Hakusui Dam

Hakusui Dam (白水ダム) is a stone masonry-faced concrete gravity dam on the upper reaches of the Ōno River in Taketa, Ōita Prefecture, Japan. Completed in 1938, the dam spans 86 m and stands 14 m tall. Designed by civil engineer Yasuo Ono (小野康夫) for irrigation purposes, it features a distinctive curved and stepped spillway that controls water flow and prevents erosion.

Widely praised by Japanese civil engineering societies for its aesthetic design, the dam is sometimes called "Japan's most beautiful dam" or "the Lady of Dams." Designated as an Important Cultural Property in 1999, it represents an important example of pre-war concrete dam technology that successfully combines functional engineering with aesthetic consideration.

Built during Japan's agricultural modernization in the early 20th century, Hakusui Dam exemplifies the development of small-scale irrigation dams crucial to supporting farmland and rural infrastructure. Unlike large-scale hydroelectric or flood control projects, it serves exclusively for irrigation and continues to provide a reliable water supply for agricultural use in the Taketa region.