Context:
In the light of the glacial lake outburst flood (GLOF) that struck the dam in October 2023, an expert committee set up by the Government of India has recommended rebooting the Teesta-3 dam in Sikkim. The dam was earlier seen as an economically viable project, however, climate change, geologic instability, and the risks associated with large hydroelectric schemes in the vulnerable Himalayas have cast doubt on the viability of this recommendation.
Disaster of 2023 & Causes
- The Teesta-3 dam was washed away by a glacial lake outburst flood (GLOF) from the South Lhonak lake.
- The flood killed over 100 people, displacing 80,000 others from four districts.
- The triggering event of this disaster was the failure of a moraine slope, allowing water to burst into the valley.
- Landslides and sediment transport aggravated the effect downstream.
Globals Warming Triggers
- Himalayan glaciers are melting at an accelerated rate due to global warming, coupled with airborne pollutants such as black carbon (soot).
- An additional rise of about 10.8% in the number of glacial lakes has been noted in the region from 2011 to 2024.
- The total surface area increased by 33.7%, hence GLOFs become more probable.
- Current models fail to foretell extreme climate related weather events, according to the experts.
The Risks of Rebuilding Teesta-3
- The new design (Teesta-3 2.0) will be made from only concrete, with a larger spillway, and will feature an early warning system.
- But climate change is a risk multiplier, a second alternative type of flood remains capable of topping the new dam.
- More landslides and earthquakes can make the dam even more vulnerable due to its location.
- Recently, a global study concluded that existing GLOF models do not factor in sediment transport and riverbank failures, leaving flood forecasting in ambiguity.
Commercial Viability vs. Human Safety
- The government insists on reconstructing Teesta-3 as it was financially viable before the disaster.
- However, the safety of human life and environment cannot take second place to financial interests.
- Pre-existing legal opposition brought into question the dam’s adherence to environmental and fiscal standards.
- Costs related to disaster preparedness and mitigation should be incorporated into the project budget.
Social & Long Term Impacts
- The life of residents in the downstream areas remains engulfed in risk; should Teesta 3 2.0 fail, it could be worse.
- Social protection schemes should ensure stability from an economic point of view among the communities affected.
- Some experts would argue that retreating from disaster prone areas is the only sustainable long term solution.
Reconstruction of Teesta 3 may resurrect lost power
