Design Method and Example of Fishways in a Tributary of the Nagara River
Proceedings of the International Symposium on Fishways '95
The Organizing Committee for International Symposium on Fishways '95 in Gifu
The Gifu Prefecture, undertakings of a fishway construction service have been proceeded in Nagara River by the Fishery Promotion Division of Agriculture Department. Improvement and construction of fishing grounds and fishways have been conducted. This paper presents an example of fishway at the Kurusu River in Yamato town. The content of this construction was to attach a fishway to an existing dam which has no fishways. An installation for adjusting of the volume of flowing water is very difficult. Therefore, it is necessary to construct the fishway structure where water can flow stably, even if the water level changes. The fishway which contains three types of structures were constructed. When the water level changes at the dry season, a constant volume of water will be afforded stably through one of three types. Fish observations were conducted by diving on the end of May, and it was confirmed that Ayu, Amago salmon, and other species ascended the fishway. And were also observed some fishes inhabiting the fishway constructed in the past. Every year after fishways constructions, more investigation of inhabiting fish species are needed.