A team of 35 people, including experts from six prominent national institutes, on Wednesday embarked on an expedition to study six glacial lakes in the Mangan district of Sikkim.
Among them are experts from the Central Water Commission, Central Water & Power Research Station, Pune, National Institute of Hydrology, Roorkee, Geological Survey of India, the Defence Geoinformatics Research Establishment that functions under DRDO, and the National Institute of Disaster Management.
The team also includes representatives of Sikkim University, six Sikkim government departments, the Indian Army and the Indo-Tibetan Border Police and local people.
“They will trek to different locations in Mangan district to carry out different tasks to assess the conditions of six glacial lakes, which are known to be of high risk. It is another expedition after the Glacial Lake Outburst Flood (GLOF) that had occurred in the state in October 2023,” said a source.
The GLOF had occurred on the South Lhonak Lake in Mangan district. The flood had caused extensive damage in the mountain state, damaging roads, washing away bridges and defence installations, which resulted in human casualties and property loss.
After the natural disaster, several expeditions were conducted in the state to study the lakes fed by the Himalayan glaciers. In one such expedition, teams had studied 320 lakes located across Sikkim and had found 16 of them to be vulnerable.
The team, which started the expedition on Wednesday, would study the North Lhonak Lake, South Lhonak Lake, Shako Chho Lake, Lachen Khangse Lake, Yulhe Khangse Lake, and Changsang Lake, all located in Mangan. Sources said the expedition would continue till September 10
During the expedition, the experts will use various technologies to conduct ERT surveys, bathymetry, and UAV 3D terrain mapping, among others.
Experts said those geophysical investigations would help understand various features of the glacial lakes, including the internal structure and stability of the moraine dams holding the lakes.
The ERT data, they said, help detect buried ice, water-saturated zones and potential seepage channels, which are important indicators of a potential GLOF. The bathymetric survey, on the other hand, helps measure the depth of a waterbody and map its underwater features.
“Drones would be used to conduct a three-dimensional mapping of these lakes. The team will assess the hazards of each lake, design retention structures, and plan early warning systems. These studies will help in developing the plan to mitigate the loss in the downstream,” said an expert.
Along with others, a five-member team from the Himachal Pradesh Disaster Management Authority has also joined the expedition.
“They have joined for an exposure-cum-field training so that in due course, they too, can conduct such studies in their state,” said a source.