Jinanqiao Dam
Encyclopedia
The Jinanqiao Dam or Jin'anqiao (meaning "golden and peace bridge") is a concrete gravity dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 on the Jinsha River
Jinsha River
Jinsha River is the westernmost of the major headwater streams of the Yangtze River, southwestern China.Its headwaters rise in the Wulan and Kekexili ranges in western Qinghai province, to the south of the Kunlun Mountains, and on the northern slope of the Tanggula Mountains on the border of the...

 25 km (16 mi) southeast of Lijiang City in Yunnan Province, China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

. The purpose of the dam is hydroelectric power production and flood control.

Construction

The Jinanqiao project was approved in August 2003 and construction began in 2005. By December of that year, the river was diverted and the construction of the actual dam began in January 2006. By February 2007, the foundation had been excavated and concrete pouring began. In June 2010, the dam's first generator was operational.

Design

The dam is a 160 m (525 ft) tall and 640 m (2,100 ft) long gravity dam composed of 3920000 cubic metre of roller-compacted concrete
Roller-compacted concrete
Roller-compacted concrete or rolled concrete is a special blend of concrete that has essentially the same ingredients as conventional concrete but in different ratios, and increasingly with partial substitution of fly ash for Portland cement. RCC is a mix of cement/fly ash, water, sand, aggregate...

. The dam's crest elevation is 1424 cubic metre above sea level and it withholds a 847000000 cubic metre reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...

 with a normal storage level of 1418 m (4,652 ft) ASL. Of the reservoir's storage, 313000000 cubic metre is active or "useful". The dam's spillway
Spillway
A spillway is a structure used to provide the controlled release of flows from a dam or levee into a downstream area, typically being the river that was dammed. In the UK they may be known as overflow channels. Spillways release floods so that the water does not overtop and damage or even destroy...

 consists of five 13 m (43 ft) x 20 m (66 ft) openings which have a maximum flood discharge capacity of 14980 m3/s. To prevent scouring, the dam has a stilling basin at the foot of the spillway. The dam's power station sits at its toe and adjacent to the spillway. It is 213 m (699 ft) long, 34 m (112 ft) wide and 79.2 m (260 ft) high. Four penstocks with a 10.5 m (34 ft) diameter feed the 4 x 600 MW Francis turbine
Francis turbine
The Francis turbine is a type of water turbine that was developed by James B. Francis in Lowell, Massachusetts. It is an inward-flow reaction turbine that combines radial and axial flow concepts....

-generators which can discharge up to 605 m3/s after generation. Each Francis runner has a 6 m (20 ft) diameter.

Because of high seismic activity in the area of the dam, special care was taken during design and construction to prepare the joints and foundation for sliding and tensile stress. Earthquake-resistant steel bars were installed in high-tensile areas, the construction joint was reduced to 2/3 its size and filled with non-woven fabrics along with the incorporation of a grouted joint between the dam and power plant.
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