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North Bihar Flood
Context:
Bihar is facing severe flooding again, affecting 1.18 million people who have been displaced and are relying on air-dropped food packets while sheltering in vulnerable conditions. Each year, North Bihar suffers from floods that destroy crops and livestock, forcing residents to rebuild their lives only to face the same devastation again.
Key Factors Behind Bihar’s Annual Flooding:
Geographical Factors:
- Proximity to Himalayan Rivers: North Bihar is crisscrossed by major rivers, including the Kosi, Gandak, and Bagmati, which originate in the Himalayas. These rivers carry significant volumes of water and sediment, making the region highly flood-prone, especially during the monsoon.
- Flat Terrain: The low-lying, flat landscape hinders the natural drainage of floodwaters, leading to water stagnation and prolonged flooding.
- Silt Accumulation: Rivers from the eroding Himalayan range deposit large amounts of loose soil and sediment, causing riverbeds to rise over time.
- This accumulation makes rivers shallower and more likely to overflow, particularly during heavy rainfall.
- Natural Depressions (Chaurs): Certain areas have natural depressions that retain water, contributing to permanent waterlogging and exacerbating flooding.
Meteorological Factors:
- Monsoon Rainfall: Bihar experiences heavy rainfall during the monsoon season (June to September), with North Bihar receiving higher-than-average precipitation due to its geographical location.
- Rainfall in Nepal: Intense rainfall upstream in Nepal further increases the flood risk as it generates additional water flow into the rivers feeding Bihar.
- Sudden Water Releases: Water releases from barrages, such as the Mirpur barrage on the Kosi River, intensify flooding, particularly when combined with heavy rainfall.
Infrastructural Factors:
- Embankments: Constructed in the 1950s to prevent flooding, embankments have narrowed river channels, restricting water flow and leading to increased silt deposition.
- The raised riverbeds have resulted in frequent breaches, including seven this year, impacting over 380 villages and 15 lakh people.
- Inadequate Drainage Systems: Poorly maintained or absent drainage infrastructure impedes the rapid movement of floodwaters, causing long-term waterlogging in many areas.
- Lack of Dams and Barrages: Proposals for major dams on the Kosi River have faced political and logistical hurdles, particularly regarding cooperation with Nepal, preventing effective water management and flood control.
Economic and Social Impact:
- Although fatalities have decreased, the economic damage from flooding remains substantial, affecting crops, livestock, and infrastructure, and leading to distress migration. Bihar allocates around ₹1,000 crore annually for flood management and relief efforts.
Potential Solutions:
- Dams and Barrages: While there are proposals for a Kosi River dam and additional barrages, progress has stalled due to a lack of cooperation from Nepal. Experts suggest that these measures alone may not suffice.
- Non-structural Measures: Improved flood warning systems, public awareness campaigns, disaster preparedness, and risk reduction strategies are crucial.
- Non-engineering solutions could effectively mitigate flood damage alongside structural interventions.
India has several successful flood mitigation examples that could inform Bihar’s flood management:
- Brahmaputra River Basin Management (Assam): Assam has built embankments and levees while involving local communities in monitoring flood levels, fostering ownership and preparedness.
- Flood Control in Kerala: Kerala combines traditional knowledge with modern technology in an integrated flood management system, including effective drainage and early warning systems for better preparedness.
- Sardar Sarovar Project (Gujarat): The Sardar Sarovar Dam regulates river flow and provides irrigation, showcasing the importance of dam and reservoir systems for flood risk management.
- Coastal Flood Management in Tamil Nadu: Tamil Nadu has developed coastal embankments and a robust disaster response framework, highlighting the need for tailored infrastructure and effective evacuation protocols.
These examples emphasise community involvement, integrated approaches, infrastructure development, and adaptive management in flood mitigation efforts.