筒狀模式應用於坡地災害警戒值－以2012年0610豪雨事件為例

坡地災害之發生主要受降雨所誘發，因此臺灣現行採用累積雨量作為土石流警戒指標，然土石流發生亦與土層含水量有關。而筒狀模式是模擬雨量在土層入滲及滲出等移動行為之概念模式，該模式中三筒內所含降雨深度總和可作為「土壤中儲留雨量深度」，日本將其定義為「土壤雨量指數（SWI），並作為全國防災整備階段準則。然在臺灣方面，SWI應用於坡地災害警戒之研究仍處萌芽階段，故本研究以SWI分析2012年0610豪雨期間土砂災害案例，結果顯示潛勢等級越高，災害發生機率相對提高，且由低潛勢至中潛勢時預測準確度提高36.7%。最後本研究建議採用SWI及RTI建立一套土砂災害警戒模式，可作為警戒發布時機及防災整備階段之依據，應可提高防災整備工作之效率。

關鍵字

筒狀模式；土壤雨量指數；坡面災害；土石流；警戒基準值

並列摘要

The cumulative rainfall is adopted as an warning index of debris flow disasters in Taiwan because the hillslope disaster events were induced by the cumulative rainfall. But the occurrence of debris flow is related to the soil moisture. Therefore, the tank model is a conceptual model simulating the moving behavior of water in the soil layers, including surface runoff, infiltration and percolation. The sum of the rainfall depth in the three tank of tank model can be considered as ”the rainfall retention depth in soil layer”, which is also considered as ”Soil Water Index (SWI)” in Japan. The SWI is also the national criteria of disaster preparedness phase in Japan. However, using the SWI index as the warning index of hillslope disasters in Taiwan is still in the early stages. The study uses the SWI index to analyze the heavy rainfall events on Jun. 10, 2012 and examine the warning value of hillslope disasters. The result in the study shows that the higher the level of risk, relatively increased incidence of disasters, and incidence increased 36.7% from low-risk to mid-risk zone. Finally, the study recommends a warning model of sediment-related disasters combining the SWI and RTI indexes to be the basis of warning release timing and stage preparing against, they should improve the efficiency of the preparing against work.