集水區地文特性因子與土石流發生機率間相關性之研究－以陳有蘭溪爲例

Relationship of Watershed Geomorphologic Characteristic Factors and the Occurrence Probability of Debris Flow-A Case Study of Chen-Yu-Lan Stream

吳輝龍(Huei-Long Wu) ； 陳文福(Wen-Fu Chen) ； 張維訓(Wei-Shun Chang)

《中華水土保持學報》 35卷3期 (2004/09) Pp. 251-259

https://doi.org/10.29417/JCSWC.200409_35(3).0006

摘要

台灣自1999年9月21日發生百年頻率之九二一大地震後，每遇豪雨輒生土石流災害。爲瞭解此問題之關鍵，宜針對集水區的地文特性因子與土石流發生機率間之相關性進行探討。
本研究以濁水溪之支流陳有蘭溪集水區爲試區，應用GIS軟體ArcView，以三維數值高程模型及衛星影像爲素材，利用統計軟體SPSS進行分析探討。由於集水區之地文特性因子爲土石流發生之潛因，故以多變量統計中之主成份分析法將20個地文參數進行分析並萃取其中之13個主要影響因子。另以試區中土石流發生高潛勢之溪流與未發生土石流之溪流的主成份參數進行區別分析，其有效性高達85.7%，且建立了一可供土石流發生潛勢判定之參考的區別函數。最後將工研院所建立之潛勢溪流代入區別函數中驗證，亦證實其間具有高度之相關性。
本研究之成果可供土石流防治、土石流發生潛勢之判定及集水區整治優先次序決策之參考。

關鍵字

土石流 ； 集水區 ； 地文特性 ； 地理資訊系統 ； 數值高程模型 ； 主成份分析 ； 區別分析

並列摘要

Taiwan has had a series of debris flow disasters since the one-hundred-year frequency 921 earthquake on September 21, 2000. In order to realize the key point of the problem, it is necessary to study the relationship of the geomorphologic characteristic factors and the occurrence probability of debris flow.
In this study, we used digital elevation model (DEM) and satellite images of Chen-Yu-Lan Stream as the material to analyze the geomorphologic characteristics through the geographic information system software ArcView and the statistic software SPSS for the watersheds of Chen-Yu-Lan Stream. Because the occurrence probability of debris flow is relevant to the geomorphologic characteristics, after we used the principal components analysis method to analyze 20 geomorphologic factors, there were only 13 factors which were primary factors. Discrimination analysis showed that the principal components of high debris flow potential creek were up to 85.7%, much higher than those creeks in which debris flow did not occur. Moreover, high debris flow potential creeks those ITRI constructed were verified to have high correlation with their geomorphologic characteristic. And the relationship affords a difference function as the reference for determining the debris flow occurrence potential.
The results of this research can be referred for preventing debris flow, determining the potential class of debris flow occurrence and making decisions for watershed management.

並列關鍵字

debris flow ； watershed ； geomorphologic characteristic ； geographic information system ； digital elevation model ； principal components analysis ； discrimination analysis