11 research outputs found
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Innovations I: The Fish-Lifting Trough: A Combined Trash-Rack Cleaner and Fish Passage Device
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Session B6: The Baffle-Brush-Fishpass - A New Concept for Non-Selective Fishpasses
Abstract:
The baffle-brush-fishway combines the properties of a superactive baffle (Larinier) fishpass with the features of the brush-furnished fishway. Both types mark the extremes of the hydraulic spectrum in fishpasses. The baffle fishway exposes a high turbulence flow with a mean velocity around 1,1 m/s while the brush-type fishway provides a multiple-structured migration corridor with low velocities. A transition zone provides a continuous crossover of flow properties. Thus, any fish can choose a migration corridor which meats it\u27s demands and abilities. The presentation explains the main features of this type and adresses basic hydraulic calculations such as rating curve, friction factor and design procedure
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Session B6: Hydraulic Design of an Innovative Baffle-Brush Type Fish Pass
Abstract:
The flow characteristics (depth, velocity, energy dissipation) of a new baffle-brush type fish pass were investigated experimentally in a 2 m wide rectangular flume which has a bed slope of 4% for discharges ranging between100-550 L/s. In all experiments quasi-uniform and subcritical flow conditions, Froude number ranging between 0.17-0.23, were observed. The Darcy-Weisbach friction factor was negatively correlated with the relative submergence of the baffle. The turbulence intensities were ranged between %38-79 in the baffle zone and %13-31 in the brush zone. The hydraulic test results showed that this type of fish pass can produce adequate flow depth and favorable local flow velocities for the design discharge of 0.2 m2/s (relative submergence of brushes=1.03). The hydraulic test results reveal that baffle-brush fish pass fulfill the requirements of an efficient fish passage by providing tranquil flows and sufficient flow depths for different fish species. Consequently, the following design procedure can be used for the proposed baffle-brush fish pass: (i) required flow depth can be specified for the target fish species, (ii) the friction factor can be estimated based on the relative submergence of baffle, and (iii) for the given bed slope, average flow velocity and discharge values can be computed from Darcy-Weisbach formula. The main advantage of the proposed hydraulic design is that we can scale-up all the parts of this type in order to adjust it to almost any demand based on the model test results