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With no special allocation from the Union Budget for Sikkim’s flood recovery, the state government is deploying a team of 32 experts to assess five threatened glacial lakes in Mangan District from August 28 to September 14. The expedition, estimated to cost Rs 32 lakh, aims to mitigate potential hazards from the lakes: Gurudongmar A, B, and C, Sakho Chu, and Khangchu, all located near the Tibet border.
Leading the expedition is State Science and Technology Secretary Sandeep Tambe, accompanied by experts from six departments: the State Disaster Management Authority (SDMA) under the Land Revenue Department, Mines and Geology, Water Resources, Forest, Science and Technology, and Sikkim University. The team will receive support from the Indian Army and the Indo-Tibetan Border Police (ITBP), bringing the total manpower to 56, including drivers and porters.
A similar expedition in the past, carried out by the National Disaster Management Authority with Swiss experts, cost Rs 48 lakh and took place before the 2023 Glacial Lake Outburst Flood (GLOF) at South Lhonak Lake.
At a press conference on Friday (August 23), Tambe emphasized the importance of this multidisciplinary study, focusing on glacial hazard mitigation, the threat of floods, and the stability of the moraine dams formed by glaciers. He explained, “The mitigation plan will explore various options to reduce water levels in these lakes, including siphoning, pumping, tunneling, channeling, and reshaping the lakebed. Additionally, we’ll test the strength of the moraine dams and install pressure probes to monitor water levels. These studies are crucial, especially after the October 4 GLOF, and other states will learn from Sikkim’s approach.”
The SDMA has established a special task force for glacial lake mitigation, sharing data with the United Nations Development Programme (UNDP), neighbouring countries Nepal and Bhutan, and Swiss experts. An automatic weather station has been set up at Sakho Chu, sending real-time data on the lake’s status. After the expedition, a team of experts is expected to visit Sikkim in October for further consultations.
The Mines and Geology Department will conduct a geophysical investigation, including electrical resistivity tests and ground-penetrating radar surveys. They will also study geological mapping, vulnerability mapping of the catchment areas, and sub-surface research. Meanwhile, the SDMA will focus on hazard mapping, using satellite imagery to identify critical areas at risk of GLOF.
State Relief Commissioner Namrata Thapa noted that the expedition represents a ‘discovery’ in glacial lake research, adding, “The areas impacted by the GLOF remain unstable. This study will examine potential threats from landslides, earthquakes, or avalanches and assess how such events could affect the moraine dams.”
Officials confirmed that South Lhonak Lake is currently stable, with one-third of its water discharged and the outlet widened significantly since the GLOF.
There are three other lakes in West Sikkim’s Geyzing District and 13 in Mangan District under threat. Sakho Chu, with a water volume of 25-27 million cubic metres, has no natural outlet and sits behind high moraine structures. It is located near the village of Thangu, the last inhabited area before reaching the isolated cold desert region. The Zemu Glacier, the largest in the region, remains under threat from climate change.
This article was first published on the website of EastMojo. Read the original article here