A study conducted by the Indian Institute of Technology, Bombay, revealed that changing land use pattern and introducing new crops can trigger massive landslides.
The research study 'Land use change and landslides- A Himalayan Apathy', was conducted in hill slopes along national highway 22 in Kinnaur district and was presented at the 3-day day workshop on 'Natural Hazards in Himachal Pradesh' held at Central University of Himachal Pradesh.
Ashutosh Kainthola, PK Singh and TN Singh of the department of Earth Science at IIT, Bombay, conducted the study which said that the Himalayas are a fragile terrain abounding in human settlements which upset the delicate environment of the area.
Incessant rains or soil formation alone were not responsible for landslides, the study revealed.
"Landslides are the major physical manifestations of environment retribution which end up killing humans and damaging property worth crores," said Kainthola.
He also said that traditional vegetation cultivated in earlier times was in harmony with the geological and physical environment of a region.
PK Singh also supported the view that new water channels for irrigation, new crop varieties that require more water and the peculiar root-soil relationship have a detrimental effect on the thin soil cover on hills.
He said the study was conducted at 30-40 degrees on hills at an altitude of 300 metres in Kinnaur district which has many hydropower projects.
Researchers created a hill slope model after assessing the geotechnical properties of loose debris and rock mass. The model was analysed for stability under both dry and soaked conditions.
"The result shed light on the dreadful effect of newer vegetation on the hill slopes as against the traditional vegetation that existed earlier," said the researchers.
"Though the roots of the new vegetation offer some coherence to the loose surface debris, they lead to the increase in pore pressure causing the slopes to slip," they added.