Rampant quarrying, sand mining, shift in crop pattern and unscientific constructions are among the major causes triggering landslips in Kozhikode and Wayanad districts, geotechnical engineering specialist S. Chandrakaran has said.
“Unfortunately, most of it occur in identified landslip-prone areas. Several factors, including geology, natural slope and soil thickness apart from rainfall, contribute to natural calamities in both districts,” Dr. Chandrakaran, who is also a Professor at the National Institute of Technology – Calicut (NITC) and has carried out extensive studies in Kozhikode and Wayanad under a project of the Ministry of Human Resources Development, told The Hindu on Friday.
Slope, lithology and soil moisture of a zone are the intrinsic susceptibility factors that could potentially cause landslips. Besides, a combination of active driving forces such as rainfall and seismicity can trigger landslips, he said.
Dr. Chandrakaran, who has also carried out studies along with the Centre for Earth Sciences Studies (CESS), pointed out that 90% of the calamity had occurred in the ecologically fragile Western Ghat region. “Now, two separate studies are being conducted to study the entire Western Ghat region and identify landslip-prone areas,” he said. Incidentally, over 110 sq.km. of land in Kozhikode district and 102 sq.km. of land in Wayanad have been classified in the highly hazard category for landslips. Studies were carried out on water content, density, saturated density, shear strength and slope stability analysis of places such as Cherunthodue, Maramchadi, Puannakadavu Estate, Puvaramthode, Kakkatupara, Cippilathode, Edathuvachakallu, Harithagiri, Manettilmala, Kulamala, in Wayanad and Kakkayam, Idiijakunnu, Vayalada, Churathode, Mudukad, Neettukota, Mulakuthottamala, Kongodu, Pirukkanthodu, Karingad, Pakranthalam, Madancheri, Koothadi, Manjakunnu and Chekyad.
Dr. Chandrakaran said that the Centrally-funded project focussed on landslips that involve rapid mass movements such as rock slide, debris flow, rainfall and earthquake. Already, a global hazard model has been developed to assess the levels of landslips.
Adoption of proper drainage, proper crop pattern, increasing surface flow, controlling land use, maintaining natural slopes during construction are some of the remedial solutions. Besides, carrying out investigations in new sites in both Kozhikode and Wayanad districts. “Further, install electronic signalling transducers in regions to detect a potential landslip a week in advance so that people could be evacuated to safe places,” he said.
However, the best practice will definitely be sticking to geological standards for cultivation as most natural disasters are man-induced, Dr. Chandrakaran said.
