[1] Constructed from 1992 to 1996, the dam has a height of 67.4 m and a length of 438 m. It creates the artificial lake Amawaka (天若湖, Amawaka-ko), with an area of 2.74 km2.

Initial planning for its construction started in 1961, as a measure to protect downstream area from frequent floods by the Katsura river.

[1] Hiyoshi Dam is used for three main purposes: flood control, river maintenance and water supply.

[1][2] The dam temporarily stores surges in river water during floods, regulating the flow and avoiding damage to downstream areas.

[1] The dam also helps to ensure that the river water flow downstream is above a certain minimum level during drought periods.