A Study of the Sediment Yield and Field Engineering Methods in Taitung-Ansowshi Watershed

• Main Authors: Chang-Su Neng, 張蘇能
• Other Authors: Dr. Chung-Li Hsu
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/43946450737470178802

碩士 === 國立屏東科技大學 === 水土保持系所 === 101 === The topography of hillslopes located at Taitung County is quite steep with fragile geological structure. It was frequency affected by typhoon flood and causes critical harm. This study is to investigate the area of Ansowshi watershed in Taitung County. Typoon Morakot caused a large amount of sediment production in Ansowshi and ruined construction of river. It not only endangers the safety of bridges in Highway No. 9 but also threats to the lives and properties of inhabitant. The results show that Ansowshi was affected by super Typhoon Haitang (2005) and caused damages of the foot of the two side’s slopes in watershed. Typhoon Morakot (2009) dumped heavy rains on August 7 to 9. It is equivalent to an average rainfall for 6 months on mountain site in Taiwan. The value of maximum 1-day rainfall in Ansowshi is over frequency of 200 years in history. It shows that the main factors of sediment yield in Ansowshi are affected by high intense and long period of rainfall. According to Khazai and Sitar formula, Ansowshi watershed sediment yield is 1.6 million (m3). Due to the characteristic curve of sediment, sediment in the area of upper river was estimated 1 million(m3) by conversion of Sediment Delivery Ratio empirical formula. Typhoon Morakot disaster produced a number of sediments in Ansowshi area and caused great damage or covered up with sediment to river construction. It could cause great damage in downstream if sediment has not effect improvement. It was expected that use local sediment as materials to river improvement could reduce disaster and save funds, even achieve the funtion of enviroment protection of saving energy and reduce the carbon dioxide.