The delayed arrival of the southwest monsoon has brought with it a fresh spell of landslides in the Western Ghats. While Wayanad in Kerala has already witnessed a debris slip that claimed three lives, heavy rainfall triggered a landslide near the KSRTC bus stand in Madikeri, Kodagu district. Earlier, three people died when a retaining wall slipped on a building at Garodi-Naguri in Mangaluru on July 1.

These back-to-back incidents, occurring within a short span of the monsoon season, which has seen a revival in some areas after a rain-deficient June, have prompted scientists and environmentalists to question whether lessons from the devastating landslide episodes witnessed in the same regions in recent years have gone unlearnt.

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Combination of factors

C.S. Patil from the India Meteorological Department (IMD) said the events could be a result of a combination of geological factors combined with meteorological and topographical changes: a large quantum of rainfall over a short period, the loss of vegetation coverage and deep root cover, and the nature of the soil, among others.

T.V. Ramachandra from the Centre for Ecological Sciences, Indian Institute of Science (IISc), concurred. “Our earlier study in the Western Ghats reveals changes in the rainfall pattern with higher instances of high-intensity rainfall, which triggers mudslides and landslides.”

He added that though the triggering factor is high-intensity rainfall, the prime causal factors are unplanned developmental activities — linear projects such as roads, tunnels and others — in ecologically fragile regions, undertaken without considering the carrying capacity of the region and without implementing stringent conservation measures.

He said accelerated large-scale land degradation leading to deforestation, removal of native forest species — whose roots would have provided structural stability by binding the soil in fragile regions — and alteration of slope integrity have further contributed to the problem.

He also pointed to the disruption of drainage networks, with houses and housing layouts being constructed in the path of water flow in Chikkamagaluru, Kodagu and Dakshina Kannada.

A recent IIT Dharwad report, Assessing Future Landslide Susceptibility and Risk Escalations Under Changing LULC and Climate Conditions in the Western Ghats of Karnataka in India, also stated that the intensity and frequency of fatal landslides in the Western Ghats are adversely influenced by human-induced land-use modifications and climate change.

Susceptibility and risks

This study evaluated landslide susceptibility and risks for the year 2050 by incorporating land-use/land-cover and future rainfall patterns. It found a significant increase in rainfall intensity and urban development by 2050, resulting in an increased risk of landslides. It said the most affected areas lie along major transport corridors and densely populated areas of Uttara Kannada, Kodagu and Chikkamagaluru districts in Karnataka.

Nagaraj Koove, an environmentalist based in Mudigere, pointed to the four-lane highways being constructed around protected areas in Coastal Karnataka and Malnad regions, deploying “unscientific construction methods” including 90-degree hill cutting. “This is why we are seeing landslides even with small rainfall amounts. Added to this is the timber mafia causing deforestation in the hills, rampant establishment of resorts and homestays replacing plantations and vegetation. In the end, it is the small farmers who suffer. Those who suffered from the 2017-2018 landslides in Mudigere and Kodagu are yet to recover to this day,” he said.

Col. (Retd.) C.P. Muthanna, coordinator of Save Kodagu and Cauvery Campaign and former president of the Coorg Wildlife Society, said there has been a “total disregard to protecting the Western Ghats.”

Extensive tampering

“There has been extensive tampering with steep slopes in landslide-prone areas despite earlier disasters. Construction of large built-up areas, including resorts, road building activity and tunnelling, coupled with loss of tree cover, are the direct causes for landslides in the Western Ghats. In this regard, mountainous regions such as the Himalayas and the Alps are relatively resilient whereas in the fragile hill ecology of the Western Ghats, such degradation of the steep slopes is a recipe for disaster,” he said.

“These tragedies will continue to occur unless and until there is accountability. Many development projects and tourist infrastructure works are driven by naked greed, often fuelled by a nexus between politicians and contractors and facilitated by bureaucrats,” he added.