Subject: Disaster Management

The recent Teesta-3 dam disaster in Sikkim (2023) and numerous other dam failures globally highlight the catastrophic nature of such incidents, causing extensive loss of life, property damage, and long-term socio-economic impacts. Dam failures represent a significant technological hazard that requires comprehensive understanding and mitigation strategies.

Major Causes of Dam Failures

1. Natural Causes:

• Extreme Weather Events: Unprecedented rainfall leading to overflow, as seen in the Tiware dam failure (2019) in Maharashtra.
• Geological Factors: Earthquakes, landslides, and foundation failures compromising structural integrity.
• Glacial Lake Outburst Floods (GLOFs): As witnessed in the Teesta-3 dam disaster where glacial lake breach caused catastrophic damage.

2. Structural and Design Issues:

• Inadequate spillway capacity leading to overtopping during heavy floods.
• Poor construction quality and use of substandard materials.
• Design flaws in foundation and structural components.

3. Operational and Maintenance Factors:

• Aging Infrastructure: Many dams approaching or exceeding their design life.
• Insufficient maintenance and repair works.
• Poor operational procedures and emergency response systems.

Examples of Major Dam Failures

1. Machhu Dam Failure (1979), Gujarat:

• Considered India's worst dam disaster.
• Caused by excessive rainfall and inadequate spillway capacity.
• Resulted in over 2,000 casualties and massive destruction.

2. Teesta-3 Dam Failure (2023), Sikkim:

• Triggered by GLOF and flash floods.
• Led to significant loss of life and infrastructure damage.
• Highlighted the vulnerability of himalayan dams to climate change impacts.

To prevent such catastrophes, India has implemented the Dam Safety Act 2021 mandating regular inspections and established the National Dam Safety Authority (NDSA). The Dam Rehabilitation and Improvement Project (DRIP) further addresses safety concerns in aging dams through structural improvements and modernization of monitoring systems.