Influence of Partial Dam Removal on Change of Channel Morphology and Physical Habitats: A Numerical Simulation Analysis of Dam#1 of Yu-Sheng River

• Main Authors: WENG,CHUNG-HAO, 翁崇豪
• Other Authors: YEH,CHAO-HSIEN
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/awx8ga

碩士 === 逢甲大學 === 水利工程與資源保育學系 === 105 === Taiwan salmon (Oncorhynchus masou formosanus) is considered a national treasure of Taiwan and it was originally an offshore migration of the Pacific salmon. After the ice age and geographical isolation, it becomes as an unique subspecies of Taiwan and evolved into landlocked salmon. In order to expand the connectivity of the fish habitats in Chi-Jia-Wan creek basin, several dam removal projects had completed with good results. Benefited by the Taiwan salmon release plan, an independent group of the hatched salmons is sucessfully inhabitted in the study reaches upstream of Luo-Ya-Wei creek. In order to expand the connectivity of the fish habitats in both creeks. Threfore, this paper focuses on the dam removal of Yu-Sheng creek Dam #1. In this paper, a digital elevation model (DEM) of about 1 kilometer channel of the Yu-Sheng creek dam is obtained by unmanned aerial vehicle (UAV). Using CCHE2D model, the simulation of dam removal revealed the impact on channel morphology. After model parameter identification and verification, this study simulated the scenarios of three historical typhoon events with recurrence interval of two years, fifteen years, and three decades under four different patterns of dam removal to identify the responses of the head erosion, thalweg, sedimentation volume, Froude number, and habitats diversity of channel. With results on channel changes and habitats improvement, the appropriate way for dam removal is then suggested. The simulation results indicated that it not suitable for removal right half of the dam body. The scenario of removal left half is more suitable than the other scenarios. However, security concerns of toll gate and road have to be taken under more careful discussion and assessment.