Examining the Suitability of Applying Index of Stream Condition(ISC) to Torrents Managed for Debris Flows

• Main Authors: Chi-Chang Tsai, 蔡奇璋
• Other Authors: 黃宏斌
• Format: Others
• Language: zh-TW
• Published: 2006
• Online Access: http://ndltd.ncl.edu.tw/handle/62143522021635186530

碩士 === 國立臺灣大學 === 生物環境系統工程學研究所 === 94 === The purpose of this research is to assess the suitability of using Index of Stream Condition (ISC), developed by the State of Victoria in Australia, in managing debris flows at seven torrents in Taiwan. This research also provides recommendations about the establishment of local stream condition assessment models in the future. The results demonstrate that the number of Hydrology Sub-index was lower than normal. It did not mean that the stream conditions were bad, since natural topographies and climates did have an impact on it. Thus, standards for grading are modified to better reflect local conditions. This research also shows that it is not appropriate to utilize the impact of artificial barrier as an indicator in Taiwan because fish survived well even though corridors had been blocked. Therefore, the existence of fish is used in this research as the standard for assessment. It was also not able to evaluate the condition of instream physical habitat on torrents in which flow changes dramatically between rain and dry seasons, and thus this evaluation is modified according to flow conditions in rain and dry seasons. The assessment of native and non-native vegetation under the Streamside Zone Sub-index is difficult and unnecessary, thus it is not conducted in this research; the consistency and width of vegetation is assessed. Due to the actual conditions of debris flow in Taiwan, the total phosphorus and electrical conductivity are not assessed, and instead of assessing the turbidity, the amount of total suspended solids is evaluated. The research maintains the test of alkaline and acidity, and adds an assessment of water temperature. Aquatic Life Sub-index is modified to address the conditions of local endangered as well as endemic fish species.