莫拉克颱風災區土石流發生因子之特性—以地形因子、降雨強度及崩塌率進行探討

Characteristics of Debris Flow-inducing Factors in Typhoon Morakot Affected Area-An Examination of the Topographic Factors, Rainfall Intensity and Landslide Rate

沈哲緯(Che-Wei Shen) ； 羅文俊(Wen-Chun Lo) ； 蕭震洋(Cheng-Yang Hsiao)

《農業工程學報》 59卷1期 (2013/03) Pp. 26-48

https://doi.org/10.29974/JTAE.201303_59(1).0003

摘要

莫拉克颱風在民國98年8月7日至9日侵襲臺灣，並在南臺灣降下了驚人的雨量，特別是屏東、嘉義、高雄等靠近中央山脈的區域。莫拉克颱風後，經由現地調查蒐集了相當多的災情資料，有鑑於此，本研究採用遙測影像、現地調查結果、農委會水保局95～99年土石流易致災因子調查資料及各項分析成果，萃取土石流發生三元素作為評估因子（地形、降雨及土砂來源，合計101個因子），以主成分分析與相關性分析，綜合探討莫拉克颱風引發土石流之顯著地形發生因子，透過描述性統計進行莫拉克颱風災區218條溪流（皆屬溪床型）之土石流發生因子特性分析，除釐清莫拉克颱風引致溪床型土石流發生因子特性外，亦可回饋分析結果於易致災調查，提供土石流易致災調查發生因子研修參考。

關鍵字

莫拉克颱風 ； 土石流發生因子 ； 特性分析

並列摘要

Typhoon Morakot lashed Taiwan during Aug. 7 to 9, 2009. It dumped heavy rainfall in southern Taiwan, especially around the Central Mountain Range in Pingtung, Chia-Yi, and Kaohsiung County. In view of this, Comprehensive field investigation was carried out by government and private organizations after Typhoon Morakot, useful information of debris flow was gathered. Besides, after Typhoon Morakot, the debris flow-inducing factors become more challenging in Taiwan, many aspects had to be considered.The scope of this study was mainly discussed in debris flow-inducing factors in serious damaged areas which including Nantou, Chia-Yi, Tainan, Kaohsiung, Pingtung, Taitung County. Totally 218 channelized debris flow torrents were included. Field investigation data and disaster records of Typhoon Morakot were utilized to analyze debris flow-inducing factors in three aspects: terrain, rainfall and sediment source. First, by using Principle component analysis and Pearson Product Moment correlation analysis to select significant factors, 101 factors were reduced to the most important 18 factors. Then through descriptive statistics and characteristics Analysis were selected to discuss the relationship among ”Average slope gradient of watershed”, ”Landslide rate along the stream within 50mbuffer zone” as well as the ”rainfall intensity during Typhoon Morakot”. The above charts were used to summarize the range of factor value which tend to occur phenomenon of debris flow in Typhoon Morakot. The results can be utilized in improving debris flow hazard management in the future.

並列關鍵字

Typhoon Morakot ； Debris Flow-inducing Factors ； Characterirstics Analysis