Abstract
Most small weir installed in Korea is concrete solidated weir. Fixed weir causes stagnant flow, which leads to deposit sediment just upstream of weir. As time goes on, it would induce reduction of water storage capacity and invoke the serious water quality issues. Therefore, there has been a growing interest in movable weir. Especially, the flexible rubber weir is easy to install and possible to operate in extreme environments. However, even though this type can be flatable, it is also not free from sediment deposition problem. Thus, to enhance the ability of releasing deposition the bypass pipe was constructed underneath it. In this study the performance of its ability was examined with hydraulic model test. This bypass pipe was designed with 3 different dimensions to connect between each bottom of upstream and downstream of a weir, such as Type A, B, and C. The efficiency of drainage of deposition upstream was studied under two water of upstream and sediment heights. In addition, the ability of sediment emission through the bypass pipe after the pipe was blocked by debris like soil, vegetation et al. was examined by video monitoring. From this study, it was suggested a dimensionless equation which show the relationship of variable parameters and amount of emission sediment through bypass pipe. And it was found that the most significant factors on efficiency of releasing were elbow angle and discharge, and the ability of emission when the pipe was blocked was most highly influenced in tilting length.
