the is an embankment dam near ibigawa, ibi district, gifu prefecture in japan. the dam was completed in 2008 and will support a 153 mw hydroelectric power station that is expected to be fully operational in 2015. currently, unit 1 at 23 mw was commissioned in may 2014. the dam was originally intended to withhold the upper reservoir of a 400 mw pumped-storage power station until a design change in 2004. the dam is also intended for flood control and water supply. it is the largest dam by structural volume in japan and withholds the country's largest reservoir by volume as well.