Landslide threatens W. Sumatra residents

Syofiardi Bachyul Jb, The Jakarta Post, Padang

West Sumatra is a province vulnerable to landslides which often lead to fatalities and will always be a threat in the future. Nearly every year, when rainfall is above the normal level or more than 55 millimeters, and continues to fall for more than 24 hours, landslides are likely to happen in several areas, resulting in roads being covered by earth from steep hillsides, houses buried under earth and placing residents lives at risk.

Two of the deadliest landslides (galodo in the Minangkabau language), in the history of the province, occurred in Bukit Tui in the town of Padangpanjang in 1987 which claimed the lives of 132 people, and the landslides in the three regencies of Agam, Pasaman and Pesisir Selatan, which buried 101 people alive in 2000.

The latest landslide which killed 25 people occurred in Gaung subdistrict in Padang city on Sept. 2. Two months before that, just four kilometers from the site, a landslide took the lives of a married couple in Bukit Batang Babungo.

Landslides are mainly caused by geological factors. The soil in West Sumatra contains tufa, silica and boulders, which have low cohesion. The soil can collapse easily when penetrated by a deluge of water. Furthermore, the province is located along the Bukit Barisan mountain range, where most sections are characterized by steep gradients.

"During heavy rain, especially after hot weather, water will easily seep into the second soil layer. Before becoming compact, the adhesion of the top and second soil layers will be penetrated by water, and thus the top soil will collapse very quickly, sometimes carrying with it huge trees," head of the West Sumatra Road Infrastructure Office, Hediyanto W. Husaini, explained to The Jakarta Post.

Landslides usually happen in hilly or cliff areas with gradients of 80 degrees to 90 degrees. However, due to limited funds, the government is forced to cut 80-degree gradients to nearly all the roads passing through hilly areas in the province, whereas in fact the safest incline is 45 degrees.

In spite of the threat they pose, many residents have built houses -- most of them without permits -- in high risk areas through the years. They cut and leveled the hills to build houses one behind another, right in front of steep hillsides.

The local administration has actually mapped out areas which are prone to landslides. The Environmental Study Center of Andalas University, in cooperation with the West Sumatra chapter of the Regional Environmental Impact Management Agency (Bapedalda) identified areas in the province prone to landslides in 2001.

For example, the areas of Gunung Padang (Lantiak, Gado-Gado, Kaciak and Airmanis hills), Bukit Lampu (including Bukit Gaung), the slope area of Teluk Kabung, and the area of Ladang Padi had been categorized as vulnerable to landslides and unsafe as housing areas.

The 2004-2013 Padang city master plan, which was approved by the Padang City Council on Tuesday, also categorized the areas as dangerous and prohibit housing.

However, more than 4,000 families or 10,000 people are still living in those areas as of this moment, and a significant amount of funds would be needed to relocate them.

"The government should work together with non-governmental organizations to inform residents living in the risky areas of the dangers they could face, or at least notify them to be alert or stay away from the areas during the current rainy season," said Hediyanto.

Chief executive of the West Sumatra chapter of the Indonesian Forum for the Environment (Walhi), Agus Teguh Prihartono said that the regular landslides in the province were not only caused by geological factors, but also due to illegal logging. He cited as an example the landslide in Agam regency in 2000.