Amid growing concerns over the resumption of quarrying on the higher ranges in and around Kottayam in Kerala, a latest study on the deadly landslides that hit Kootkal, Kokkayar and Plapalli last year attributed it mainly to human intervention and high-intensity rainfall.
The study, conducted in collaboration with KS Sajin Kumar, member of the Kerala Landslide Expert Committee and the Kerala State Disaster Management Authority, calls for a stringent land use policy for areas prone to such landslides. The steep slopes of all three sites, which lie in the same valley and were originally natural contiguous forests, are now dominated by human intervention in the form of plantations, highways and settlements.
“All agricultural techniques on mountain slopes affect lower-order drainage by being obstructed by rubble masonry, redirecting it to a more dangerous slope. Except in forest areas with dense vegetation, these lower-order courses are usually seasonal, and during the monsoon season, these practices disrupt the normal flow of water,” the study pointed out.
Meanwhile, a closer investigation also revealed that the Kokkayar landslide was entirely caused by human activities, while the Plapalli landslide was also influenced by geomorphic and tectonic factors. Meanwhile, the landslide in Kavali was caused by the fragmentation of the forest.
With the intense rainfall of 266 meters on October 16, 2021 triggering these landslides as an ‘anomalous event’, the study emphasizes that an accurate and accurate rainfall forecast based on the region’s rainfall extent is an early warning. Issuance permits, that is, necessary to limit the risks. Automatic rain gauges that report rainfall information in near real time will be critical to developing early warning systems.
“Climate change has started to bring more extreme rainfall events, but the events are very complex and the data is too poor to predict such disasters. Hence the important feature to be researched is the rainfall dynamics, which can be converted into an early warning system, saving countless lives,” Mr. Kumar explained.
According to him, setting up of a close network of automated weather stations in the hilly areas would help the experts to assess the soil saturation extent and rainfall extent in a timely manner and issue necessary instructions to the public.