Tragedies in the Himalayan Region
Context:
- The recent glacial lake outburst flood (GLOF) that devastated Sikkim’s Teesta river highlighted the increasing danger of GLOF caused by climate change throughout the Indian Himalayan region.
Outburst flood of glacial lakes (GLOF):
- A glacial lake flood (GLOF) is a type of outburst flood that results from a dam failing.
- According to a research this year published in Nature, 1,089 basins with glacial lakes are home to 90 million people living in 30 different nations. Sixteen of them reside 50 km or less from a glacial lake and one kilometre from possible GLOF run-out channels.
- In the highlands, dangers can happen in a cascading manner: intense rains can start a landslip, which might then cause another landslip downstream and possibly even an eruption of a glacier lake, setting the stage for ash floods.
- It is difficult to predict this sequence of occurrences. Institutions are becoming more aware of these risks, but developing a mechanism to reduce risks and issue early warnings from such hazards is a difficulty.
Early alerting mechanisms:
- The catastrophe that took place at the South Lhonak glacial lake in Sikkim on October 3 is still being felt to its full extent. Scientists are leaning towards the theory that the collapse of a massive quantity of rock or moraine from the lake’s northwest side served as the primary catalyst for the catastrophe. Ash floods were caused by the large amount of melt water that it displaced, expanding the river mouth at the eastern end.
- A variety of hydrometeorological, tectonic, climatic, and human-induced mountain risks can affect the Himalayan Region. A comprehensive set of early warning, mitigation, and monitoring techniques are needed for each of them. A sufficient mapping of the glacial melting process chain exists. However, tracking and estimating the risk are more challenging due to the large number of glaciers and temporal fluctuations in glacial recession.
- Over 28,000 glacial lakes can be found in three major river basins: the Indus, Ganga, and Brahmaputra, according to the National Remote Sensing Centre’s (NRSC) Glacial Lake Atlas of 2023. Of them, six States and Union Territories in India account for 27%. Over the previous few decades, this area has seen devastating GLOF episodes.
- Various geotechnical methods have been attempted worldwide to mitigate floods, including as channel excavation for controlled outflow, pipe and pump drainage, construction of spillways, and installation of minor catchment dams to slow down outflow. Even though these steps are difficult and labor-intensive, high-risk lakes must adopt them.
- The downstream hill towns and authorities, who have a very short lead time to respond, are most at risk from such a tragedy. They risk suffering severe harm to their livelihood, assets, and quality of life.
- Along with other hydrometeorological and geophysical hazards, the risks associated with landslides, heatwaves, severe precipitation, melting glaciers, and slope shifting are increasing. Disaster and climate resilience principles need to be integrated into government policy and practise, as well as private investment, while also fulfilling the development needs of hill communities.
Interdisciplinary endeavour:
- This calls for a coordinated, interdisciplinary effort spanning several universities. By using high resolution data from remote sensing, the NRSC’s atlases have made it possible to track changes in space.
- The Central Water Commission (CWC) uses digital elevation models to map water flow, height, and route simulations, as well as to perform hydro-dynamic assessments of high-risk lakes.
- The national guidelines for NDMA (2020) offer States a technical synopsis of risk and hazard zonation together with recommended practises for risk reduction, mitigation, and monitoring.
- The last steps of approval are being applied to a comprehensive plan to mitigate the GLOF danger. This plan will involve installing monitoring and end-to-end early warning systems at high-risk glacier lakes. All governments and scientific organisations must collaborate in this quest to combine capacities and resources in disaster risk reduction.
Way Forward:
- Even though the right synergies have been established, hill communities will experience less loss and harm and more stability if prevention and mitigation are given more attention.
