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Draining a Glacial Lake in Nepal

 
 

Early on November 23, a group of eight Buddhist monks in maroon robes sat cross-legged on the banks of a glacial lake located at 5,010 meters above sea level. They offered Buddhist prayers as dignitaries from Kathmandu descended on a military helicopter. A group of Sherpa women in traditional dresses offered silken scarves to the delegates.

This was the culmination of months of painstaking work to lower the water level of one of the most dangerous glacial lakes in the Himalayas. In summer this year, Bharat Lal Shrestha, a lieutenant colonel at Nepal Army’s Engineering Department, led a group of 40 army soldiers and 100 high altitude workers, including Sherpas, to drain the waters of Imja Tsho, one of six most dangerous glacial lakes of Nepal, home to 1,466 such lakes.

Experts have warned that Imja Tsho, which lies just south of Everest, poses a danger to tens of thousands of people living downstream and threatens to damage the teahouses, settlements, and trekking trails that are key to attracting tourists. Until 1960, the lake, one of 21 lakes in the Nepali Himalayas at risk of bursting, was small in size, but since then, it has expanded rapidly: now it covers an area of 1.28 square kilometers and is 150 meters deep. Three major events of Glacial Lake Outburst Floods (GLOF) in the Everest region between the late 1970s and late 1990s, along with last year’s devastating earthquake, prompted Nepal’s government and United Nations Development Program (UNDP) to carry out the mammoth task of draining Imja Tsho.

The team drained almost 4 million cubic meters of water, lowering the lake’s water level by 3.4 meters. “This was very challenging because of high altitude. We had to be motivated to keep going in such harsh environment,” Shrestha told The Diplomat. His team faced a host of challenges, including transporting heavy equipment for the construction of an outlet and a 45 meter cement and concrete canal. “We worked in two shifts from seven in the morning to five in the evening. People needed a lot of rest and we constantly supplied hot water and coffee to the workers,” he said. The team members were served dry food, which was carried to the site using yak, a large, shaggy-haired animal domesticated in the Himalayas. “Whenever a worker suffered from altitude sickness, we arranged for a trip to lower altitude. We also had medical doctors, who regularly carried out check-ups,” Shrestha said.

This was not the first draining of a glacial lake in the Nepali Himalayas. In 2000, Nepal’s Department of Hydrology and Meteorology lowered Tsho Rolpa, a glacial lake in northeast Nepal’s Dolakha district, by three meters. The lowering of water in Imja Tsho averts the bursting of the lake and could help save the lives of the 87,782 people living downstream, according to the UNDP. If the Imja Tsho bursts, it would incur an estimated loss of $11 billion, according to a 2009 study by International Center for Integrated Mountain Development, a regional knowledge center based in Kathmandu. But for now, such risk has been significantly reduced.

Deepak Adhikari is a Kathmandu-based freelance journalist, who covers Nepal for international publications.

Nabin Baral is a Kathmandu-based freelance photojournalist specializing in social and environmental issues.

Draining a Glacial Lake in Nepal
The front part of Imja Glacial Lake in Everest Region, Solukhumbu District, Nepal. located at the altitude of 5,010 m above sea level, Imja Glacial Lake is one of the potentially dangerous lakes in Nepal's Himalayas. The risk of the lake bursting was reduced by lowering the water level of the glacial lake by 3.4 meters.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
The controlled exit channel built by the Nepal Army in Imja Glacial Lake. The project managers tried their best to use locally available materials to make the channel.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Namche Bazaar, the gateway to Everest, during the evening. Should Imja Glacial Lake burst, it would threaten settlements and tourist havens downstream.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
A porter and tourists trek by the side of Dhudkodhi River in Jorsalla, Chaurikharka. Due to climate change, glacial lakes that are formed upstream poses a threat to the many trekkers in the Everest Region.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Tinkuli Rai, a porter, rests by the side of Imja River in Solukhumbu District, Nepal. Thousands of porters earn their livelihood in the Everest Region thanks to large numbers of tourists. The porters are unaware of the threat posed by the glacial lake upstream.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Glecial meltwater flows in the Imja valley in Chukin, Solukhumbu District.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Ranjita Rai works as a laborer with her husband in Dengboche Village, on the way to Imja Glacier and Everest Base Camp. She was really worried last year by a small flash flood, triggered from another glacial lake that mixed with Imja River. Fortunately, the flood only destroyed one bridge near Dengboche.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
A vulnerable bridge over the Dhud Koshi River near in Pangboche, Solukhumbu District, Nepal. Due to climate change , growing glacial lakes upstream pose a threat to the valley.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Another view of the exit channel built by the Nepal Army in Imja Glacial Lake.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Local monks from the Everest region perform religious rituals during the completion ceremony of the much-awaited Imja Glacial Lake water lowering project (November 23, 2016).
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Sherpa women in their traditional attire welcome delegates to Imja Glacial Lake for the completion ceremony.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
An army helicopter flies near Imja Glacial Lake during the completion ceremony.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Mimmar Lama, local resource person for Glacial Lake Outburst Flood risk reduction, shows the early warning system installed in Phungithanka, his village. The early warning system will receive automated warning messages from Automated Hydromet Sensor installed in Imja Glacial Lake.
Image Credit: Nabin Baral
Draining a Glacial Lake in Nepal
Pasang Sherpa, from the Tamakhani VDC in Solukhumbu, has climbed Everest six times. He offers a religious "khada" to a mani-stone constructed in front of Imja Glacial Lake during the completion ceremony. He believes that there are other lakes that pose the same kinds of risks in the Nepali Himalayas.
Image Credit: Nabin Baral
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