Pool-type fishway on the Sembayat barrage

This paper presents the hydraulic flow system in a fishway to simulate the flow of a pool-type fishway. A fishway is a waterway to allow some fish species to pass by a human-made obstruction in a river or stream. The construction on the river, which has no fishway, will impact the river ecosystem balance. The purpose of this research is to give an alternative to reduce negative effect on the river ecosystem because of the obstruction. The velocimeter and the flow type in fishway must be able to be passed by the fish. In a kind of the pool-type fishway, there is an orifice in the bottom that has a potential supercritical flow before it becomes subcritical flow. The purpose of this experiment is to identify the surge in the pools of the fishway. The physical model of the pool-type fishway in Sembayat Barrage, Gresik was created to analyse the hydraulic condition of the flow in the fishway structure. The velocity has a greater value than the permissible velocity of the fish, and thus several fishways are not able to function optimally because the fish refuse to swim through the fishway. From the results of the study, it can be concluded that the velocity can be reduced by adding baffles at the downstream part of the orifice.