Are Dams Prone to Natural Disasters?
Yes, dams can indeed be vulnerable to damage caused by natural disasters such as floods and cloudbursts. The extent of this vulnerability hinges on factors such as the dam’s age, the quality of its construction, and its adaptability to the changing climate. The recent incident involving the Chungthang dam in Sikkim was triggered by a glacial lake outburst flood (GLOF). This particular dam was approximately two decades old, and concerns had been raised over the years about the formation of glacial lakes and the potential for GLOFs. The Union power ministry has expressed its intention to conduct a comprehensive assessment once the floodwaters have receded.
Prominent Dam Failures on a Global Scale
According to a report from the National Institute of Public Finance and Policy (NIPFP) in 2021, there have been 4,000 instances of major dam failures in 84 countries. One of the most catastrophic incidents was the Banqiao dam failure in China in 1975, which led to the collapse of 60 downstream dams and claimed the lives of over 80,000 people. In 1976, the Teton Dam in the United States also collapsed, resulting in 11 fatalities. The Dam Safety Organisation reports 23 significant dam failures in India between 1960 and 2010, some of which resulted in multiple casualties. The most devastating was the Machchhu Dam failure in Morbi, Gujarat, in 1979, which claimed the lives of more than 2,000 people, as indicated in the report.
Many dams in India were constructed before the impact of climate change altered rainfall patterns across the country. Consequently, they may not be adequately equipped to withstand sudden surges in water flow.
How Many Indian Dams Could Be Vulnerable?
India possesses numerous dams that are highly exposed to natural hazards. As of 2019, Jal Shakti Minister Gajendra Singh Shekhawat stated that approximately 293 dams in India were over a century old. Additionally, a substantial number of dams were built at a time when the consequences of climate change were not fully comprehended, and their designs likely did not account for significant shifts in rainfall patterns, as highlighted in the NIPFP report.
Impact on Hydropower Initiatives
India’s installed hydropower capacity is projected to increase to 78 GW by 2030, up from 52 GW in FY23. India is presently executing ten projects with a total capacity of 6.8 GW in Jammu and Kashmir and Himachal Pradesh. The nation also has plans to construct its largest dam in Arunachal Pradesh, boasting a 10 GW capacity, as a response to China’s water diversion project. Despite the recent incident, it is unlikely that planned mega projects will undergo reconsideration. A government official has conveyed that India will proceed with adding hydropower capacity, albeit with heightened caution.
Preventive Measures Taken
In response to potential geological shocks in hydro projects, the Central Electricity Authority has established a technical committee to conduct studies. The Dam Safety Act of 2021 was passed by parliament, leading to the establishment of the National Dam Safety Authority last year. The country also maintains 29 state dam safety organizations, each responsible for conducting pre-monsoon and post-monsoon inspections of dams within their respective jurisdictions through their dam safety units, according to the Centre.