Describe the flood-prone areas and their management problems in the Ganga Plains.

Flood-Prone Areas in the Ganga Plains

The Ganga Plains are broadly divided into several flood-prone zones:

• Upper Ganga Plains (Uttarakhand & Uttar Pradesh): Prone to flash floods and glacial lake outburst floods (GLOFs) due to the Himalayan terrain.
• Middle Ganga Plains (Bihar): Experiences widespread inundation due to heavy rainfall during the monsoon and river overflow. This is the most severely affected region.
• Lower Ganga Plains (West Bengal): Vulnerable to both riverine and cyclonic floods, exacerbated by tidal influences and poor drainage.
• Ganga-Brahmaputra Plains (Assam): Though primarily Brahmaputra, the Ganga’s tributaries contribute to flooding in this region.

Reasons for Frequent Flooding

Several factors contribute to the recurrent flooding in the Ganga Plains:

• Geomorphological Factors: Low-lying topography, flat terrain, and high silt deposition reduce the river’s carrying capacity.
• Climatic Factors: Intense monsoon rainfall, particularly in the catchment areas of the Ganga and its tributaries, leads to increased river discharge.
• Anthropogenic Factors: Deforestation in the Himalayas increases runoff, construction of embankments restricts the river’s flow, and encroachment of floodplains reduces the river’s capacity to contain floodwaters.
• Glacial Melt: Increasing glacial melt due to climate change contributes to higher river flows, especially during the pre-monsoon season.

Management Problems in the Ganga Plains

Structural Measures & Their Limitations

Structural measures like embankments, dams, and drainage channels have been traditionally employed for flood control. However, they often create more problems than they solve:

• Embankments: While protecting areas behind them, embankments restrict the river’s flow, increasing water levels and causing flooding in unprotected areas. They also hinder sediment deposition, leading to riverbed aggradation.
• Dams: Dams regulate river flow but can disrupt the natural sediment transport, impacting downstream ecosystems and increasing flood risk during dam failures.
• Drainage Channels: Insufficient capacity and poor maintenance render drainage channels ineffective.

Non-Structural Measures & Challenges

Non-structural measures, such as flood forecasting, early warning systems, and floodplain zoning, are crucial for mitigating flood impacts. However, their implementation faces challenges:

• Inadequate Flood Forecasting: Limited network of hydrological stations and lack of real-time data hinder accurate flood forecasting.
• Poor Early Warning Dissemination: Lack of effective communication channels to reach vulnerable populations in remote areas.
• Lack of Floodplain Zoning: Encroachment of floodplains continues due to weak enforcement of regulations and lack of awareness.
• Limited Community Participation: Insufficient involvement of local communities in flood management planning and implementation.

Institutional & Coordination Issues

Effective flood management requires strong institutional coordination between various agencies. However, several issues hinder this:

• Fragmented Responsibilities: Multiple agencies (Central Water Commission, State Irrigation Departments, Disaster Management Authorities) are involved, leading to overlapping responsibilities and lack of coordination.
• Insufficient Funding: Inadequate allocation of funds for flood management infrastructure and programs.
• Lack of Capacity Building: Limited training and capacity building for personnel involved in flood management.

Example: The Kosi River, known as the ‘Sorrow of Bihar’, frequently changes its course, causing widespread devastation. Embankments built to contain the river have often failed, exacerbating the flood situation. The 2008 Kosi floods, triggered by a breach in the embankments, displaced millions and caused immense damage.