A study of hydrodynamic characteristics of resting pools of vertical slot fishway

Several studies have shown that many fishes will be detained in the fishway resting pools, especially in the turning section of the resting pool. A 3D numerical model using the RNG k-ε turbulent closure is applied to study the influences of vertical slot position, resting pool length, and auxiliary baffle placed at the resting pool on the hydraulic characteristics of the resting pools located in the straight section and turning section. The research results show that the turbulent kinetic energy and turbulent energy dissipation rate of the water flow in the resting pools are much lower than those in the ordinary regular pools of the fishway, and the longer the fishway resting pool is, the lower the turbulent kinetic energy and the turbulent energy dissipation rate of the water flow, and the larger the resting space is in the resting pools. The position of the vertical slot of the fishway has little influence on the flow characteristics of the resting pool located at the straight section. It is reasonable that the length of the fishway resting pool specified in the code should be more than twice that of the ordinary pool. For the fishway resting pools located at 29° turning section, the layout of the vertical slot at opposite side is more advantageous, while for the fishway resting pools located at 180° turning section, the layout of the vertical slot at the same side is more advantageous. Due to the existence of a large area of high velocity reverse current zone in the center of the fishway resting pools located at 180° turning section, full attention should be paid to it. Adding an auxiliary baffle in the fishway resting pools can effectively eliminate the large reverse current zone in the center of the pools and greatly increase the areas of the velocity zone, which is worthy of popularization and application.