Yuli Tri Suwarni, Syofiardi Bachyul, Bandung, Padang – Research by the Volcanology and Geological Disaster Mitigation Agency (PVMBG) in Bandung disclosed that during the past 10 years environmental degradation had changed the pattern of many landslides into flash floods, which potentially would then hit wider areas, an official said on Sunday.
Meanwhile, the search for victims of the landslide in Cianjur that buried 15 people on Thursday evening was temporarily stopped on Sunday due to heavy rain in the area, which might cause another landslide.
The landslide also damaged at least 77 houses in Girimukti village, prompting residents to seek refugee in temporary shelters.
The head of the disaster potential evaluation division of the agency, Gatot Sudrajat said that before 1998, landslides mostly occurred in limited or specific areas. Gatot said the pattern has changed in the past 10 years due to environmental degradation: a landslide in one area now affected other areas lower down.
"The disaster was categorized as a flash flood because the stream of water and materials damaged wider areas," Gatot said, adding that during the past 10 years there had been 75 flash floods, with 40 percent out of them in West Java.
He said the environmental damage was caused by the conversion of conservation areas into residential areas on sloping land at an angle of 12 to 45 degrees.
He said many residents living in critical areas had planted seasonal crops, like cassava, corn and bananas, which had weak roots leaving soil structures that could not absorb water easily.
"Many residents want to have the plantation near to their homes. That's why they have planted corps on slope areas and then live in lowers areas. They do not only harvest fruits, they also harvest disaster," said Gatot.
To avoid further disasters, Gatot suggested the government as well as the people should recover critical lands by planting hard trees. He also called the government to activate early warning systems and to alert residents, who lived near the areas prone to disasters, so they would be more cautious about the possibility of sudden environmental disasters.
Gatot said, based on research by the Indonesian Institute of Sciences that the speed of landslides in Indonesia reached about 50 kilometers per hour.
Flash floods also happened in Cikalongwetan, Bandung regency in 2003, killing nine residents; in Cililin, Bandung regency in 2004, killing 15 residents; in Jember, East Java in 2006, killing more than 30 residents.
PVMBG recorded that during January-November this year, there were 64 landslides that changed into flashfloods (mud floods) across Indonesia, with at least 80 fatalities. Meanwhile, during the past five years there were 147 similar disasters, claiming 390 lives.
It was reported that the local authority had stopped searching for Nadirsyam, 55, a flashflood victim in East Malalak, Agam regency, Sunday, after a-week-long evacuation.
Local official, Ade Edward, said that the evacuation team had to end the search for the victim's body as heavy rains had been unceasing and mud had spread widely.
He said that the Friday mud flood had claimed six lives and caused damage of more than Rp 17 billion (US$1.4 million), including three broken bridges, which would have to be repaired by local government and 100 hectares of damaged agriculture land covered by mud.