The Application of Monitoring and Early Warning System of Rainfall-Triggered Debris Flow at Merapi Volcano, Central Java, Indonesia

Abstract

The 2010 Mt.Merapi eruption has produced approximately 140 millionm3 of pyroclastic deposit, in which more than 10 million m3 deposits are potential to move downstream through Boyong/Code River towards Yogyakarta City. The flow behavior of Code River may be affected by the presence of accumulated sediment at the upstream of the river (namely Boyong River). By rainfall trigger, this potential source can cause debris flow disaster that may contribute damage to the settlement areas in Yogyakarta City. This paper presents the application of monitoring and early warning system to mitigate the impact of debris flow disaster along Boyong/Code River as revealed bymost adaptive, lowcost, and collaborative-based technology. The real-time monitoring equipment consists of automatic rainfall recorder, automatic water level recorder, debris sensor, and interval camera. The system was developed by considering the community aspiration in determining the types and placement of monitoring equipment, and maintaining its sustainability. The information flow of the proposed early warning system has been introduced accordingly. The central station receives the results of the real-time monitoring and the information through radio communication from the focal points located along Boyong/Code River. Afterward, the warning alert is sent to focal points and the debris flow monitoring radio. This newly built system is expected to be integrated with the monitoring system of other volcanic rivers at Merapi Volcano.