Magelang Lahar Flow Takes Bite Out of Highway to Yogyakarta
Candra Malik | January 24, 2011
Magelang. The repeated dumping of volcanic mud, or lahar, onto the main highway between Central Java’s Magelang district and Yogyakarta took its toll on Sunday when the mud carved a 60-meter-wide furrow through the blacktop.
Flushed down the slopes of Mount Merapi by heavy rain, the rocks, sand and other volcanic debris are being carried downstream by the Putih River.
The affected section of road has now been rendered virtually impassable by the rift, which is up to 5 meters deep in some parts.
Central Java Police spokesman Sr. Comr. Djihartono said traffic was still trickling past the damaged section.
“We’re trying to keep traffic going,” he said. “However, drivers have to be prepared for tailbacks of more than 2 kilometers because the traffic flow is being increasingly hampered by the abrasion of the road.”
Heri Prawoto, head of the Magelang disaster mitigation office, said 12 villages in the area had been swamped by lahar, leaving hundreds of homes inundated and forcing 5,000 people to flee.
Three people have been reported killed by the mud.
Heri added the mud barreling down the river had also damaged 52 levees and swept away 14 bridges.
“The conditions we’re facing now are a real emergency. We’re trying as hard as we can to evacuate the residents,” he said.
As the disaster plays out, an expert has suggested that dividing the Putih River into two divergent streams could provide a solution.
Junun Sartohadi, head of the Center for Disaster Studies at Yogyakarta’s Gadjah Mada University, said rivers disgorging on the slopes of a volcano are unique in that their paths are always changing, driven by the torrential mudflows.
Therefore, the government should build a permanent dike along the river’s length, starting far upstream, Junun said.
“The government should split the Putih River by following its old path,” he said.
“Then the new torrents will follow the old line. While splitting it into two streams will expand the lahar flood area, the scale of the mud washing down will be reduced. That’s a risk we should take.”
He added that dredging the Batang River, which diverges from the Putih, would also help, as that would lead to more lahar being channeled into the Batang River’s path.
ma 24 jan 2011 - 23:04