Himalayan plunder: Manipur landslides raise environmental questions

Himalayan plunder: Manipur landslides raise environmental questions

Subject: Geography

Section: Indian Physical geography

Context: A large landslide that struck the Tupul Railway station building site on June 30, 2022, resulted in 61 fatalities and 18 injuries.

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• Extreme rains, long-term exposure to hill slopes cut for development projects, debris obstructing the flow of Ijei river and shifting land use patterns, such as deforestation, are thought to have contributed to the tragedy in the seismically active western Manipur region.
• The landslide was caused by an extensive slope cut for the construction of the railway station, presence of break in slope in the upslope area, affluence convergence of water and unprotected slope cut for long duration (from 2014 onwards).
• A major factor that caused the landslides was the debris restricting the normal water flow of Ijei river. The materials dumped at the railway construction sites and improper drainage made the hills geologically weak.
• Changes in the land use pattern on the top hill, caused by deforestation, jhum cultivation and banana cultivation, also accelerate soil erosion and might have triggered landslides.
• The fluctuation in the ongoing precipitation pattern and excessive rainfalls lead to the percolation of water below the slopes.
• Contour cutting/ gentle slope cutting per hydrological aspect can prevent huge water flow from uphill to downhill.
• Considering the long-term nature of the ongoing project, it is necessary to adopt regulatory and monitoring mechanisms at the vulnerable slopes along the railway line where the cut portion and yards are to be exposed.
• Reassessment of slope stability (Factor of safety) analysis for open cut and yard of the Jiribam-Tupul railway line, regular drone survey and monitoring to detect mass movement along the open cuts and yard as well as beyond railway land boundary before and after monsoon season without significant failure event, detection of subtle slope movement will likely help mitigate the problem.