Road-building leads to deadlier landslides

In Nepal, 80 percent of people live in the mountains and are not easily reached, but efforts to improve access have led to an increase in landslide deaths because of poorly planned roads built on fragile, ever-shifting land, say specialists.

“Aid philosophy [in Nepal] has been shaped around trying to reduce poverty in rural areas by providing access – access to water, education, markets, and the way to provide access is through rural roads,” David Petley, chair in hazard and risk at the UK’s University of Durham, said. “I don't disagree with any of that, but more thought needs to go into the road and the society that lives around the road.”

Researchers attribute an increase in landslides over the past 15 years to roads rashly cut into unstable slopes, heavy rains falling on deforested land and tectonic shifts in the relatively young Himalayan mountain ridge. But often deaths are caused when communities spring up alongside the poorly planned roads.

“As long as there’s a bulldozer, these roads can withstand a landslide,” Petley said. “That picture rather changes if people are living beside the road.”

When cutting into slopes, supporting land is removed and landslides become a greater risk – especially during the monsoon season, from June to October.

“You can’t just make a road following the contour, you have to be very careful about the slope and how to cut into the hillside,” said Amit Kumar, a senior project manager with the Bangkok-based Asia Disaster Preparedness Center (ADPC) urban disaster risk management programme.

ADPC has mapped disaster-prone regions of the country, but conveying the research and sound building practices to local communities eager to get rural road projects under way is still a challenge, said Kumar.

Rain-saturated earth

Landslides 1971-2006
People killed: 3,889
Injuries: 1,188
Buildings destroyed: 16,799
Buildings damaged: 1,209
Land loss: 21,797ha
Livestock killed: 9,046
Source: National Society for Earthquake Technology-Nepal, 2008

This year’s monsoon season, with the highest rainfall in August for eight years, resulted in 33 landslides, burying thousands of homes and killing 100. Though down from last year’s 43 landslides that left more than 150 people dead, according to the UK-based NGO International Landslide Centre, the overall 28-year trend shows more roads have led to more landslides. A notable spike in fatalities starting in the mid-1990s corresponded to a rise in road-building in the hill districts.

“You can really follow the landslides along the new rural road construction,” said Rita Jayasawal, national coordination officer for the UN Office of Coordination of Humanitarian Affairs (OCHA) in Nepal.

When history repeats itself

Asia has a high number of landslide hot spots - from India to the Philippines - and is the continent most affected by landslides due partly to its positioning along active faultlines, according to the ADPC.

As a result, most future landslide threats are linked to earthquakes, not rainfall, according to ADPC. “Nepal is due for a big catastrophic earthquake,” Jayasawal said. “So this is our top priority for preparedness.”

The ADPC’s assessment projects the deadliest areas will be in the central hill districts including the capital, Kathmandu, a city approaching a population of one million people. Conversely, predictions of landslides linked to rain and poor infrastructure span the nation, but are most concentrated in the central and eastern hills.

While most forces of nature cannot be controlled, building safer roads and raising awareness of warning signs - such as water spilling over the edge of a cliff, trees leaning into the earth or cracks in the mountain - could save lives, said Kumar.