Abstract
The purpose of this study is to clarify the effects of the flow and bed fluctuation on the swimming behavior of fish around the spur dike with changes in the permeable and impermeable spur dike. The experiments in relation to hydraulics, movable bed, and real fish behavior were conducted accordingly. As the result of these experiments, a difference in the permeable and impermeable spur dike of the flow velocity reduction effect in the vicinity of the spur dike was observed. In addition, single permeable spur dike was less influential in the flow. Fish stayed in around the impermeable spur dike area, however they run up through the permeable spur dike. They stayed in the flow velocity of 15(cm/s) (2BL(cm/s)) or less, and the more the vorticity increased, the longer the staying time took. The impermeable spur dike had a local scouring tip of spur dike, however the permeable spur dike was less influential on the bed fluctuation.
