Generalized Study of Hydraulics of Culvert Fishways

Abstract

This study presents a comprehensive analysis of the experimental observations, collected previously in an extended project on culvert fishways with offset baffle, slotted weir baffle, weir baffle, spoiler baffle, Alberta fishweir, and fishbaffle systems. It has been found that a general correlation exists between the dimensionless discharge Q*=Q/(gS0D5) and the relative depth of flow (y0/D) for each value of the relative baffle height (h/D). Furthermore, for relative baffle heights in the practical range of 0.1–0.15, longitudinal baffle spacing should be limited to a maximum of D. The velocity field in the centerplane of each of these culvert fishways was analyzed and was found to be similar with the similarity profiles having different shapes for different baffle systems. A general correlation was also found for the normalized velocity scale. Even though most of the baffle systems worked reasonably well in the range of parameters recommended, the weir and slotted weir baffle systems are simpler yet equally effective. The results presented in this paper will hopefully facilitate the design and building of successful culvert fishways.