Wayanad tragedy: Landslides natural.. can’t prevent them but impact can be minimised
WAYANAD: The devastating landslides in Wayanad that killed hundreds and left thousands homeless have once again brought climate change to the limelight.
Amid the raging debate over whether the landslides were caused by natural fury or human intervention, TNIE brings together four experts to ponder over the causes.
In a freewheeling chat, Dr V Ambili, deputy director general, Geological Survey of India, Kerala unit, Dr K G Thara, former head, Disaster Management Centre, Kerala, Dr Sajin Kumar K S assistant professor in geology, University of Kerala, and Kerala State Landslide Advisory Committee member and Sridhar Radhakrishnan, environmentalist and policy observer, deliberate on the reasons, contributing factors, Kerala’s vulnerability, and disaster preparedness.
Excerpts
We’ve just witnessed two devastating landslides in Wayanad. What caused them?
Ambili: Many factors influence landslides. Kerala’s terrain, with its tropical humid climate, is prone to landslides. This landslide started at an altitude of 1,500m and later had a sharp drop to 800m. Besides intense soil formation and a sharp slope, the entire terrain is a tectonically active zone, especially towards the northern part. My study of the Chaliyar basin has clearly shown the river exhibiting old-age symptoms (like braiding and delta formation at the confluence with the sea) in the early stages of its course. The presence of a valley in Nilambur in the upper reaches shows signs of tectonic activity. It has been proved that the area comes under Zone-2 for neotectonic activity. This means there are fractures in the rocks that get reactivated under weather conditions (heavy rain).
What symptoms are usually seen in a landslide-prone area?
Ambili: The river is seen braiding here, in its upper reaches. Water always follows gravity. But if the river takes a turn, it is only because of a groove-like structure to facilitate it. During the landslide, the debris came down en masse, breaching the normal course.
What are the characteristics of such a zone?
Ambili: Weather is a major factor in determining landslides in a susceptible area. Other factors are slope, type of soil, structure of rocks, aspect etc. When there is a geological change, all such factors get reactivated. Water has ways to seep out of rocks as springs. But when the rain is heavy and continuous, it goes beyond the capacity of rocks to withhold water. When it crosses the threshold limit, these burst with disastrous effect.
Does human intervention figure in this?
Ambili: Human intervention is not the reason behind this landslide. The rocks couldn’t hold the water due to torrential rain in a place with a high slope.
What kind of human activities contribute to landslides?
Ambili: Quarries are a major contributor. We operate quarries without studying the geology of the area. There are many fractured quarries. The blasting that takes place in quarries will result in rock-fall in other locations. Plantation also contributes to landslides. It should be suited to the location. Plants should be chosen according to the soil and rock types. People have the habit of obstructing first-order streams to prevent them from entering their property. If we block the flow, the water seeps down and exerts pressure, resulting in smaller landslides. The landslides at Erattupetta were due to such human interventions. In Thrissur, we have seen people converting streams into pathways and roads.
Dr Thara, how do you see the current landslides from a disaster-management perspective?
Thara: Human interventions aggravate landslides. This landslide happened in a forest area above a populated area. The township was developed to facilitate plantations. The valley marked by such mono-crop cultivation dilutes the biodiversity required to prevent a landslide. There are large-scale human interventions in the name of promoting tourism. A lineament map gives a picture of rock-fractures beneath the soil. Calamities happen at places with maximum lineaments, the impact of which increases through human interventions.
You spoke about tourist inflow. Have we conducted any studies on the carrying capacity of Wayanad?
Thara: No, we haven’t. Any place with a slope greater than 20 degrees is landslide-prone. In Kerala, more than 50% of places are like that. When we construct multi-storey buildings atop hills, they exert greater pressure because of their weight, and landslides happen. Similarly, cutting the toe-end of the slope to build houses or canals also causes landslides.
The Wayanad landslide should have been declared a national calamity the very next day. The fact that they haven’t done it can be termed as apathy or a lack of political will. We may also have to term the construction of national highway as a national calamity... there are no safety precautions adopted.
Sridhar, in your opinion, has human intervention aggravated landslides at Mundakkai and Chooralmala?
Sridhar: I have gone through the landslide data between 1950 and 2018. Wayanad had a forest area of 85% in the 50s. By 2018, 62% of it was lost. At the same time, the plantation area has increased by 1,500% during the period. We should look at the Madhav Gadgil panel report in the light of the seven-decade long interventions made. According to him, 75% of the Western Ghats should be included in the list of ecologically sensitive areas. Both Meppadi panchayat (under which falls Mundakkai and Chooralmala) and Vellarimala were included in Zone-I. The areas where the landslides happened were tea estates. The second issue that we are clearly facing is the impact of climate change. According to a report by the Hume Centre for Ecology and Biodiversity, a staggering 4,000mm rain occured in areas where they had issued warnings, from June to July 31. Why then were no steps taken for preparation? Is this man-made or caused by nature? That climate change is human-induced, is a settled scientific position. To correct this, we need time. Instead, we are aggravating it all the more. For instance, if 10 lakh people had travelled to these landslide-prone areas, what does it mean?
Dr Sajin, what, according to you, are the causes for the landslides in Wayanad?
Sajin: I can emphatically say that it is not human-induced. I have been fully engaged with landslides, exclusively in the Kerala context, since 2018. There were 4,726 landslides — big and small — in the state in 2018 alone. Half of them occurred in Idukki district – 2,223 — including many in deep forests. How do we explain these? If these were induced by human interference, it could have occurred even in the months of March, April and May. However, 99.9% of our landslides are seen from June to October/November. Rain is hence the real trigger. But the rain that usually falls within a year’s time, is now pouring with high intensity in a much shorter period, and landslides happen.
Is it possible to predict landslides?
Sajin: We may be able to predict a landslide. However, no one can identify the exact route the runoff-rainwater would take. The best example of this was seen at Pettimudi. The same thing happened at Meppadi. Both Pettimudi township and Chooralmala are not landslide-prone areas. In addition to the landslide-susceptibility map, we also need a landslide-route map. Frankly, this is not a human-made landslide. But it doesn’t mean that human activities played no role at all.
Sridhar, if you believe that the landslides are down to human intervention, what do you have to say to Dr Sajin’s observations?
Sridhar: I didn’t say that the landslide happened because of human interventions. What I meant was the extent of casualty that occurred was purely due to human error.
What’s the role of human activities in the Wayanad landslides?
Sridhar: Though the landslides in Wayanad are a natural disaster, human actions significantly contributed to increased casualties. One major factor is the increasing tourism activities in ecologically vulnerable areas like Meppadi. Allowing construction in such areas is a grave human error that exacerbates the impact of landslides. Attributing these disasters solely to rain, as some scientists and the public do, oversimplifies the issue and turns it into a mere political statement. It’s crucial to acknowledge that climate change, driven by human interventions, does play a significant role in such events.
What are the solutions to avoid such occurrences in the future?
Ambili: The Geological Survey of India launched a National Landslide Forecasting Centre in Kerala on July 19. This system utilises historical landslide data from Kerala to provide more accurate landslide forecasts. The system has been operational in Darjeeling and Nilgiris since 2020 and it’s now a full-fledged system there. Trial runs for landslide alerts in Kerala began on July 20. The centre offers an online portal and application where both officials and the public can provide real-time data inputs, including rainfall observations, which is crucial for precise predictions. This initiative aims to enhance landslide preparedness and mitigation efforts through collaborative data-sharing and analysis. Reliable rainfall data is key for accurate landslide predictions. The primary data we use to generate predictions is the rainfall data provided by IMD (India Meteorological Department). In this case, based on the rainfall data provided by IMD at 2.30pm on July 29, we issued a green alert. However, there was a technical glitch. We are now planning to take data from other agencies too, as there are active rain gauges in the region. Making real-time satellite data available will also be crucial, allowing us to continuously monitor the situation.
Do you think insufficient funding for post-disaster research activities and limited sharing of scientific data between agencies pose a threat to mitigating disasters?
Sajin: There is a lack of funding for post-disaster research activities in India. While disasters in Kerala, like the Wayanad landslides, attract global research attention, there’s a noticeable absence of dedicated funding for such studies within the country. This hinders in-depth investigations and the development of locally relevant mitigation strategies. Sharing data between agencies is crucial for research activities. While international agencies openly share data, it remains unavailable in the public domain here. This hinders collaborative research and the development of effective solutions.
The experiences from the 2018 flood and the 2024 landslides indicate that rainfall predictions by IMD are unreliable…
Thara: The claims by Union Defence Minister Amit Shah that the Centre issued a landslide warning four days in advance are unscientific. Predicting a landslide four days prior is impossible. The IMD upgraded the warning to a red alert only after the landslide occurred, proving the claims to be false. Pinpointing the exact moment a landslide will be triggered is impossible, making the issuing of alerts extremely challenging. While we cannot prevent such disasters, we can mitigate their impact.
Sajin: Existing rain gauges were installed to support farming activities, and not specifically to monitor landslide-prone areas. Consequently, their placement and data collection may not be adequate to provide effective landslide warnings.
Ambili: Adequate and strategically located rain gauges are not there in critically vulnerable landslide-prone areas in Wayanad.
What can be done to avoid a repetition of such tragedies in future?
Ambili: Landslides are a natural phenomenon, and while we cannot prevent them entirely, we can take steps to minimise their impact. As experts suggest, reducing human interventions in ecologically sensitive areas can help avoid exacerbating these disasters.
Sajin: We should create awareness on the lines of what was done in the ‘80s and ‘90s. We should visit landslide-prone areas in April-May. Video classes by experts should be shown in schools. Students will spread the message on what needs to be done before and after a landslide. Such video demonstrations can be a viable solution if we don’t have funds for mock drills.
Do you mean to say that it should be made part of the curriculum?
Ambili: This has been implemented well in the northeastern states. Students are equipped to predict landslides when there is any suspicious movement and take precautionary action. Such training is necessary.
Can we predict landslides accurately using rain gauges?
Ambili: We cannot do it accurately. If heavy rain stops suddenly, a landslide may not happen. So, it is highly sensitive. When the alert is not up to the mark a few times, people will lose their trust.
Sajin: I beg to differ on that aspect. We now consider the rainfall of the previous day. Actually, the world over, what is being checked is the rainfall in the last 30 days. By analysing one month of rain, you will make a trial and error combination. We should look at how much rainfall is needed to saturate a certain amount of soil. When the level reaches 50%, you should give the first warning and ask people to evacuate.
Thara: Even if you give an alert when it reaches the threshold, you are going to speak to people who are asleep. An alert system is the most important factor. Unless the alert reaches the common man, nothing can be done. Secondly, rainfall is not the only factor. We construct national highways, homestays, and remove large amounts of soil. Each day, the vulnerability is increasing. I don’t think setting up rain gauges will solve the problem. People should know where to go when alerts reach them. There should be a socially-oriented disaster management plan.
But people wake up after the landslide and are clueless where to go...
Thara: In the matter of landslides, we have limitations. There is very little you can do after getting an alert but there is a lot of scope in things that can be done before that. In the case of a flood, you may get time but not in the case of a landslide. We should examine how many public offices are located in flood plains, which means an area of half a kilometre on either side. This area is for the river to flow freely or else it will bring huge rocks when it flows through a narrow strip. There should be efforts to relocate people from flood plains.
Dr Sajin, as a landslide expert, do you think quarrying and plantations contribute to landslides?
Sajin: If we look at Kavalappara, the other side is a rubber plantation. I could see rainwater pits after the landslide. The government supports rainwater pits but many don’t know where it should be done, scientifically. For rubber, farmers dig huge pits to hold water. After 20 years, the rubber plantation is destroyed. Earthmovers remove the root, totally disturbing the area. Instead, stubble mulching is the ideal method to be followed, where the root is retained. Plantation is a real cause, except for tea plantations.
Ambili: Usually, areas under tea-coffee cultivation are relatively less problematic. But when replantation happens, it is disturbing. Also, in places with more than a 20-degree slope, ideally, there should be no pits for rainwater-harvesting.
What about quarrying?
Sajin: All hard rocks seen in Kerala are at least 250 crore years old. But the top soil is only 10,000 to 15,000 years old. Studies have shown that the waves of uncontrolled blast cause a vibration of up to 200 metres. There will also be a lot of cracks due to quarrying. I won’t say it causes landslides, but it can facilitate the same. During monsoons, quarrying should be stopped. They can conduct sales, but shouldn’t go for blasting during the rainy season.
Thara: We cannot toe the approach that quarries are unavoidable as building materials are required for developmental activities. The Building Material Technology Council has come up with several alternatives to rock, sand, and other such building materials. There are many options available now. Why don’t we use them? We can look at options like fly ash and hollow bricks. In fact, we can re-use materials from demolished buildings and illegal constructions. We can also say that in landslide-susceptible zones, private buildings shouldn’t exceed a stipulated area. Also, do we need a six-lane road? We should look at alternatives, like improving the public transport system.
We all need good roads and we all travel by cars on these roads. So, is it correct to take such a hypocritical stand?
Sridhar: It is not a hypocritical stand. Per se, we are not saying no to roads. We need good roads. But what we now have are murderous roads where people die because of potholes.
Sajin: Those who oppose six-lane highways will go to Bengaluru via Tamil Nadu (laughs out).
Now that landslides are a reality, we can only adapt to them...
Sridhar: It’s not just about adapting. It’s about preparing for the same and creating resilience. Preparedness is an important aspect. The authorities should have data on who all are equipped to move out, who all should be evacuated, and how to facilitate the same. We have become experts in post-disaster management. We learnt that lesson the hard way. We have also become a sensitive society in providing relief. We should establish a similar mechanism for disaster-preparedness too.
Thara: We need measures in place to mitigate the same.
Sridhar: We should look at the fact that the government is planning a tunnel project in this area. The 6.9km four-lane road project will require blasting. There’s also a 1,000-acre project facilitated by the government — Asia’s biggest tourism destination with an airport — coming up in the same panchayat.
Will the proposed tunnel project accentuate the vulnerability of Wayanad?
Sajin: Not really. We now have many sophisticated technologies. If we drill using sophisticated technology, it won’t harm the environment. When a new path is created, we save a lot of money. If there are good roads, all of us will use the same. Let’s say there’s no tunnel, and if you want to go to Wayanad, will you risk it? We would be scared to go via the mountain pass. When you have a tunnel, you feel safe.
Sridhar: If you look at the alignment of the tunnel project, it’s not without a mountain pass. Once the project is completed, we save 22km of travel. You are going to spend about Rs 2,500 crore for that. Using this money, we could move at least 10,000 people. That should be the priority of the government.
The tunnel road connects three districts and the people of these districts need this... what you are saying may be considered as environmental fundamentalism…
Sridhar: No. I’m questioning developmental fundamentalism. Environmental fundamentalism is not going to kill you. Everywhere, developmental fundamentalism is what’s killing you now.
Sajin: We do need better roads and other infrastructure that are necessary for human beings.
TNIE team: Cithara Paul, Anil S, K S Sreejith, Unnikrishnan S, Shainu Mohan
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