Author(s): Noriaki Kawara; Kouki Onitsuka; Juichiro Akiyama; Daisuke Kiuchi
Linked Author(s):
Keywords: Pool-and-weir fishway; Plunging flow; Streaming flow; Migration
Abstract: Fishways are river constructions which give a helping of migration to fish. There are three types of flow formations in pool-and-weir fishways such as a plunging flow, streaming flow and intermixed flow of plunging and streaming flows. Rajaratnam et al. (1984) proposed a criterion formula that predicts flow formations. However, this criterion formula has no physical meaning. Further the accuracy of prediction of their formula is not good. In this study, the criterion formula, which can predict the flow formation in a pool-and-weir fishway, is derived semi-theoretically. The experiments were conducted with changing the aspect ratio and discharge in the pool-and-weir fishways. The water surface profiles were measured with a point gauge and also three components velocities were measured with a 3-D electromagnetic current meter. A new criterion formula, which can predict the flow formation in the pool-and- weir fishways, is proposed under the condition that the channel slope is 1 on 12.
Year: 2005