Slide to safety

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Slide to safety

Sunday, 28 October 2018 | MUSBA HASHMI

Slide to safety

MUSBA HASHMI travelled to Gangtok, Sikkim to bring you a detailed report on landslides, their causes and how the region has come up with an early warning model that can help in reducing loss of lives and property damage

  • On June 5, 2018, heavy rain affected Mizoram State, causing landslides and casualties
  • On July 11, 2018, landslides swept at least nine people to their deaths in Manipur
  • On July 11, 2018, six people were killed in floods and landslides in Uttarakhand
  • On August 24, 2018, in Guwahati, heavy rainfall  caused landslides at Hastinapur and Sankardev Nagar in Jorabat area with three casualties and on August 31, a landslide in Kharguli area damaged infrastructures
  • On August 13-14, 2018, heavy rainfall triggered the initiation of new landslides and reactivated existing ones along NH-22 in Solan district, Himachal Pradesh blocking and disrupting the traffic along NH22
  • On August 2, 2018 incessant rainfall reactivated a landslide that occurred in mid-July along the state highway about 22 km from Gangtok on Gangtok-Mangan road via Phoodong causing disruption of traffic. The landslide is a planner rock slide blocking the road for a week


The newspapers are always full of such reports and off late, the number of casualties is on the rise especially the North-eastern States. To address this social and natural disaster, Amrita University took an initiative to develop and install a landslide warning system which can raise an alarm in case of an expected landslide.

The good news is that the early warning system which has been installed in Munnar, Kerala has had a successful run. The second system is deployed at Chandmari, Gangtok. The reason why this particular region was chosen first is because the area is the most prone to landslides due to the gradual shifting of the Tectonic plates in two different directions.

The largest town and the capital of Sikkim — Gangtok is a home for people of different ethnicities — Nepalis, Lepchas and Bhutias. The State Capital is known for its beauty and the breathtaking views that the town offers you from various points including the Ganesh Tok point. On your way from Siliguri to Gangtok you can spot the majestic river following you to the mountains. Though river Teesta is not as fierce as other rivers but you can spot the river's aggression at some points in between your journey.

Although Gangtok proves to be a beautiful tourist destination where one can have a break from their monotonous life and spend some time with Nature, it doesn’t prove to be the same for its residents. The Sikkim-Darjeeling belt is among the world’s most prominent landslide hotspots. Small-scale landslides are a common view for the residents here. Though small-scale landslides doesn’t cause much disturbance to the people living here but some large landslides are a constant threat to life and property to the locals.

The locals are helpless in the face of such a disaster. Ask them what do they do whenever a landslide happens, they reply with an awkward smile: “What can we do? We just sit and watch the destruction happening. There is no escaping from this disaster. Our houses are made on the mountain slope from where we don’t have an easy escape. Once the landslide occurs, access to the other side is blocked and we are struck.”

Dr Maneesha V Ramesh, director, Center for Wireless Networks & Applications, Amrita University, tells you that landslide is the third most deadly natural disaster. Around 12.6 per cent of India’s land mass is prone to landslide hazard. “The major factors that can trigger landslides are rainfall and earthquakes. Other factors that can trigger landslides are manmade like the removal of vegetation from the slopes, interference with natural drainage, leaking water, modification of slopes by the construction of roads and buildings, overloading the slope and vibrations from traffic. Through the landslide early warning system, we aim at disaster risk reduction.”

The aim of the system is to create awareness about the landslides, its impact and the factors that trigger it through the community engagement programme under the early warning system. While the system can’t prevent disaster, at least it can save lives through early warning.

The idea of the project came to Maneesha because she wanted to write a research paper on landslide warnings. This idea to Amma and she responded by saying that that instead of writing research papers Maneesha should do something to save human lives who then started on working on a model that could  issue warnings for landslides and started working on it with the help of the funds arranged by the university and the Government.

“The university has always worked towards the betterment of the society and it has a tagline of Education For life and Compassion to Human Life. For Amma, service is spirituality and love is the only religion. She has always helped people in every way possible. She had set up hospitals, educational centres, relief camps during natural calamities and recently helped to set up of this warning model,” she says.

Improving upon the Munnar model, the Chandmari model has overcome the flaws and improved the system and one can expect more accurate results here with no false warnings. “We have studied other parameters like the moisture density in the soil and have now employed Artificial Intelligence in the system to reduce the risk of false warnings. For Sikkim, we have introduced the rainfall threshold model which will study the rainfall in the area, analyse the data and then issue warnings on the basis of the rainfall received. The warning system will cover an area of 10 kilometers,” Dr Maneesha says and tells you why they chose Chandmari.

“The area is spread over 150 acres and there are about 3,000 inhabitants excluding the tourists that visit the place. The vulnerability of the area increases due to the increment in the population density. The area is selected by the Government on the basis of the history of the events that took place in the area in the past years. The first landslide here was reported in 1997,” she says.

Explaining how the system  works, she tells you that the first step is the placement of the battery which works on the solar panel that are installed nearby. The box is then installed in the ground. The region is prone to rains and days on no sun; in such a scenario the battery derives its energy that has been stored. The system has an artificial algorithm which automatically switches on and off in order to save and preserves energy for use in the future. Along with the battery in the box, there is a hole from which the pipes are drilled into the ground. These pipes are made of Acrylonitrile butadiene styrene (ABS) plastic. Each pipe is three metres long. The pipes are joined with the help of connecting rods so that they can go underneath — to a depth of 30 metres. In each pipe, there are about 30-40 sensors. These are pore pressure sensors which work on the vibrations they receive when the moisture reaches the ground in a saturated state and activates the pore pressure in the soil.

“The system works on multi-level warnings which include the first warning or the early stage warning that will be given 24 hours prior to the disaster. This warning will be based on the rainfall threshold. This level has successfully completed the testing phase and is ready to issue warnings. The second warning will be given six hours before and the third and the final warning will be given six hours prior to the disaster which will be based on the vibrations received by the sensors on the basis of several parameters like pore pressure and moisture. The warnings will be mailed to the registered email ID and mobile numbers that are saved in the system and then you can raise an alarm to the Government and the people can be asked to evacuate the area. This project will be deployed in two phases. The first phase deployment took place in 2015 and the second phase started in 2018. The phases include deployment of the pipes inside the ground. There are about 20 people involved in this project,” Maneesha says.

The State Government provided the land to set up the control office which is equipped with monitors that are connected to warning system. All the movement and vibrations can be seen on the monitor in the form of a graph. The officer also keeps everything handy in from pipes to sensors, everything is in stock. There are two people who are in-charge; they operate the monitor and work in the office in two shifts — day and night. These have been are appointed by the university. A local, 20-year-old boy, has also been hired to take care of the place where the system has been deployed. Though it may sound all easy, there were certain challenges faced during the deployment of the project.

“The major challenge that we faced was while deploying the systems. When we completed drilling the bore up to 30 metres depth and removed the drill machine the bore would collapse. This happened multiple times and then we went looked for a solution. Amma suggested that after we finished drilling, we should not remove the machine and look for the leakage. After spotting the leak, we should seal it with cement and be ready with the sensors and only then remove the machine. This worked wonders and the sensors were deployed successfully. The other challenges that we faced were to be cost-effective, large-scale deployment and to persuade the locals to take ownership of the system and look after it on a daily basis. A problem that we faced once the system was deployed was vandalism,” she tells you.

It was through community engagement programme that the team was able to persuade residents and Amrita University and the Government arranged all the funds for the project. The cost of the project stands at Rs 5 crore.

The good news is that the warning model can issue warnings for other natural disasters as well. “This system has been made in a manner that it can be helpful in detection of  earthquakes and floods. Though it will require certain tweaks in the sensors, it can effectively detect and trigger early warnings," Maneesha says and tells you that for now, they are working in the  Gangtok region. However, if the Government wants they would only be happy to work in other areas as well. “I am very grateful to the people of Sikkim, they have been very helpful throughout and it didn't take much to educate them about the system. They have helped us a lot and supported us. From my past deployment this is the best state as the people are very supportive,” Maneesha says.

Meanwhile, the Indian Institute of Technology,  Mandi has successfully developed a low-cost landslide monitoring and warning system against landslide disasters, which are a common problem in the Himalayan mountain belt.

Every year, on an average about 200 lives are lost due to landslides in India and Rs 550 crore are spent to cover damages to infrastructure. Prof Varun Dutt, School of Computing and Electrical Engineering at IIT Mandi said: “To address the problem of landslides and to reduce the cost of sensing these disasters, a faculty-student group named, iIoTs, incubated by Indian Institute of Technology (IIT) Mandi’s technology incubator, Catalyst, has developed an indigenously built low-cost landslide monitoring and warning technology. The system, which costs around IRs 20,000, can record weather parameters and soil properties.”

The system can generate warnings both locally (via blinkers and hooter) and globally (via SMSes) if there are soil movements of different magnitudes in the vicinity of the deployed system. With support and encouragement from the Mandi district administration, iIoTs recently deployed 10-systems in the Mandi district at different landslide sites along the Mandi – Jogindarnagar and Mandi – Kullu highways. The systems deployed along the Mandi – Jogindar Nagar highway includes the following: one system at Narla village, two systems at Kutropi village, and two systems at Gumma village. The systems deployed along the Mandi – Kullu highway include the following: one system each at Deode, Hanogi, Thalot, Dwada, and Pandoh villages.

‘It’s a model that gives a 24-hour heads up’

Landslides are a common occurrence in Sikkim. Every year, more than thousands are injured, there is loss of property and hundreds die due to this disaster; sadly the number of the dead has been on the steady rise. Small landslides are a common sight for the people of the State. While travelling to Sikkim, one can easily spot rocks falling from the mountains in succession. The drivers are always on a look out for such rocks while one travels from Bagdogra to Gangtok.

Dr GC Khanal, additional secretary, State Disaster Management Authority, tells you that apart from Chandmari, there are many other active and dormant slope failure spots in and around Gangtok, the main making impact on the life and property. “These are Tatangchen landslide, the sinking zone at Sichey, the sinking zone at ‘zero point’ along NH 10 near Hotel Mayfair, sinking zone below Holy Cross School along NH 10,” Khanal shares.

These landlsides not only cause loss to life and property, it hangs like a Damoclean sword over the locals who may have to run from their homes leaving everything behind. The thought of such horror unfolding is a cause for nightmares and just children but adults too.

In such a case, a landslide early warning system can be a life-saviour for the people of the area. Talking about the reliability of the system, Khanal said: “The system is reliable because it has multiple heterogeneous sensors which are triggered dynamically in different time period. The kit has multi-level decision model integrated into it. As each level crosses, its reliability increases so that it reduces the fault. This system has multi-sensors and multi-decision models, increasing its reliability.”

The system uses new technology which has not been used before and because of the latest technology it gives a warning 24 hours ahead of the event. It uses Artificial Intelligence and the data derived from the sensors to issue warnings. This adds to the accuracy of the system. The system is not restricted to Gangtok only, it is developed for mountain areas and can be replicated in all the hilly States.

The good things about this model is that the shelf life is of more than 10 years. It has been already proven in Munnar, Kerala.

“The system is perfectly working more than 10 years there. Regular maintenance is required for the power system and the electronics boards require slight maintenance in between,” Khanal says and tells you that the Government encourages such projects.

“The Sikkim Government and the Centre through National Disaster Management Authority encourages projects for mitigation of landslides in the area. It provides training to the stakeholders of landslide management and provides funding for its mitigation on priority areas,” Khanal tells you.

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