Another lake formed upstream, poses danger: Experts


(This story originally appeared in on Feb 12, 2021)

DEHRADUN: Geologists of the Hemwati Nandan Bahuguna Garwal University (HNBGU) who are conducting a survey of the Rishiganga area – from where the flash floods started on Sunday have said a water body has formed near the Rishiganga which can cause floods again.

This revelation came even as water levels of the Rishiganga, which was flowing as a small channel on a stretch near the disaster site for the past four days, rose on Thursday, leading to a temporary halt in rescue operations and an alert being issued to villagers in the area.

In a video that he released, with the hope that authorities see it and are aware of the potential threat, professor Naresh Rana from the earth sciences department of HNBGU can be seen pointing at what he termed “a blue-coloured lake” that had formed near the Rishiganga.

“I am here at a peak from where I can see the Raunthi and the Rishiganga streams clearly. It seems that the flash floods have come from the Raunthi stream. The flood created a temporary dam and because of this dam the Rishiganga is still blocked. I can also see a blue-coloured lake having formed in the distance, which means that water has been ponding here since long. This ponding is very stable and hence, I can assume that this lake extends far. From the point I am standing however, I cannot see its full extent,” he says in his video.

Rana added that the formation of the lake is a serious matter as “this means that the Rishiganga will breach again and this can impact rescue operations too. We will pass on this information to the administration so that necessary action can be taken. On our part, we will also try and go to the site where the lake has been formed to get a better idea of its size”.

Confirming the formation of a water body upstream of the Rishiganga, Kalachand Sain, director of Dehradun-based Wadia Institute of Himalayan Geology (WIHG), said that water accumulation was seen after an aerial view of the region was recorded by a WIHG team that is presently at the spot. “We cannot say as of now whether that water accumulation has triggered the current rise in the water level of the Rishiganga or Dhauliganga. I am yet to get the details of the size of the pond and reason of its formation. This can either be a new lake or an old one,” he said.

Explaining what has happened in the valley on February 7, director of the institution said, “A rock-mass at 5,600 meters above sea level broke from the main rock-mass. The hanging glacier overlying this chunk of rock also got broken and entire mass fell downstream. This has created a temporary dam and later converted into the disaster which was witnessed by the valley,” added the director.

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