Destabilising geological processes, coupled with extreme rainfall events and unscientific farming and construction activities, pose a serious threat to human habitation in the highlands of Kerala, according to scientists.
A team of scientists from the National Centre for Earth Science Studies (NCESS) here who carried out an investigation in the wake of the heavy rain and devastating floods in August 2018 had found that land subsidence, lateral spread, and soil piping were an immediate threat to life and property in the uplands.
During the investigation, which primarily focussed on landslip-prone areas in Thrissur and Kannur districts, the researchers found huge cracks across farmlands and dwellings.
Many houses had developed cracks on the walls and basement, rendering them unsuitable for habitation.
Monitoring network
Based on the recommendations of the NCESS, the Union Ministry of Earth Sciences (MoES) has initiated steps to establish a network of landslip monitoring stations in the highlands. The units based on acoustic emission technology will also have an early warning mechanism to alert the local community. Secretary, MoES, M.Rajeevan said moves were afoot to set up 10 monitoring stations.
“Heavy intense rainfall triggers slope failure in locations where lateral spread and soil piping have occurred,” explains V. Nandakumar, Head, Crustal Process Group, NCESS.
“In the areas we surveyed, most of the slopes were used for raising crops and farmers had blocked the natural drainage systems. Any developmental activity like construction of roads and buildings in such vulnerable areas requires remedial measures for slope stabilisation.”
The team also surveyed areas in Malappuram and Wayanad, including Kavalappara and Meppadi, where rescue teams are still sifting through the debris of destructive landslips which occurred last week.
Alarming situation
“We had found the situation in the highlands alarming,” says Dr. Nandakumar. “Lateral spreading, subsidence, and crack development are quite unusual phenomena and the sites need immediate rehabilitation.”
The team alerted the District Collectors in Thrissur, Kannur, and Kasaragod, outlining the remedial steps to be adopted. The scientists also recommended the formation of a trained task force for the highlands to monitor ground signatures like hollows, cracks, and water spouts that often precede land subsidence, lateral spread, and landslips.
