The Glacial Lake Inventory report launched at a webinar on Monday says that of the expanding glacial lakes in the Himalaya, 47 on the watersheds of Nepal’s three main rivers are at high risk of bursting, and causing catastrophic floods downstream. Of these, 42 lakes are on the Kosi River basin in eastern Nepal, three are on the Gandaki and two on the Karnali watersheds.
However, not all the lakes are located in Nepal. Of the 47 dangerous lakes, 25 are in Tibet and empty into rivers that flow down directly into Nepal. One of the high risk lakes is in Indian territory near Karnali.
This week’s report by the Kathmandu-based International Centre for Integrated Mountain Development (ICIMOD) and UNDP mapped 3,624 glacial lakes in the three river basins in Nepal, China and India, of which 2,070 are within Nepal’s boundaries. The other 1,509 are on the Tibetan Plateau in China and 45 are in India, but drain into Nepal.
The researchers evaluated the risk factors for the glacial lakes depending on the integrity of their moraine dams, topography of the surroundings and the risk of avalanche into the lakes, as well as downstream settlements and infrastructure and divided them into three categories.
Of the 47 dangerous lakes on the Kosi, Gandaki and Karnali basins, 31 were found to be at very high risk of bursting and causing damage. Twelve other lakes are at moderate risk and there are four lakes in the lower risk category.