in december 1957, electric power development company (j-power) selected the ibi river for study at the 23rd electric power development coordinating meeting. by may 1976, the ministry of construction released their bulletin "policy on tokuyama dam construction project". in december 1982, the project was incorporated into the electric power development basic plan. it was approved by the government in 1998. the original project was a pumped-storage hydroelectric scheme which consisted of the tokuyama dam as the upper reservoir, the sugihara dam as the lower and the 400 mw sugihara power plant.