Landslides result from factors like rainfall, geological conditions, and human activities, causing devastation to lives and infrastructure. The National Landslide Risk Management Strategy comprises risk assessment, early warning systems, infrastructure planning, and community awareness, aiming to minimize vulnerability and enhance resilience against landslide hazards in India.
UPSC Mains General Studies Paper – 3 Mains 2021
UPSC Mains Civil Services IAS Exam Question Paper – 2021
Approach
- Start with a brief introduction of the keywords the landslides .
- Describe the various causes and the effects of landslides.
- Mention the important components of the National Landslide Risk Management Strategy.
- Conclude suitably.
Answer
Introduction
- A landslide refers to the downward movement of a mass of rock, debris, or earth along a slope. It falls under the category of mass wasting, which encompasses any form of soil and rock movement driven primarily by the force of gravity.The occurrence of slope movement arises when the downward forces, primarily gravity, surpass the strength of the materials constituting the slope. Landslides can be attributed to three principal factors: geology, morphology, and human activity.India, a geographically diverse country with varied topography, is prone to natural hazards such as landslides.
Body
The various causes of landslides: Landslides can occur due to a combination of natural and human-induced factors. The causes of landslides can be categorised into the following:
Geological Factors
- Slope Composition: The type of soil and rock present on a slope plays a significant role in determining its stability. Loose, unconsolidated materials like clay and silt are more prone to landslides than cohesive rock formations.
- Slope Gradient: Steep slopes are more susceptible to landslides as the force of gravity acting on the slope is greater. A slope’s angle and its ability to retain moisture influence the stability of the slope.
- Geological Structures: Fault lines, joint patterns, and weak geological formations can contribute to the instability of a slope, increasing the likelihood of landslides.
Hydrological Factors
- Precipitation: Heavy or prolonged rainfall can saturate the soil, increasing pore water pressure and reducing its shear strength. This leads to a loss of stability and potential landslides.
- Surface Water: The presence of surface water, such as streams or rivers, can erode slopes and weaken their stability. Seepage and saturation of slopes due to water accumulation can trigger landslides.
Human-Induced Factors
- Deforestation: The removal of vegetation cover through deforestation reduces slope stability by reducing the interception and absorption of rainfall. Tree roots also help bind soil and prevent erosion.
- Construction Activities: Excavation, improper slope cuts, and modifications during construction projects can alter the natural slope stability, leading to landslides.
- Mining and Quarrying: The extraction of minerals and quarrying activities can weaken slopes, disturb natural drainage patterns, and trigger landslides.
- Irrigation and Water Management: Poorly designed irrigation systems or improper water management practices can lead to waterlogging and slope instability.
The various effects of landslides: Landslides can have significant and wide-ranging effects on both the natural environment and human communities. The effects of landslides can be categorised as follows:
- Loss of Life and Injury: Landslides can result in the loss of human lives and cause injuries. For instance, the 2014 Oso landslide in Washington, USA, claimed the lives of 43 people and caused multiple injuries when a large slope failed, burying an entire neighbourhood under debris.
- Infrastructure Damage: Landslides can damage or destroy infrastructure, disrupting daily life and economic activities. In 2020, heavy rainfall triggered landslides in Kerala, India, damaging roads, bridges, and buildings, and leading to the collapse of houses and disruption of transportation networks.
- Displacement and Loss of Property: Landslides can force communities to evacuate and result in the loss of homes and property. The 2017 Sierra Leone landslide in Freetown displaced thousands of people and destroyed houses, leaving many homeless and in need of immediate shelter and support.
- Environmental Impact: Landslides can have severe environmental consequences. The 2014 Oso landslide mentioned earlier caused the destruction of forests, altering the landscape and resulting in the loss of valuable wildlife habitat.
- Economic Consequences: Landslides can have significant economic impacts. The 2018 Kedarnath landslide in Uttarakhand, India, caused extensive damage to infrastructure, including hotels, shops, and roads, resulting in a decline in tourism and affecting the local economy.
- Disruption of Services: Landslides can disrupt essential services, leading to further hardships for affected communities. In 2021, landslides in Himachal Pradesh, India, damaged electricity transmission lines, resulting in power outages and affecting the provision of electricity to households and businesses.
- Psychological and Social Impact: Landslides can have long-lasting psychological and social effects on individuals and communities. The 2017 Mocoa landslide in Colombia resulted in the loss of homes, friends, and family members, leading to psychological trauma and community distress.
- Long-term Slope Instability: Landslides can create ongoing challenges by destabilising slopes and increasing the risk of future landslides. In 2022, heavy rainfall triggered landslides in the Idukki district of Kerala, India, causing recurring slope failures and necessitating long-term measures to address slope stability.
The important components of the India National Landslide Risk Management Strategy: The National Landslide Risk Management Strategy of India encompasses several important components aimed at mitigating landslide risks and reducing the impact of landslides. Some of these components include:
- Hazard Zonation Mapping: The strategy emphasises the development of hazard zonation maps that categorise areas based on their susceptibility to landslides. For example, in the state of Uttarakhand, hazard zonation mapping has been carried out to identify vulnerable areas and guide land-use planning decisions.
- Early Warning Systems: The strategy focuses on the installation of weather monitoring stations, rain gauge networks, and automated landslide monitoring systems in high-risk areas. These systems provide real-time data on rainfall patterns and ground movements, enabling authorities to issue timely warnings. For instance, in the Darjeeling district of West Bengal, early warning systems have been set up to alert communities about potential landslide events.
- Capacity Building and Awareness: The strategy emphasises the need for training programs, workshops, and educational campaigns to equip communities, government officials, and other relevant stakeholders with knowledge and skills to understand and respond to landslide risks. In Himachal Pradesh, awareness campaigns have been conducted to educate locals about landslide mitigation measures and emergency preparedness.
- Land-Use Planning and Regulation: The strategy emphasises the adoption of building codes and regulations that take into account landslide risks. It promotes measures such as slope stabilisation, proper drainage systems, and land-use zoning to prevent uncontrolled construction in high-risk areas. For example, in the hilly regions of Meghalaya, land-use planning regulations have been enforced to restrict construction activities in landslide-prone zones.
- Disaster Response and Recovery: The strategy recognizes the importance of an efficient disaster response mechanism to minimise the impact of landslides and facilitate post-landslide recovery. It focuses on improving emergency response systems, establishing emergency shelters, and coordinating relief efforts. Following the devastating landslides in Malappuram district, Kerala, in 2019, prompt disaster response measures were taken, including search and rescue operations, provision of relief materials, and the establishment of temporary shelters for affected communities.
Conclusion
- Hence, Landslides pose significant threats to both the environment and human communities. Understanding the causes and effects of landslides is essential for effective risk management. The National Landslide Risk Management Strategy encompasses important components that address risk assessment, early warning systems, capacity building, land-use planning, infrastructure resilience, community engagement, research and development, and institutional collaboration. By implementing these components, countries can work towards minimising the impacts of landslides and protecting lives, infrastructure, and the environment from this natural hazard.
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