Numerical Study on Fish Collection and Transportation Facility with Water Temperature Compensation

Abstract

Fish collection and transportation facilities have been widely constructed as man-made passages that allow fish to bypass dams. These facilities usually provide proper conditions that attract and gather fish inside, and then transport them upstream over the dam. A novel design that includes water temperature compensation was presented, and the velocity, temperature distribution, and turbulent kinetic energy inside the fish collecting channel were studied using numerical tools. The facility mixes the warm cooling water from the electrical transformer with the tailwater in order to reduce the negative ecological effect of the low-temperature discharge. It can operate under a 2 m water level range in the tailrace channel. The numerical results show that the temperature inside the fish collecting channel increased by about 2 °C and settled within the suitable range of the target fish species. The water body maintained a relatively uniform and steady temperature. The velocity and the turbulence kinetic energy (TKE) field near the fish entrance were distinct from those of the background and were beneficial for fish migration. This study could potentially motivate ecological engineers to mitigate the negative impacts of low-temperature tailwater from hydropower plants when designing fish collection and transportation facilities.