The warning for the six Himalayan states has been issued by the Central Water Commission (CWC), which comes under Ministry of Jal Shakti, last week. The directive comes amid mounting concerns over rapidly melting glaciers and swelling glacial lakes, largely attributed to climate change. According to recent research, the Indian Himalayas now have over 329 glacial lakes larger than 0.05 sq km—nearly 70% larger in area than in 1990. Many of these are perilously close to critical downstream infrastructure.
India is home to over 6,000 large dams—ranking third globally—and has already experienced the devastating consequences of GLOFs. The 2021 Chamoli disaster in Uttarakhand and the 2023 breach of the Teesta-III dam in Sikkim, after South Lhonak Lake overflowed, are stark reminders of the threat.
The CWC has identified avalanches, landslides, and earthquakes as key triggers of GLOF events. To address these, the new guidelines recommend a combination of structural and non-structural safety measures.
For new dams, the guidelines require the inclusion of high-capacity spillways, high-speed sluices, and gates that can open rapidly—1.5 to 2 metres per minute—to prevent overtopping during sudden surges.
Existing dams are advised to retrofit mechanical hoists, reinforce piers, and upgrade critical components such as gates, trunnions, and power packs. The use of high-performance concrete and downstream sediment traps has also been recommended. For earthen dams, additional safeguards like parapet walls and reinforced riverbanks are advised.At the source, structural measures like siphoning of lake water, building artificial drainage channels, and installing debris-trapping weirs are encouraged wherever feasible. The Chorabari glacier near Kedarnath—retreating at 7 metres per year between 1976 and 2016—is just one example of emerging threats from shrinking glaciers.Non-structural measures include early warning systems, SCADA-based gate controls, satellite-enabled communication, and comprehensive emergency action plans. In hydropower cascades, upstream reservoirs are expected to maintain lower water levels during monsoon as a buffer against sudden inflows, with downstream operators sharing related costs.
The CWC has also urged better coordination with defence agencies for real-time monitoring and rapid response during emergencies.
