Fish Movement Modeling in Rivers with Fishways

修建鱼道是为了使鱼类能够越过河流上的人为障碍物，如堰。本课题的主要目的是：(1)对沟道和有鱼道的河流进行水流模拟；(2)对鱼类的行为特征进行研究；(3)对鱼类的行为进行模拟。各目标的结果和说明如下：(1)建立了适用于嵌石鱼道、垂直槽鱼道和冰港鱼道三种鱼道的计算机模型。建立了基于浅水方程的水平二维模型，模拟了嵌石鱼道和垂直槽型鱼道内的水流；采用三维流体体积法（VOF）对冰港鱼道内的流动进行了模拟。前一种模型可以处理有鱼道的河流中的流动，但后一种模型尚未完成，不能包括河流。(2)采用3台水下电视摄像机，分别设置在岩崎河堰池内和堰道内，观察和调查了鱼的上升行为。从现场观察结果来看，在快速水流的刺激下，鱼类在相对低速区域（池中央低区域、缺口下游和底孔周围）上升得更快、更聪明。此外，底栖鱼类利用吸盘爬上垂直挡板，游过槽口。(3)鱼的运动建模。该模型结合了基于爬升能力特征的随机爬升路线决策模型和基于红白肌肉特性的游动速度决策模型。结合上述模型，模拟了垂直槽型鱼道中鱼类的行为。模拟结果清楚地表明，鱼类上升的速度随着它们的体长而增加，鱼类使用水池，换句话说，停滞区，作为它们的休息场所。

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.