Teesta-3 Dam Reconstruction

The Indian Environment Ministry’s expert committee recommended the reconstruction of the Teesta-3 dam in Sikkim. This decision comes after a catastrophic glacier lake outburst flood in 2024 caused damage and loss of life. The new dam design aims to enhance safety and operational efficiency while addressing the shortcomings of the previous structure.

Background of the Teesta-3 Dam

• The Teesta-3 dam is the largest hydropower project in Sikkim.
• It was commissioned in 2017 at a cost of ₹13,965 crore. The dam was a hybrid of rock and concrete, which contributed to its vulnerability during extreme weather events.
• The 2024 flood resulted in the loss of at least 100 lives and extensive damage to the infrastructure.

New Design Features

• The proposed new dam will be entirely made of concrete.
• This change is designed to increase structural strength and resilience against future floods.
• The spillway’s capacity will be increased to handle a peak flow of 19,946 cubic metres per second, higher than the previous capacity of 7,000 cumecs.

Early Warning System Implementation

An essential recommendation is the implementation of an early warning system in the upper catchment. This system will enable timely opening of the dam gates to mitigate flooding risks. The previous failure to operate the flood gates during the 2024 disaster contributed to the extent of the damage.

Cost Implications

The estimated cost for the new dam construction is ₹4,189 crore. This is a substantial increase from the original project cost. However, the expert committee believes that the investment is justified given the dam’s commercial viability and the need for enhanced safety measures.

Operational Safety Enhancements

To improve safety for personnel, the control room will be relocated to a higher elevation. This move aims to protect staff during potential flood events. Additionally, plans are in place to ensure that manpower can be safely evacuated from the dam site in case of emergencies.

Restoration Timeline

The underground powerhouse and electro-mechanical equipment are expected to be restored in 10 to 12 months. Most of the water conductor system remains unaffected, allowing for a quicker restoration process. The overall timeline for bringing the dam back into operation is approximately one year.

Environmental Considerations

The new dam design incorporates a “worst-case scenario” analysis based on potential rainfall patterns over the next century. This modelling, conducted by the India Meteorological Department, aims to ensure that the dam can withstand future climatic challenges.

Community Impact

The reconstruction of the Teesta-3 dam is anticipated to have socio-economic impacts. It will restore power generation capabilities and provide employment opportunities during the construction phase. The local community is expected to benefit from the enhanced infrastructure and safety measures.

Questions for UPSC:

1. Critically analyse the impact of glacier lake outburst floods on hydropower projects in Himalayan regions.
2. Point out the significance of early warning systems in disaster management. How can they be improved?
3. Estimate the economic implications of reconstructing large-scale infrastructure projects in disaster-prone areas.
4. What are the environmental challenges associated with hydropower projects in India? Discuss with suitable examples.

Answer Hints:

1. Critically analyse the impact of glacier lake outburst floods on hydropower projects in Himalayan regions.

1. Glacier lake outburst floods (GLOFs) can cause catastrophic damage to hydropower infrastructure, as seen with the Teesta-3 dam.
2. These floods can lead to loss of life, displacement of communities, and economic losses.
3. GLOFs are becoming more frequent due to climate change, increasing the vulnerability of existing hydropower projects.
4. Mitigation measures such as improved dam designs and early warning systems are essential to reduce risks.
5. Regulatory frameworks need to incorporate GLOF risk assessments during the planning stages of hydropower projects.

2. Point out the significance of early warning systems in disaster management. How can they be improved?

1. Early warning systems (EWS) provide timely alerts to mitigate the impacts of disasters, potentially saving lives and property.
2. They enable proactive measures, such as evacuating personnel and opening dam gates to manage floodwaters effectively.
3. Improvement can be achieved through better data collection, advanced forecasting models, and community engagement in preparedness plans.
4. Integration of technology, such as satellite monitoring and real-time communication, can enhance the effectiveness of EWS.
5. Regular drills and training for local communities can ensure readiness and improve response times during actual events.

3. Estimate the economic implications of reconstructing large-scale infrastructure projects in disaster-prone areas.

1. Reconstruction costs can be substantial, as seen with the estimated ₹4,189 crore for the Teesta-3 dam.
2. Investment in resilient infrastructure can lead to long-term economic benefits by ensuring stable power generation and job creation.
3. Insurance and risk management strategies must be developed to protect investments in disaster-prone areas.
4. Government funding and public-private partnerships can help share the financial burden of reconstruction.
5. Economic assessments should include potential losses from future disasters if infrastructure is not upgraded.

4. What are the environmental challenges associated with hydropower projects in India? Discuss with suitable examples.

1. Hydropower projects can disrupt local ecosystems and biodiversity, as seen in the Teesta river basin.
2. Alteration of water flow can affect fish populations and other aquatic life, leading to ecological imbalances.
3. Land acquisition for dam construction often leads to displacement of communities and loss of livelihoods.
4. Climate change impacts, such as altered rainfall patterns, pose risks to the sustainability of hydropower generation.
5. Examples include the impact of the Sardar Sarovar Dam on the Narmada River, which faced environmental and social challenges.