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Devastating Landslides In Wayanad
Context: Recently, Wayanad, Kerala experienced severe landslides due to extreme rainfall and fragile ecological conditions, with over 140 mm of rain in 24 hours, reminiscent of the 2018 floods.
Understanding Landslides:
- Definition: Landslides are the downward movement of rock, soil, and debris on slopes, caused by factors like rainfall, earthquakes, volcanic activity, and human activities.
- Types: Includes slides, flows, spreads, topples, and falls, each defined by the movement and nature of materials involved.
Landslide Atlas of India:
- High Risk: India ranks among the top five landslide-prone countries. About 0.42 million sq. km (12.6% of land area) is prone to landslides.
- Regional Distribution: 66.5% in Northwestern Himalayas, 18.8% in Northeastern Himalayas, and 14.7% in the Western Ghats.
Major Landslide-Prone Areas in India:
- Regions: Northeastern region, Himalayas (Uttarakhand, Himachal Pradesh, Jammu & Kashmir), Western Ghats (Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu), and Araku region in Andhra Pradesh.
Causes of Landslides:
- Natural Causes:
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- Gravitational Forces
- Heavy Rainfall: Increases soil moisture, reducing cohesion.
- Earthquakes: Destabilise slopes through ground shaking.
- Erosion and Hydrological Factors: Undermine slope stability through water movement.
- Human Activities:
- Deforestation: Removes vegetation that stabilises soil.
- Construction and Land Use Changes: Disrupts natural drainage and load distribution.
- Infrastructure Development: Intensifies land pressure and disrupts natural drainage.
- Historical Deforestation: For agriculture and plantations weakens soil stability.
Differences Between Western Ghats and Himalayan Landslides:
- Western Ghats: Triggered by concentrated rainfall, overburdening of hills, mining, and anthropogenic activities.
- Himalayas: High seismicity, easily erodible rocks, young energetic rivers, and heavy downpour/snowfall.
Challenges of Landslides:
- Human Impact: Loss of life, displacement of communities, infrastructure damage, and economic impact.
- Environmental Impact: Soil erosion, vegetation loss, habitat destruction, and biodiversity effects.
Predicting Landslides:
- Complexity: Involves various geomaterials and environmental factors.
- Data Limitations: Insufficient data and technological limitations make predictions difficult.
Government Initiatives
- Strategies and Schemes: National Landslide Risk Management Strategy, Landslide Risk Mitigation Scheme, Flood Risk Mitigation Scheme, and National Guidelines on Landslides.
- Landslide Atlas of India: Provides detailed documentation of landslide events and risk assessments.
Recommendations and Measures:
- Expert Panels:
- Gadgil Report: Advocated for declaring the Western Ghats as Ecologically Sensitive Areas with limited development.
- Kasturirangan Committee: Suggested balancing development with environmental protection.
- Preventive Measures: Real-time monitoring, sustainable socio-economic progress, retaining walls, reforestation, responsible urban planning, and comprehensive early warning systems.
- Soil Nailing and Hydroseeding: Techniques used in Kerala to reinforce soil and promote plant growth to mitigate landslides.
Conclusion:
Regulation, education, and scientific research are crucial to mitigate landslide risks and protect vulnerable communities. Prioritising research, early warning systems, and sustainable practices is essential to reduce the impact of landslides.