Empirical Erosion Rate for Soft Rock Bed Channel - Da-An River and Ba-Chang River as Exampless

• Main Author: 彭俊文
• Other Authors: Liao, Jyh-Jong
• Format: Others
• Language: zh-TW
• Published: 2009
• Online Access: http://ndltd.ncl.edu.tw/handle/28512365889007587831

碩士 === 國立交通大學 === 土木工程系所 === 97 === Because of environmental changes or human factors, middle and downstream of rivers of western of Taiwan are flowing through the soft rock bed channel which appears drastic river-bed incision problems. The erosion of soft rock bed channel at two rivers, the Da-An river and the Ba-Chang river is studied in this thesis. The reasons to cause the strong erosion between two rivers are different. The Da-An river is caused by the river bed uplift induced by the 1999 Chi-Chi earthquake. The Ba-Chang river is caused by the the weir building and gravel mining. In Taiwan, Study and mitigation of riverbed erosion is limited to alluvium riverbed. This thesis aims to propose an empirical erosion rate model based on the study on the two rivers. To development the model, the erosion mechanisms for soft rock bed channel are investigated. Based on the field results, the factors affected the erosion rate are explored including the stream hydraulics, geology, geomorphology, etc. The erosion depth of main channel is calculated from DEM preparing from areal photos and LiDAR with different periods. Also, the corresponding hydraulics data are collected. Then, regression analysis is adopted for developing the models. An empirical erosion rate model in terms of channel slope, peak discharge, and accumulated discharge is presented in this thesis.