The dam's design utilizes a 'suribachi' or mortar-shaped spillway to disperse kinetic energy, preventing the riverbed from being scoured by the force of the water.
It was constructed during the early Showa period to resolve chronic water shortages in the local rice fields of the Oita region.
The dam is one of the few in Japan built primarily for irrigation purposes that has achieved status as a National Important Cultural Property.
Local engineers designed the surface to be rough in specific areas to break the fall of the water, which creates the dam's characteristic 'flowing silk' appearance.
The structure is built from volcanic tuff, a material abundant in the surrounding Taketa area.
Hakusui Dam is a uniquely designed irrigation dam located in Taketa, Oita Prefecture, completed in 1938. The structure is distinguished by its curved overflow section, which is specifically engineered to create a waterfall effect that reduces water erosion on the dam foundation. The dam wall is 14 meters high and 86 meters long, featuring a deliberate concave shape that forces water to flow over the top like a curtain. It is designated as a National Important Cultural Property of Japan due to its blend of functional civil engineering and aesthetic landscape design. Visitors can walk along the river banks to observe the water patterns created by the dam's tiered overflow design. The surrounding area remains largely rural and integrated into the local volcanic topography of the Aso region.
From the observation trail on the opposite bank to capture the full width of the curved spillway.
Bring a tripod if you intend to photograph the water flow, as slower shutter speeds effectively capture the silk-like motion.
Wear shoes with good grip as the paths alongside the river can be damp and slippery due to spray.
Visit after a light rainfall to see the dam's waterfall effect at its most voluminous.
Do not attempt to visit during or immediately after heavy typhoons, as the river level can rise rapidly and the area becomes inaccessible.
Stay behind designated safety railings and do not attempt to climb or wade into the spillway area.
