This study developed a new potential-evaluation method for potential debris flow torrents in central and southern Taiwan based on the prone ability of hillslope debris flow (HDF). In a field survey, channelized debris flow was frequently triggered by HDF within the upper stream of the catchment. The method used to recognize HDF potential is the key to estimate the occurrence of channelized debris flow. In the present study, an HDF recognition model was first developed, and then Fisher discriminant analysis was conducted considering 102 events (HDFs and landslides) to develop the HDF recognition model and an HDF potential model. To develop a new potential-evaluation method for potential debris flow torrents, 42 such torrents were selected from slate regions along the Kaoping, Chen-
Yu-Lan, and Da-Chia Rivers. Three estimation methods of potential of debris flow torrent were achieved, namely the
accumulation area of HDF units in the catchment,
accumulation of the initial area of HDF units in the catchment, and average elevation difference ratio of the pass of HDF units in the catchment. Their performances were tested, and the results showed high efficiency.
Key Words: Topography, hillslope type debris flow, channelized debris-flow, recognition model, Occurrence potential assessment model.