Fishways have been studied at the University of Oulu, Finland, since the early 1980's in cooperation with biologists and engineers. Studies have concerned fishways made mainly for whitefish and other migrating freshwater fish. The research has been carried out in small experimental fishways, existing fishways, and natural migrating routes. Fishway hydraulics has been studied in laboratory scale models. Fishway scale model at the University of Oulu consists of a transparent polycarbonate chute and a water circulating system. The chute can be inclined to slopes 0-30% and it can be fitted with different kinds of baffles and vanes. The scale model was constructed originally to improve the hydraulic conditions of the Poyry fishway in the River Siikajoki. Later it has been used in improving other fishways and in studying hydraulics of vertical slot and Denil fishways. It was used also in the design of the Isohaara fishway in the River Kemijoki, which is an interesting combination of vertical slot and Denil fishways.