Natural Disasters: Floods, Droughts, and Landslides Impact

Floods, droughts, and landslides are natural disasters that profoundly impact landscapes and communities. Floods occur when water exceeds normal levels, inundating areas, droughts signify prolonged water scarcity, affecting agriculture and ecosystems, and landslides involve the downward movement of rock and soil, posing threats to settlements. These events, driven by various environmental factors, demand comprehensive strategies for mitigation and management.

Sudden Threat: Understanding Landslides in Mountains

• Definition: A sudden movement of rock, boulders, earth or debris down a slope is termed a landslide.
• Features: They are natural disasters occurring mainly in mountainous terrains where there are conducive conditions of soil, rock, geology and slope
  • They are sudden, unpredictable and are largely controlled by macro or regional factors, landslides are largely controlled by highly localised factors. 

Landslides Risk Zones: Mapping Vulnerability Across India

• Very High Vulnerability Zone: Highly unstable, relatively young mountainous areas in the Himalayas and Andaman and Nicobar.
  • High rainfall regions with steep slopes in the Western Ghats and Nilgiris, the north-eastern regions,
  • Areas that experience frequent ground-shaking due to earthquakes. 
  • Areas of intense human activities, particularly those related to the construction of roads, dams, etc. are included in this zone.
• High Vulnerability Zone: All the Himalayan states and the states from the northeastern regions except the plains of Assam are included in the high vulnerability zones.
• Moderate to Low Vulnerability Zone: Areas that receive less precipitation such as Trans-Himalayan areas of Ladakh and Spiti (Himachal Pradesh).
  • Undulated yet stable relief and low precipitation areas in the Aravali.
  • Rain shadow areas in the Western and Eastern Ghats.
  • The Deccan plateau also experiences occasional landslides. 
  • Landslides due to mining and subsidence are most common in states like Jharkhand, Odisha, Chhattisgarh, Madhya Pradesh, Maharashtra, Andhra Pradesh, Karnataka, Tamil Nadu, Goa and Kerala.
• Landslides Safe Zone: The remaining parts of India, particularly states like Rajasthan, Haryana, Uttar Pradesh, Bihar, West Bengal (except district Darjeeling), Assam (except district KarbiAnglong) and Coastal regions of the southern States.

Consequences of Landslides: Disruptions, Floods, and Developmental Challenges

• They have a relatively small and localised area of direct influence.
• Roadblocks, destruction of railway lines and channel-blocking due to rock falls.
• Diversion of river courses due to landslides can also lead to flood and loss of life and property. 
• It makes spatial interaction difficult, risky as well as a costly affair, which adversely affects the developmental activities in these areas.

Mitigation: Targeted Strategies for Safer Communities

• Adoption of area-specific measures to deal with landslides. 
  • Promoting large-scale afforestation programmes.
• Regulating Infrastructure Development: In the high vulnerability zones, there should be restrictions on the construction and other developmental activities such as roads and dams.
• In Mountain Region: Limiting agriculture to valleys and areas with moderate slopes.
  • Control on the development of large settlements should be enforced. 
  • Construction of bunds to reduce the flow of water. 
  • Terrace farming should be encouraged in the northeastern hill states where Jhumming (Slash and Burn/Shifting Cultivation) is still prevalent.

Understanding the causes and effects of landslides, floods and Drought are crucial for implementing preventive measures and preparedness strategies to minimize their impact on communities and infrastructure in susceptible areas.

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