Operation of Flushing Gate on Sediment Flushing Efficiency: A Case Study of Alale Weir

This study discuss about hydraulic physical model tests of Alale weir to ensure hydraulic flow behaviour of design flood, condition on downstream of weir, and sediment flushing. In this study, observation were made on a physical hydraulic model in the laboratory with a scale of 1 : 50. Flushing tests were carried out to determine effectivity of the flushing, condition of sedimentation or scouring that occurred at downstream. Alale Weir has 3 flushing gate on the right side of the weir. Flushing is carried out using discharge Q25yr with a flowing duration of 1 hour. Flushing gate has considered quite effective in flushing sediment from upstream of weir. The sediment carried is almost 50% in all flushing scenarios. 6th flushing scenario (gate 1 and 2 were closed and gate 3 was fully opened) has the highest efficiency, 53.81%.