Major Glacial Lake Surveys Underway in Arunachal Pradesh and Sikkim to Prevent GLOF

In a significant national initiative to mitigate the risks of Glacial Lake Outburst Floods (GLOF), the National Disaster Management Authority (NDMA) has launched an extensive survey of glacial lakes in the Eastern Himalayas. The survey focuses on Arunachal Pradesh and Sikkim, two crucial regions along the border with China, to map glacial lakes and assess the feasibility of early warning systems and other mitigation measures.

Survey in Arunachal Pradesh

Expert teams are currently conducting a comprehensive survey and study of six high-risk glacial lakes located in the Tawang and Dibang Valley districts of Arunachal Pradesh. This state, which shares a 1,080 km-long border with China, has recently experienced significant infrastructure damage due to glacial lake outbursts. Notably, more than five bridges have been washed away by an outburst from Sangnga Nehgu Lake in Tawang district. This ongoing survey is the first of its kind in Arunachal Pradesh, aiming to address these critical issues.

Sikkim’s Expedition to At-Risk Glacial Lakes

Sikkim has mobilized a team of 32 experts to assess five glacial lakes in the Mangan district, which borders Tibet. The lakes under scrutiny include Gurudongmar A, B, and C, Sakho Chu, and Khangchu. The expedition, led by State Science and Technology Secretary Sandeep Tambe, involves personnel from six different departments of the State Disaster Management Authority (SDMA) including Land Revenue, Mines and Geology, Water Resources, Forest, Science and Technology, as well as research scholars from Sikkim University. The total estimated cost for this survey is ₹32 lakh.

The survey team, which will be supported by the Indian Army and the Indo-Tibetan Border Police (ITBP), comprises 56 individuals, including drivers and porters. The experts will conduct their research from August 28 to September 14 at elevations reaching 18,000 feet.

Objectives of the Survey

The primary goal of this survey is to conduct advanced studies on the geology of the glacial lakes, understand glacial behaviors, analyze slope stability, and evaluate the probabilities of avalanches and GLOF occurrences. Sandeep Tambe emphasized the high-tech nature of the study and outlined that the findings will be used to develop a comprehensive mitigation plan. “We are going to do very hi-tech studies to understand the geology of the glacial lake, understand the glacial behaviours, study the slope stability and probabilities of avalanches and GLOF. This will be a study at an altitude of 18,000 feet. Once our study is done, we will plan the mitigation plan,” said Tambe.

Historical Context and Future Steps

The current survey follows a previous expedition conducted by the NDMA in collaboration with Swiss experts prior to the 2023 lake outburst in South Lhonak, Sikkim. The ongoing surveys in Arunachal Pradesh and Sikkim reflect a heightened focus on preventing future GLOFs and ensuring the safety of the affected regions through proactive measures and advanced research.