To solve the problem that the flow pattern was in contradiction with the demand of fish, the fish passage structure was studied.Taking the rare speciesSchizothorax Prenantiliving in the Dadu River as an example,an velocity index system was established to describe the fish’s swimming ability by using a series of annular flume tests,and a feasible structure and layout of fishway for creating flow pattern were proposed by analyzing numerical simulation and physical model data.The results showed that the three-dimensionalk-εturbulence model coupling with the VOF model dealing with free surface problem is feasible to simulate the fishway flow field. The maximum velocity appears at the end of waterfall after the vertical slot,the biggest influences on flow field is the slope of fishway and theSchizothorax Prenantiis adapted to the slope of fishway less than 2.6%.
