Sikkim's Teesta III river dam disaster: When neglect flows downstream

Larger questions have also emerged on the ecological sensitivity of the glacial regions around Sikkim, their susceptibility to extreme weather events, rapid infra creation and lack of climate adaptati

In merely 10 seconds, the 60-metre-high dam of the Rs 13,000 crore Teesta III hydropower project was completely washed away by floods originating from the South Lhonak Lake. The project, which took two decades to complete, changing hands from private companies to state government and now a public-private joint venture (JV), stares at an uncertain future with questions raised about its viability.

Larger questions have also emerged regarding the ecological sensitivity of the glacial regions around Sikkim, their susceptibility to extreme weather events, rapid infrastructure creation, and the lack of climate adaptation efforts.

The Teesta River has also washed away parts of the national highway (NH10), disrupting connectivity between Gangtok and other parts of Sikkim from the rest of the country. NH10 had already undergone damage due to landslides and flash floods last month. According to reports, at least 14 bridges have collapsed.

Years in the making?

A glacial lake outburst flood (GLOF) has been identified as the key reason for the flood. The South Lhonak Lake is located in the northwestern region of Sikkim at an altitude of 17,000 feet above sea level. The lake, formed from the melting of the Lhonak glacier, is considered one of the dangerous lakes susceptible to GLOF by geological researchers.

GLOF occurs when a glacier-fed lake experiences a sudden release of water, often due to a naturally built moraine wall’s inability to contain the water. Flooding can occur due to various reasons, including earthquakes and landslides.

GLOF events are increasing due to rapid glacier melting caused by global warming.

India has previously experienced GLOF events in the Himalayan region, from the Kedarnath tragedy in 2013 to the Chamoli disaster in 2021. However, this is the first time a GLOF event of this scale has impacted the Northeastern region of the country. Neglecting scientific warnings exacerbates this situation.

Over the years, scientists have warned about the increasing size of glacial lakes in Sikkim. In 2012, a Sikkim government-commissioned study by Centre for Development of Advanced Computing noted a doubling in the area of the Lhonak and South Lhonak glacial lakes between 1965 and 1989. These lakes were listed as potential GLOF sources.

In 2021, a study published in the Geomorphology journal stated that the enormous volume of water in this “highly dynamic high-mountain environment” makes South Lhonak Lake a priority for GLOF risk management.

“Hazard intensity mapping based on GLOF scenarios shows that many settlements along the valley, including the largest town Chungthang, are at high risk. Due to the construction of the hydropower dam at Chungthang in 2015, GLOF risk mitigation in relation to South Lhonak and other critical lakes in the basin is of utmost importance,” observed the eight-author study.

Experts suggest a serious reassessment of legislation and climate readiness for infrastructure projects.

Abinash Mohanty, sector head of climate change and sustainability at IPE Global and an expert reviewer of the Intergovernmental Panel on Climate Change’s sixth assessment report, emphasised, “If a 20-year dam can’t withstand a single incessant and erratic rainfall event, along with increasing GLOF incidents, then the current legislation and climate readiness of infrastructure projects need a serious revisit.”

A jinxed project faces its worst fate

The Teesta III hydropower project was conceptualised in 2004, but it did not start supplying power until 2017. Originally estimated to cost Rs 5,000 crore, delays and multiple stake sales escalated its cost to Rs 13,000 crore.

The project was initially allocated to Hyderabad-based Athena Advisors, which partnered a state public sector undertaking, Andhra Pradesh Power Generation Corporation. Subsequently, it formed a JV with the then Sikkim state government, winning the project through a memorandum of understanding route without any tendering.

The project faced heavy criticism for flouting environmental norms and awarding it to a company with no hydel experience. Construction progressed slowly and came to a standstill in 2011 after an earthquake hit the region. After a decade-long dispute, the Sikkim government finally bought a 26 per cent equity stake in the project in 2012 for Rs 290 crore.

In 2020, another Hyderabad-based green energy company, Greenko Group, acquired a 35 per cent stake in the project.

Mahesh Kolli, founder of Greenko, said, “At present, the focus is on rescue work only. We are yet to assess the reasons for the disaster. All our employees are safe.”

He indicated that there was a higher inflow of water into the dam.

Since 2002-03, the local Lepcha community has been protesting against the dams on Teesta under the banner of the Affected Citizens of Teesta (ACT).

Tseten Lepcha, a leader of ACT and Sikkim Lepcha Association, said, “We were protesting for more than two decades, and today we are witnessing the disaster. In downstream areas, rescue efforts were timely, which helped save many lives. We are unsure about the extent of damages in the upstream areas.”

There are currently five operational dams and at least a dozen under consideration on the Teesta River. The impact of the Teesta III dam has also affected the under-construction Teesta IV and Teesta VI, which are now filled with its debris.

As Sikkim cleans the wreckage and counts its dead, whether this one event will seal the fate of rampant dam construction on this vital river in the Northeast remains to be seen.

With inputs from Dhruvaksh Saha