Xiaowan Dam ( Chinese:小湾水坝 ) is located on the Lancang River (Mekong) in Xiaowan Town, Fengqing County, Lincang City, Yunnan Province in southwest China.
The installed capacity of Xiaowan Hydropower Station is 4,200 MW. Construction started in 1999 and was completed in 2010. It took 11 years and cost 32 billion yuan (US $3.9 billion). It was built by Huaneng Lancang River Hydropower Development Company and is the second tallest arch dam in the world, with a height of 292 m (958 ft).
The Xiaowan Dam is mainly used for power generation, with functions such as flood control, irrigation, sand blocking and shipping. The annual power generation capacity reaches 19 billion kWh.
The inundated area of the reservoir involves 30 towns and villages in 8 counties of Lincang, Dali, and Baoshan, and a total of 35,899 people have migrated.
- 1986: The Planning Report on the Middle and Lower Reach of the Lancang River was completed and approved by the Chinese government in 1987.
- June 1999: “Yunnan Xiaowan Hydropower Station Construction Preparation Office” was established to take charge of the preparations for Xiaowan Hydropower Station’s construction.
- January 20, 2002: the Xiaowan Dam officially started.
- October 25, 2004: the river closure was achieved one year ahead of schedule.
- December 12, 2005: the concrete of the dam’s first warehouse was poured.
- December 16, 2008: the diversion tunnel was closed for water storage.
- September 25, 2009: the first unit was put into production for power generation.
- August 22, 2010: the sixth unit of the Xiaowan Hydropower Station was officially put into operation after 72 hours of trial operation, marking the commissioning of all the 6 units of the Huaneng Xiaowan Hydropower Station with a total of 4.2 million kilowatts.
The Xiaowan Dam is 292 m (958 ft) high and 902 m (2,959 ft) long. It is a double-curved arch dam. Its crest width is 13 m (43 ft), and the base height is 69 m (226 ft). The dam’s crest is at an altitude of 1,245 m (4,085 ft), while the normal reservoir level is slightly lower at 1,240 m (4,068 ft).
The dam body is equipped with 5 open surface spillways, 6 drainage holes and 2 vent bottom holes.
The hub’s total discharge volume is 17,680 cubic meters per second at the design flood level and 20680 cubic meters per second at the check flood level.
Economic and environmental benefits
The Xiaowan Hydropower Station focuses on power generation and has comprehensive utilization benefits such as flood control, irrigation, sand blocking and shipping:
- Reduce carbon emissions: After completing the Xiaowan Hydropower Station, the electricity that can replace coal-fired thermal power is about 25.24 billion kW.h, and it can save about 860t of standard coal each year.
- Sediment interception: The Xiaowan Reservoir above the dam site can intercept an average of 48 million tons of suspended sediment and 1.5 million tons of bedload annually, thereby solving the sediment problem of the Manwan and Dachaoshan hydropower stations.
- Flood control: Xiaowan Reservoir can provide a flood regulation storage capacity of 1.318 billion cubic meters combined with Xingli storage capacity. Flood regulation to ensure the safety of the dam can reduce flood peaks by 12%.
- Shipping: The river section where the Xiaowan Hydropower Station is located is currently not navigable. After the completion of the reservoir, a 178km deep-water channel in the main reservoir area and a 123km deep-water channel in the tributary Heihuijiang reservoir area will be formed, creating conditions for the development of shipping in the reservoir area; Later, the low-water flow of the lower reaches of the Lancang River will increase, which can improve shipping conditions. At the same time, it also develops local tourism and can meet the electricity demand for the development of the national economy in Yunnan Province in China after 2010.
Xiaowan Dam Data
- East Asia
- In use
- Official name
- Other name
- Xiaowan Hydropower Station
- Xiaowan Town, Fengqing County, Lincang City, Yunnan Province, China
- Huaneng Power International, Inc. (HPI)
- 32 billion yuan ( US $3.9 billion )
- Jan-01, 2002
- Mar, 2010
- Dam height
- 958 ft (292 m )
- Dam Length
- 2959 ft (902 m )
- Hydraulic head
- 251 m (823 ft)
- Top elevation
- 1,245 m (4,085 ft)
- Spillway type
- Spillway capacity
- 10,014 m³/s (353,641 cu ft/s) Flood discharge (all outlets): 20,709 m³/s (731,331 cu ft/s)
- Installed capacity
- 6 × 700 MW
- Lancang River
- Reservoi name
- Xiaowan Reservoir
- Total capacity
- 15,043,000,000 m³ (12,196,000 acre⋅ft)
- Active capacity
- 9,895,000,000 m³ (8,022,000 acre⋅ft)
- Catchment area
- 113,300 km² (43,700 sq mi)
- Reservoir area
- 190 km² (73 sq mi)
- Reservoi Surface elevation
- 1,240 m (4,068 ft)
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