Author(s): Takayuki Nagaya; Kouki Onitsuka; Makoto Higashino; Tohru Takami; Noriharu Otsuka; Juichiro Akiyama; Yoshiki Shiraishi

Linked Author(s):

Keywords: Spawning bed; 2-D model; Suitability index; Plecoglosses altivelis; PHABSIM

Abstract: Hydraulic structures such as a dam, weir and water gate affect on the flow depth, velocity, bed topology, water quality and so on, so that the hydraulic structures may affect on the water environment for plants and aquatic lives in and around rivers. Therefore, before construction of such hydraulic structures, it is necessary to conduct the environmental assessment. However, the accuracy of the environmental assessment is not so high at present, because the preference curves of the flow depth, velocity and so on are not clear. Recently, it is pointed out that the flow depth does not affect on the suitability of spawning for ayu, Plecoglosses altivelis. In contrast, the velocity strongly affects on the suitability of spawning for ayu. The preference curve of the velocity of spawning is suggested by Onitsuka et al. (2005). In this study, a numerical simulation in and around spawn bed of ayu was carried out using a horizontal 2-D numerical model. Further, the suitability of spawning for ayu is predicted with the preference curve of the flow depth and velocity obtained by Onitsuka et al. (2005). The predicted results of the suitability of spawning for ayu and field data are compared. As a result, it was confirmed that the accuracy of the prediction is high.

DOI:

Year: 2005