Hydraulics and swimming behavior of schizothorax prenanti in vertical slot fishways

Abstract

This paper presents a novel experiment for the correlation between the hydraulics and the swimming behavior of Schizothorax prenanti, a rare species of fish in southwest China, in passing a vertical slot fishway. With an acoustic Doppler velocimeter, the velocities of a physical model in the equidimension fishway in the Shaping II power station are measured. The hydraulic parameters include the hydraulic head drop, the velocity patterns and the flow rate, and the swimming behavior includes the burst-coast, the sustained swimming and the migratory path, and they are analyzed under the test conditions. The sustained swimming velocity is in the range from 0.65m/s to 1.09m/s. The estimated hydraulic head drop of each pool is calculated and is in the range from 0.08-0.11 m, which means that 2.6% slope is reasonable. For the same slope, the maximum velocity is further reduced from 1.24 m/s to 1.14 m/s by using an L shape baffle structure. The above findings are used as the basis to evaluate the hydraulic performance of the fishways, where the L shape baffle structure is expected to be effective for creating a preferencial flow for the fish. For the main stream of the pool, an “Ω” shape flow pattern is more fish-friendly, which can effectively extend the energy dissipation distance and avoid the bursting through a high velocity zone. This paper provides a useful complementary tool for practical designs.