鱼道进口水流对草鱼幼鱼上溯行为的影响研究

Study on impact of water flow at fishway entrance on migratory behavior of juvenile grass carp

为使鱼类能够快速发现和顺利进入鱼道进口并成功过坝，设计了鱼道进口概化模型。以草鱼幼鱼为研究对象，在18±1℃的条件下研究了鱼道进1：7流速对鱼类上溯行为的影响。研究发现：鱼道进口水流存在一个最佳流速，在该流速下，鱼类进入鱼道进口的效率最高。利用诱鱼流道补水有助于进一步提高鱼道进鱼效率，诱鱼流道水流与鱼道进口水流之间存在一个最优流速比。针对草鱼幼鱼的鱼道进口最佳流速约为O．3m／s，诱鱼流道水流与鱼道进口水流的最佳流速比约为2．3。通过对洄游区鱼类游泳轨迹以及流场耦合，可知草鱼幼鱼上溯的喜好流速范围是0．20～0．30m／s。研究成果对于鱼道进口水力设计具有重要意义。

In order to make fish quickly find out fishway entrance and smoothly enter into it, and then successfully pass over dam, a generalized model of fishway entrance is designed. By taking the juvenile grass carp as the study object, the impact from the flow velocity at fishway entrance on fish migration under the condition of 18 ± 1 ℃ is studied. The study finds out that there is an optimal flow velocity for the flow at the fish entrance. Under that flow velocity, the efficiency of fish entering into the fishway entrance is highest, thus the water supplement from a fish luring flow passage is helpful to further increase the efficiency of the fish entering, for which there is an optimal flow velocity ratio between the flow from the fish luring flow passage and the flow at the fishway entrance. For this study, the optimal flow velocity at the fishway entrance is about 0. 3 m/s for the juvenile grass carp, while the optimal flow velocity ratio between the flow from the fish luring flow passage and the flow at the fishway entrance is about 2. 3. Through coupling the fish migration trajectory with the flow field, it is known that the preferred range of flow velocity for the migration of the juvenile grass carp is about O. 20 to 0. 30 m/s. The study results have an important significance for the hydraulic design of fishway entrance.