花蓮縣土石流潛勢溪流地文特性初探

A Preliminary Study of Geomorphologic Factors Characteristics of Potential Debris Flow Torrents in Hualien County

10.30040/JSWCT.201204.0004

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

土石流潛勢溪流 ； 地文因子 ； 描述性統計 ； Debris Flow Potential Torrent ； Geomorphologic Factor ； Descriptive Statistics

水保技術

7卷2期（2012 / 04 / 01）

96 - 105

繁體中文

本研究針對行政院農委會水土保持局98年公開的花蓮縣160條土石流潛勢溪流為研究範圍，根據數值高程模型與崩塌地圖層萃取地文因子，分別為集水區幾何形狀因子、集水區高程因子、集水區坡向因子、集水區坡度因子與集水區崩塌地因子，計有五類共12項地文因子，本研究利用描述性統計探討花蓮縣土石流潛勢溪流地文因子值域分布狀況，另參考水土保局易致災因子調查表，將上游發生區平均坡度分為三個級距，分別為大於50度、30~50度與小於30度，依照土石流歷史災害目錄將花蓮縣160條土石流潛勢溪流分成敏感溪流與非敏感溪流，以此兩類歸納地文因子於不同坡度分級之特性。最後針對本研究地文因子統整說明敏感溪流與非敏感溪流差異，藉由相互比較獲致誘發土石流之地文條件特性。

This study extracted 12 geomorphologic factors of the 160 potential debris flow torrents in Hualien County and sorted in five categories: factor of form, factor of aspect, factor of aspect, factor of elevation, factor of slope, and catchments. Descriptive statistics was applied to analyze the distribution of geomorphologic factors of potential debris flow torrents in Hualien County. The slope gradient of upper streams of the 160 potential debris flow torrents in Hualien County were classified into 3groups based on slope gradient of catchment: more than 50 degrees, 30 to 50 degree, and less than 30 degrees, and divided the torrents into sensitive and non-sensitive based on debris-flow hazard inventory, and plotted different slope groups. Finally, the 12 geomorphologic factors were compared within the sensitive and non-sensitive torrents to identify the characteristics of geomorphologic factor which might trigger debris flow.