Ertan Dam



The Ertan Dam is an arch dam on the Yalong River, a tributary of the Yangtze River in Sichuan Province, in southwest China.

The dam has six hydroelectric generators, each with a generating capacity of 550 MW. The total generating capacity of the facility is 3,300 MW, one of the largest hydroelectric stations in China. The annual production is 17 TWh, and until December 5, 2006, it has produced over 100 TWh of electricity. Construction of the dam started on September 1991 and was completed on December 26, 1999. A total of 12638000 m3 of material was excavated during construction.

The Ertan Dam was designed by the China Hydropower Engineering Consulting Group Survey and Design Institute in Chengdu, and was constructed and is currently operated by Ertan Hydropower Development Company Limited, the owners of the dam. The company is invested by State Development and Investment Company (52% share) and Sichuan Chuantou Energy Limited (48% share).

Design
The Ertan Dam is a 240 m high and 774.7 m long double-curvature arch dam. The dam withholds a normal reservoir of 5800000000 m3 with a drainage area of 116400 km2 and normal surface area of 101 km2. The dam has four different ways to discharge water downstream. First, the dam's spillways which contain 7 x floodgates at the crest and two flood tunnels can discharge 6,260 m3/s and 7400 m3/s respectively. The dam also contains 6 x middle outlets and 4 x bottom outlets that can discharge 6,930 m3/s and 2084 m3/s respectively. The dam's power station is located underground along with its transformer room which is in a separate cavern. Additionally, the power station is supported by an underground surge chamber as well.

Main Features
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