Mains Daily Question
March 27, 2024
Q.1 Explain the concept of "land subsidence" and its distinction from "landslides." Discuss the measures that can be implemented to address the impacts of land subsidence. (10M/150W)
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Approach to the Answer: Understanding and structuring the answer: The question has three main headings: 1) land-subsidence 2) difference between land-subsidence and landslide 3) Solution to reduce the crisis. Introduction: Type 1: You can introduce by talking about the recent land-subsidence crisis in Joshimath or Type 2: Can also start with definition of land-subsidence. Body: Heading 1: Write about what is meant by the term land subsidence Heading 2: Differentiate between land subsidence and landslides in a tabular form Heading 3: Write about the different methods to reduce land subsidence crisis. Conclusion: Type 1: You can include recommendation by any committee/report in the form of way forward or Type 2: You can also mention the harmful effect of land subsidence and how to deal with it in brief. |
Answer:
The recent land subsidence crisis in the Joshimath town of Uttarakhand has caused panic among environmentalists not only in India but across the world. The subsidence increased the occurrence of structural fissures in households, necessitating the evacuation of inhabitants to state-operated aid facilities highlighting the extent of the crisis.
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Land Subsidence |
Land subsidence is gradual settling or sudden sinking of the Earth’s surface due to removal or displacement of subsurface earth materials. Subsidence is often caused by the removal of water, oil, natural gas, or mineral resources out of the ground by pumping, fracking, or mining activities.
It can also be caused by natural events such as earthquakes, soil compaction, erosion and sinkhole formation. Subsidence can occur over very large areas such as whole states or small corners such as a person’s garden.
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Difference between land subsidence and landslide: |
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Land Subsidence |
Landslide |
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1. Landslide refers to a downslope movement of earth materials (rock or soil) under the effect of gravity. |
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2. Landslides encompass all categories of gravity related slope failures in earth materials. Its cause can be both natural or man-made. |
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3.There is both vertical and horizontal movement involved. |
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4. Landslides typically occur on steep slopes and can be triggered suddenly. |
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Various solutions to reduce land subsidence crisis: |
- Deep soil mixing: It involves injecting stabilising agents deep into the ground to reinforce the soil and prevent land subsidence caused by soil compression.
- Artificial recharge: It involves injecting water into depleted aquifers to replenish them, thus reducing the need for excessive pumping and preventing further subsidence.
- Alternative construction techniques: Using alternative construction techniques such as lightweight building materials and foundation systems can help reduce the weight of buildings thus minimizing the risk of land subsidence.
- Ground improvement techniques: such as deep soil mixing and soil stabilisation can help reinforce weak or soft soils to enhance the stability of structures and prevent subsidence in cases where a mass of buildings is unavoidable.
- Planting trees: Planting trees on slopes can help to strengthen soil and can help stabilize a slope. Trees and other deep-rooted plants are particularly effective in holding the soil together.
- Control of drainage: It is essential to manage and maintain drainage systems in hilly areas because inadequate drainage can cause the land to sag. To move water away from slopes and prevent erosion, culverts or other drainage systems can be installed.
- Planning and zoning: With careful planning and zoning, structures can be kept away from areas that are prone to subsidence. This may require the declaration of some places as no-build zones or the adoption of unique construction methods in high-risk areas. This will help in mitigating the impacts of land subsidence.
In India, the main causes of subsidence are the unregulated pumping of groundwater and the rapid pace of urbanization. It is important for authorities to consider and implement measures to mitigate the risks of subsidence, which may include better planning and regulation of construction projects in the area, proper regulation of mining activities, early warning systems, disaster preparedness plans, and community-based disaster management initiatives.
