"We are removing the lava to restore the stream of Opak River. Otherwise, some hamlets in Cangkringan District could be engulfed by the hardened lava flood," a head of Water, Energy, and Mineral Office of Sleman District, Widi Sutikno said here Sunday.
According to Widi, the hardened lava flood may likely happen on Opak River`s upstream reaches had become active after the last eruption after years of inactivity and even inhabited by people.
The sedimentation level of Opak River was the highest when it rained on the mount`s peak, volcanic materials and broken tree branches and trunks might be carried by the river flow through Opak River, Widi said.
The local authorities had built guiding channels on Opak River but of no avail as several lava floods were triggered by eavy rain, Widi said.
"All the heavy machinery used on the Opak river have been moved to Gendol River to restore normal river flow," Widi said.
The process was focused on Opak River to protect houses in the lower area, Widi said, adding that the authorities had three heavy machinery to normalize Panggung Hamlet.
Boulders on Opak river had been moved aside and part of Panggung Bridge was torn down allowing volcanic material to flow through the river, Widi said.
Three Sub-districts in Yogyakarta, namely Cangkringan, Ngemplak, and Prambanan, were prone to hardened lava floods hitting people residing in the area who had been asked to stay alert, Widi said.
According to Widi, two bridges in Kepuharjo Village, Cangkringan Sub-district had been destroyed the floods endangering lower areas.
Opak River had not been too heavily flooded since for the last ten years, and the volcanic materials from Mount Merapi most likely flowed through Opak, Gendol and Kuning rovers, Widi said.(*)
Editor: Jafar M Sidik
Copyright © ANTARA 2011
