Landslides Threaten Bali

By Barrie | February 4th, 2008 | No Comments

A recent study found landslide to be a major threat to a large tract of Bali. The study identified 213,136,740 hectares of land in 46 of Bali’s 50 districts, or 37.3 percent of the island’s total area, as landslide-prone. The study was conducted by Udayana University’s Center for Environmental Research (PPLH) and the Bali administration Regional Development Planning Agency (Bappeda).

“Of those landslide-prone areas, we identified 85,121,550 hectares as the areas in the highest danger of avalanche, with the rest in moderate danger,” head of the research team R. Suyarto said last week.

The high-risk areas span from West Bali National Park at the island’s western tip to the Batukau nature reserve area in the center of the island and to the areas around Batur lake in the east of the island.

“Of the 46 landslide-prone districts, 10 have been identified as having the highest chance of landslides,” he added.

Those districts were Kintamani, Pupuan, Kubu, Sukasada, Banjar, Gerokgak, Busungbiu, Abang, Petang and Rendang.

“Bali is an island created by volcanic processes. Therefore, a large part of its topsoil is sandy, not solid, and tends to break away easily. These factors increase its vulnerability to avalanche,” Suyarto said.

The fact that most of the landslide-prone areas lie in the middle of the island, Suyarto said, had a lot to do with the area’s unique topography.

“It is an area dominated by steep cliffs and sloped land, with degrees of inclination ranging from 20 to 60 degrees. These kinds of topographic features will surely experience landslides the moment a powerful downpour occurs,” he said.

A member of the research team, Sandi Adnyana, said human interference also played a pivotal role in increasing the vulnerability of a land mass. He pointed out land-conversion as an example of human-made change.

“Conversion of forest into farms, housing complexes or tourism facilities have robbed the land of plants and trees that had protected it from landslides,” he said.

Farms and plantations, he said, often replaced the native trees, which have strong roots, with commodity crops such as rice, corn and oranges, whose shallow roots are unable to protect the land.

Sandi said such substitution in Petang and Pancasari had increased the areas’ vulnerability to landslides. Petang’s villagers chopped down their coffee trees and planted orange trees, while Pancasari’s farmers replaced coffee with vegetables.

Sandi urged the administration to prohibit land conversion in landslide-prone areas to prevent future disaster.

An expert of Udayana University’s Agriculture Department, I Wayan Rusna, advised the local administration to carry out a focused reforestation program.

“This reforestation program should take into account the character of the targeted soil and find the most suitable plants for that soil,” he said.

The team also recommended the administration declare the riverbanks and the cliffs along the river as protected, no-development areas.

“Any paddy fields and plantation areas with a level of inclination 25 degrees or more must be planted with trees that have strong roots to strengthen the topographical features of the areas,” Suyarto said

I Wayan Ananta Wijaya