Evaluation of a system for detecting debris flows and warning road traffic at bridges susceptible to debris-flow hazard

This study establishes an integrated detection system for the occurrence of debris flow, as applied to roads and bridges within hazard areas to protect pedestrians and vehicles. The preliminary hydrologic analyses provided the basis for estimating characteristics of debris flow and the basis for mounting instruments. The adopted detection sensors were categorized into two types: one is the traditional monitoring sensor, which is activated by contact with debris flow; and the other is a non-contact detection device that follows the "machine-vision theory". Compared to traditional sensors, the image process for detecting the occurrence of debris flow has the advantage of being reusable. Flume tests of debris flow were also conducted to verify the feasibility of image-recognition system. Finally, a detection system was constructed at a chosen site to make an overall assessment of the system.