If you are a climate change expert who knows all about the impact of hydroelectric projects in the mountains and elsewhere, then you already know what this is about. But those who know that dams in the Himalayas are a bad idea and that glaciers are melting but are gobsmacked by terms like ‘GLOF’ and other specifics, please read on. While the experts must weigh in, it is time also for common people to stand up and be counted in the fight to prevent what happened in Sikkim on the night of October 3-4, a disaster that is already in the eye of a storm – was it a natural calamity or man-made?
Think of it as a tsunami in a river flowing down a narrow valley.
That is how former journalist Anand Shankar described the events in Sikkim to me. A tsunami hurtled down from a glacial lake in the Himalayas with unimaginable force, shearing away part of an entire hydroelectric dam. The dam’s breached reservoir increased the volume of water rushing downstream while carrying the deadly debris of enormous boulders and chunks of concrete, and battered the Teesta riverbanks, washing away houses, cars, and human beings. Shankar, who spent years writing on hydropower projects, said that this phenomenon is called Glacial Lake Outburst Flood (GLOF).
DC Goswami, a former professor at Guwahati University popularly known as ‘Brahmaputra River Man’, explained a GLOF event. A glacier melts due to global warming and recedes. If there is a ravine or a deep crevasse below it, then the melting glacial waters form a lake, hemmed by the glacier on one side and its debris of rocks (called moraine) on the other. As the glacier melts, the lake expands, and the water level rises, threatening to burst the banks at any time.
That dreaded “anytime” happened at the South Lhonak lake on the night of 3-4 October. IMD Gangtok’s director Dr Gopi Nath Raha on Thursday ruled it out, but most authorities are citing a cloudburst in the mountains, which may have triggered the GLOF event. Basically, either due to very heavy rain or an earthquake somewhere in the vicinity or some fault in the ground, the lake burst its banks, and the waters gushed into the Lachen river. Its swollen waters joined the Lachung river at Chungthang to form the Teesta, which then swept into the reservoir of the Chungthang hydroelectric power project dam with such force that it broke the dam. The reservoir’s waters added further volume to the GLOF-hit Teesta that turned killer.
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A disaster everyone knew about
The tragedy is that it was a disaster waiting to happen, and the experts knew about it.
In 2013, the National Remote Sensing Centre in Hyderabad alerted authorities that some of the glacial lakes in the upper reaches of Sikkim were increasing in size, including the South Lhonak lake. The state government dispatched a team, which reported that the inflow of water into the lake was indeed much more than the outflow. So, some outlets were created to increase the discharge.
In 2016, another team went up and again reported low discharge from the lake. That’s when engineer and innovator Sonam Wangchuk was roped in. Wangchuk, a celebrated environmental activist in Leh-Ladakh who is believed to have inspired Aamir Khan’s character in 3 idiots, was brought to Sikkim to see if he could solve the problem of South Lhonak lake. Wangchuk decided to use several150-metre-long pipes that would suck water out of the lake and keep the level under control. Called the siphoning system, Wangchuk was extremely positive about it.
But seven years later, satellite pictures showed that two lakes in Sikkim’s upper reaches, South Lhonak and Shako Cho, had expanded significantly. So, in September this year, a team comprising officials of the National Disaster Management Authority (NDMA), the Sikkim State Disaster Management Authority, and the Swiss Development Corporation went there and set up a monitoring system.
According to authorities, while the monitoring system for Shako Cho lake is working fine, the system for South Lhonak lake failed on 21 September, barely a few days after they were set up around 15-18 September. Experts from Switzerland were expected to arrive any day to fix the problem and set up the Early Warning System. But that never happened.
It was only when a camp of the Indo-Tibetan Border Police (ITBP), located close to the South Lhonak lake at Janak, called officials at Chungthang around 11 pm on 3 October that the alarm was sounded. ITBP reported that the water in the Lachen river had risen drastically. SSDMA raised an alarm immediately, a senior official said, and sirens and hooters started blowing. Many people thought it was a drill. It wasn’t. It was a disaster foretold now unfolding.
It’s obvious, isn’t it?
The debate that has erupted now is over the dam at Chungthang, which is part of the 1200 MW Teesta III hydroelectric power project. Commissioned in 2017, the project faced vehement objections from environmental activists who argued that the hydroelectric power systems on the Teesta would completely disturb the fragile ecosystem of the Teesta river basin, which traversed a seismically active zone.
Today, those activists say that if there had been no dam at Chungthang or at the power plants downstream, then the water from the GLOF at South Lhonak lake may have swollen the waters of the Teesta river to some extent, but the addition of over 5 million cusecs of water from the reservoir that burst is what the river could not handle. A local activist in Sikkim said 5 million cusecs of water could fill up 20,000 Olympic size swimming pools. Dams are built to last a hundred years. The Chungthang dam, built at a reported cost of Rs 14,000 crore, has come down in six.
So, was it a man-made disaster or a natural calamity? Even for the most amateur watchers of climate change and the environment debate, the answer is obvious. Everything is man-made. Not just the dams across the Teesta. Even the melting of the glaciers. Everything.
The author is a senior journalist based in Kolkata. She tweets @Monideepa62. Views are personal.
(Edited by Prashant)