Author(s): Park; Seong-Yong; Yoon; Byung-Man; Lee; Seung-Hwi; Kim; Seo-Jun
Linked Author(s): Byungman Yoon, Kuk-jin KIM, Hyoungchul Park
Keywords: Critical swimming velocity; Fixed velocity test; Incremental velocity test; Occupied velocity; Mean flow velocity (Vmean)
Abstract: The Pale chub (Zacco platypus) is a main species that inhabit rivers of South Korea and the body length of the adult Pale chub is about 8~12cm. The migration behavior of Pale chub in the stream is related to feeding, spawning, growing, dispersing, and refuging. Lateral connections between main channel and off-channel habitats are commonly regulated by culverts which can restrict the fish movement due to the high flow velocity. The fish movement at the confluence or the hydraulic connection is very important especially for the life of small species. The purpose of this experimental study is to evaluate the critical swimming velocity in the swimming performance of Pale chub. Swimming ability of fishes was evaluated in an experimental flume in which water velocity could be manipulated. Some other form of species was also tested for comparison. Both fixed velocity and incremental velocity methods have been used in the past to provide water velocity criteria for experimental flume. The fixed velocity and incremental velocity methods were used to evaluate the critical swimming velocity of Pale chub using the flume which was similar to the actual culvert in the field. As a result, the critical swimming velocity of Pale chub was corresponding to 0. 7m/s of mean flow velocity. According to the analysis results of Case I and II, , the group of 100 fishes provided more definite result for the critical swimming velocity than the group of 10 fishes. Also, Pale chub tends to swim in the region of lower velocities near the bottom and sidewall of the flume when the flow velocity was 0. 7m/s. The flow velocity of the occupied zone (Vocc), which is the area where fish (Pale chub) swim, was 70% of the mean flow velocity (Vmean). Therefore, the flow velocity for culvert design in the low flow condition should not be exceed the fish swimming ability, especially 0. 7m/s for Pale chub.
Year: 2007