CWC conducting simulation studies on New Glacial lake; Rescue teams start widening hole in Tapovan Tunnelutatr

08:02 PM Feb 13, 2021 | PTI |

The Central Water Commission (CWC) is conducting simulation studies on the artificial lake formed in the upper stretches of the Rishiganga river after the catastrophic Uttarakhand flood early this week, and also examining the possibility of carrying out a controlled blast to drain out the water. CWC chairman Saumitra Haldar on Saturday said studies are being conducted keeping in mind the forecast of the India Meteorological Department (IMD) that the area could receive a rainfall of 1 cm and snowfall of 10 cm on February 15 and 16.


The CWC is also examining possibilities of what can be done if the water to rises to “critical” level. “We are assessing what could be the impact if the water level rises following rains and snowfall as predicted by the IMD. We are also studying what volume of water would be released if the lake bursts and how much time it would take to reach downstream,” Haldar told PTI.

He said the lake is 400 metres in length, 25 metres wide and 60 metres deep. “We don’t want the size of the lake to increase any further. We are examining all possibilities that also include controlled blast at the lake,” Haldar said.

He, however, pointed out that the site is not accessible and it has not been decided which agency will execute the controlled blast. “So in case if the controlled blast is not possible, we are also exploring other ways to tackle the situation,” he added.

Haldar said several agencies/ institutes like the Wadia Institute of Himalayan Geology, Defence Research Development Organisation (DRDO), ISRO’s Indian Institute of Remote Sensing and Uttarakhand State Disaster Management Authority have conducted studies on the lake. The temporary water body was formed after sediments that the Sunday’s flash floods brought down, blocking the mouth of a stream that joins the Rishiganga river.


The CWC chairman said as of now there is no increase in the water level from Joshimath to Haridwar. “We are continuously monitoring the water levels downstream,” he said. In a tweet on Friday, the CWC said, “An artificial Lake has formed on river Rishiganga in Chamoli district, Uttarakhand, with a length of 350 m height of 60 m with slope of 10 deg.” The Himalayas has more than 2,000 glacial lakes of 10 hectares or more. The CWC monitors 477 glacial lakes of a size more than 50 hectares. These lakes also feed the Himalayan rivers.


Meanwhile, rescue teams began widening a hole drilled into an approach tunnel on the way to the possible location of over 30 people trapped inside a sludge-choked tunnel of the NTPC’s Tapovan-Vishnugad hydel project after a flash flood ravaged the area on Sunday. “We are working under a three-pronged strategy to reach to those trapped in the tunnel. The hole we drilled yesterday is being widened to one feet so as to reach a camera and a pipe inside the silt flushing tunnel where the trapped are said to be located, General Manager of the NTPC project, R P Ahirwal, told PTI.

A hole with a diameter of one feet will help send in a camera to ascertain their location and a pipe to flush out accumulated water from the tunnel, Ahirwal said. The other two parts of the strategy are clearing the desilting basin of the NTPC barrage through which muck is constantly flowing into the tunnels and restoring the flow of the Dhauliganga to the right which has tilted to the left after the flash flood hampering the sludge clearing operation, he said.

Describing the rescue of people as a priority, he said the NTPC has put more than 100 of its scientists on the job. When asked whether an attempt could also be made to send rescue personnel to the possible location of those trapped inside the tunnel through the hole, the GM said it will need to be widened further for that and will be done if the need arises.

“More than 100 of our scientists are on the job. They are devising strategies and having them implemented,” Ahirwal said. He said all resources and mechanical equipment required for the operations are available at the project site.

However, citing the conditions inside the tunnel, he said, “We can operate only with a few machines at a time. Rest of them have to be kept on standby because our strategy is to keep the operations underway round the clock.” If for some reason an equipment stops working, there are alternatives on the standby to ensure that the operations do not stop, he said. He said many experienced workers of the project went missing in the calamity and those put on the job are new people but still they are working with total dedication.

Talking about the biggest challenge being faced by the rescue team, the NTPC official said, “The rescue personnel are going to the tunnel where the men are likely to be trapped via HCC Adit where muck is constantly coming down from the NTPC barrage and its desilting basin to hamper the rescue efforts. The water of Dhauliganga too is coming into our tunnels through the desilting basin as it has tilted to the left after the avalanche.” “Hence, restoring the flow of the Dhauliganga to the right is a big part of our strategy,” Ahirwar said. The sludge choked contours and conduits of the barrage’s desilting basin can also be removed more effectively only if the flow is restored back to its earlier position. The work on restoring the flow of Dhauliganga has begun already with the help of heavy machines, he said. So far, 38 bodies have been recovered from the affected areas while 166 are still missing.

DIG Nilesh Anand Bharne said 11 of the dead have been identified. Eighteen body parts had also been recovered from the flood-hit areas, of which 10 have been cremated after taking their DNA samples so far, he said. The State Emergency Operation Centre here said scientists of the Indian Institute of Remote Sensing during an aerial survey of the Rishiganga found that the glacial lake formed due to the avalanche over it has begun to release water which reduces chances of its breaching or causing a fresh flash flood. The lake which has formed over the Rishiganga after the flashflood had increased the concern of experts on Friday.


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