基於坡面型土石流潛能之溪流型土石流潛勢評估模式－板岩地區

Occurrence Potential Assessment Model of Debris Flow Torrents Based on the Hillslope Debris Flow Index in a Catchment in a Slate Region

陳天健(Tien-Chien Chen) ； 陳思妤(Szu-Yu Chen)

《中華水土保持學報》 50卷3期 (2019/09) Pp. 89-101

https://doi.org/10.29417/JCSWC.201909_50(3).0001

摘要

由災害調查顯示，溪流型土石流之形成與其集水區內坡面型土石流之活動高度相關。因此，本文以微地形特徵因子，發展野溪集水區內潛在坡面型土石流之新判釋模式及潛勢評估模式，再應用此模式評估各野溪集水區之坡面型土石流潛能，進一步建立溪流型土石流潛勢評估方法。本研究採用板岩區坡面型土石流災害事件51處；另選以高屏溪、陳有蘭及大甲溪三流域板岩地質區內，共42條土石流潛勢溪流為分析對象。成果顯示以集水區之坡面型土石流單元總面積（高中低潛勢以84－263公頃為分界）、發生區分析單元總面積（以79－189公頃為分界）、與平均隘口高程比（以0.62－0.71為分界）三個指標，可適當作為溪流型土石流發生潛勢之評估指標。以此三項指標進行潛勢分級，其正判率比現行水土保持局潛勢評估法更為優良。結果亦顯示，以微地形觀點考慮溪流集水區內潛在坡面型土石流之特性，亦可有效作為溪流型土石流發生潛勢之評估指標。

關鍵字

微地形 ； 坡面型土石流 ； 溪流型土石流 ； 判釋模式 ； 潛勢分析模式

並列摘要

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.

並列關鍵字

Topography ； hillslope type debris flow ； channelized debris-flow ； recognition model ； Occurrence potential assessment model