Teesta Flood And Dam Disaster Hydropower And Environmental Misgovernance

First published in Sanctuary Asia, Vol. 43 No. 12, December 2023

On the intervening night of October 3 and 4, 2023, a glacial lake outburst flood (GLOF) in North Sikkim, exacerbated by large hydropower projects on the Teesta river, caused havoc to people, environment and infrastructure downstream in Sikkim and West Bengal. Many lives were lost. The dam of the 1200 MW Teesta III hydropower project was washed away, leading to cascading impacts. Post mortems will follow on the compounding causes of the flood and dam disaster, failures of monitoring and early warning systems, as well as broader concerns about environmental hazards in the Himalaya in an era of climate change. Neeraj Vagholikar reminds us how concerns about environmental risks, including GLOFs, have been repeatedly undermined in the deeply flawed environmental governance process of hydropower projects on the Teesta for over two decades.

The public hearing for the 1200 MW Teesta III hydropower project was held on June 8, 2006 in Chungthang, North Sikkim. My colleague Manju Menon and I were observers. Sikkim had been a poster boy of good – and green – governance, and we were curious how things would pan out. The ruling party MLA and Minister in the state government, Hishey Lachungpa, set the tone early. While arguing in favour of the project, he reminded the audience how actor Aamir Khan’s film Fanaa was banned in Gujarat after he expressed concerns regarding poor rehabilitation of those displaced by the Narmada dam. Later in the hearing, the Chairperson of the Sikkim State Pollution Control Board (SPCB), C.C. Sangdarpa, labelled those raising concerns and opposing the Teesta III project as anti-social, anti-Sikkimese and anti-national. The SPCB is the organisation that, by law, is tasked with organising a free-and-fair public hearing, but their Chairperson openly warned dissenters. Opinions on a wide range of issues including environment, livelihood and socio-cultural aspects were expressed in the hearing. Members of the Affected Citizens of Teesta (ACT) raised several concerns through oral and written submissions. Importantly, they supported their view by strongly highlighting flaws in the Environment Impact Assessment (EIA) report. The submission by Pemzang Tenzing, for instance, noted that, “The retreating glaciers are altering the hydrological regime in the Himalayan region and also pose environmental risks such as Glacial Lake Outburst Floods (GLOFs) and increased sedimentation. Therefore, information on the glaciers and impact of climate change on them are critical to gauge the long-term viability of dams in the Himalayan region. There is no information on glaciers and the environmental risks due to changing glacial behaviour on the Teesta river system in the EIA report.”

The dam of the 1200 MW Teesta III project was washed away on the intervening night of October 3 and 4, 2023 on account of a glacial lake outburst flood (GLOF) from the South Lhonak lake glacial-moraine-dammed lake. The flood in the downstream was magnified by the dam disaster. Photo: Mayalmit Lepcha.

The public hearing proceedings recorded the response of the developers, Teesta Urja Ltd. (TUL), now Sikkim Urja Ltd., to Tenzing’s submission: “Most of the aspects have been comprehensively covered. However, necessary rectification wherever required shall be taken up both in the EIA & EMP.”

To date, no meaningful rectification was carried out with respect to re-evaluating the risks from GLOFs, among other issues. After the public hearing, TUL sent a more detailed response dated July 14, 2006 to the Ministry of Environment, Forest and Climate Change (MoEFCC) on the submissions of ACT members Tseten Lepcha and Pemzang Tenzing. Responding to Tenzing’s submission they state: “5) Glacial studies and Floods: Sufficient mitigation measures have been proposed and covered as part of the EMP to take care of any eventual flood…. The spillway for the project has been designed to handle Probable Maximum Flood of 7,000 cumecs, which is already on a highly conservative side. To prevent any natural disaster sufficient mitigation measures have been proposed as part of disaster management plan.”

What TUL did not point out is that the Probable Maximum Flood (PMF) of 7,000 cumecs (cubic metre per second), which the dam spillways could pass through, was only considering rainfall events and no additional component of GLOF, despite knowing the site carried serious GLOF risks. The Environment Ministry and its Expert Appraisal Committee (EAC) accepted such clarifications and environmental clearance was granted to the project. The Central Water Commission (CWC) and Central Electricity Authority (CEA), which examine such technical parameters also failed to take into account that the ‘design flood’ the dam can pass through should also include the likelihood of a GLOF in addition to PMF. These are not ‘minor’ omissions. Similar loose clearances will continue to have killing effects, unless the EACs are held to much higher standards of scrutiny. While detailed investigations will reveal more, it is understood that the developers were unable even to open most spillway gates in the Teesta III project on the intervening night of October 3 and 4, 2023. But even if they had, a spillway capacity of 7,000 cumecs was inadequate to handle the GLOF and this was a clear recipe for disaster. EIA consultant WAPCOS Ltd., in the chapter on the Disaster Management Plan in June 2006, said: “A lot of care needs to be taken during the design and construction of dams and there are several checks, which make it impossible for a dam to break. For this dam, several dam safety surveillance systems have been suggested to ensure that the dam never fails even under most adverse conditions.”

Yes, the dam was washed away.

An Uphill Battle For Environmental Security

ACT challenged the environmental clearance granted to the 1200 MW Teesta III project in the erstwhile National Environmental Appellate Authority (NEAA) – the predecessor of the National Green Tribunal (NGT). The issue of inadequate environmental risk assessment, including risks from GLOFs, was part of the appeal which specifically highlighted: “Detailed study of the environmental risks and their economic implications before granting clearance to the project is extremely important, particularly for the state government of Sikkim, which is going ahead with these projects to gain economic benefits for the state at a great ecological and social cost to
its people.”

An NEAA bench constituting retired IAS officer Dr. I.V. Manivannan and two retired IFS officers, Kaushlendra Prasad and J.C. Kala, heard the matter. Kala had also retired as Director General of Forests & Special Secretary in the Environment Ministry. In the NEAA hearing held on February 28, 2007, when the risks from GLOFs and floods were raised and argued, the bench opined that the construction of the project in question would be a mitigating factor in the event of a flood, as downstream areas of the project would not receive the flood waters on account of the presence of the project. This observation was made despite the fact that the project has no flood moderation component. The appeal was dismissed in July 2007 and GLOFs found no mention in the NEAA order. On the fateful night, as the dam got swept away, the water stored in the reservoir and bulk of the 60 m.-high concrete-faced rock-filled (CFRD) dam was added to the GLOF flowing downstream. This greatly added to the devastation, which included significant damage to the already commissioned 510 MW Teesta V and the under-construction 500 MW Teesta VI projects.

Locals walk on top of the dam of the 510 MW Teesta V project examining the post-flood damage. The GLOF, exacerbated  by the  dam-break in the upstream 1200 MW Teesta III project, magnified the disaster in the downstream, impacting people, ecosystems and infrastructure. Photo: Wangchuk Bhutia.

Significantly, the Teesta Stage V project located downstream was granted environmental clearance in May 1999 with a mandatory condition that a Teesta river basin carrying capacity study will be conducted and the specific clearance condition was: “No other project in Sikkim will be considered for environmental clearance until the carrying capacity study is completed.”

Wilfully Ignoring Risk

The carrying capacity study was completed in 2007. Yet the Environment Ministry relied only on interim reports to then grant environmental clearance for several hydroelectric projects in the Teesta river basin before the study was finalised. The report, in both the draft and final versions, distinctly identified the threat from GLOFs in North Sikkim. The question arises as to why this was ignored when granting clearances to individual projects. The coordination agency for this study was the Centre for Interdisciplinary Studies for Mountain and Hill Environment (CISMHE) – University of Delhi, plus several other institutions including WAPCOS Ltd., Sálim Ali Centre for Ornithology & Natural History (SACON), Sikkim Government College, North Bengal University, NBSS, Kolkata and IIT, Delhi were involved.

WAPCOS Ltd., which was part of this consortium and acknowledged the risks of GLOFs as part of the Teesta basin carrying capacity study, inexplicably, never included such risks in the individual EIA report for the 1200 MW Teesta project in 2006, for which it was in fact the consultant. The Comptroller and Auditor General (CAG) of India in its 2016 report on Sikkim observed other major contradictions between the Teesta basin carrying capacity study and the WAPCOS EIA report for Teesta III on the ecological and wildlife fronts. While the carrying capacity study recorded this area as ecologically sensitive and rich in biodiversity, the project-specific EIA report dismissed the importance of the area as having no significant wildlife. The CAG further observed that on June 4, 2008, a serow Capricornis sumatraensis, a Schedule I species under the WLPA, was found dead at the under-construction project site itself, questioning the basis of the Sikkim government having earlier endorsed the WAPCOS EIA report before the MoEFCC.

During the environmental clearance process for the proposed 520 MW Teesta IV project, CISMHE, co-ordinating the carrying capacity study, also thought fit not to mention or raise an alarm about GLOF risks in the 2012 EIA report for Teesta IV, for which it was a consultant. ACT members and many project-affected people from Dzongu, the Lepcha reserve, boycotted the public hearing for the proposed 520 MW Teesta IV project held on March 29, 2012 after the futile experience of the Teesta III public hearing in 2006. The project was finally granted environmental clearance in January 2014, which was challenged before the NGT by locals from Dzongu, who were affected by the project. The developer, NHPC Ltd., in its 2014 affidavit said that GLOFs are relevant only for projects north of Chungthang, where Teesta III is located, and not to them, since they are located further downstream. That was an illogical position to take, since they knew that gravity would undoubtedly carry such a flood downstream of Chungthang! In the event, the NGT bench comprising Justice S.P. Wangdi from Sikkim, and Professor P.C. Misra, seemed satisfied with such responses, and the appeal was dismissed in 2017 without insisting on crucial studies on GLOF risks.

As of today, the Teesta IV project has not been built, yet the downstream hydropower projects, the commissioned 510 MW Teesta V, and the under-construction 500 MW Teesta VI, suffered damage on account of the cascading impact of the GLOF and dam disaster, thus proving the developers and courts wrong.

The Government of Sikkim has now formed a high-level committee to examine the dam breach of the 1200 MW Teesta III project. We must wait to see what emerges from this process. Going forward, will India now pay careful heed to the well-articulated concerns of ACT members and other locals on poor environmental risk assessment, including of potential GLOFs, which were either ignored or dismissed by people sitting in different forums while examining hydroelectric projects on the Teesta over the past two decades? The 1200 MW Teesta III project was built at a cost of Rs. 13,965 crores, and with the washing away of the dam, it is a huge loss of public money and power infrastructure. The flood, magnified by the dam disaster, led to loss of lives, property and environmental damages. A disaster, which could have been substantially reduced if we had listened to concerns repeatedly raised by locals at different forums during the planning of hydroelectric projects on the Teesta.

Neeraj Vagholikar A member of the Pune-based NGO Kalpavriksh since December 1998, he has tracked hydropower and environmental governance in Northeast India for over two decades.


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