This paper presents the results of an experimental study of louvers that are used for diversion of fish from water intakes and canals. This investigation was conducted in two phases. Phase I involved the field testing of a louver with curved slats for the guidance of hatchery-reared juvenile rainbow trout (Onchorhyncus mykiss) for louver angles θ of 7.2° and 17.0°. Phase II was a laboratory study with flat slats placed perpendicular to the approaching flow with θ of 10.0° and 15.0°. The velocity in the bypass in terms of the approach velocity increased to 1.7 and 2.5, respectively, for the curved and flat louvers for a bypass width b equal to 5% of the width of the approach channel B. The discharge in the bypass channel Qb in terms of the discharge in the approach channel Q was 0.15 and 0.20 for b/B = 0.10 for the curved and flat louvers, respectively, and Qb/Q = 0.07 for b/B = 0.05 for both the curved and flat louver slats. Key words: fish diversion, louvers, canals, open channels, water intakes, turbulent flows.
Direct effects of boundary permeability on turbulent flows: observations from an experimental study using zero-mean-shear turbulence