Experimental Investigation on the Effect of V- and W-Shaped Fishway Weir Combinations on Velocity and Turbulence Parameters

Fishways help fish pass dams and weirs and reduce fish deaths caused by these structures. Improving fishway design is important to make fishways work better and safer for fish passage. A first set of laboratory experiments were performed on combinations of different V- and W-shaped fishway weirs to study how they affect hydraulic and turbulence characteristics. Seven different weir arrangements were investigated in a flume, data on water velocities were collected for one fishway discharge and slope, and turbulent kinetic energy (TKE) and turbulence intensity (TI) were calculated. The results showed that four of the seven arrangements offer promise for successful fish passage while TKE and TI levels were within acceptable threshold values. A fishway configuration characterized by predominantly simpler V-shaped weirs and a limited use of W-shaped weirs was found to provide more suitable hydraulic conditions for effective fish passage and a less structurally complex arrangement that may simplify construction. However, physiological and behavioral aspects of fish movements were only inferred but not investigated directly with live fish tests and should be assessed in future laboratory or field research. More comprehensive hydraulic studies of the most promising weir configurations should be studied further, including different fishway discharges and slopes, documentation of plunging and streaming flow regimes, spatial distributions of velocity, as well as turbulence parameters.