Fukuji Dam

Fukuji Dam
Official name	福地ダム
Country	Japan
Location	Higashi, Okinawa
Coordinates	26°38′51″N 128°10′27″E / 26.64750°N 128.17417°ECoordinates: 26°38′51″N 128°10′27″E / 26.64750°N 128.17417°E
Status	Operational
Construction began	1969
Opening date	1974
Dam and spillways
Type of dam	Embankment, rock-fill
Impounds	Fukuchi River
Height	92 m (302 ft)
Length	260 m (853 ft)
Elevation at crest	90 m (295 ft)
Dam volume	1,622,000 m^3 (2,121,496 cu yd)
Reservoir
Total capacity	55,000,000 m^3 (44,589 acre·ft)
Active capacity	52,000,000 m^3 (42,157 acre·ft)
Catchment area	32 km^2 (12 sq mi)
Surface area	3 km^2 (1 sq mi)[1]

The Fukuji Dam (福地ダム) or Fukuchi Dam is a rock-fill embankment dam on the Fukuchi River 2.5 km (2 mi) northeast of Higashi, Okinawa Prefecture, Japan. The purpose of the dam, the tallest in Okinawa, is water supply and flood control.^[2]

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.^[3] The dam was completed in 1972, and the auxiliary spillway in December 1974.^[3] The dam was later raised to accommodate an improved intake and an additional 2.4 m (8 ft) in water elevation. This additional work was completed in 1991.^[4]

Design

The dam is a 92 m (302 ft) tall and 260 m (853 ft) long rock-fill embankment type with a structural volume of 1,622,000 m³ (2,121,496 cu yd) and a crest elevation of 90 m (295 ft). The dam sits at the head of a 32 km² (12 sq mi) catchment area and its reservoir has a surface area of 3 km² (1 sq mi). The reservoir's capacity is 55,000,000 m³ (44,589 acre·ft) while 52,000,000 m³ (42,157 acre·ft) serves as active (or "useful") capacity.^[1] The dam is equipped with a drum gate-controlled chute spillway. On the eastern edge of the reservoir, 6.3 km (4 mi) east of the dam, there is an auxiliary spillway at 26°38′15″N 128°14′12″E / 26.63750°N 128.23667°E. This spillway is a siphon-type and operates automatically to help drain the reservoir during flooding. It has a 900 m³/s (31,783 cu ft/s) capacity and discharges directly into the Pacific Ocean.^[5]

References

1. "Key Features of Dams in Okinawa". North Dam Construction Office. Retrieved 24 July 2011.
2. "Fukuchi Dam" (in Japanese). DamMania. Retrieved 26 July 2011.
3. "Fukuchi Dam" (in Japanese). Japan Dam Handbook. Retrieved 25 July 2011.
4. "Fukuchi Dam" (in Japanese). Okinawa General Bureau North Dam Integrated Office. Retrieved 25 July 2011.
5. "Fukuji Dam Upstream Spillway" (in Japanese). Okinawa General Bureau North Dam Integrated Office. Retrieved 25 July 2011.