Overview

Bihar is one of India's most flood-prone states, with 11.84 lakh people affected by annual flooding. The state grapples with the devastation of homes, crops, and livestock, prompting a cycle of recovery only to face similar disasters each year.

Geographical Vulnerabilities

Flood-Prone Conditions

• Demographics: 76% of North Bihar’s population lives under the threat of floods.
• River Systems: The state is crisscrossed by multiple snow-fed and rain-fed rivers, contributing to various flood types:
  • Flash Floods: Rapid onset due to rainfall in Nepal (lead time: 8 hours).
  • River Floods: Slower onset with a lead time of 24 hours, lasting over a week.
  • Drainage Congestion: Extended flooding throughout the monsoon season (lead time: over 24 hours).
  • Permanent Waterlogging: Caused by various factors including sedimentation and encroachments.

Factors Contributing to Flooding

• Himalayan Rivers: Rivers like Kosi, Gandak, and Bagmati carry significant sediment, leading to overflow during heavy rains.
• Waterlogging Causes: Silted rivers, encroachment of drainage channels, and local topographical features called Chaurs contribute to permanent waterlogging.

Historical Management Efforts

Embankments and Their Impact

• Kosi River: Known as the "sorrow of Bihar," embankments built in the 1950s to control the Kosi’s flow have led to unintended consequences.
• Sediment Accumulation: Narrowing of the river’s course has caused sediment to build up, increasing the riverbed height and flood risks.
• Current Crisis: Recent flooding was exacerbated by the release of 6.6 lakh cusec of water from the Birpur barrage in Nepal, leading to multiple embankment breaches.

Economic and Social Effects

Impact on Livelihoods

• While annual flooding may not always lead to significant loss of life, the economic repercussions are severe:
  • Damage to crops and infrastructure.
  • Loss of livestock and economic migration outside the state.
• Government Spending: Approximately Rs 1,000 crore is allocated annually for flood management and relief efforts.

Proposed Solutions

Structural vs. Non-Structural Approaches

• Dam Construction: Proposals for new barrages on the Kosi and other rivers have been discussed, but require cooperation from Nepal.
• Need for Comprehensive Strategies: Experts suggest a dual approach:
  • Structural Solutions: Dams and embankments.
  • Non-Structural Solutions: Policy development, risk mitigation, and improved community awareness.

Emphasis on Risk Reduction

• The Flood Atlas of Bihar advocates for minimizing flood risk rather than relying solely on structural measures.
• Focus on enhancing early warning systems and community preparedness is crucial for effective flood management.

Conclusion

Bihar’s unique geographical and socio-economic landscape necessitates a multifaceted approach to flood management. While structural solutions like dams are important, the state must also invest in non-structural measures that promote resilience and reduce vulnerability among its population.