Human activity causes increase in landslides
INDISCRIMINATE tree felling, construction, mining and quarrying, combined with heavy rainfall, have increased the fragility of the Himalayan mountains, leading to an increase in the incidence of landslides in the region. Of all the world's landslides, 30 per cent occur in the Himalaya, according to a South Asian Association for Regional Cooperation (SAARC) study on the causes and consequences of natural disasters in the region and the protection and preservation of the environment.
The study, based on official reports, notes an average of about 75 major landslides occur annually in just central and western Nepal and this costs the country about $130,000 in damages to land and cattle alone.
The Nepalese government believes that indiscriminate mining and ill-planned road building are to blame for the widespread wastage of land resources, which forces rural communities to encroach into forests and further aggravates soil erosion. However, not all experts agree with this conclusion. Numerous studies argue that natural processes play a far greater role in the Himalayan region in causing landslides than human-induced ones.
In Sri Lanka, too, the government believes that landslides are increasing largely because of development projects that have spread even to steep hill slopes and other unstable locations in the country's central and southwestern regions. More intensive cultivation, which means more irrigation and more denudation of watersheds, also is being blamed.
Monsoon- and cyclone-induced rainfall are said to be major causes of landslides and land collapses, including riverbank erosion, in Bangladesh's hill districts, particularly the Chittagong region and parts of Sylhet. Experts say there is urgent need for a sound land-use policy in a land-hungry country like Bangladesh, if a halt is to be put to indiscriminate cutting of forests and poorly planned roads.
During the rainy season in Pakistan, landslides along highways in the Murree hills, Pir Panjal and the Hindu Kush are also triggered by dam construction and open-pit mining.
Besides natural factors, landslides in Bhutan have also been brought about by human activity, especially the building of roads and canals, which result in deep slope cutting and land saturation.