Rebuilding Teesta-3 Dam poses risks and challenges

Source: The post Rebuilding Teesta-3 Dam poses risks and challenges has been created, based on the article “The Teesta dam and the long shadow of climate change” published in “The Hindu” on 15th February 2025

UPSC Syllabus Topic: GS Paper3-Disaster and disaster management.

Context: The article discusses the risks of rebuilding the Teesta-3 dam in Sikkim after its destruction by a 2023 glacial lake outburst flood. Experts warn that climate change increases such risks, and rebuilding should prioritize local safety over commercial viability.

For detailed information on Issue with hydropower projects on the Teesta River read this article here

Why Was the Teesta-3 Dam Destroyed?

1. Glacial Lake Outburst Flood (GLOF): In October 2023, the Teesta-3 dam was destroyed by a GLOF originating from South Lhonak Lake.
2. Moraine Slope Failure: The dam’s destruction was triggered by a slope failure at the lake’s moraine, causing rocks to tumble into the water, creating a powerful ripple effect.
3. Volume of Water Released: Satellite data showed that approximately 50 billion litres of water surged into the valley below, carrying dam debris that intensified the destruction downstream.
4. Catastrophic Impact: The flood killed over 100 people and affected more than 80,000 across four districts, also triggering landslides about 30 to 40 kilometres downstream.

How Is Climate Change Making GLOFs More Dangerous?

1. Accelerated Glacier Melting: Rising temperatures are melting Himalayan glaciers faster, increasing water accumulation in glacial lakes.
2. Increase in Glacial Lakes: Between 2011 and 2024, the number of glacial lakes grew by 10.8%, and their surface area expanded by 33.7% (Central Water Commission report).
3. Black Carbon Deposition: Soot from industries speeds up glacier melting, worsening the risk.
4. Unstable Geological Formations: Glacial retreat weakens mountain slopes, making landslides and floods more likely. For example – South Lhonak Lake: It grew to 167 hectares by 2023, leading to the Teesta-3 dam disaster.

Why Is the Government Planning to Rebuild the Dam?

1. Successful and Commercially Viable: The Teesta-3 dam was considered a successful project before its destruction and was commercially profitable.
2. Power Generation Equipment Intact: The hydroelectric machinery survived the GLOF, making restoration easier.
3. Growing Power Demand: India’s rising electricity needs require continued hydropower production.
4. Stronger Design Proposed: The new design includes a larger spillway, stronger concrete construction, and an early-warning system.
5. Worst-Case Scenario Modeling: The India Meteorological Department used maximum future rainfall predictions to guide reconstruction.

Why Is Rebuilding the Dam Controversial?

1. Seismic and Landslide Risks: The dam is in an earthquake- and landslide-prone area, making it vulnerable to future disasters.
2. Flawed Clearance Process: The dam has faced public interest litigations over techno-economic approval issuesand alleged corruption.
3. Unpredictable Disaster Patterns: Experts warn that rainfall models alone cannot predict future floods, as seen in 2023 GLOF.
4. Potential for Greater Destruction: If another, stronger flood occurs, the new dam might fail catastrophically, causing greater downstream damage.
5. Erosion and Sediment Transport: A study in January 2025 highlighted that existing models do not fully account for erosion and sediment transport, making risk predictions uncertain.
6. Engineering Limitations: Some experts argue that engineering solutions alone cannot prevent climate-related disasters and suggest that long-term safety measures should be prioritized.

For detailed information on On Dam Safety read this article here

What Are the Broader Risks?

1. The dam increased damage in the 2023 flood by obstructing water flow.
2. A stronger or different flood in the future could cause even greater destruction.
3. Some experts argue that rebuilding in disaster-prone areas is unsustainable.
4. They suggest prioritizing local safety, social security, and economic resilience over commercial viability.
5. The cost of risk mitigation should be included in the dam’s power tariff.

Question for practice:

Examine the risks and challenges associated with rebuilding the Teesta-3 dam in Sikkim after its destruction by the 2023 Glacial Lake Outburst Flood.