A community-based landslide forecasting system in India

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Community scientists, with the help of professional researchers, have developed a weather-based landslide prediction system for the Western Ghats mountain range in India, according to a published article earlier this year. Called “Satark,” the model is able to predict landslides along the mountainous southwest coast of India one day in advance with an accuracy of 76.5%.

Thirteen of the paper’s 15 authors are “community scientists” with non-meteorological backgrounds, including in banking, journalism, mechanical engineering and microbiology. They are part of Citizen Science Center (CCS), a volunteer-driven non-governmental organization based in Pune, India.

“In 2014, a landslide happened in Malin [in the Pune District], and the whole village was buried under the rubble. About 150 to 200 people died. And when we checked past records, we saw that such occurrences are common in Malin and even generally in the Western Ghats,” said JR Kulkarni, the main author of the article. Kulkarni is a CCS administrator and was previously a meteorologist at the Indian Institute of Tropical Meteorology (IITM), Pune, and the World Meteorological Organization.

Scientists have found that weather conditions such as precipitation, as well as geological factors such as slope, soil type and land cover, are common to such events. “In a scenario with no earthquake or cyclone, rainfall is the only trigger,” Kulkarni pointed out.

Scientific and community collaboration

Prior to the collaboration, scientists and CCS worked independently to monitor rainfall patterns in the Western Ghats. Researchers collected rainfall data from the mission to measure tropical rains (TRMM) and radar data for two points in the Western Ghats: the town of Bombay and the state of Goa. The model also relied on weather forecasts from the Indian Meteorological Department (IMD). The paper lists 54 rain-triggered landslides in the Western Ghats between 2000 and 2016 and notes that the highest frequency of landslides occurs in July and August, the peak monsoon months in India.

Meanwhile, CCS volunteers have identified landslide-prone sites in the Western Ghats. They also worked with scientists to identify precipitation thresholds that could trigger landslides. “We [community volunteers] visited areas prone to landslides, and with the help of meteorologists [like Kulkarni] and geologists, we were able to analyze our hypotheses with data and technology and develop a prediction system,” said Mayuresh Prabhune, one of the authors of the newspaper and a journalist by profession. Prabhune is also the secretary of CCS.

Together, the two groups tracked the intensity and duration of rainfall. Not all places in India have weather monitoring stations to track these patterns, and this is where communities are helping fill a crucial gap in both monitoring and preparedness.

The team distributed rain gauges to around 50 people in the Western Ghats and also provided training on how to take measurements and read scientific literature. With these tools, communities could measure and assess rainfall data themselves.

“They don’t have to wait for data from IMD or anyone else,” Prabhune said. They can also take precautionary measures if the data they track shows threshold violations for a continuous period.

“When the rainfall begins during the monsoon season, we ask people to be careful. And if intense rains persist for 3 days, they know it is now the ‘alert stage’,” Kulkarni explained. The next stage is the “warning”, where the precipitation exceeds the thresholds for the next 3 days and the risk of landslides is greater than 90%. Once this stage is reached, residents are encouraged to temporarily move to safer locations.

The CCS team provides alerts to a wider audience via a websitesocial media and messaging platforms like WhatsApp.

In many cases, “taluka [local administration] officials contacted CCS for information on rainfall and landslides,” Prabhune said, highlighting opportunities for collaboration between communities, scientists and policymakers. The strength of the Satark model, he continued, is that because local people are already involved in scientific studies and measurements, the task of raising awareness is reduced.

Climate change

Climate change is intensifying the need for a weather-based landslide prediction system, said Roxy Mathew Koll, climatologist at the IITM. The frequency and intensity of downpours and extreme rainfall have increased in the Western Ghats, he said, and although the IMD has a system to monitor and forecast weather events, “being a national agency , it may not always be possible to have their products cater to remote areas on a very local level.

Incidents such as landslides and river floods are not monitored by any meteorological service on their own and require cross-departmental and cross-departmental cooperation and data sharing. “This is where citizen science networks can play a major role.”

In addition, Koll added, incidents such as landslides and river flooding are not monitored by any meteorological service on their own and require cross-departmental and cross-departmental cooperation and data sharing. “This is where citizen science networks can play a major role,” he said.

Other community rainfall measurement efforts (such as the Meenachil River – Rain Watch project in Kerala) also demonstrated how communities, and schoolchildren in particular, can fill critical gaps in areas such as flood preparedness simply by tracking rainfall and water levels.

Satark is an “interesting decision-making system” based on simple precipitation thresholds, said Rajeevan Madhavan Nair, former Secretary, Ministry of Earth Sciences, India. Overall, he added, it’s “a great initiative to engage people in socially relevant research work.”

Noting that rainfall measurement is often part of school curricula but is rarely used, Prabhune said that “even students are very enthusiastic about measuring rainfall. All you need is an interest in science.

As a next step, Koll suggested having a set of guidelines to make such monitoring activities uniform across India. “Quality-checked data from calibrated rain gauges can return to IMD and can be used for research and forecasting purposes,” he said.

—Rishika Pardikar (@rishpardikar), science writer

Quote: Pardikar, R. (2022), A community-based landslide prediction system in India, Eos, 103, https://doi.org/10.1029/2022EO220269. Posted June 7, 2022.
Text © 2022. The authors. CC BY-NC-ND 3.0
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