Relationship between migration route of swimming fishes and velocitycharacteristics in pool-type fishways with a trapezoidal section

摘要

In Japan, pool-type fishways with vertical weirs in rectangular section have beeninstalled in most drop structures. In this case, most swimming fish jump to migrateupstream through the vertical weir of the fishway. Recently, pool-type fishways withtrapezoidal weirs in trapezoidal section were proposed by Yasuda. For a wide widthof fishway, a symmetric trapezoidal section has been applied. For a narrow width offishway, a half trapezoidal section (one side is sloping, and other side a vertical wall)has been applied. The proposed fishways enable the upstream migration forswimming fish, crab, shrimp, eel, and shell. In this paper, velocity fields in pool-typefishways with trapezoidal weirs in trapezoidal section have been shown by usingmeasurement results from a proto-type. And, the migration route for swimming fishin the fishways has been made clear for both physical model and proto-type.