourable.” (Note: the power of one 8Mw earthquake is equal to that of about a thousand 6Mw earthquakes).
  2. Following the paper, in an interview with PTI, Prof Wesnousky stated, “The entire Himalayan arc extending from the eastern boundary of Arunachal Pradesh (India) in the east to Pakistan (in the west) has in the past been the source of great earthquakes. These earthquakes will occur again and scientifically, it would not be a surprise if the next great earthquake occurred in our lifetimes.  But the resolution of our studies is at best on the order of 100 years, longer than a human lifetime.” 

  3. Himalayas poised for a series of big earthquakes, says study- Deccan Herald

  4. Hazard from Himalayan glacier lake outburst floods, by Georg Veh, Oliver Korupa, and Ariane Walz

    “Sustained glacier melt in the Himalayas has gradually spawned more than 5,000 glacier lakes that are dammed by potentially unstable moraines. When such dams break, glacier lake outburst floods (GLOFs) can cause catastrophic societal and geomorphic impacts. …….. Flood peaks from GLOFs mostly attenuate within Himalayan headwaters but can rival monsoon-fed discharges in major rivers hundreds to thousands of kilometres downstream. Projections of future hazard from meteorological floods need to account for the extreme runoffs during lake outbursts, given the increasing trends in population, infrastructure, and hydropower projects in Himalayan headwaters”

  5. Uncertainty in the Himalayan energy-water nexus: estimating regional exposure to glacial lake outburst floods. This study was done by an interdisciplinary team, led by Prof Wolfgang Schwanghart, a geologist at the Institute of Earth and Environmental Sciences, University of Potsdam, Germany.  In an email interaction with The Hindu, Prof Wolfgang Schwanghart stated that “Our key result is that the majority of the projects are currently planned or constructed where these uncertainties become relevant and potentially dangerous.”
  6. “Our estimated GLOF hazard is tied to the rate of historic lake outbursts and the number of present lakes, which both are highest in the Eastern Himalayas. There, the estimated 100-y GLOF discharge (∼14,500 m3 ·s −1) is more than 3 times that of the adjacent Nyainqentanglha Mountains, and at least an order of magnitude higher than in the Hindu Kush, Karakoram, and Western Himalayas”. Quoted from the above study.
  7. IEEFA: Understanding India’s latest peak power demand record. 
  8. “Appropriate policies can hasten our energy transition” by Suvojoy Sengupta & Kamya Jaiswal. Mint, dated July 22nd 2021
  9. The role of hydropower projects in development and disasters in Uttarakhand. dated August 2nd, 2021. Mongabay
  10. How India can accelerate its green energy transition, Mint, dated July 22nd 2021
  11. A hydro onslaught the Himalayas cannot take. The Hindu, dated September 3rd, 2021
  12. Satellites reveal cause of Chamoli disaster. ESA. dated 14th June 2021
  13. Chamoli disaster: ‘It hit the valley floor like 15 atomic bombs’. BBC, dated 13th June 2021


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