| Summary: | 碩士 === 國立中興大學 === 水土保持學系所 === 106 === Due to rise of ecological awareness, the traditional river regulations have failed to meet the demand for stream remediation in Taiwan. The Near Nature Engineering Methods has guidelines to follow. However, it still lack of validation in practice work. Therefore, its effectiveness is usually questioned. In this study, Yong Ming Stream was selected as an example, different cross-sections, slopes and transverse structures were applied to river regulation works. The traditional regulation works, such as river channel straightening and channelization, were abandoned. The regulation works took the Near Nature Engineering Methods for consideration. The two-dimensional hydrodynamic model CCHE2D was used to access the effectiveness of the regulation works. The flow characteristics before and after the regulation works were simulated by the model. Moreover, the effects of the regulation works for different ecological aspects were investigated.
According to the simulation results, the treatment method of the sample area in this study is slightly different from the traditional configuration of the stream management structure. Because of the river channel in the work area, it has a certain effect on preventing the water from impacting the concave bank and weakening the water flow. The change of the width of the river channel can slow down the scouring and silting in the river channel. The local river channel width, curvature, bed sediment, water volume and slope should be considered, and appropriate engineering structures should be arranged to achieve control of water flow, stable flow and relaxation. Good results in flushing volume.
The simulation results show that the treatment can effectively control the erosion and siltation in the river channel; in addition, the sample area is the pit ditch topography of the upstream small catchment area and the slope is steep, and the research simulation is almost consistent with the trend of the riverbed in the field investigation. CCHE2D also has good bed simulation results for the above types of plots.
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