Despite warnings from scientists over the past three decades, the upper Himalayan region continues to face the threat of Glacial Lake Outburst Floods (GLOFs).
Credit: DH Illustration
India has witnessed three major glacier-related disasters, each bearing an uncanny resemblance to its predecessor. The question arises: what has been our learning curve from these disasters, which have resulted in the loss of thousands of lives and extensive damage to property running into lakhs of crores?
Consider the Kedarnath tragedy in June 2013. Like in all parts of the upper Himalayas, glaciers are melting, and the melt water at the snout of the Chorabari glacier formed a lake, the Chorabari Lake, located at a height of 3,960 feet, almost two kilometres upstream of Kedarnath. Unprecedented rainfall from June 13 in the upper Himalayas led to the lake breaching on June 17. A massive flood of water, complete with debris and boulders, powered down the slopes of Kedarnath and into the Mandakini River. Not only did the flash floods wipe out the town of Kedarnath, but several other towns located downstream, including Rambara, Gaurikund, Sonprayag, and Agastyamuni, were also destroyed. Thousands perished, and the exact death toll remains uncertain, with a government estimate reporting over 5,000 missing.
Climate change has altered Himalayan weather patterns. Typically, January and February see heavy snowfall in the upper Himalayas. In February 2021, an unusual warm spell triggered a combination of snow and rainfall in these higher altitudes. Scientists are divided on whether a part of a glacier broke off or whether a massive avalanche brought down boulders and debris that caused a flood in the Rishiganga, a tributary of the Alaknanda River. The turbulent waters destroyed the 11-megawatt Rishi Ganga dam and impacted the Tapovan Vishnugad power project. When water entered the intake tunnel, 35 labourers were washed away immediately, and the precise number of missing workers is not available; co-workers claim the number of those dead to be around 200. The situation was exacerbated by the absence of an early warning system.
The Supreme Court had ordered all hydropower projects in India to compulsorily install early warning systems in every hydroelectric project, but these orders are often flouted or simply ignored.
A similar incident occurred in Sikkim, which also witnessed a glacial lake outburst flow, this time from the Lhonak lake, which was formed due to the melting of a glacier. While the glacier has been shrinking, the size of the lake has been steadily increasing, and by 2019, the lake covered 1.35 square kilometres.
This year, the northern part of Sikkim is witnessing heavy rainfall. Because of its remoteness, the India Meteorological Department has not been able to gather rainfall data for this area. Nevertheless, the fact is that heavy rainfall saw the waters of the lake breach its sides late on October 3, bringing with it vast amounts of debris and boulders into the Teesta River.
Once again, in a case of criminal negligence, there was no early warning system to warn residents living downstream of the impending disaster. The force of the Teesta river can be gauged from the fact that it took a mere ten minutes for the flood waters to destroy India’s second largest run-of-the-river project, the 1,200-MW Teesta Urja located between the towns of Chungthang and Mangan in north Sikkim. Built at a cost of Rs 14,000 crore, today, to build a dam of this size would cost over Rs 24,000 crore.
The executive chairman of Sikkim Urja Ltd, earlier called Teesta Ura Ltd, told the press that when they received a warning from the Indo-Tibetan Border Police, they rushed a team to open the gates of the dam, but the force of the water was so enormous that the team failed in their mission, having managed to save their own lives. Manual operations were required, exposing flaws in the electrified and automatic functioning of the dam gates. This reflects poorly on the functioning of the Central Water Commission, which oversees the functioning of all dams in the country.
The result is one more tragedy where there are still no definite numbers of people dead, but already the Sikkim chief minister has declared this to be a state disaster, with several towns, including Dikchu and Rango, reeling under the flood waters. Several people have lost their lives, including a large number of army personnel.
And as happened in the Chamoli incident, many workers are trapped in a network of tunnels in the Chungthang region. A team of 60 rescuers from the Nationla Disaster Rapid Force has been sent to try and rescue them; whether they survive for long in these extreme altitudes is anyone’s guess.
Despite warnings from scientists over the past three decades, the upper Himalayan region continues to face the threat of Glacial Lake Outburst Floods (GLOFs). Scientists from the Indian Institute of Science, Bengaluru, who had visited north Sikkim to study the phenomenon of GLOF, had warned that Sikkim had as many as 25 glacial lakes that were a potential risk for the state.
Experts, including scientist Dr Ravi Chopra, have repeatedly emphasised that the upper Himalayan regions are unsuitable for hydroelectric projects. In a report on this subject prepared for the Ministry of Environment and Forests over a decade ago, Chopra emphasised that regions at an elevation above 2,000 metres are unsuitable for such projects due to their vulnerability to avalanches and unstable moraines left behind by retreating glaciers. The construction of power projects further destabilises these ecologically vulnerable areas as they generate tonnes of debris that are dumped in the rivers.
Extreme weather events are on the rise, and this has resulted in an increase in landslides. While the immediate focus of the Ministry of Power will be to assess the damage caused to the hydroelectric projects in Sikkim and operationalise them at the earliest, it needs, in the long run, to come up with a strategy whereby new projects should be kickstarted in only those areas that can safely withstand the increasing vagaries of extreme climate-induced calamities.
(The writer is a Delhi-based senior journalist)