Abstract: The cross-section of the traditional nature-like fishway is typically wide and shallow; but due to space limitations and efforts to reduce project costs, a narrow and deep type of nature-like fishway is often required. The flow structure of such fishway is very complicated, making it difficult to meet the flow condition requirements of different species of fish migrating upstream. In this research we examined the influences of different structure sizes on the hydraulic characteristics of fishway according to the concept of “vertical stratification and horizontal partitioning” of the flow field via theoretical analysis, three-dimensional numerical simulation as well as physical modelling. Preliminary achievements were made on the hydraulic characteristics of narrow and deep nature-like fishway.

Key words: multiple target population, narrow and deep nature-like fishway, vertical stratification, horizontal partition, hydraulic characteristics