Fish Movement Modeling in Rivers with Fishways

修建鱼道是为了让鱼类克服河流中的人为障碍，如堤坝。本项目的目标是：(1)模拟河道和河流中的水流，(2)调查鱼类的行为特征，(3)模拟鱼类的行为，每个目标的结果和评论如下：(1)建立了适用于三种鱼道的计算机模型：嵌石鱼道、垂直槽鱼道和冰港鱼道。建立了基于浅水方程的水平二维模型，用于模拟嵌石鱼道和垂直槽鱼道中的流动；采用三维流体体积法(VOF)模拟冰港鱼道中的流动。前一种模型可以处理有鱼道的河流中的水流，而后一种模型还没有完成将河流包括在内。(2)利用设置在池塘中的三个潜水电视摄像机和安装在磐木河堰上的堰式鱼槽来观测和调查上升鱼的行为。从野外观测结果可以看出，在急流的刺激下，鱼类在相对低速的区域(水池的低中心区、凹槽下游和底孔周围)以较快的速度向上爬升。此外，底栖鱼类利用吸盘爬上垂直挡板，并通过凹槽游泳。(3)建立了鱼类运动模型。该模型是基于上升力特征的随机上升路径决策模型和基于红白肌肉特性的游泳速度决策模型相结合的模型，结合上述模型，在垂直槽鱼道中模拟鱼的行为。模拟结果表明，鱼的上升率随着体长的增加而增加，鱼类利用池塘，即停滞区休息。

Fishways are constructed to enable fishes overcome man-made obstructions across the rivers, such as weirs. The aims of the project am : (1) Modelling the flow in flshways and in rivers with fishways, (2) Investigation of fish behavior characteristics, and (3) Modelling the fish behavior The result and remark on each objective are as follows(1) Computer models were made which am applicable for three types of fishways: fishway embedded with stones, vertical slot fishway and ice-harbor fishway. Horizontally two-dimensional model based on the shallow water equation was developed for simulating the flows in a fishway embedded with stones and in a vertical slot fishway; and a three-dimensional Volume of Fluid (VOF) method was used for simulating the flow in an ice-harbor fishway. The former model can handle the flow in the rivers with fishways, but the latter one has not yet been completed to include the river.(2) Ascending fish behavior was observed and investigated by using three submerged TV cameras set in the pool and weir fishway installed at a weir in Iwaki River. From the results of the field observation, it was found that fishes ascend wisely and faster using relatively low velocity regions (low central region of the pool, downstream of notch, and around bottom holes) under stimulation by rapid flow. Also, benthic fishes climb up vertical baffles using a sucker and swim through the notch.(3)Fish movement modeling was made. It was a combined Stochastic Ascending Route Decision Model which is based on the characteristics of the ability to ascend and the Swimming Speed Decision Model which is based on red and white muscles properties.Combining the models described above, the fish behavior was simulated in a vertical slot fishway. The simulated results made clear that the rate offish ascent increased in accordance with their body length and fishes used the pools, in other words stagnation areas, for their resting.