Xiluodu Dam, Jinsha River, China
The Xiluodu double-curvature arch dam is being built by China Three Gorges Corporation (CTGPC). It will be the second largest dam in China, next only to the Three Gorges Dam (TGD) in terms of size, construction cost and generating capacity.
The new dam is being constructed in the lower Jinsha River, which is a major tributary of the Yangtze River. The dam will be located on the upper reaches of the Yangtze River between Yunnan Province and Sichuan Province.
Construction of the CNY50.34bn ($6.2bn) dam project began in December 2005, with the concreting commencing in 2008. The dam is expected to be ready by 2014.
With a reservoir capacity of 12.67 billion cubic metres and flood control capacity of 4.65 billion cubic metres, the Xiluodu Dam along with the TGD, will be capable of preventing floods up to 4.6 billion cubic metres in the middle and lower parts of the Yangtze.
Purpose of the Xiluodu Dam project
The Xiluodu Dam will alleviate the control of flooding on the Yangtze River, apart from generating power. It will also help in flood prevention, sediment control and navigation improvement.
The new dam will complement the TGD and ease the sediment collection in the latter's reservoir. The navigation system downstream will also be improved.
The dam is being built as part of the China West Development Strategy, which aims to boost the economy of six provinces, five autonomous regions and one municipality in Western China.
CTGPC is currently constructing three other dams: Xiangjiaba, Baihetan and Wudongde, all of which are also located on the Jinsha River.
Details of the Chinese dam
The overall elevation of the dam crest will be 600m, with the concrete double-curvature arch dam being 285.5m high and 700m long. Up to 16.72 cubic metres of concrete are expected to be used for constructing the dam.
The dam will consist of seven surface spillways and eight outlets. There will be four overflow tunnels, two each on the left and right banks. The reservoir capacity will be about 12.67 billion cubic metres, out of which 4.65 billion cubic metres will be utilised for flood control.
The dam will generate power from two underground power stations, with one station located on the right bank and the other on the left. The two power stations will be equipped with nine turbines each with an overall power generation capacity of 12.6GW.
The Jinsha River was dammed using five control gates in November 2007, with the area of the dammed part measuring 47m wide and the flow of water at seven metres per second. Four of the five control gates weigh 1,200t each, while one control gate weighs 1,600t.
The construction of the dam is being carried out using belt conveyors, crawler tractors, hydraulic excavators, rock trucks and wheel loaders.
Problems faced by CTGPC
The construction of Xiluodu Dam began in December 2005, after being halted temporarily by the State Environmental Protection Administration (SEPA) in January 2005 due to the lack of a satisfactory environmental impact assessment. The project site, located in a rare fish reserve and earthquake prone area, required preservation measures to get the permit for construction.
In 2009 it was decided that the dam's height should be increased to 285.5m, which resulted in design changes and escalated the construction cost by about $250m. It also required the generation of about CNY10m in unauthorised funds.
The project is said to have relocated about 7,300 people and is expected to displace about 50,000 people in the long run.
Contractors and finances behind Xiluodu Dam
The dam's design was provided by the Chengdu Hydroelectric Investigation Design & Research Institute of State Power Company (CHIDI). Ansys played crucial roles in studying the dam's feasibility.
The financiers for the project included Yangtze Power, China Development Bank (CDB) and China Construction Bank.
Citic Heavy Machinery supplied the headstock gears used for operating the gates at the dammed area of Jinsha River, while Vacon provided 20 NXP drive units for powering the headstock gears.
Belt conveyors for the laying of concrete were supplied by Putzmeister. The belt conveyer used for the project is the Telebelt TB 110G.
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