Fukuji Dam

The or Fukuchi Dam is a rock-fill embankment dam on the Fukuchi River northeast of Higashi, Okinawa Prefecture, Japan. The purpose of the dam, the tallest in Okinawa, is water supply and flood control.
Background.
Under the Ryukyu Domestic Water Corporation, the U.S. Army Corps of Engineers began constructing the dam in 1969. After the United States Civil Administration of the Ryukyu Islands returned administration of Okinawa back to Japan in 1972, construction became the responsibility of the Japanese government. The dam was completed in 1972, and the auxiliary spillway in December 1974. The dam was later raised to accommodate an improved intake and an additional in water elevation. This additional work was completed in 1991.
Design.
The dam is a tall and long rock-fill embankment type with a structural volume of and a crest elevation of . The dam sits at the head of a catchment area and its reservoir has a surface area of . The reservoir's capacity is while serves as active (or "useful") capacity. The dam is equipped with a drum gate-controlled chute spillway. On the eastern edge of the reservoir, east of the dam, there is an auxiliary spillway at . This spillway is a siphon-type and operates automatically to help drain the reservoir during flooding. It has a capacity and discharges directly into the Pacific Ocean.