The Hindu Editorial Analysis
15 February 2025
The Teesta dam and the long shadow of climate change
(Source – The Hindu, International Edition – Page No. – 6)
Topic: GS 1: Important Geophysical phenomena such as GLOF, GS 3: Disaster and disaster management
Context
- Recommendation: An expert committee suggested rebuilding the Teesta-3 dam after it was destroyed by a glacial lake outburst flood (GLOF) in October 2023.
- Impact: The disaster resulted in over 100 deaths and affected more than 80,000 people in Sikkim.
South Lhonak Lake Moraine Failure
- Moraine Failure: A slope failure on the moraine led to a significant rockfall into the lake.
- Water Release: About 50 billion liters of water flooded into the valley after the outlet collapsed.
- Landslides: The event triggered multiple landslides downstream, indicating ongoing instability in the area.
Link to Global Warming
- Accelerated Melting: Global warming and soot pollution are speeding up the melting of Himalayan glaciers.
- Increased Lakes: The number of glacial lakes in the Himalayas grew by 10.8% from 2011 to 2024, with a 33.7% increase in surface area.
- Geological Risks: Glacial retreat destabilizes geological formations, creating new risks.
Teesta-3 Dam Controversy
- Rebuilding Concerns: Experts worry about rebuilding the Teesta-3 dam due to its location in a disaster-prone area.
- Previous Issues: The dam has faced legal challenges regarding its environmental clearance and alleged corruption.
Teesta-3 2.0 Design and Climate Risks
- New Design Features: The proposed Teesta-3 2.0 will use concrete, have a larger spillway, and include an early-warning flood system.
- Modeling Risks: The design is based on a worst-case scenario, but climate change complicates risk assessments.
Experts’ Perspectives
- Risk Multiplication: Climate change acts as a risk multiplier, exacerbating the effects of natural disasters.
- Model Limitations: Current climate models struggle to accurately predict extreme weather events and their impacts.
Comprehensive Assessment of the 2023 GLOF
- International Report: A team of experts identified gaps in GLOF modeling, emphasizing the need for better erosion and sediment transport assessments.
- Flood Dynamics: Water waves travel faster than sediment waves, affecting flood impact evaluations.
Impact on Teesta-3 Hydropower Project
- Commercial Viability: The pre-GLOF viability of Teesta-3 was tied to rising energy demands.
- Potential Consequences: Climate change increases risks, possibly leading to greater downstream damage in future floods.
Social Considerations
- Community Resilience: Improving social security for residents is crucial for recovery after disasters.
- Retreat from Risk: Experts argue that simply engineering solutions won’t suffice; retreat from high-risk areas may be necessary.
Conclusion
- Risk Management Framework: Decisions should prioritize minimizing risks to local communities and enhancing socio-economic resilience.
- Cost Inclusion: The costs of risk management should be factored into the dam’s power tariffs to ensure sustainability.