Fish requires different hydraulic conditions and environment at different life cycle stages, including reproduction, juvenile, and sexual maturation. Species migrate from one environment to another to survive and complete their life cycle. The population of many species is demised due to the hydraulic structures made across the rivers. Generally, a fishway is constructed at hydraulic structures that help fish in migration. Multiple fish species can migrate through the conventional vertical-slot fishway (DVWK, 2002). However, more discharge is needed in vertical-slot fishways to maintain the required flow depth and velocity compared to multi-slot fishways. Prior knowledge about the interaction between fish behavior and flow hydrodynamics is required for optimum fishway design.
The swimming performance of different fish species in the water body is essential to design the fishway. Hence, swimming performance experiments are planned in the laboratory using a swim tunnel. Primarily, these experiments focus on assessing the critical speed and burst speed of the Indian native migratory fish species (Labeo Rehu, Labeo Catla, and Cirrhinus cirrhosis (Mirgal)). The first phase of experiments for different discharge Q, shape factor (L/b), and shape ratio (B/b) are planned in the designed multi-slot fishway from the literature. The flow field and fish tracking measurements will be measured using an acoustic Doppler velocimeter (ADV) and high-speed digital cameras in the multi-slot fishway. Later, numerical simulations are planned for the optimization in the multi-slot fishway with changing discharge, bed slope (S_o), and slot angle (α), where 'L' is the pool length, 'B' is the pool width, and 'b' is the slot width. The simulation results shall undergo analysis, and the optimum configuration of the multi-slot fishway shall be proposed. Finally, fish tracking experiments are scheduled to be conducted in the optimal configuration of the multi-slot fishway to obtain preferred values of hydraulic variables. The preferred values obtained shall be employed in developing a fish trajectory model using the Eulerian-Lagrangian-agent method (ELAM) and formulating comprehensive guidelines for an optimal multi-slot fishway for Indian migratory fishes.