Dr K S Anoop Das, an ecological conservation expert, talks to TOI on how we can improve our hazard mapping and risk management.
Dr K S Anoop Das is an assistant professor at the Centre for Conservation Ecology & dept of Zoology, at MES Mampad College. He also serves as a visiting professor at WSL The Swiss Federal Institute for Forest, Snow and Landscape Research, Switzerland.
Edited excerpts of an interview:
Was the landslides a disaster waiting to happen? Wayanad was among the vulnerable districts mentioned in Isro’s Landslide Atlas of India released in 2023 Feb. Central govt recently said that the regional Landslide Early Warning System will be available nationwide by 2030. Why don’t we still have foolproof warning systems?
Our past experiences teach us that we should be prepared for calamities in areas prone to heavy rainfall. Kerala, with an average annual rainfall of over 3,000mm, receives significantly more rain than the Indian average of approximately 1,000mm. In this instance, there were no warnings issued by any govt agencies. Climate change-induced heat has significantly increased sea evaporation, leading to the formation of heavy nimbus and cumulus clouds. These clouds are likely to condense above the mountains, potentially resulting in heavy downpours or cloudbursts rather than normal rain. A major reason for much of the devastation is the lack of coordination among relevant departments, highlighting our failures in
disaster management
preparedness.
The Geological Survey of India has a National Landslide Forecasting Centre in Wayanad. When it was pointed out that its advisory on July 29 put the landslide possibility at ‘low’ for the Wayanad district, GSI said the process was a “part of building a prediction model”, which will take 4-5 years to be ready for public use…
Our data collection process is highly complex and involves numerous factors, including obtaining consent from various departments such as agriculture, revenue, panchayats and estate managers. Additionally, internal interests can influence or divert the objectives. In short, the responsibility lies with a system that operates on a case-by-case basis. Another issue is the lack of continuity, follow-up, and the fragmented nature of projects with similar objectives. Authorities should have installed rain sensors in the region to measure soil water pressure and intensity. This data could have been used to alert their network, which in turn, would notify revenue officials and residents.
Experts have pointed out that agencies such as IMD, Central Water Commission, GSI etc have to work in tandem and that we need a multi-institutional framework for developing robust landslide prediction systems...
Despite numerous studies on disaster-prone areas, there’s a glaring gap between research and implementation. While knowledge is abundant, its practical application in formulating effective mitigation strategies remains a persistent challenge.
As someone living near the epicentre of the disaster, what are your thoughts on the causes behind the disaster?
A study conducted in 2020 following the Kavalappara and Puthumala landslides offered recommendations for better land use planning and the implementation of real-time flood and landslide monitoring systems. It also emphasized the importance of building community resilience in high-risk areas. The study identified structurally weakened bedrocks and compromised residual materials, worsened by human activities, loss of cohesive strength and saturation of the earth, as primary triggers for the landslides. The same reasons are the factors behind the present disaster.
Does climate change influence the frequency and intensity of landslides?
Climate change is expected to heighten the frequency and intensity of landslides by causing more extreme weather events, such as intense and prolonged rainfall, as well as higher temperatures that accelerate snowmelt. These conditions result in greater soil saturation and increased runoff, both of which can trigger landslides. Moreover, shifts in vegetation patterns due to climate change can further impact slope stability.
Given the numerous studies conducted after repeated tragic events, do you believe that neglecting disaster studies is the real cause of the issue? Could collaboration with international agencies be the solution?
The benefits of scientific discoveries have been shared by many nations worldwide. Therefore, collaborations in these fields should be promoted, and a robust interconnected alert system with coordinated efforts from relevant departments should be established.
What are the immediate and long-term environmental impacts of landslides on affected areas?
The landslide-affected area turns into monotonous plains scattered with rocks and debris. The lack of topsoil means it will take a long time to restore the landscape. Immediate environmental impacts include vegetation destruction, wildlife habitat disruption, and altered waterways leading to flooding. Long-term impacts involve changes in topography, loss of fertile soil, and lasting ecosystem disruption. Landslides can also cause sedimentation in rivers and lakes, affecting water quality and aquatic life.
Can you recall any recent advancements in landslide prediction and monitoring technologies?
Recent advancements in landslide prediction include remote sensing technologies like satellite imagery and LiDAR to detect terrain changes and identify potential landslide zones. Ground-based systems such as GPS, inclinometers, and piezometers offer real-time data on slope movement and soil conditions. Improved data analysis and modelling have also enhanced prediction capabilities. A study in Switzerland revealed that floods, landslides, and related hazards cause significant annual damage. To address this, the Swiss Federal Research Institute WSL has maintained a comprehensive flood and landslide damage database since 1972. This invaluable resource is primarily compiled from news reports and records of financial losses, casualties, and event details. It offers crucial insights into disaster patterns, aiding in hazard mapping and risk management strategies.
Do quarries and plantations contribute to landslides? A 2022 study revealed that Wayanad’s forest cover decreased by 62% between 1950 and 2018, while plantation areas increased by 1,800%...
Quarries, despite their size, only affect a small fraction of the land area and extract granite primarily from the top 50% of the surface. But that is not the case with plantations. Forests have a complex, multi-layered structure where rainfall is distributed through various layers like the canopy, sub-canopy, and shrubs. Rainfall hitting the canopy is scattered and filtered through these layers before reaching the ground. Consequently, only a fraction of the rainfall penetrates the soil, with much absorbed by leaves, roots, and forest floor. In the case of plantations, however, rainfall directly reaches the ground and flows into rivers with less natural filtration.
