Workshop Highlights Measures for GLOF Risk Mitigation in Sikkim

IPR Department, September 4, 2026, Gangtok: A one-day media sensitisation workshop on ‘GLOF Risk Mitigation’ was held on Thursday at the Conference Hall of the Department of Science and Technology.

Press Secretary to the Chief Minister, Mr Yougan Tamang, in his address, highlighted the importance of sensitising the media fraternity on Glacial Lake Outburst Flood (GLOF) risk mitigation to counter speculative information through greater awareness of the scientific measures in place and the dissemination of verified information to the general public.

He also noted that, under the leadership of Chief Minister Mr Prem Singh Tamang, the Department of Science and Technology was designated as the nodal department for GLOF hazard assessment and risk mitigation studies in the state. The decision was notified in February 2025 and is being implemented through an interdisciplinary approach in coordination with the concerned line departments. He further reiterated the state’s advancement in disaster preparedness and its readiness to respond to any future natural calamities.

He acknowledged the sustained efforts of the Minister, Forest and Environment Department and Department of Science and Technology, Mr Pintso Namgyal Lepcha and all the officials of the Department of Science and Technology in undertaking preliminary studies, scientific research, risk assessments and strategic planning towards strengthening GLOF risk mitigation in Sikkim.

He particularly appreciated the Department’s efforts towards developing what could become the country’s first dedicated GLOF Risk Mitigation Protocol, aimed at establishing a standardised and scientifically informed framework for assessing, preparing for and mitigating GLOF-related risks. He emphasised that such a protocol could serve not only as an important institutional mechanism for Sikkim but also as a potential model for other Himalayan states and regions facing similar glacial and climate-induced hazards.

Principal Secretary, Department of Science and Technology and Education Department, Dr Sandeep Tambe, in his address, stated that remote sensing technology and satellite imagery help in monitoring changes in the size and extent of glacial lakes.

He informed that 40 lakes have been identified as high-hazard lakes in the state, of which 16 have been classified as Category A, making them the most vulnerable. Two lakes have been classified as Category B, nine as Category C, while 13 remain unclassified. He stated that field studies for vulnerable lakes have commenced, covering remote sensing, discharge and water-level studies, Electrical Resistivity Tomography (ERT), other geophysical investigations, DGPS surveys, flood modelling, hazard assessment, feasibility studies for lake-level lowering and flood-retention structures, and bathymetric investigations. He emphasised that a uniform strategy cannot be applied to all lakes and, accordingly, proposals have been formulated for three different locations namely, Lhonak Complex, Shako Chho Lake and Gurudongmar Complex.

He informed that the Detailed Project Report (DPR) for Shako Chho Lake has been submitted to the National Disaster Management Authority (NDMA). A Preliminary Project Report (PPR) has also been submitted to the Ministry of Jal Shakti, while the Central Water Commission (CWC) is working on a DPR, in collaboration with the Department of Science and Technology, Government of Sikkim, for a flood-retention structure at Dolma Sampa near Muguthang in the Lhonak Complex. Regarding the Gurudongmar Complex, he stated that a moraine plug wall at the lake outlet has been proposed. The Department of Science and Technology, in collaboration with the Brahmaputra Board, is developing the proposal with the objective of mitigating GLOF risk while preserving the cultural and religious sanctity and significance of the lake.

Principal Director-cum-Secretary, Department of Science and Technology, Mr D. G. Shrestha, in his presentation on the GLOF study in Sikkim, stated that the state government had incurred a huge loss due to the catastrophic damage caused by the GLOF event in 2023. He outlined the government’s vision and priorities, including safeguarding the state from future glacial flood events; establishing early warning systems alongside resilient infrastructure; protecting mountain infrastructure such as roads, dams, bridges and habitations from future calamities; developing mitigation proposals for GLOF risk reduction; and positioning Sikkim as a leader in GLOF risk mitigation.

He highlighted the baseline status prior to the initiative and various interdisciplinary studies undertaken as part of the integration of science and technology into risk mitigation. These include hydro-meteorological studies, Electrical Resistivity Tomography (ERT), bathymetric investigations, hydrological and geological studies, and UAV-based terrain mapping.

He also highlighted action-oriented initiatives, including the standardisation of scientific protocols to assess lake volume, mass movement, hazards and moraine stability through the integration of five interdisciplinary studies; development of capabilities in hydrodynamic modelling using HEC-RAS software to model flood flow paths; reimagining GLOF propagation; and development of structural mitigation proposals.

He further noted significant advancements in policy development, including the adoption of a Whole-of-Government Approach (WGA), greater clarity in business rules, bridging the gap in technical expertise, and the proposed establishment of a commission on glacial hazards.

He outlined various approaches for lake-level lowering, including siphoning, pumping, enhancement of existing channels, construction of artificial open channels, moraine cutting with safety walls, and tunnelling. He also elaborated on the four-step approach to GLOF risk mitigation: preliminary assessment, comprehensive assessment, designing mitigation measures, and executing mitigation measures.

He highlighted the development of institutional and technical capabilities for GLOF risk mitigation through the establishment of administrative systems, technical capacities and financial assistance. He stated that these initiatives also constitute a contribution to national security and would further strengthen Sikkim’s recognition as a national leader in GLOF risk mitigation.

He further informed that, following a virtual meeting with Secretary, Ministry of Home Affairs, Mr Govind Mohan, additional early warning sensors have been proposed for installation across the state to which he gave a positive assurance.

Chief Engineer, Department of Science and Technology, Mr Ashim Basnet, in his presentation, apprised the gathering of GLOF modelling and the methodology for defining GLOF hazard zones. He also presented the three proposals prepared for Shako Chho Lake, the Lhonak Complex and the Gurudongmar Complex. He stated that according to Dam Safety Act 2021 the power projects have legally established their early warning system to monitor the reservoir or downstream population, hydrometeorological monitoring, inflow forecasting, emergency flood warning, real-time data exchange and Emergency Action Plans. He further acknowledged the role of Indian Army in playing a crucial part in disseminating information regarding cautionary measures for prompt and early warning.

Regarding Shako Chho Lake, he stated that it is one of the 16 high-risk lakes in the state and has been classified as Category A by the NDMA. He explained that the lake has no natural outlet and is an unstable, triangular-shaped lake with a permeable moraine dam and a low width-to-height ratio.

He stated that the nearest habitation, Thangu village, is located approximately 13 km downstream of the lake, making it a high-risk location and underscoring the need for intervention. He presented the findings and recommendations of various agencies, along with the bathymetric depth and volume estimates of the lake. As part of the option analysis, solar pumps have been identified as a practical solution for lake-level intervention, as structural intervention is not considered advisable and a siphon system is not feasible due to the lift head exceeding 20 metres. He also presented the tentative layout for the proposed solar pumping system and concluded with the safeguards incorporated into the proposal.

Regarding the Gurudongmar Complex, as part of the second proposal, he stated that a moraine plug wall mitigation strategy has been proposed. The Department of Science and Technology, in collaboration with the Brahmaputra Board, is developing the proposal with the objective of mitigating GLOF risk while preserving the cultural and religious sanctity and significance of the lake.

Regarding the Lhonak Complex, as part of the third proposal, he stated that a Preliminary Project Report (PPR) has been submitted to the Ministry of Jal Shakti. The Central Water Commission (CWC) is working on a DPR in collaboration with the Department of Science and Technology, Government of Sikkim, for a flood-retention structure at Dolma Sampa near Muguthang in the Lhonak Complex.

Special Secretary-cum-Director, Sikkim State Disaster Management Authority (SSDMA), Mr Pravakar Rai, in his address, apprised the gathering of the activities and initiatives undertaken by the SSDMA in the area of disaster management.

The workshop also witnessed an interactive discussion between members of the media fraternity and stakeholders involved in disaster management, providing an opportunity to exchange views and clarify queries related to GLOF risk mitigation and preparedness. The welcome address and vote of thanks were delivered by Assistant Scientific Officer, Department of Science and Technology, Dr R. K. Sharma. The workshop was also attended by officials of the Department of Science and Technology, along with members of the press and media fraternity.