- 期刊
濁口溪流域的地表作用與曲流地形間之相對應關係
The Relationships between Earth Surface Processes and Meandering Forms along the Catchment of the Jhuokou River
摘要
濁口溪為荖濃溪支流之一，其最顯著的河道地形為成育曲流，沿線之地質材料主要是以板岩的組成為主。集水區內有多處河道變遷的遺跡，在長時間尺度下集水區內侵蝕作用強烈。因此，本研究利用1996年賀伯颱風、2000年碧利斯颱風、2001年桃芝颱風、2004年敏督利颱風、2005年海棠颱風等5個事件前後的衛星影像，以及2版航照來判釋颱風前後崩塌地的分布和河道中心線的變化，並輔以1989年至2005年的年輸砂量，來探討研究區域內的山崩、土石流、降雨以及輸砂量等地表作用和曲流地形間之相對應關係。研究結果顯示，5次颱風事件的崩塌率介於1.0%至3.96%之間，其中以海棠颱風為最高，且集水區內崩塌面積有逐年增加的趨勢，表示侵蝕作用日益強烈。然而，在數十年的尺度下，河道的平均曲率由1980年的1.84變化至2001年的1.86，且河道並未有明顯改道的現象，顯示地表作用對曲流河道的影響，在短時間內並不顯著。
並列摘要
Jhoukou River is one of the branches of the Laonong River which consists of slate, and its most featured fluvial form is ingrown meander. Because of the strong erosion along the Jhoukou River, there are some indications of channel migration under the long time scale. This study used different SPOT satellite images and aerial photos of two different versions to count the landslide ratio and draw the channel centerline, including typhoon Herb (1996), typhoon Bilis (2000), typhoon Toraji (2001), typhoon Mindulle (2004), and typhoon Haitang (2005). We also calculated annual sediment discharge from 1989 to 2005, to explore the relationships between the sediment discharge and earth surface processes, such as landslides, debris flow, and rainfall. The result shows the landslide ratio of the five typhoon events is between 1.0% and 3.96%, and Haitang typhoon was the highest one. In this study area, landslide areas are increasing year by year, indicating erosion is becoming stronger. However, the fluvial mean curvature value changed from 1.84 in 1980 to 1.86 in 2001 under the time scale of decades, but there was no channel migration of the Jhoukou River. This implies the earth surface processes do not affect meandering forms over a short period.