The Burst-coast swimming of Schizothorax Prenanti and hydraulics in Vertical Fishways

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Ruidong An, Jia Li

Tuesday 30 june 2015

16:45 - 17:00h at Amazon (level 1)

Themes: (T) Hydro-environment, (ST) Ecohydraulics and ecohydrology

Parallel session: 7G. Environment - Ecosystem

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This paper describes a novel experiment testing the correlation between hydraulics and biological behavior in passing vertical slot fishway of Schizothorax Prenanti, a rare species fish in southwest China. According to the swimming ability test and behavior analysis of Schizothorax prenanti, they usually adopt the burst-coast mode for continued swimming in long distance fishway for saving energy. To obtain quantitative information about the correlation of velocity pattern_energy dissipation efficiency and migratory path in the pool, experiments were conducted in a physical model with equidimension to a section of fishway in Shaping _power station, Dadu River. With acoustic Doppler velocimeter and video camera, hydraulic parameters including water head drop, velocity patterns and flow rate, the biological behavior including burst-coast, sustained swimming and migratory path were analysed under test conditions. A novel structure of L Shape baffle was introduced creating more energy dissipation efficient and sustained fish-friendly velocity distribution. In accordance with conservation of energy, the head drop for the elevation difference between the upstream and downstream of the pool is 0.08~0.11m. Fish move along the jet flow almost to the side of the pool by frequently wagging tail from the maximum velocity area, then slide along the convergence are of the mainstream without crossing until the long Baffle and make the turn rapidly. For the main stream of the pool, the ‘_’ shape flow pattern behaves more fish-friendy, which can effectively extend the energy dissipation distance and avoiding bursting through high velocity zone. The above findings were used as the basis to evaluate the hydraulic performance of the fishways, which the L shape baffle structure are expected to be effective on creating preferences flow for fish.