Journal of the Japan Society of Erosion Control Engineering, Vol.62,No.4,2009

Analysis for early warning of sediment]related disaster in Mt.Bawakaraeng Caldera, South Sulawesi, Indonesia

HASNAWIR and KUBOTA


Abstract

This study aims to determine empirical rainfall intensity]duration thresholds for landslides and debris flow and to find standard rainfall warning for debris flow overflows in Mt. Bawakaraeng Caldera, Indonesia. The debris flow overflow happens when excess sediment (debris) flows over the top of channel works and check dams. The study is based on the hourly]rainfall data recorded from 1997 to 2007. The threshold, as defined by the lower boundary of the points representing landslides and debris]triggering rainfall events, is expressed as I=41.85D|0.85 before the large scale landslide on March 26,2004 and I=‚R‚V.‚V‚PD|0.‚X‚O after the large scale landslide, where I is the rainfall intensity (mm/hr) and D is the duration of rainfall (hr). The Debris flow overflow warning in the study area may be issued when rainfall is expected to exceed the warning line.

Key wordsFMt. Bawakaraeng Caldera, rainfall threshold, rainfall intensity, sediment disaster, warning


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