The study of morphology of step-pool－A case study in Chinkualiao stream

• Main Authors: Hsiang-Yun Wang, 汪祥雲
• Other Authors: 李建堂
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/97436662368548204059

碩士 === 國立臺灣大學 === 地理環境資源學研究所 === 97 === Step-pools are commonly found in mountain streams which are characterized by an alternating sequence of steps and pools. Step-pools are functionally important because they provide hydraulic resistance to dissipate energy. This study attempts to investigate the morphological structure of step-pools. The study area is located at the Chin-Kua-Liao stream which runs through Ping-Lin town in Taipei County. Ten fluvial reaches with step-pool sequence were selected for measuring fluvial morphology and collecting stream bed composition to analyze the relationships among step wavelength, step height, slope, width and particle size. Most step-pools in this study are classified as rock type. The average slope of the study reaches is between 1.6% and 8.0% and the geology is mainly composed by sandstone and shale. Most steps are formed by sandstone due to its resistance to fluvial erosion is much stronger than shale. Results indicated that step wavelength has an inverse relationship with reach slope. There are no significant relationships among step wavelength, channel width and bed particle size. Step height shows a positive relationship with step interval, reach slope, bed particle size and width. In summary, the relationships among selected morphological parameters are not significant, that implies the step-pool morphology in the Chin-Kua-Liao stream are possibly influenced by other factors of river bank environment.