Too close for comfort – a rockslope failure at Shongtong in northern India

In northern India major works are underway to construct a new hydroelectric facility at Shongtong Karcham in Kinnaur.  This will be a 450 kW run of the river scheme generating an estimated 450 MW, reportedly enough to power 800,000 households.  This is another scheme being constructed in an area with high landslide potential.  There is an interesting article on Himdhara about the environmental impact of these major construction projects in the Kinnaur area, which includes a section on the impact of this scheme:-

“The 450 MW Shongtong-Karchham project which is now under construction had been impacting 5 villages. Its tunnel was being constructed in a landslide-prone area—no wonder then that fresh landslides are being reported from the area with alarming frequency. The people of one of the affected villages, Barang, had brought to a halt the construction activities for the project in 2013 to negotiate their demands. Last year the work on the project’s tunnel began in full swing and led to caving in of private lands belonging to four families.

“Similar was the case of the neighbouring Mebar village. In April 2015, a section of the national highway, where the tunnel construction was going on, was blocked as a mass of rocks just collapsed. This area called Laal dhank (rocky cliff/over hang) has the village Barang situated right above it. It took close to 48 hours to fully clear the road as vehicles and travelers lined up at both ends of the road.

“Perhaps the one striking case which managed to get some coverage over the last year is of the Urni landslide. “Urni is sitting precariously above the junction of the flushing tunnel, Head Race Tunnel and Adit tunneli of the newly operational 1200 MW Karchham Wangtoo project. In July 2014 the Urnidhank collapsed blocking the national highway,” said Ramanand Negi of the village.”

This image shows the magnitude of the problem:-

The magnitude of the landslides in Kinnaur, such as the event at Shongtong this week. Image from Himdhara.

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In the last few days a video was posted on Youtube, collected by a group of workers at a part of the project, showing a rockslope failure at Shongtong:-

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The video captures the initial failure with unusual clarity:-

The initial failure at Shongtong. Still from a video on Youtube

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And the development of the rockfall:-

The development of the rockfall at Shongtong. Still from a video on Youtube.

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I have noted before that these Himalayan HEP developments are generating an unacceptable level of landslide risk.  This is another example.