Appendix 3. Denil fishways – studies at the University of Alberta, Canada
The Denil fishway is probably the most extensively studied fishway design at the University of Alberta. Studies have dealt with several aspects concerning the hydraulics of Denil fishways and they have been carried out with a large variety of bed slopes and discharges.
In the beginning of 1980’s, the first study on Denil fishways was carried out with three Denil fishway designs, of which one a steeppass fishway and the others rather simple Denil designs recommended already in 1941 (Katopodis & Rajaratnam 1983). The studies were carried out on a full-scale model. The experiments were conducted in a steel-framed flume with plexiglass sidewalls. The flume measured 4.9 m in length, 0.56 m in width and 0.69 m in height. Prefabricated vanes were fitted in the flume. A head tank, equipped with stilling arrangements, was attached to the flume inlet. Water was pumped into the head tank. Discharges were measured by a magnetic flow meter installed in the pipeline. For the water surface profiles, a point gauge with a least count of 0.3 mm was used. The velocity readings were obtained using a mini current meter or sensing probe, which had an external ring diameter of 15 mm. All velocity readings were parallel to the bed. Experimental data is given in Katopodis & Rajaratnam (1983).
The first study lead to a number of other studies. Among other things, the similarity of scale models of Denil fishways was studied in order to find out whether air entrainment would cause significant errors in the results (Katopodis & Rajaratnam 1984, including the experimental data). Large studies on the hydraulics of steeppass fishways (Rajaratnam & Katopodis 1990, 1991) and modified simple Denil fishways were carried out (Rajaratnam & Katopodis 1984). The effect of backwater on the velocities below the outlet of a Denil fishway was also studied (Rajaratnam et al. 1985) and a Denil fishway design for high relative water depths was developed (Rajaratnam et al. 1987). Hydraulics of the resting pools between Denil sections were studied (Rajaratnam et al. 1997). In the late 1990’s, studies on Denil fishways with varying geometry were compiled (Katopodis et al. 1997). In all the studies, the experimental arrangements have been essentially the same as in the first studies. Only the flume dimensions have varied, as well as scales and model dimensions. A set of the designs with design dimensions studied is shown in Fig. A3.1.
Reports and papers
Katopodis C (1992) Introduction to fishway design. Unpublished working document. 62 p.
Katopodis C & Rajaratnam N (1983) A review and laboratory study of the hydraulics of Denil fishways. Can. Tech. Rep. Fish. Aquat. Sci. 1145: viii + 181 p.
Katopodis C & Rajaratnam N (1984) Similarity of scale models of Denil fishways. IAHR Symposium on Scale Effects in Modeling Hydraulic Structures, September 3-6. Technische Akademie Esslingen, W. Germany. H. Kobus (Ed.). p. 2.8-1 to 2.8-6.
Katopodis C, Rajaratnam N, Wu S & Tovell D (1997) Denil fishways of varying geometry. Journal of Hydraulic Engineering, ASCE 123 (7): 624-631.
Rajaratnam N & Katopodis C (1984) Hydraulics of Denil Fishways. Journal of Hydraulic Engineering, ASCE 110 (9): 1219-1233.
Rajaratnam N & Katopodis C (1990) Steeppass Fishways. Tech. Rep. WRE 90-1, Dept. of Civil Eng, University of Alberta, Edmonton. Canada 1990. 71 p.
Rajaratnam N & Katopodis C (1991) Hydraulics of steeppass fishways. Can. J. Civ. Eng. 18: 1024-1034.
Rajaratnam N, Katopodis C & Flint-Petersen L (1987) Hydraulics of two-level Denil fishways. Journal of Hydraulic Engineering, ASCE 113 (5): 670-674.
Rajaratnam N, Katopodis C & Van der Vinne G (1985) M1-type backwater curves in Denil fishways. Proc. 7th Canadian Hydrotechnical Conference, Saskatoon, SK. Vol. IB:141-156.
Rajaratnam N, Katopodis C, Wu S & Sabur MA (1997) Hydraulics of resting pools for Denil fishways. Journal of Hydraulic Engineering, ASCE 123 (7): 632-638.