Appendix 4. Vertical slot fishways – studies at the University of Alberta, Canada
Vertical slot fishways have been studied at the University of Alberta in several separate studies. The studies have dealt with several aspects concerning the hydraulics of vertical slot fishways and they have been carried out with a variety of bed slopes and discharges.
The first large study on vertical slot fishways was carried out in the beginning of 1980’s (Rajaratnam et al. 1986). A total of seven designs were studied experimentally. Design 1 was similar to that in use at Hell’s Gate Canyon and commonly used in Canada. The experiments were performed in a 0.46-meter-wide flume with an aluminum bed and plexiglass sides of a height of 0.91 meters and a length of 5 meters. The flume was equipped with different kinds of weirs. Water was supplied at the upstream end of the flume from a pump, and the flow rates were measured with a magnetic flow meter. A tailgate was provided at the downstream end of the flume for downstream depth control. Water depths in the model were measured with either a precision gauge or a metal ruler fixed to the baffle near the centerline of the pools. Velocities were obtained with a 2-mm external diameter Prandtl tube. Experimental data is given in Rajaratnam et al. (1986).
The studies were later continued with 11 additional designs. All 18 designs studied are shown in Fig. A4.1. The experimental data is given in Rajaratnam et al. (1989). The basic arrangements were the same, except the inner width of the 4.88-meter-long flume was 0.305 m and the height of the sidewalls was 0.56 meters. The number of pools was nine. Uniform flow was the sole concern in this study. The tests were carried out for slopes of 5%, 1% and (about) 15% with several discharges (Rajaratnam et al. 1989). Based on the results, they suggested that for a vertical slot fishway, a width of 8bo and a length of 10bo for the pools, where bo is the slot width, are satisfactory. However, minor variations can be made to these dimensions without affecting their performance.
Later, additional studies on the hydraulics of vertical slot fishways were carried out. For example, an extensive study on the structure of flow in the pools of vertical slot fishway was carried out by Wu et al. (1999). The studies were carried out in a 0.912-meter-wide flume with 0.60-meter-high sidewalls for the design number 18 (see Fig. A4.1). The length of the flume was 9.75 meters. The structure of flow in the pool and slot, the path of the jet, and the geometry of the recirculation regions in the pools were studied for a range of slopes and discharges.
Figure A4.1. Vertical slot fishway design layouts including circulation patterns in the pools (Katopodis 1992).
Reports and papers
Katopodis C (1992) Introduction to Fishway Design. Unpublished working document. 62 p.
Rajaratnam N, Katopodis C & Solanki S (1989) New Designs for vertical slot fishways. Tech. Rep. WRE 89-1, Dept. of Civil Eng, University of Alberta, Edmonton. 50 p.
Rajaratnam N, Katopodis C & Solanki S (1992) New designs of vertical slot fishways. Canadian Journal of Civil Engineering.19(3): 402-414.
Rajaratnam N, Van der Vinne G & Katopodis C (1986) Hydraulics of Vertical Slot Fishway. J. Hydraulic Eng. ASCE 112 (10):909-927.
Wu S, Rajaratnam N & Katopodis C (1999) Structure of flow in vertical slot fishway. J. Hydraulic Eng. ASCE 125 (4):351-360.