Denil fishways of varying geometry

This paper presents the results of an extensive laboratory study aimed at improving the design of Denil fishways. For the standard design of the simple Denil an equation has been developed between the dimensionless discharge Q* and the relative depth of flow d/b for d/b as large as 5.5. The normalized velocity distributions in the centerplane of the Denil were found to have certain shapes depending upon the dfb ratio. For the nonstandard designs of the Denil fishway, based on the results of about 660 experiments, a method has been found to predict not only the relation between Q* and d/b but also the normalized velocity profiles in the centerplane of the Denil. The coefficient of friction between the central stream in the Denil and the circulating water on the sides as well as the bottom has been evaluated along with the equivalent Manning's n for the Denil. fishway. These results are believed to be important in extending the depth range of the standard Denils as well as making changes to the standard Denil for passing different species of fish.