Darjeeling: Ill-planned roads and neglect of indigenous erosion-control measures coupled with haphazard construction in hilly areas triggered the massive landslide in Darjeeling last week, an expert said on Monday.
"Widening and constructing roads in the plains is easy but in the hills it poses a challenge," Professor and head, Geo Hazards division, National Institute of Disaster Management (NIDM), Chandan Ghosh told a news agency here.
In the hills, there is a need for supporting and stabilising systems to protect the exposed surface of the hills due to construction, he said.
"The harsh truth remains there is a lot of haphazard construction going on without following proper guidelines and without any supporting steps, post-construction," Ghosh said.
He said water accumulation was the root cause of rock, debris and earth sliding down slopes which is caused once the hills are cut open and water directly flows inside and accumulates.
"If we take care of drainage, 80 to 85 percent of landslides which we are seeing every now and then in the rainy season can be avoided. Such measures will incur a cost of around 1-2 percent of the road construction process," Ghosh said.
The expert pointed out countries like Japan, where around 80-85 percent of the land area is hilly, did not experience such frequent landslides.
Further though landslides do not happen all of a sudden, and locals get inkling of certain anomalies like water blockage and erosion, scant attention is paid to these factors, Ghosh rued.
Given that the Himalayas is prone to landslides, Ghosh called for more vulnerability mapping of potential landslide locations and adoption of ground modification strategies like growing Vetiver grass, which is famed for its erosion-hedging properties.
"You cut the slope, you grow this grass, it stops erosion and tackles drainage issues. More than 100 countries have taken this grass from us. I have been trying to promote the use of this grass in Darjeeling for the last five years but unfortunately it is not being done," he lamented.
Heavy overnight rain triggered a string of landslides in the mountainous Darjeeling district of West Bengal on July 1, killing at least 40 people.