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 dimension less 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 th e Denil were found to have certain shapes depending upon the dfb ratio . For the nonstandard designs of the Denil fishway, based on the resul ts of about 660 experiments, a method has been found to predict not on ly the relation between Q and d/b but also the normalized velocity pr ofiles in the centerplane of the Denil. The coefficient of friction be tween the central stream in the Denil and the circulating water on the sides as well as the bottom has been evaluated along with the equival ent Manning's n for the Denil. fishway. These results are believed to be important in extending the depth range of the standard Denils as we ll as making changes to the standard Denil for passing different speci es of fish.