The recent Wayanad landslides have emerged as one of Kerala's most devastating landslide-related disasters in terms of casualties, with more than 100 people confirmed dead. This incident has surpassed previous landslides in scale and impact, making it a significant tragedy for the region.
FACTORS BEHIND THE WAYANAD LANDSLIDE:
The Wayanad disaster highlights the combined influence of extremely heavy rainfall, fragile ecological conditions, and increasing population pressures in the region.
High Landslide Susceptibility: According to the Landslide Atlas released by the Indian Space Research Organisation's (ISRO) National Remote Sensing Centre last year(2023), 10 out of the 30 most landslide-prone districts in India are in Kerala, with Wayanad ranked 13th. This highlights the district's significant vulnerability to such disasters.
Extremely Heavy Rainfall: Wayanad experienced unprecedented rainfall, with over 140 mm in a 24-hour period, five times the expected amount. Certain areas within the district reported over 300 mm of rainfall, significantly contributing to the disaster.
Fragile Ecology and Geological Conditions: Wayanad, part of the Western Ghats, is characterized by steep slopes and a geological composition of soil layers atop hard rocks. Heavy rainfall saturates the soil, causing water to flow between the soil and rock layers, weakening the soil's grip and triggering landslides.
Population Pressures and Land Use: Increasing population and human activities have exacerbated the region's vulnerability to landslides. Environmentalists emphasize the need for strict land use regulations to prevent activities that heighten risks.
Ignored Warnings from the Madhav Gadgil Panel Report: The Madhav Gadgil-led Western Ghats Ecology Expert Panel (WGEEP) report of 2011 had warned against activities in Ecologically Sensitive Areas (ESAs) like Meppadi, where the landslide occurred. The report recommended categorizing regions into ESZ-I and ESZ-II with strict restrictions on quarrying and construction, which were largely ignored by successive governments.
WHAT ARE LANDSLIDES:
The term “landslide” denotes the downward and outward movement of materials including rock, earth or debris down a slope due to gravitational force.
Avalanche is the down slope movement of large detached mass of snow and ice along with rock fragments, soil and vegetation.
They are disasters of Hydrogeological origin, which result in the failure of the materials which fall down the slope due to force of gravity.
INDIA’S VULNERABILITY:
According to the Geological Survey of India, landslides affect at least 12.6% of India's land area, which exceeds 0.42 million square kilometres. The phenomenon is pronounced during the monsoon period.
Landslides of different types are frequent in geodynamically active domains in the Himalayan and Arakan-Yoma belt of the North-Eastern parts as well as in the relatively stable domains of the Meghalaya Plateau, Western Ghats and Nilgiri Hills.
The two regions most vulnerable to landslides are the Himalayas and the Western Ghats.
The Himalayan mountain belt is comprised of tectonically unstable younger geological formations subjected to severe seismic activity. The Western Ghats and Nilgiris are geologically stable but have uplifted plateau margins influenced by neo-tectonic activity.
Compared to the Western Ghats region, the slides in the Himalayas region are huge and massive, and in most cases, the overburden along with the underlying lithology is displaced during sliding, particularly due to the seismic factor.
Sporadic occurrences of landslides have been reported in the Eastern Ghats, Ranchi Plateau, and Vindhyan Plateau as well.
The Geological Survey of India (GSI) is the nodal agency for landslide management.
WHAT MAKES INDIA VULNERABLE:
Young geology:
Himalayas are mostly composed of highly unconsolidated sedimentary rocks, which get easily disturbed under stress.
For instance, the 2013 Kedarnath floods, exacerbated by the region's fragile geological structure, resulted in over 5,000 deaths. The disaster highlighted the instability of the Himalayan geology under stress?
Swift rivers:
The numerous rapid flowing streams in the Himalayan and Western ghats region erodes and undercuts hills, creating steep banks which aid in rapid movement of materials.
For instance, the August 2018 landslides in Kerala, caused by unprecedented rainfall, were worsened by the natural erosion processes of swift rivers, leading to significant destruction and loss of life.
Tectonic activities:
Himalayas lie at the convergence zone of the Indian and Eurasian tectonic plates. Hence, the range is geologically very active, resulting in the formation steep slopes, fragile rock structure and rugged topography.
For instance, the 2021 landslides in Himachal Pradesh, triggered by heavy rains and tectonic activity, caused significant damage, blocking highways and resulting in fatalities?
Heavy rainfall:
Water or snowfall can trigger landslides as it alters the pressure within the slope, which leads to slope instability. Also, it can lead to the rise in groundwater levels and formation of water saturated particles. The Himalayas and the Western ghats are among the areas that receive short-period, high-intensity rainfall and hence landslides are frequent here.
For instance, the recent Wayanad disaster, with over 140 mm of rainfall in 24 hours, is a stark example of how intense rainfall can cause devastating landslides?.
Anthropogenic activities:
Deforestation, highway and building excavations, mine-waste piles, open-pit mines and quarries and shifting cultivation result in the region alters the slope and leads to landslides. Also, hydraulic constructions such as Multipurpose dams alters the groundwater levels, thereby aiding landslides.
For instance, the Char Dham road project in Uttarakhand has significantly increased landslide risks by damaging the fragile Himalayan ecosystem. The project involved extensive cutting of hills and deforestation, which destabilized slopes and led to numerous landslides?.
Activities in Ecologically Sensitive Areas:
The Madhav Gadgil-led Western Ghats Ecology Expert Panel (WGEEP) report of 2011 warned against activities in Ecologically Sensitive Areas (ESAs) and recommended strict restrictions on quarrying and construction.
For instance, ignored warnings from the Madhav Gadgil report about regulating activities in Ecologically Sensitive Areas like Meppadi, where the recent Wayanad landslide occurred, have increased vulnerability due to continued quarrying and construction.
Forest fires:
Severe wildfires damage the forest canopy, the plants, as well as the soil. The loss of deep-rooted vegetation creates loose soil. These factors can result in increased runoff after intense rainfall or rapid snowmelt, which increases chances of landslides.
NDMA GUIDELINES ON LANDSLIDE MANAGEMENT:
The National Disaster Management Guidelines for Management of Landslides and Snow Avalanches include a wide range of scientific, planning, and administrative tools to address various aspects of these hazards to effectively reduce losses from them.
OTHER MEASURES TAKEN:
National Landslide Risk Management Strategy:
It is a strategy document by the NDMA to strengthen and mainstream landslide management. Its key aspects include:
Preparation of Landslide Hazard Zonation maps
Developing and implementing Landslide Monitoring and Early Warning System
Participatory approach in awareness generation and preparedness
Management and Inclusion of new technology inputs for capacity building and training programs
Preparation of Mountain Zone Regulations and Policies
Stabilization and Mitigation of Landslide and Creation of Special Purpose Vehicle (SPV) for Landslide Management
Landslide Atlas of India:
The National Remote Sensing Centre (NRSC) under ISRO has released the Landslide Atlas of India in 2023. It is a detailed guide identifying landslide hotspots in the country.
For the first time, scientists did a risk assessment on the basis of 80,000 landslides recorded between 1998 and 2022 in 147 districts in 17 states and two Union Territories to build a "Landslide Atlas" of the country.
The atlas used satellite data of ISRO to map all seasonal and event-based landslides, like the Kedarnath disaster in 2013 and landslides triggered due to the Sikkim earthquake in 2011.
National Landslide Susceptibility Map by IIT Delhi:
IIT Delhi has developed India's first national landslide susceptibility map with high-resolution mapping at 100 square meters. The map identifies traditional and new high-risk zones, including areas in the Eastern Ghats. Using ensemble machine learning, it improves prediction accuracy and addresses data gaps.
National Landslide Susceptibility Mapping (NLSM) programme:
Geological Survey of India has launched a national programme on landslide susceptibility mapping with an aim to cover the 0.42 million sq. km landslide prone areas of the country. This national programme was formally launched in 2014.
CHALLENGES TO LANDSLIDE MITIGATION & MANAGEMENT:
Ad hoc strategies:
Landslide managementmeasures are generally planned on an ad hoc basis to give immediate relief to affected people. The strategies focus on post disaster relief measures than on pre-disaster risk reduction planning.
Outdated maps:
Majority of the existing Land Zonation Maps (LSZ) lack micro levels details of slopes and landslide events of the past. Also, State-wise and district-wise landslide zonation maps are mostly not available for landslide prone areas.
Weak forecasting:
In Indian Himalayas, the poor network of weather stations and lack of high elevation rain gauges mars the collection of useful data that can help establishing meaningful predictions. Climate change induced variations is worsening this situation.
Poor law enforcement:
Laws exist to regulate activities in landslide-prone areas, but enforcement is lax, as seen in widespread construction, illegal mining, and deforestation in sensitive regions like the Himalayas and Western Ghats.
Lack of Public awareness:
The main cause of losses during landslides is the lack of awareness among the people regarding the potential landslide zones and mitigation strategies, as awareness programmes are not reaching the communities.
Population pressure:
The demand for land in India is severe due to its rising population. Also, hilly areas have economic significance in the form of plantations, timber and construction material. Hence, it is difficult to completely prohibit land use in the areas or enforce stringent environment laws.
WAY FORWARD:
Preparedness-Centric Approach: Implement integrated pre-disaster preparation and disaster risk mitigation strategies as a key aspect of governance and development planning in India.
Research and Development: Establish a national center for landslide research, studies, and management; develop strategies for micro and meso level zonation maps and a landslide database.
Budgetary Allocation: Allocate funds specifically for landslide management in the budgets of Public Works, Irrigation, Rural Engineering Services, and Disaster Management Departments in landslide-prone states.
Eco-Sensitive Zones: Implement recommendations from the Madhav Gadgil report to establish Ecologically Sensitive Zones (ESZs) across the Western Ghats, regulating activities such as quarrying and construction to preserve the fragile ecosystem and prevent landslides.
Forecasting & Early Warning Systems: Enhance forecasting capabilities through maintenance and investment in new systems, and utilize IT tools for real-time data dissemination and warnings.
Techno-Legal Regime: Regulate development in landslide-prone areas with specific land use policies, zoning regulations, and socio-economic profiling of local communities.
Community Participation: Engage local communities and NGOs in awareness and capacity building, including Community Education Programmes in vulnerable areas.
International Cooperation: Facilitate interaction between state governments, NDMA, and international bodies to exchange best practices and advancements in landslide management.
PRACTICE QUESTION:
Q. Discuss the various factors that contribute to India's vulnerability to landslides. Suggest comprehensive measures to mitigate landslide risks in India. (15 marks, 250 words)
