Why Western Ghats are seeing landslides
MUMBAI: Anthropogenic activities such as settlements and cutting for road construction, fluctuations in vegetation loosening the soil layer, deforestation, unchecked mining, concentration of extremely heavy rain at particular spots are, according to geologists and experts, to blame for the series of landslides in Raigad, Ratnagiri and Satara districts of the state last week.
Last week, a landslide occurred in Taliye village in Raigad’s Mahad killing over 82. Besides Taliye, landslides also occurred in Ratnagiri’s Pedhe and Khed, and Satara’s Mirgaon, Ambeghar, and Dhokawale tehsils. Two to three landslides have been reported from uninhabited areas, blocking roads and highways in Raigad district, officials said. Deputy chief minister Ajit Pawar on Monday said the state will appoint a panel of geological experts to study the causes of landslides in the Western Ghats, which have claimed more than 100 lives and displaced thousands over last week.
Geologists, who have studied the Western Ghats, say construction activities such as highways lead to haphazard cutting of mountain slopes. Dr Praveen B Gawali, scientist at Indian Institute of Geomagnetism, an autonomous research institute under the Department of Science and Technology, Government of India, has studied parts of Western Ghats and identified landslide susceptible villages in Ahmednagar district. He said heavy rain-triggered landslides are on the rise along the ghats.
“Anthropogenic activities have given rise to anomalous slopes and due to gravitational pull and rain, the overlaying material comes down. In the Western Ghats, if you have continuous rainfall for a couple of days, the soil gets soggy, leading to landslides. This time, the rain was very heavy, which was concentrated at a few spots [leading to series of landslides]. If it is evenly spread out, it does not lead to landslides,” said Dr Gawali.
According to Gawali, change in vegetational cover is also responsible for landslides in the region. He added that in India, landslides occur mainly in Himalayan region, Western Ghats and in the Nilgiris. While the incidents in Himalayan region occur due to tectonic movements, the landslides in Western Ghats and Nilgiris happen mainly due to heavy rain events.
“We see a lot of landslides in the Himalayan region because the Himalayas is the youngest mountain range. The sediments are not yet compacted; they are loose. There is a tectonic activity with the plate moving up, which causes instability. It doesn’t require any precipitation activity, landslides occur in dry season there. In the Sahyadris, it is different. It isn’t any plate movement that is causing it. The vegetational cover is also responsible. During the monsoon, there is greenery, but afterwards it dries. The soil is exposed to natural conditions, many natural process occur with dampness. With excessive rainfall, chances of the soil cover creeping down increases manifold,” he added.
Ecologist Dr Madhav Gadgil, who headed the state appointed Western Ghat Ecology Expert Panel in 2010-11, said the committee’s recommendations to stop haphazard road construction, illegal mining, etc were not implemented by the state.
“In 2011, we had submitted a report stating several activities that shouldn’t be carried out in such eco-sensitive zone. We had said that haphazard planning of highways by cutting mountains slopes, unchecked construction and mining activities should not be done. The windmill projects that have come up on the ghats have caused huge fractures on the mountains loosening structures. Similar issues are happening in Kerala and Maharashtra is seeing this. The recommendations of the committee were not followed by the government and these landslides are a result of these,” Gadgil said.
Vijay Nahata, chairman of the State Environment Impact Assessment Authority, said all measures are fully followed before providing clearances to any project on the Konkan region.
Nahata said, “Environmental clearances for new projects are provided based on several parameters. We are very cautious of the environment and ecology while doing so. The incidents of landslides mainly occur due to heavy and continuous rainfall in the region.”
“The government can still implement the recommendations made by the committee. Activities that hamper the region need to stop and eco-restorations measures have to be adopted to tackle such incidents,” said Gadgil. Despite attempts, Aaditya Thackeray, minister for environment and climate change, was unavailable for a comment.