Sunday, November 26, 2023

Photographic record of the impact of 04Oct2023 GLOF at Chungthang (North Sikkim) and its vicinity.

Chungthang (Lat 27 36 13.3 N Long 88 38 43.5 E, Elevation:1612.5m) is a small town (population around 4000) in North Sikkim located at the confluence of Lachen Chu ('Chu' means 'Water' in Tibetan) and Lachung Chu. It was also where the Sikkim Urja (Teesta III) dam, a 1200MW, 60 M high Concrete Faced Rockfill Dam (CFRD) was built - it was commissioned in Feb 2017. The dam was the largest run of the river project in the region and the power house was located downstream at Singhik village.
Sikkim Power Investment Corporation Limited (SPICL), a 100% wholly owned public limited company of Government of Sikkim, is the holding company of the project.
The growth of Chungthang between 2006 and 2020 is shown below:

In this regard, quoting from The Sikkim Tourism Development Corporation (STDC) website: 'With the recent hydropower development in the area, the landscape of Chungthang is changing rapidly and is becoming a major settlement in North Sikkim.'
The glacial lake outburst flood (GLOF) from South Lhonak glacier in the late hours of 03Oct2023, released a massive volume of water along Lachen Chu which deluged and engulfed almost the whole of Chungthang at around 12.30am on 04Oct2023. It took down the double lane concrete bridge at Chungthang after sweeping away at least 3 bridges towards Lachen and one bridge across the Lachung Chu.
Amidst the rain, roar and rumble of the river and pitch dark conditions no one is precisely sure when the Teesta III dam collapsed but it did so sometime during the night. It was only on the next day that everyone in Chungthang became aware of the horror and scale of devastation.
The GLOF and the dam collapse caused an unprecedented disaster all along Teesta river valley which SaveTheHills has been documenting since 04Oct2023.
We were in Chungthang for the entire day on 18Nov2023 and talked to many affected people while photographing the disaster - besides just being awed at the raw and vicious power of nature.

What remains of Sikkim Urja (Teesta III), 1200MW dam

Drone image from Chungthang town looking down stream.
The magnitude of nature's forces involved is evident from the giant boulder which has been hoisted to that height and parked in a slot.
Drone image of the dam looking upstream; Chungthang town is in the distant with Lachen Chu on the left and Lachung Chu on the right. The extent of damage is visible even from far.
Satellite image of the dam

This was where Sikkim Urja (Teesta III) dam had its entire office setup. The GM's office and other residential quarters were also here. The surging waters swept away all and left behind some trash and gigantic boulders.
Gigantic rock formations have emerged after the GLOF gouged out all the earth on top (which now form the sand and sludge deposits downstream). The massive boulder clogging up a dam structure can be seen in the background.
Parts and machinery from the Stage III dam now litter the river bed at Chungthang.

The 'GLOF Only' areas. 

By this we mean, areas upstream along Lachen Chu river where the dam burst did not have any impact and the destruction was caused solely by the GLOF from South Lhonak lake.
It was surprising (and scary) to see the amount of damage which had been caused by the GLOF alone. In the distant one can see the ITBP colony where the road to Lachen seen on the right ends.
The damage caused by only the GLOF from South Lhonak lake is huge as can be seen.This drone image reveals the scouring of the river bed caused by the violent waters just a few kilometers towards Lachen from Chungthang.
The impact on Lachen Chu river bed by the GLOF approx 2 km north of Chungthang is seen here. The road to Lachen is only upto the ITBP colony seen in the distant.
Close up of the damage caused by the GLOF alone. A bridge to Lachen has been torn down here (27 36 47.4 N 88 37 47.2 E), further north 2 more bridges have been destroyed by the GLOF, numerous power pylons and towers have been damaged. Army personnel in areas around Lachen reported strong vibrations during the event.
This is where the road to Lachen ends (27 36 42.7 N  88 37 51.4 E) Elev 1705m (Drone image).

Impact on Government assets

Sikkim Government assets located towards the southern tip of Chungthang town were severely damaged by the GLOF
The Legal cell building at Chungthang on 18Nov2023
The SIB office at Chungthang.
The shredded Police Station (Thana) at Chungthang is on the right. A huge truck has been neatly shoved into an office in the thana by the GLOF as if someone had parked it inside. The Chunthang Fire department building, Sikkim Tourism Department guest house has also been extensively damaged in this area.
ITBP shacks along the Lachung Chu which were buried by the backflow from the GLOF. This river was otherwise not affected by the event. Notice this river has turned green as it is winters now - surprisingly, the Lachen Chu is still loaded with silt and brownish. A bridge further up was destroyed by the backflow.
The Chungthang playground and stadium which were deluged by the GLOF.
The army lost a lot of assets  in this area - fortunately no life was lost.
A rifle rack from the Sikkim Police Station (Thana) with the weapons swept away by the swirling waters, at the dam site.
This, along with the loss of army assets adds another dimension to the safety of our riverine areas and even dams.

Chungthang town

The GLOF of 04Oct2023, left the tiny town of Chungthang on its death throes. The midnight floods affected almost every part of the town and the only sounds audible, when we visited Chungthang on 18Nov2023, were the grinding and clanking of heavy machinery as the residents tried to excavate their homes and get their lives back together.
More than 54 RCC buildings and homes were damaged by the floods, many smaller wooden homes and shacks were simply swept away. Also what was lost were countless Buddhist artifacts, monuments and antiques which every affected home had and which the floods snatched away.
A school was destroyed in the centre of town.
Drone image of Chungthang town on 18Nov2023, showing the extent of damage by the GLOF.
Satellite image of the above area.
On the left, Lachen Chu or the Teesta river flows downstream and a Bailey bridge has been  constructed by the army engineers on 16Nov2023 at 'A' above which allows some sort normalcy of movement and supplies coming into the town.
Drone image showing the devastation wrought by the GLOF in areas adjacent to the river bank.
Drone image from the road to Lachen showing erosion of the river bank adjacent to Chungthang town. In the foreground are areas where there were several army installations.
Satellite image of the playground area of Chungthang town.
The town on 18Nov2023. Massive rocks are strewn all over and 10-15 feet of sludge plasters much of the town area.
An army truck has been parked inside a room by the GLOF. Notice the level to which the flood waters reached.
Chungthang on 18Nov2023.
The gilded dome of Gurudwara Nanak Lama Sahib is seen in the background.
The Gurudwara and its staff provided and continues to provide extraordinary service to the denizens of Chungthang. The ground floor of the Gurudwara was inundated by the GLOF and the staff evacuated temporarily to return quickly and provide food and shelter to thousands of people. While we were in Chungthang, 70 odd homeless people were staying in the complex and everyday 3 - 4000 meals were being provided to anyone who wanted food.
Photo of 05Oct2023 showing removal of sludge and debris in front of the Gurudwara at Chunthang (Photo credit: Lhendup Lepcha)
Officials of the Sikkim Government conducting a survey on losses to homes and property at Chungthang. They said government engineers were also testing the structural stability of damaged buildings. With much of the town in ruins, this process will take some time to complete.

The Rivers and the Environment

Photo of 05Oct2023 shows a gap where there was a double lane concrete bridge over the Teesta at Chungthang. It was taken down by the GLOF. (Photo credit: Lhendup Lepcha).
A tiny bamboo bridge over the Teesta for ferrying men and material before the current Bailey bridge (below) was completed by army engineers.
Photo of 18Nov2023 shows a bridge across the same spot, which army engineers put across the Teesta on 16Nov2023..
The armed forces have always taken a lead role in helping out in all disasters and so it was in Chungthang in Oct2023 where they were instrumental in providing warning, evacuating tourists and saving lives and the civilians in Chungthang I talked to gratefully acknowledged this.
Photo of 07Oct2023 showing army/BRO/ITBP/ and other people trying to put a ropeway across the Teesta at Chungthang.The river was again in spate and there was light rain as such the effort was abandoned.(Photo credit: Lhendup Lepcha)
Heavy road construction machines and men of the BRO working on the road towards Lachen.
(Photo credit: Lhendup Lepcha)

The completion of repair of the Chungthang - Lachen road may take anywhere from 3 - 6 months and right now Lachen is connected to Zema and Thangu only by a temporary bridge. The people of these areas will require extensive help to face the harsh winters ahead.

All in all, I am amazed at the scale and ferocity of nature's revenge.

My humble thanks to all who helped.

Praful Rao
Kalimpong district
Darjeeling-Sikkim Himalaya


Praveen Chhetri
Junkeri Studios,

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