Skip to main content

Dam shortcut results in hydropower project hit by massive landslide in North-East

Counterview Desk 
The advocacy group South Asia Network on Dams, Rivers and People (SANDRP), commenting on a massive landslide which hit the Subajsiri Hydropower project on the border of Assam-Arunachal Pradesh, has said that this is in continuation of India facing “multiple dam disasters”. One of the biggest in recent times washing away of the massive 1200 MW Teesta 3 dams in Sikkim.
It underlined, “It is high time that the authorities wake up and do no allow hydropower developers allow to adopt short cuts, the way Teesta 3 dam developers did and now NHPC seems to be doing in case of Lower Subansiri HEP.”

Text:

Once again, after several such incidents in the past, the controversial 2000 MW Lower Subansiri Hydropower project on Assam Arunachal Border was hit by a massive landslide at around 11.30 am on Oct 27 2023. The landslide damaged the project, further delaying the commissioning of the first unit, increasing the cost and time over runs of the expensive, much delayed project. Following the landslide, the only functioning diversion tunnel no 1 of the project, about 200 m upstream from the dam was blocked.
The river water, about 997 cumecs (cubic meters per second) suddenly started flowing towards the dam, where the spillway gates were still under installation, yet to be tested. The water could overflow from the under construction spillway gates once the reservoir reached 145 meters level (above Mean Sea Level).
The massive, majestic Subansiri river was completely without any flow till the river water started flowing through the spillway gates about twelve hours later. (Feature photo above shows the snapshot when landslide started and in the foreground, water is seen rushing towards the dam).
Diversion Tunnels (DT) are constructed to take river water from the upstream of the coffer (temporary) dam to downstream of the dam site so that dam site can remain dry for the work to go on. For Lower Subansiri HEP, five such diversion tunnels each of diameter 9.5 meters have been constructed on the left bank at about 100 m above mean sea level.
A senior official of NHPC said: “The other four numbers of diversion tunnels had already been blocked earlier”, partly due to landslide, the official did not say. Even this last functioning DT was also hit by a landslide in April 2023 and also October 2022.

NHPC needs to follow CEA directions

An “Indian Express” report earlier mentions that the “Central Electricity Authority (CEA) in April 2022 had advised the NHPC to engage a specialized agency to examine the strength of the project’s powerhouse retention wall and also assess the impact of diversion tunnels on the site’s slope stability before the onset of monsoon”.
However, the studies were not carried out. The report also lists the landslide incidents at project site since beginning of the project work in 2005. This negligence by NHPC in not taking measures suggested by CEA and not taking necessary follow up action has once again led to the fresh damage to the project and delayed its commissioning.
Interestingly, a senior NHPC official told media: “We are working in the hills and construction activity can trigger such situations.” This acceptance that the hydropower projects can trigger landslides is something hydropower companies never accept.
The NHPC is likely to say that the reduction in water flow in the Subansiri river for about twelve hours will in any case happen whenever they close the DT. However, this closure of DT is not happening as per a planned activity. Since the spillway gates are not yet ready, they will either have to open one of the DTs or build a coffer dam to isolate the spillway gates where work is still incomplete, which will take additional cost, time and impacts ultimately.
CEA had clearly said in its tour report of April 2022: “Further, the reservoir filling would commence only after the dam achieves a certain height and provided all Spillway Radial Gates have been erected and tested.” The reservoir filling taken up now on Oct 27 2023 clearly violates this CEA directions since it is happening while all Spillway Radial Gates have not been erected and tested.
The CEA report further states: “It is understood that the civil works would proceed only in dry/ lean season. Further, after the Civil Contractor hands over the (Spillway) bays to HM Contractor, it would take a minimum of 3.5 months for erection of Spillway Radial Gates and their testing.”
All these processes need to go as directed, else there is bound to be serious issues concerning safety of the project. We hope NHPC is not bypassing any of these directions and CEA, CWC and NDMA (National Disaster Management Authority) will not allow NHPC to bypass of the safety measures. It is not clear why the NHPC did not use the silt flushing tunnel to continue the flow in the river downstream, assuming the dam has silt flushing tunnel at the bottom. 
Local authorities have reported that lakhs of fish have died due to the sudden drop in the water level of the Subansiri River. This will have huge implications not only for the aquatic biodiversity, habitat and livelihoods not only currently, but for future too.
The Assam government must assess these impacts and ensure that NHPC compensates the losses to the affected people. The North Lakhimpur District came out with an advisory notice for safety in the downstream area, but the official needs to go far beyond to ensure the affected people are compensated.

In conclusion

As India faces multiple dam disasters this year, including washing away of the massive 1200 MW Teesta 3 dams in Sikkim, it is high time that the authorities wake up and do no allow hydropower developers allow to adopt short cuts, the way Teesta 3 dam developers did and now NHPC seems to be doing in case of Lower Subansiri HEP.
Subansiri is a much bigger river and it also has numerous glaciers in the catchment. It may be added that like in case of Teesta 3, Lower Subansiri HEP spillway also are not designed for Glacier Lake Outburst Floods. On top of it, any shortcuts adopted in construction of spillway for the project can only be invitation to trouble. Like the short cuts adopted in construction of Medigadda Dam on Godavari leading to sinking of its pillars last week. Clearly our Dam Safety Mechanism needs to do a lot more to inspire confidence.

Comments

TRENDING

What's Bill Gates up to? Have 'irregularities' found in funding HPV vaccine trials faded?

By Colin Gonsalves*  After having read the 72nd report of the Department Related Parliamentary Standing Committee on alleged irregularities in the conduct of studies using HPV vaccines by PATH in India, it was startling to see Bill Gates bobbing his head up and down and smiling ingratiatingly on prime time television while the Prime Minister lectured him in Hindi on his plans for the country. 

Muted profit margins, moderate increase in costs and sales: IIM-A survey of 1000 cos

By Our Representative  The Indian Institute of Management-Ahmedabad’s (IIM-A's) latest Business Inflation Expectations Survey (BIES) has said that the cost perceptions data obtained from India’s business executives suggests that there is “mild increase in cost pressures”.

Magnetic, stunning, Protima Bedi 'exposed' malice of sexual repression in society

By Harsh Thakor*  Protima Bedi was born to a baniya businessman and a Bengali mother as Protima Gupta in Delhi in 1949. Her father was a small-time trader, who was thrown out of his family for marrying a dark Bengali women. The theme of her early life was to rebel against traditional bondage. It was extraordinary how Protima underwent a metamorphosis from a conventional convent-educated girl into a freak. On October 12th was her 75th birthday; earlier this year, on August 18th it was her 25th death anniversary.

Govt putting India's professionals, skilled, unskilled labour 'at mercy of' big business

By Thomas Franco, Dinesh Abrol*  As it is impossible to refute the report of the International Labour Organisation, Chief Economic Advisor Anantha Nageswaran recently said that the government cannot solve all social, economic problems like unemployment and social security. He blamed the youth for not acquiring enough skills to get employment. Then can’t the people ask, ‘Why do we have a government? Is it not the government’s responsibility to provide adequate employment to its citizens?’

A Hindu alternative to Valentine's Day? 'Shiv-Parvati was first love marriage in Universe'

By Rajiv Shah*   The other day, I was searching on Google a quote on Maha Shivratri which I wanted to send to someone, a confirmed Shiv Bhakt, quite close to me -- with an underlying message to act positively instead of being negative. On top of the search, I chanced upon an article in, imagine!, a Nashik Corporation site which offered me something very unusual. 

IMA vs Ramdev: Why what's good or bad for goose should be good or bad for gander

By Dr Amitav Banerjee, MD* Baba Ramdev and his associate Balkrishna faced the wrath of the Supreme Court for their propaganda about their Ayurvedic products and belittling mainstream medicine. Baba Ramdev had to apologize in court. His apology was not accepted and he may face the contempt of court with harsher punishment. The Supreme Court acted on a public interest litigation (PIL) moved by the Indian Medical Association (IMA).

'Flawed' argument: Gandhi had minimal role, naval mutinies alone led to Independence

Counterview Desk Reacting to a Counterview  story , "Rewiring history? Bose, not Gandhi, was real Father of Nation: British PM Attlee 'cited'" (January 26, 2016), an avid reader has forwarded  reaction  in the form of a  link , which carries the article "Did Atlee say Gandhi had minimal role in Independence? #FactCheck", published in the site satyagrahis.in. The satyagraha.in article seeks to debunk the view, reported in the Counterview story, taken by retired army officer GD Bakshi in his book, “Bose: An Indian Samurai”, which claims that Gandhiji had a minimal role to play in India's freedom struggle, and that it was Netaji who played the crucial role. We reproduce the satyagraha.in article here. Text: Nowadays it is said by many MK Gandhi critics that Clement Atlee made a statement in which he said Gandhi has ‘minimal’ role in India's independence and gave credit to naval mutinies and with this statement, they concluded the whole freedom struggle.

Youth as game changers in Lok Sabha polls? Young voter registration 'is so very low'

By Dr Mansee Bal Bhargava*  Young voters will be the game changers in 2024. Do they realise this? Does it matter to them? If it does, what they should/must vote for? India’s population of nearly 1.3 billion has about one-fifth 19.1% as youth. With 66% of its population (808 million) below the age of 35, India has the world's largest youth population. Among them, less than 40% of those who turned 18 or 19 have registered themselves for 2024 election. According to the Election Commission of India (ECI), just above 1.8 crore new voters (18-and 19-year-olds) are on the electoral rolls/registration out of the total projected 4.9 crore new voters in this age group.

Indians witnessing 'regression to Hindutva politics' under Modi ahead of elections

By Bhabani Shankar Nayak*  The forthcoming general election in India, scheduled from April 19, 2024, to June 1, 2024, to elect the 543 members of the 18th Lok Sabha and the new Government of India, carries immense significance for the preservation of India's identity as a liberal, secular, and constitutional democracy.

An equine landmark, Cheltenham Gold Cup centenary 'epitomized' heights unparalleled

By Harsh Thakor*  The Cheltenham Gold Cup  is the most prestigious jumping race in the British Isles Steeplechasing calendar and the Cheltenham festival, a cynosure of every English and Irish racegoer. Few sporting events match or surpass the sheer intensity, competitiveness and joy that radiates its legacy. Few moments are more pulsating than witnessing a Gold Cup or a Cheltenham festival. In addition to that the race is run amidst the background of an evergreen English countryside, encircled by hills and pastures, giving a sensation of a paradise or heavenly location.