The death toll from the Wayanad landslides crossed 400 and around 152 people are still missing.
What is landslide?
Landslides– They are hydro-geological hazards of mass wasting of rock falls, mudflows, shallow or deep-seated slope failures and debris flows happening over surface and sub-surface.
Impacts – It leads loss of live and large scale destruction of infrastructures, properties and industries.
It profoundly alters the landscape of the region causing loss of flora and fauna.
It changes the course of river and divert in path.
It forces people in the region to migrate.
India - 15 % of the India’s landmass is prone to landslides.
It includes majorly of
Himalayas
The Northeastern hill ranges
The Western Ghats and the Nilgiris
The Eastern Ghats
The Vindhyas
Measure taken – Government had formed Gadgil expert committee in 2011 and Kasturirangan committee in 2012.
Landslide atlas has been prepared by ISROs National Remote Sensing Center and National Landslide Risk Management Strategy has been formed by National Disaster Management Authority.
Monitoring by satellites like IRS-1D , Resourcesat, Cartosat, Sentinel , InSAR are used.
River Basin specific Flood Early Warning System was developed to handle the landslide associated with floods.
Landslide Risk Mitigation Scheme (LRMS) was started to provide financial support for landslide prone states.
Why Kerala is prone to landslide disaster?
Landslide in Western Ghats – It is characterized by a lateritic cap and steep slopes in Western Ghats in the South Konkan coast besides Nilgiris.
Laterite cap – Thick laterite soil cover.
Vulnerability of Kerala - About 8% of the area in the Western Ghats in the Kerala is labelled as a critical zone for mass movements.
According to the landslide atlas in 2023, 10 out of the 30 most landslide-prone districts in India were located in Kerala, with Wayanad ranked 13th.
Status of Kerala’s vulnerability - Of the 3,782 landslides between 2015 and 2022, 2,239 (nearly 59.2%) were reported from Kerala.
In 2022, the Ministry of Earth Sciences informed that Kerala witnessed the highest number of major landslides in the country over the past seven years.
Causes – There are natural and man-made causes.
Geographic vulnerability – Roughly 50% of Kerala consists of hills and mountainous regions with slopes greater than 20 degrees, making these areas prone to landslides during heavy rains.
Disruption in soil cover - Western Ghats in Kerala are marked by thick soil cover but human interventions have affected them.
During monsoon, the soil gets saturated due to percolating rainwater, making it unstable and when the water content reaches a threshold level, the soil mass becomes weak triggering debris flows.
Changing nature of clouds – The thicker cumulonimbus clouds, which extend up to 14 km in height and could create sudden, short spells of heavy rain over smaller areas, are forming over Kerala during the Southwest monsoon.
Earlier, low-hanging, thinner clouds were usually the norm.
Extreme rains – It is intensifying across India and over the Western Ghats from Kerala to Maharashtra.
Cyclones in Arabian Sea - The Arabian Sea is warming at a high rate and with it, the possibility of severe cyclonic storms is rising.
All over Kerala, the monsoon pattern has been changing.
Climate change – Spells of heavy rain, which lead to calamities like floods and landslides, are a result of climate change induced by global warming.
Anthropogenic causes – There is widespread deforestation and denuding of hills due to landform changes.
Unsustainable developments – Unscientific construction activities in vulnerable areas also lead to disasters.
Deforestation – Reduction in forest cover makes the soil in the slopes loose and increase the fragility of the terrain.
59% of the total landslides in Kerala occurred in plantation areas.
Lack of updated data - Engineering structures are being built based on the amount of rainfall and intensity of rainfall in older days.
Blockage of water channels – Small drainage channels present on the surface of the hilly areas are blocked by erecting buildings and contour bunds block their natural flow.
During the rains, the water that percolates get concentrated leading to increased pore pressure along the channel.
Indiscriminate quarrying – Such activities in Ecologically Sensitive Areas (ESAs) make the landscape unstable.
Misgovernance – Measures recommended by the expert committed were neglected.
In 2011, Western Ghats Ecology Expert Panel led by Madhav Gadgil had had recommended that the entire Western Ghats be notified as ESAs.
The Kasturirangan committee reduced the extent of ESAs to 37% of the Western Ghats.
What lies ahead?
There is a need to rethink new or added risk factors while constructing roads or culverts.
All mountain drainage channels should be free helping easy runoff.
Maintaining adequate buffer zones in constructing buildings on or near water channels.
Ban on mining, quarrying and other red category industries new thermal power plants, hydropower projects and large-scale wind energy projects in ecologically sensitive zones.
Increase the forest cover in the region with endemic species of trees.
Reducing the population pressure on eco sensitive sensitive regions.
Implementing the Gadkil and Kasturirangan expert committee recommendations.
Sensitizing people, tourism and industries sector about the ecological vulnerability of the region.
Development of landslide early warning systems.
Capacity development of National and State Disaster Management Authorities to handle landslides.
