Field application of element technology for prevention of rain-fall induced debris flow disaster in urban areas

Abstract

Recently, local heavy rains due to climate change have caused frequent mud and debris flows in urban areas. However, the existing laws related to landslide only focus on mountain areas, and the regulations on the debris flow disasters occurring in cities (or urban sediment disasters) remain to be established. In addition, the criteria for the defense technology against urban sediment disasters are not clear to install defense facilities in cities. This study presents two field demonstrations in real-scale testbeds to verify the sediment disaster defense technologies that can be applied to urban areas. We conducted field surveys during a rainfall season at the Sejong and Busan cities, and obtained continuous rainfall data. Based on the monitoring results of the test-beds, we found the pronounced effect on delaying the and reducing the debris flows and sediment disasters, in which the amounts of gravels and sands flowed into the downtown area were significantly reduced by the installed defense facilities. It is expected to be possible to secure golden time for resident evacuation and rescue by using an early warning system. Further investigation with continuous systematic monitoring is required to secure the reliability and practical applicability of these defense technologies.