Mains Practice Questions

Approach:

• Begin by defining dam failure and its repercussions.
• Discuss the causes of dam failures and a few examples of dam failures.
• Conclude with a positive note.

Introduction:
A dam failure is simply an uncontrolled release of water from a reservoir through a dam because of structural failures or deficiencies in the dam. Ranked third in terms of building large dams, dam failure in India can potentially result in a release of large quantities of water imposing risks on the people or property downstream.

Body:

Causes of dam failures

• Overtopping: It is caused due to poor spillway design, leading to a reservoir filling too high, especially in times of heavy rainfall.
• Foundational Defects: Instability of slopes can lead to seepage of water beneath the dam.
• Operational Failures: Valves and conduit failures often cause improper functioning which can lead to inadequate water discharge.
• Geological Instability: Tectonic induced calamities like landslides, earthquakes can pose a threat to dam structures.
• Ageing Dams: Rising frequency of flooding and other environmental changes can accelerate the dam’s ageing process.
• Structural Failure: Inadequate design, construction materials, or maintenance can lead to dam collapse.

Examples of large dam failures

• Machchu II Dam Failure (1979): Due to heavy rainfall and improper design, the Machchu II Dam in Gujarat burst, resulting in a catastrophic flood. The torrential flow destroyed villages, claiming the lives of over 2,000 people.
• Tiware Dam Failure (2019): Situated in Ratnagiri, Maharashtra, the Tiware dam breached due to excessive rainfall, flooding seven villages and killing several people.

Conclusion:

Efforts like the Dam Safety Act 2021 and Dam Rehabilitation and Improvement Project (DRIP) are the steps in right direction to prevent catastrophic events of dam failure in India.