Using Surface Notches for Fish Passage at Low Head Dams
Proceedings of the International Symposium on Fishways '95
The Organizing Committee for International Symposium on Fishways '95 in Gifu
A hydraulic model study was conducted to investigate the feasibility of notching a low head feeder dam (3.65 m high) to provide attraction flow and adequate water depth for upstream fish passage of various species, particularly American shad (Alosa sapidissima). Two and three dimensional models were utilized to characterize water velocities and flow patterns. Simulated river flows ranged from 85 m3/s to 850 m3/s. Velocities within and downstream of the proposed notch were high (» 6m/s) and unsuitable for passage. Addition of labyrinth weirs and side slots reduced velocities to below 3.65 m/s, provided adequate depth for swimming, enhanced attraction flow and maintained positive flow throughout the design.