Hydraulics and design of fishways II: vertical-slot and rock-weir fishways

The pool-type fishway, such as pool-weir, vertical-slot, and rock-weir fishways, is one of the most common fishways that presented the highest efficiency for all fish species. Understanding the flow hydrodynamics inside the fishway is crucial to elicit the fish responses and improve passage for multiple species. This review paper summarizes and discusses the main findings of different research studies on the hydraulics of vertical-slot type technical and rock-weir type nature-like fishways under experimental, numerical, and natural conditions. This paper discusses the effects of geometric characteristics on the pools' flow patterns, flow regimes, depth-discharge relationships under uniform and non-uniform flow conditions, and maximum velocity prediction methods that are encountered. This review paper synthesizes the long-term advancement of flow hydraulics in vertical-slot and rock-weir fishways, which ultimately will help engineers and fish biologists involved in the design of fishways.