Simple and inexpensive technology could warn of possible landslides to prevent loss of lives and propertyEncouraged by the results of the system with sensors for soil moisture content, land movement and rainfall, the government plans to install it next year after risk assessments.
In mid-August, a landslide in Lidi village of Sindhupalchok district killed 36 people while three persons are still missing. This was one of the most deadliest incidents in what has been one of the worst years for landslide fatalities in recent memory.
The Lidi landslide, locals say, was a “preventable disaster”.
The settlement had seen frequent mudslips this year and the locals had in fact written a letter to the District Disaster Management Committee expressing concern about impending disaster. The locals’ appeal to be relocated went unheeded.
“I lost seven family members and my land in the landslide,” said Resham Dong of Lidi. “Without my land how will I live?”
Landslides across the country have killed 247 people so far this year, in contrast to 86 in 2019 and 91 in 2018. Fifty-one people are still missing while nearly 200 people have been injured, according to official data.
Landslides occur because of both natural and man-made reasons.
“While the earth’s tremors, topography, vegetation type and frequency of rainfall, are natural causes of landslides, of late in Nepal, unsustainable approach to construction of road networks—without proper technical research and without a proper drainage system—are contributing to many fatal landslides,” said Dhruba Gautam, a geologist and disaster researcher.
But in the hills of Nepal, it is not only the roads that are being built but also hydro-power plants that affect the land topography.
Dong, 57, feels that the construction of Upper Balephi A Hydropower Project below his village might have weakened the structure of the hill causing the landslide.
“We need a fair investigation and justice,” said Dong. “We want compensation for lives and properties lost. Leaders coming to visit us in helicopters provide us little solace.”
Many Nepali villages are located in high slopes of hills, areas naturally prone to landslides.
Relocating entire villages is a complex process that cannot always be done and gabion walls cannot be constructed above settlements like they are done above highways to prevent landslides because it is very expensive and complex, according to Basanta Raj Adhikari, assistant professor of engineering geology at Institute of Engineering, Tribhuvan University.
A thorough mitigation of the impacts of the landslides across the country is nearly impossible but the one artificial measure that geologists have been suggesting and the government has also placed at a “high priority” is the landslide early-warning system.
The system is composed of three mechanisms to know whether a landslide is imminent: extensometer, soil moisture sensor and rain gauge station.
The first measures the loosening of the earth, the second measures soil moisture, and rain gauge measures the density of rainfall. These three are the major factors that trigger landslides. If any of the three systems receive a signal that a certain threshold has been crossed, the siren goes off. A solar panel provides the necessary power for the siren.
The extensometer is tied to several small poles with metal threads that stretch when the soil loosens. If it loosens too much the small poles move and when it moves beyond a certain threshold the extensometer notices and activates the siren. The extensometer with the in-built micro-chip itself is located at a place that won't get affected by a landslide, ensuring its safe functioning.
In August of 2018, the duo of Adhikari and Prakash Singh Thapa, technology development officer at the Department of Forest and Soil Conservation, set up the system in Sundrawati village, a high landslide-prone zone, in Dolakha district. The total population of the village was 495 in 117 households.
“The system worked and sirens went off a few times and residents could move to safer places,” said Adhikari.
Encouraged by the pilot project in Sundrawati village, the National Disaster Risk Reduction and Management Authority is keen to use the system.
“It’s in our priority,” said Anil Pokhrel, chief executive officer of the authority which is presently conducting a risk assessment on areas vulnerable to landslides.
“The system is inexpensive and, for the time being, the most effective method to lessen the impact of landslides,” Adhikari said.
Each warning system costs about Rs 500,000 and can be assembled with components available in the market in Nepal, according to him.
“Even communities can afford the system and maintain it,” Adhikari said.
The system in Dolakha was handed over to the local community.
"Even if it was an experiment, it showed promising signs that a system like this would be instrumental in saving lives and properties," said Ram P Mainali, ward chair of Sundrawati village in Dolakha.
According to Sushila Prasai, a local resident, since many villagers living under tin roofs said that they couldn't hear the sound of the siren in heavy rainfall, a more advanced version of the system with louder sound would be more effective.
Although the system may be inexpensive, experts and geologists need to identify the areas that are prone to landslides before installing the machine.
“New landslides often occur around places where there have been frequent landslides in the past, but it’s not as simple as that and generalising it would be a mistake,” said Adhikari.
A similar pre-warning system is being implemented in forecasting floods in the Tarai and it’s getting sharper, averting disasters, and saving lives, Pokhrel said.
“Unlike floods, however, the landslide pre-warning system is complex,” he said. “Many government agencies and communities need to come together. But despite all the complexities, we are placing it in high priority and we aim to implement it next year. Our aim is to mitigate human loss by any means.”
The Department of Mines and Geology studies the topography and the Department of Hydrology and Meteorology studies the amount of rainfall.
“Collaboration with the community will ensure that the system is sustainable,” said Adhikari.
The landslide early warning system may not, however, be hundred percent accurate. “While it’s a scientific method, there may be false signals, when, say, a cattle runs over the metal thread and stretches it,” Adhikari said. “But even though it’s not cent percent accurate, it’ll be the most effective for Nepal now.”
But for Dong of Lidi the proposed technology comes too late.
He's currently living at a temporary residence in Kattike after he moved from Shelang, where many of the villagers are still staying.
“I moved to Kattike because of the substandard facilities and food in the local unit's temporary settlement,” he said. "I don't know anything about my future."