Over a year ago, a devastating flood in Sikkim destroyed a key dam in the Teesta-III hydel project. This was caused by a sudden outburst from the South Lhonak glacial lake, leading to the loss of 40 lives and significant damage to infrastructure. Now, the Environment Ministry’s panel has approved a plan to build a new concrete gravity dam to replace the old one, despite ongoing concerns and without a new public hearing.
The proposal from Sikkim Urja Ltd received approval on January 10, under the pretext of project expansion. This new dam is designed to be 118.64 meters high and is expected to be stronger but also more expensive than the previous one. The Teesta-III project is crucial, providing a significant 1,200 MW of power.
After the flood in October 2023, the Environment Ministry’s Expert Appraisal Committee (EAC) voiced serious concerns about the safety of the new structure. In December, a special sub-committee evaluated potential plans for the new dam, focusing on hazards like glacial lake outbursts.
A concrete gravity dam, built entirely from concrete, typically offers better strength than a rockfill dam. However, the committee highlighted the importance of having an adequate spillway capacity to manage potential floods. The concerns stemmed from the old dam’s low capacity, which contributed to its failure when the South Lhonak lake burst.
Sikkim Urja responded to the EAC’s concerns by stating that the new dam’s spillway capacity has been significantly improved, with plans accounting for both maximum flood scenarios and possible future glacial lake outburst floods.
Of the 119 glacial lakes in the area, researchers identified 13 that pose a real risk. Reports indicated that, in a worst-case scenario, two lakes could release a massive amount of water, making the need for caution critical. Despite the urgency, the EAC decided not to call for a new public hearing, arguing that no new land would be acquired.
Experts have raised alarms about moving forward with the project without fresh evaluations, especially considering the shifting patterns of rainfall and flooding events. Independent specialists suggest that a new environmental impact assessment would be necessary to adapt to recent data and changing conditions.
As this plan develops, it remains vital to prioritize safety and the long-term effects of such projects on the environment and local communities.
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Sikkim dam, Teesta dam hydel project, glacial lake outburst flood, Sikkim Urja, environment ministry, Expert Appraisal Committee, Central Water Commission, Chungthang Dam, Hydroelectric projects, Indian Express
