Compound strategy forward to compound disaster mitigation: Lessons from Hsiaolin village, Typhoon Morakot 2009

In 2009, the heavy rainfall induced by Typhoon Morakot hit Hsiaolin Village that caused catastrophic flooding, landslides, landslide dam breakages and debris flows. Such a called “compound disaster” is defined as a disaster in which extensive floods or sediment transports occur simultaneously or consecutively at the catchment area during an event. It challenges current warnings, forecasting and responses to sediment disasters. New concepts and procedure thus are needed to cope with such “compound disasters.” Rainfall hydrographs show downpours of long duration, high intensity, high accumulation and large extent. To better delineate these disasters and provide possible coping strategies, we rebuild the temporal order and spatial distribution of the disaster processes involved. The study suggest correlating individual disaster types with rainfall through simulation. This could clarify the causality between what happened in Hsiaolin Village and related disasters. Our results will strengthen disaster prevention in debris flows and shallow landslides using strateghies that could then be applied to warning systems for deep-seated landslide and landslide dams. The derivative issues and the approach to compound disaster prevention are suggested for future tasks.