Article 3: Bihar floods underline need for basin-wide cooperation
Why in news: Bihar is facing severe flooding despite a 27% rainfall deficit, as major rivers crossed danger levels due to high upstream flows, localised heavy rainfall, siltation and the Ganga’s backwater effect.
Key Details
- Flooding despite rainfall deficit: Bihar received 27% below-normal rainfall from June 1 to early September, yet the Ganga, Gandak, Kosi, Budhi Gandak, Punpun and Ghaghra crossed danger levels.
- Multiple causes: High upstream river flows, erratic and localised heavy rainfall, silt accumulation and reduced channel capacity contributed to flooding. The Ganga’s high level caused a backwater effect in the Gandak and Punpun.
- Limitations of embankments: Embankments separate rivers from floodplains, while continuous silt deposition raises riverbeds. Breaches can cause rapidly flowing water to inundate homes and agricultural fields.
- Need for integrated management: Bihar should combine embankment maintenance with drainage restoration, floodplain protection, wetlands restoration, better land-use planning and early-warning systems, allowing rivers adequate space during high discharge.
- Inter-state & international coordination: Reservoir-release coordination among riverine states is crucial. Bihar’s concerns regarding the Farakka Barrage and 1996 India-Bangladesh Ganga Water Sharing Treaty should inform its renegotiation using updated flow and climate data.
Bihar’s Flood Paradox
- Bihar received 27% below-normal rainfall between June 1 and early September, yet large parts of the state remain flooded.
- The Ganga, Gandak, Kosi, Budhi Gandak, Punpun and Ghaghra crossed danger levels at various locations.
- Heavy upstream flows and erratic, localised rainfall amid an overall deficit contributed to river flooding.
Backwater Effect and River Overflow
- The unusually high level of the Ganga created a “backwater effect” in the Gandak and Punpun.
- As these tributaries could not effectively discharge into the swollen Ganga, water backed up and intensified flooding.
- This highlights the interconnected nature of river systems within the Ganga basin.
Limitations of Embankment-Based Management
- Bihar has historically relied on embankments to confine rivers within defined channels.
- Embankments disconnect rivers from their floodplains, while silt deposition raises riverbeds and reduces channel capacity.
- Therefore, simply constructing higher or stronger embankments cannot provide a sustainable solution to flooding.
Need for Integrated Flood Management
- Flood management should combine embankment maintenance, drainage restoration, floodplain protection, better land-use planning and wetland restoration.
- Early-warning systems and giving rivers adequate space to spread safely during high discharge are also essential.
- Better coordination among riverine states, particularly regarding reservoir releases, is needed.
Farakka, Ganga Treaty and Regional Cooperation
- Bihar argues that the Farakka Barrage and 1996 India-Bangladesh Ganga Water Sharing Treaty have added to its river-management challenges, though their role in flooding remains contested.
- The treaty’s renewal/renegotiation should consider Bihar’s concerns, updated river-flow data and climate-change projections.
- Countries and states sharing river basins need stronger coordination and data-based water management to reduce flood-related distress.
Conclusion
Bihar’s recurring floods demonstrate that rainfall deficit does not necessarily prevent flooding when river flows, siltation, drainage constraints and extreme weather interact. Sustainable flood management requires moving beyond an exclusive dependence on embankments towards floodplain and wetland restoration, early warnings and improved land-use planning. Greater coordination among basin states and India-Bangladesh is equally essential for managing shared water resources.
Descriptive question:
Flood management in India requires a shift from structural measures to an integrated, basin-level approach. Discuss the limitations of conventional flood-control measures and suggest a comprehensive strategy for reducing flood vulnerability. (150 words, 10 marks)
Source: The Indian Express