Wayanad Landslide

• Location: Vythiri taluk, Wayanad district, Kerala
• Impact: Multiple landslides flattened three villages, resulting in hundreds of deaths.

Possible Reasons Behind the Wayanad Landslide

• Heavy Rainfall
• Rainfall Measurement: The region received more than 140 mm of rainfall in 24 hours, significantly higher than the expected amount.
• Impact: Extreme rainfall leads to soil saturation and increased water flow between soil and rock layers, weakening the soil's binding force and triggering landslides.
• Hilly Terrain with Sharp Slopes
• Landslide Prone Area: Wayanad is one of the most landslide-prone districts in India, as per ISRO’s National Remote Sensing Centre's 2023 landslide atlas.
• Terrain Characteristics: The region has a layered structure with soil on top of hard rocks. Excess moisture from rainfall compromises the stability of this soil-rock interface, causing landslides.
• Loss of Green Cover
• Study Findings: A 2021 study indicated that 59% of landslides in Kerala occurred in plantation areas.
• Impact: Deforestation and loss of vegetation exacerbate the fragility of the terrain, increasing susceptibility to landslides.
• Climate Change
• Warming Trends: The southeast Arabian Sea is warming, leading to unstable atmospheric conditions and increased rainfall.
• Effects: The warming causes deep cloud systems to form, contributing to unpredictable and intense rain patterns.
• Environmental Neglect and Mining
• Gadgil Committee Recommendations: Since 2011, the Western Ghats Ecology Expert Panel, led by ecologist Madhav Gadgil, recommended declaring Wayanad’s hill ranges as ecologically sensitive.
• Recommendations:
• Ecological Sensitivity: 75% of the Western Ghats area should be declared ecologically sensitive due to dense forests, endemic species, and unique geology.
• Activity Restrictions: The panel suggested banning mining, quarrying, new thermal power plants, hydropower projects, and large-scale wind energy projects in ecologically sensitive areas.
• Implementation Issues: Despite the recommendations, there has been resistance from state governments, industries, and local communities, leading to non-implementation of the panel's suggestions.

Landslide Prevention Measures

1. Banning/Regulating Construction Activities in Ecologically Sensitive Zones (ESZ)

• Gadgil Panel Recommendations: The 2011 Gadgil panel report suggested declaring the Western Ghats, covering 129,000 square kilometers across six states, as an Ecologically Sensitive Zone (ESZ).
• Objective: To restrict or regulate construction activities in sensitive areas to prevent disturbances that could exacerbate landslide risks.

2. Upgrading Institutional Capacities and Coordination

• Improved Weather Predictions: The Indian Meteorological Department (IMD) should integrate advanced technologies for more accurate and timely weather forecasts.
• Objective: Enhanced prediction capabilities can help in early warning systems and better preparation for extreme weather events.

3. Engineering Solutions

• Slope Stabilization: Adding structural elements like retaining walls, rock bolts, or nets to slopes to enhance their stability.
• Objective: To reduce the likelihood of soil movement and landslides.
• Grading and Terracing: Modifying the shape and gradient of slopes through grading and terracing to decrease the risk of landslides.
• Objective: To create more stable landforms and reduce erosion.
• Soil Reinforcement: Adding materials such as geotextiles or cement to strengthen the soil on slopes.
• Objective: To increase the soil's strength and stability, reducing the risk of landslides.

4. Natural Solutions

• Vegetation Control: Planting trees, shrubs, or grasses to stabilize soil, absorb excess water, and prevent erosion.
• Objective: Natural vegetation helps to anchor the soil and manage water flow, which can prevent landslides.
• Mulching: Applying a layer of organic or inorganic material to the soil surface to retain moisture, prevent erosion, and stabilize slopes.
• Objective: To protect the soil surface and enhance its stability.
• Bioengineering Techniques: Combining plant growth with engineering principles to stabilize slopes.
• Objective: To use vegetation in conjunction with engineering methods for effective slope stabilization.
• Water Management: Implementing systems to manage and slow down water flow, allowing it to infiltrate the soil gradually.
• Objective: To prevent excessive water runoff and soil saturation that can trigger landslides.

5. Early Warning Systems and Monitoring

• Landslide Monitoring: Utilizing technology such as satellite imagery, ground sensors, and real-time monitoring systems to detect early signs of potential landslides.
• Objective: To provide timely alerts and enable prompt evacuation or mitigation actions.

6. Emergency Preparedness for Landslides

• Preparedness Plans: Developing and implementing emergency response plans that include evacuation routes, communication strategies, and community drills.
• Objective: To ensure that communities are ready to respond effectively in the event of a landslide, minimizing risks and damage.

Landslide Atlas of India

About the Atlas:

• Prepared by: National Remote Sensing Centre (NRSC) of ISRO.
• Coverage: 147 districts across 17 states and 2 Union Territories in the Himalayas and Western Ghats.
• Database:
• Landslides Mapped: Approximately 80,000 landslides documented from 1998 to 2022.
• Categories:
• Seasonal Inventory: Landslides from specific rainy seasons (e.g., 2014, 2017).
• Event-Based Inventory: Major landslide events (e.g., Kedarnath disaster, Kerala floods, Sikkim earthquake).
• Route-Wise Inventory: Landslides along significant tourist and pilgrimage routes.
• Data Sources: High to very high-resolution satellite data (IRS-1D, Resourcesat, Cartosat, Sentinel, Pleiades, WorldView) and aerial images.

Key Findings:

• Highest Number of Landslides (1998 – 2022):
• Mizoram: 12,385 events (8,926 in 2017 alone).
• Uttarakhand: 11,219 events.
• Kerala: Not specified, but significant.
• Nagaland: 2,071 events (2,132 total, with most occurring in the 2017 monsoon).
• Manipur: Similar trend to Nagaland.
• Alarming Situations:
• Uttarakhand:
• Recent Issues: Land subsidence in Joshimath.
• Landslides: Second highest number (11,219).
• Kerala:
• Recent Trends: Significant landslides post-2018 floods.
• Year-Wise Events:
• 2018: 5,191 landslides
• 2019: 756 landslides
• 2020: 9 landslides
• 2021: 29 landslides
• Most Vulnerable District:
• Rudraprayag, Uttarakhand:
• Ranking: Top among 147 vulnerable districts.
• Characteristics: Highest landslide density, high exposure to population and houses.

Conclusion:

The Landslide Atlas of India provides a comprehensive view of landslide occurrences, highlighting the regions most affected and the trends over time. The data underscores the significant risk faced by states like Uttarakhand and Kerala, which have experienced severe landslide events in recent years. The findings also emphasize the importance of targeted interventions and preparedness in the most vulnerable districts to mitigate the impacts of future landslides.