Problems with a Fishway on an Irrigation Barge in Japan
Proceedings of the International Symposium on Fishways '95
The Organizing Committee for International Symposium on Fishways '95 in Gifu
In this paper, we discussed about problems of fishways on irrigation barrages in Japan from site studies, a model experiment of N barrage which is typical as a recent irrigation barrage. The results are below. (1) Low capability for weaker fishes than Ayu. Most of irrigation barrages have pool and weir fishways designed for Ayu which is the most important fish for fishing. (2) Instability of fishway inlet water level - Back water level can't be controlled with old irrigation barrages. Accordingly, flow state in a fishway may be unstable. (3) Obscurity of fishway inlets - Discharge over the barrage is conducted in whole width of the barrage with irrigation barrages. (4) Damages by flooding and scouring.