Monideepa Banerjie | Sikkim Tsunami in a River: A Man-Made Tragedy Long in the Making

Till the December of 2004, I had no idea how devasting a tsunami could be. But when I travelled to Car Nicobar, one of the islands in the Bay of Bengal battered by the tsunami, I saw devastation unlike anything I had seen before in real life, photos or movies, caused by a towering wall of water that came crashing down on human habitation and wiped it off the face of the earth.

A “tsunami in a river”. That’s how a former journalist Anand Sankar, who has reported for years on the impact of “development” across the Himalayas, described to me the tragedy that hit Sikkim late on the night of October 3. A tsunami of muddy, debris and rock-filled water, he explained.

And it resonated.

I could imagine a mountain of water thundering down the steep slopes and narrow valleys of the Lachen river, gathering momentum, joining the Lachung river to birth the Teesta and then crashing into the Chungthang dam, smashing it and battering everything in its way downstream.

What happened? A natural calamity or a man-made disaster? As Sikkim picks up the pieces, politics has already kicked in. Sikkim chief minister P.S. Golay has squarely blamed his predecessor. “Careless work while constructing the Teesta III dam (at Chungthang) resulted in the Sikkim catastrophe,” Mr Golay has been quoted as saying.

“We would have survived the catastrophe if the previous government had made had made a stable, standard dam. But the then government made a substandard dam despite inflating the project cost from Rs 5,000 crores to Rs 13,000 crores. It was a careless piece of work,” he said.

But all this is really old hat. What Mr Golay should have talked about is GLOF and Black Carbon and the unthinking pace at which hydroelectric power projects have come up in several states across the Himalayas.

Sikkim has certainly stamped the term GLOF into our vocabulary: “Glacial Lake Outburst Flooding”.

When glaciers melt, its waters collect in deep ravines beneath it and turn into lakes. As the melting continues, the lakes expand. This has been happening in the Himalayas for several decades. There are at least 56 such lakes in the mountains that scientists have identified as GLOF-prone. At least 14 of those are reportedly in Sikkim.

In the last decade, remoting sensing satellites have put out alerts that the South Lhonak Lake in Sikkim, which is at 17,000 feet above sea level, was expanding significantly. Since 2013, interventions were made to siphon out water from the lake. In 2016, Sonam Wangchuk, Ladakh’s celebrated environmentalist, went and laid pipes at Lhonak to siphon out water. Wangchuk was the inspiration for the character played by Aamir Khan in the movie 3 Idiots.

This September, a team from the NDRF, the Sikkim State Disaster Management Authority and the Swiss Development Corporation trekked up to set up a monitoring system at two lakes, Lhonak and Shako Cho. The team returned on September 20 to Gangtok. On September 21, the monitor at Lhonak stopped working though the one at Shako Cho continued to work. The Swiss team was informed and was expected to return soon to fix the monitors and also install an early warning system.

But time ran out.

On the night of October 3, an ITBP camp at Janak close to Lhonak called up the administration at Chungthang to report a drastic rise in the water in the Lachen river and a statewide alert was sounded.

What happened at Chungthang dam is not clear yet. Did officials there have time to open a spillway?

If there is a sudden rush of flood water into the reservoir, the spillway can be opened to drain it out in a controlled manner. But the spillway’s capacity was simply not adequate to drain out the water from Lhonak and the reservoir combined.

To keep the numbers simple, Lake Lhonak spilled out 100 hectares of water. The reservoir had 10 hectares of water. That gigantic volume with the momentum of the lake outflow rushing down steep slopes down some 50 km from a height of 17,000 feet to Chungthang at about 6,000 feet -- the dam didn’t have a chance.

Part of the Teesta III Hydropower Project that was commissioned in 2017 to produce 1200 MW of power, the Chungthang dam, like most, was built to last a hundred years. But it is gone in six. The project was dogged by controversy with environment activists protesting dam construction in a fragile ecosystem in a seismic zone. But they failed to stop it. Today they believe had there been no dams on the Teesta, the impact of the GLOF event would have been much less damaging.

The Chungthang factor in the Sikkim disaster is unquestionably man-made. What about the melting water of the glaciers? That too, caused by global warning and climate change. Anand Sankar, the former journalist who gave the Sikkim tragedy the name by which I shall remember it – “river tsunami” -- reports that in his travels in the Himalayas, he has found black patches of soot on glaciers and ice formations. It is Black Carbon, something that is being studied by scientists now because it apparently hastens the melting of ice.

Black Carbon is something we create and put to the atmosphere from cars, factories and burning crops in farms. It’s a threat to our glaciers that we are yet to start talking about. The river tsunami in Sikkim should certainly change that.