A new fishway is planned to enhance upstream migration over the Imawatari Dam of the Kiso River. To cope with fluctuation of water level of the reservoir (3 meters a days), combination of a Denil fishway and an orifice fishway equipped with float-driven shutter gates is developed. To make the best use of discharge from a power station as attraction flow, two fish entrances are placed at both sides of the outlet. Detailed tests on models and the actual structure are prepared to examine flow control capability.