Scientists say climate change is causing Himalayan glaciers to melt at an alarming rate, creating huge glacial lakes which could burst their banks and devastate mountain communities.
Imja Tsho, located at an altitude of 5,010 metres, just 10 kilometres south of the world's highest peak, is the fastest-growing glacial lake in Nepal.
The surface area covered by the lake expanded from 0.4 to 1.01 square kms between 1984 and 2009, triggering concerns that it may breach its banks and flood villages downstream.
"A mechanical gate will be installed and will be manually operated to control the water flow through the channel," Karki told AFP.
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The work began in April and the army expects to complete the project by the end of the year, he said.
A flood would have a catastrophic impact on the lives of more than 56,000 people living in villages located as far away as Nepal's densely populated Terai plains, one scientist said.
"The lake had been gaining in volume over the last 30 to 40 years due to climate change."
Nepal is home to some 3,000 glacial lakes, of which seven are regarded as high-risk, Sharma said.
The move to partially drain the lake comes one year after a major international study warned that glaciers in the Everest region could shrink by 70 per cent or disappear entirely by the end of the century, owing to climate change.