Feitsui Dam

Feitsui Dam
Official name	翡翠水庫
Country	Taiwan
Location	Shiding District, New Taipei
Coordinates
Opening date	June 1987
Dam and spillways
Type of dam	Concrete arch
Impounds	Beishi River
Height	122.5 m (402 ft)
Length	510 m (1,670 ft)
Dam volume	700,000 m3 (920,000 cu yd)
Reservoir
Creates	Feitsui Reservoir
Total capacity	460,000,000 m3 (372,928 acre·ft)
Active capacity	335,510,000 m3 (272,002 acre·ft)
Catchment area	303 km2 (117 sq mi)
Surface area	10.24 km2 (2,530 acres)
Normal elevation	170 m (560 ft) max
Power station
Name	Gueishan Power Station
Commission date	1987
Hydraulic head	89 m (292 ft)
Installed capacity	70 MW
Annual generation	223 GWh

Feitsui Dam (Chinese: 翡翠水庫; pinyin: Fěicuì Shuǐkù, also Feicui Dam) is a double curvature concrete arch dam on the Beishi River in northern Taiwan. The dam is located in Shiding District, New Taipei City, and is one of the principal water sources for the Greater Taipei area. The name of the dam and reservoir translates as "emerald lake", in reference to the pure quality of the water. The area is managed by the Taipei Feitsui Reservoir Administration. Public access is heavily restricted in order to protect water quality, which is among the highest of Taiwan's reservoirs.

History

The dam was proposed in the 1970s during a period of severe drought in northern Taiwan. The reservoir site was located on the Beishi River, which joins with the Nanshi River to form the Xindian River which flows through New Taipei City. A dam built here would hold back water during the wet season, when the flow in Nanshi River alone is enough to meet water demands, and release water to augment supplies as needed during the dry season.

This dam site was considered favorable because of good soil and forest conditions of the upstream watershed; at the time human development consisted mainly of tea plantations. The quality was much better than the watershed behind Shihmen Dam, the other major water source for greater Taipei, which has suffered crippling sediment issues due to deforestation. In order to preserve the watershed, the Taiwan government evicted many residents in upstream areas.

Although the Dam is located in New Taipei, construction was funded by Taipei City, in order to provide water to the capital. Construction began in August 1979 and was completed in June 1987. The dam cost NT$11.4 billion to construct. Today about 46 percent of the water is delivered to Taipei City and 54 percent is used in New Taipei. The service area incorporates about 6.3 million people–a quarter of Taiwan's population.

In 2014, the Feitsui Reservoir supplied a total of 344.5 million cubic metres (279,300 acre feet) of water for municipal and industrial uses, or about 944,000 cubic metres (249 million gallons) per day.

Specifications

Feitsui Dam is the largest concrete dam in Taiwan. The dam is a three-centered double curvature arch, 122.5 metres (402 ft) tall, 510 metres (1,670 ft) long, and consisting of 703,675 cubic metres (920,372 cu yd) of material. The dam crest has an elevation of 172.5 metres (566 ft) above sea level. A forebay dam 33 metres (108 ft) high is located immediately downstream, to reduce erosion from floodwater releases. Located in a seismically active zone, Feitsui Dam is designed to withstand a magnitude 7.0 earthquake.

The Feitsui Reservoir has a water storage capacity of 460 million cubic metres (370,000 acre feet) and an active capacity of 335.5 million cubic metres (272,000 acre feet). The reservoir is operated for water supply, with flood control and hydropower generation as secondary purposes. The main purchasers of water are Taipei Water Department and Taiwan Water Corporation. After the Zengwun Reservoir, Feitsui is the second biggest lake in Taiwan.

File:GueiShanPowerPlant.jpg

Gueishan Power Plant

Hydroelectricity is produced at the Gueishan Power Station, which has one Francis turbine with a capacity of 70 megawatts. The plant operates under a gross head of 89 metres (292 ft), and the annual power generation is 223 million kilowatt hours. The maximum flow rate is 102 m³/s (3,600 cu ft/s).

Water is released through three sets of gates. The crest spillway is controlled by 8 radial gates, each 9.3 metres (31 ft) high and 14 metres (46 ft) wide. The bottom sluiceway is controlled by three fixed wheel gates of 3 by 2.5 metres (9.8 ft × 8.2 ft). There is also a tunnel spillway, consisting of a tunnel 386.13 metres (1,266.8 ft) long and 10 metres (33 ft) wide. With all gates open the dam can release 9,870 cubic metres per second (349,000 cu ft/s) of floodwater.

Access

The dam and reservoir are noted for the lack of public access, in order to protect the quality of the drinking water. With the exception of maintenance workers and Taipei City officials, visitation to the dam itself requires a special appointment and must be accompanied by a certified guide. In 2014, a total of 15,798 people toured Feitsui dam compared to 1.7 million people who visited the Shihmen Dam. There are also few, if any designated access and view points on the 15 km (9.3 mi) long Feitsui Reservoir. The closest major road is Provincial Highway 9.

See also

• List of dams and reservoirs in Taiwan
• List of power stations in Taiwan

External links

• Current Feitsui Reservoir water level