Landslides in India: impacts and management – Explained, pointwise

Introduction

A landslide has struck the Kinnaur district of Himachal Pradesh, the 2nd time within 15 days, killing at least 14 people and burying several others. The catastrophe has been severe, with mud, rocks, and debris raining down on vehicles, including a state transport corporation bus on National Highway 5.

15% of the Indian landmass are prone to landslides, however, its vulnerability is going to rise in the future due to climate change and population pressures. This enhanced magnitude can be tackled by adopting a multi-pronged approach covering all aspects of disaster governance i.e. mitigation, preparedness, response, and rehabilitation.

What is Landslide?

A landslide is defined as the movement of a mass of rock, debris, or earth, down a slope due to the action of gravity. Areas with steep slopes, for example, mountainous regions, are particularly susceptible to landslide hazards. Earth flow, mass movement, mudflow, rotational slip, and avalanches are all examples of landslides. 

Types of Landslides

• Falls: It happens due to the abrupt movements of the mass of geologic materials, such as rocks and boulders, that become detached from steep slopes or cliffs.
• Topples: It happens due to the forward rotation of a unit or units about some pivotal point, under the actions of gravity and forces exerted by adjacent units or by fluids in cracks.
• Slides: In this type, rocks, debris, or soil slide through slope forming material.
• Spread: It usually occurs on very gentle slopes or flat terrain.

Landslides and India

• Landslides and avalanches are among the major hydro-geological hazards that affect large parts of India. 
• Around 15% of the country’s region is prone to landslides. The Himalayas of Northwest and Northeast India and the Western Ghats are two regions of high vulnerability.
• Some major recent incidents are Kerala (2018), Himachal Pradesh (2018), Uttarakhand (2018), Tamenglong-Manipur (2018), and Kalikhola, Manipur (June 2017).

Landslide Zonation Map

Causes behind Landslides

Natural causes

• Earthquakes: They cause a sudden shaking of earth’s crust which creates stress on materials, thus leading to landslides.
• Heavy Rainfall: The occurrence of heavy or continuous rainfall may lead to heavy landslides in the areas of steep slopes. Water works as a lubricating agent and loosens up the material. For instance, the 2013 Uttarakhand Cloudburst brought immense landslides in the region.

Anthropogenic causes

• Infrastructure Development: The creation of roads, railways, dams, etc. in the mountainous region can result in landslides. For instance, the development of Konkan Railways in western ghats is considered a significant reason behind the frequent occurrence of landslides in the region.
• Mining: It involves removing the surface of the earth for mineral exploration, which loosens the grip of material. Further explosions are also a part of mining, which may result in landslides.
• Deforestation: Trees are cut for agricultural and industrial activities which loosens the soil grip and makes the region more vulnerable to landslides. 
• Unsustainable Tourism: The rising tourist influx in the Himalayan region puts greater pressure on land as more infrastructure and amenities are needed to accommodate them. This leads to more construction and greater landslides. 

Landslide Vulnerability in India

• Climate change: The most recent report by the Intergovernmental Panel on Climate Change (IPCC) stated that a global rise of 1.5 degrees Celsius (from pre-Industrial times) was inevitable in the next two decades. This would increase glacier melt and more water would flow over the steep slopes, thereby generating more landslides.
• Tectonically active Himalayas: They are young fold mountains that lie on the convergence of two tectonic plates. This enhances the probability of earthquakes, which can result in an increased number of landslides.
• Population Pressure: India has only 2.4% of the world’s area, but holds approximately 17% of the world’s population. Further, the population is going to rise till 2050, this calls for creating more infrastructure in the fragile ecosystems. 
• Nature of Rivers: The rivers in Himalayan regions are mighty and in their youthful stage. They do a lot of downcutting, which enhances the occurrence of landslides.

Impacts of landslides

• Loss of Lives: The most traumatizing impact of a landslide is the loss of precious human and animal lives. In the recent Kinnaur Landslide, already 14 confirmed deaths have been reported.
• Restricts Movement: The mud, rocks, and debris moving down the slope create a barrier on critical transportation routes like highways, railway lines, etc. This restricts the movement of goods and people.
• Infrastructural Damage: Several houses, buildings, roads, and other infrastructure get damaged whenever a landslide occurs.
• Economic Losses:  A significant amount is spent on reconstructing the lost infrastructure, rehabilitating of masses, and providing relief support to the impacted people.
• Jeopardize Water Availability: When landslides occur on the slopes of a river valley, the sliding mass may reach the bottom of the valley and cause partial or complete blockage of the river channel. This accumulated mass of landslide debris resulting in the blockage of a river is commonly termed as a Landslide dam. It may impair the availability of water for nearby people.

Steps taken for Landslide Management in India

• National Landslide Risk Management Strategy (2019): It addresses all the components of landslide disaster risk reduction and management, which includes –
  • hazard mapping, monitoring, and early warning system, awareness programs, 
  • capacity building, training, regulations, and policies, stabilization and mitigation of landslides, etc.
• National Disaster Management Authority (NDMA) Guidelines on Landslide Hazard Management (2009): It tells measures that should be taken to avoid or mitigate the risk posed by landslide hazards. Some guidelines – 
  • Delineating areas susceptible to landslide hazards
  • Encouraging implementation of successful landslide remediation and mitigation technologies.
  • Developing institutional capacity and training for geoscientists, engineers, and planners is necessary for the effective management of the landslide hazard.  
• National Institute of Disaster Management (NIDM): It is a premier institute that provides Capacity Building support to various National and State level agencies in the field of Disaster Management & Disaster Risk Reduction.

However, the above efforts are unable to deliver optimum results due to limited resources, financial constraints, and the use of obsolete technology for landslide management. 

Suggestions

• First, states like Himachal Pradesh and Uttarakhand which are in the high-risk zone should take great caution in pursuing disruptive projects. There should be proper implementation of Environmental impact assessment norms before initiating mining or dam construction.
• Second, there should be the adoption of landslide micro zoning procedures for mountainous and other highly vulnerable regions.
• Third, more funding should be given to Landslide planning and mitigating agencies to improve disaster management potential.
• Fourth, there should be involvement of locally available trained manpower to intensify the hazard reduction and public awareness programs.
• Fifth, mitigation strategies like limiting agriculture to valleys and areas with moderate slopes, promoting large-scale afforestation programs, and construction of bunds to reduce the flow of water, etc. should be encouraged.

Conclusion

India has a high degree of vulnerability towards the occurrence of Landslides. It is therefore not possible for the government to completely stop their occurrence. Although, it can definitely curtail their adverse impact by developing robust resilience in consonance with the Sendai Framework for Disaster Risk Reduction 2015-2030.

Source: The Hindu (Article 1, Article 2)