FLOW STRUCTURE AND SWIMMING BEHAVIOR OF LEUCISCUS HAKONENSIS AT POOL-AND-WEIR TYPE FISHWAY WITH SLOPE 1/5

Abstract

There is the case to have to make the slope of the fishway steeper than the standard range, according to the geographical features condition. In this research, measurement of flow structure and observation of swimming behavior of Leuciscus hakonensis at the hydraulic model of the pool and weir type fishway with slope 1/5 were conducted. Main results are shown as follows; 1) Ascending rate of this species in TYPE C which has short pools in flowing direction is higher than in TYPE B which has big steps between each pools when the overflow depth equals 5-10 cm, ascending rate of this species over 9-10 cm in TYPE B is higher than in TYPE C when the overflow depth equals 15-20 cm. 2) The difference of flow structure doesn't necessarily greatly influence ascending rate of this species. 3) About this species, it is necessary to select TYPE B or C corresponding to the assumed range of the overflow depth.