Author(s): Nobuyoshi Akashi; Yukio Ota; Makoto Ishikawa; Naozo Fukuda; Shinji Wakamiya
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Keywords: Fishway; Pipe-type; Reducing coupling; Loss coefficient; Flow simulation
Abstract: Fishways are playing an important role in the conservation of fish resources, fish habitat conditions and river environment. when fishways have lost their functions, it is important but not easy to repair and recover their functions. our goal is to develop fishways, called pipe-type fishways, for fishes going upstream freely, and to recover fish habitat conditions. The flow characteristics and the flow velocity control system of the pipe-type fishway were analyzed from laboratory experiments and numerical flow simulations. the ascent function of the fishway was observed by using plecoglossus altivelis (ayu in japanese). to find the preference speeds of the fishes for design, rush speeds and cruising speeds of fishes were calculated from observing the fish swimming routes in the pipe. shading of the pipe-type fishway was preferred for ayu fish clearly at the fishway inlet from observation. the effectiveness of the pipe-type fishway was certificated, and also the simplified design method was presented based on the research.
Year: 2012