Tread carefully on the Himalayas
The GLOF in Sikkim underscores climate crisis impacts; while dam redesign aims to enhance safety, experts warn mega hydro projects in the Himalayas are risky.
The Glacial Lake Outburst Flood (GLOF) in October 2023 that killed nearly 100 people in Sikkim highlighted how the climate crisis is wreaking havoc in the Himalayas. A mega-dam on the Teesta, constructed as part of the Teesta Hydroelectric Project Stage-III (1,200 MW), was washed away, leading to a suspension of the project. Now, the expert appraisal committee of the Union environment ministry has approved major design changes so that the project can be revived. The new design (a concrete gravity dam), it is claimed, will help the dam withstand the worst kind of flash flood. The design also enhances the dam spillway capacity from 7,000 cumecs to 19,946 cumecs to account for GLOF and other kinds of floods. This is not a good idea.
Mega hydro projects in the Himalayas are increasingly looking unviable. The Hindu Kush Himalayan cryosphere is warming at twice the global average rate, according to the International Cryosphere Initiative. About 210,000 glaciers are being monitored globally for elevation changes through geodetic samples. The data shows that almost all glacier regions are receding. Mapping trends between 1976 and 2023 show large-scale deglaciation in recent years. The National Disaster Management Authority (NDMA) is now undertaking expeditions to map high-altitude glaciers (at 4500 m and above) in India, which could pose a threat to populations downstream. In July, the Centre cleared the National Glacial Lake Outburst Floods Risk Mitigation Plan and NDMA has prepared a list of 189 high-risk glacial lakes (there are about 7,500 glacial lakes in the Indian Himalayas) for mitigation measures, particularly from GLOFs. But the truth is, there are few technological solutions to potential disasters that can occur in this vulnerable geography. Experts have warned that it’s difficult to forecast GLOFs and other disasters at high altitudes. A glacial breach in the upper reaches of the Himalayas in February 2021 led to a flash flood that swept away the Rishiganga hydel dam project and the Tapovan Vishnugad project, killing over 200 people. But despite the warnings, there has been no let-up in the construction of such projects here: capacity is expected to rise from 42 GW to 67 GW by 2031-32.
India is committed to clean energy, and hydropower is key to the country meeting its targets for this. Peninsular rivers have been exhausted and the focus is now on the fast-flowing mountain rivers in the north, including the Ganga, Teesta and the Brahmaputra system. However, given recent experiences, projects need to be reassessed. When it comes to public safety and protecting the environment, there should be no talk of trade-offs.
