Research on Narrow and Deep Type Simulated Natural Fishway for Multi-target Fish Population

Water conservancy projects in rivers cut off the fish migration pathway, affecting the integrity and species diversity of the river ecosystem. Fishways are an important means to reduce the influence of water conservancy projects on the environment.Simulated natural fishways are intended to provide an optimal structure and cross-section type based on natural fishways to improve the ecological conditions of the river corridor, and these structures have been promoted and applied in recent years. The cross-section of the simulated natural fishway is typically wide and shallow, but due to space limitations and efforts to reduce the project cost, a narrow, deep type of simulated natural fishway is often required. The flow structure of this type of fishway is very complicated, making it difficult to meet the flow condition requirements of different species of fish migrating upstream.In this paper, the influences of different structure sizes on the hydraulic characteristics of fishways is studied according to the concept of the " longitudinal stratification and horizontal partitioning " of the flow field combined with the methods of theoretical analysis, three-dimensional numerical simulation and physical modeling to meet the needs of fish species hierarchically and regionally. All-round research on the hydraulic characteristics of narrow and deep simulated natural simulated natural fishways is presented. The study provides scientific and technological support for fishway design and considerations for their engineering and construction.