Respective project dimensions Power station Okutadami Otori Existing Expansion Existing Expansion Maximum power discharge 249 138 220 207 (m3/sec) Maximum 0utput MW) 360 200 95 87 Civil structures of expanded power stations Power station Okutadami Otori Type of dam (existing) Concrete gravity arch Semi arch Dam height (m) 157 83 Dam volume (m3) 1636×103 160×103 Type of tailrace Underground free-flowing tunnel