Effects of the Diversity of Flow Velocity on the Upstream Migration Behavior of Grass Carp in the Reaches of Spur Dikes

The construction of spur dikes alters the flow pattern rivers and affects upstream migration behavior fishes. Traditional rock-fill experimental permeable with a “Weighted Excess Storage” (WES) profile were evaluated using hydrodynamic experiments on juvenile Grass Carp (Mylopharyngodon idella). swimming ability paths in dike analyzed, relationship between success rate diversity velocity was studied. induced critical body length 5 ± 0.5 cm are 0.1 m/s 0.7 according to experiment. index increased roughly power function trend increase discharge, under same conditions, greater than that dikes. When within preferred range Carp, linearly velocity. 60% dropped sharply. Compared dikes, provide passage for fishes reduce impact fish. results this research theoretical support ecologically optimized designs ecological management rivers.