Experimental study of depth-discharge equations and velocity patterns on vertical slot fishways

Abstract

Fishways are hydraulic structures that enable fish to go through transverse obstructions to continue their upstream migrations. This paper presents the results of a scale model of a vertical slot fishway. For two different slopes, the performance of two particular designs of vertical slot fishways was studied for a wide range of discharges. Water depths were measured in the almost all the surface of pools. A linear relation between dimensionless discharge and depth of flow, and the same flow patterns for each design were found. With an acoustic Doppler velocimeter (ADV), three-dimensional velocities were measured at several levels in the entire pool to appreciate the structure of the flow. Two different regions in flow patterns were found: a direct flow region characterized for maximum velocities; and a recirculation region, defined by small velocities and horizontal eddies.