The Shuangjiangkou dam will be located in Ngawa Tibetan Autonomous Prefecture, approximately two kilometers from the point where Barkham county’s Kyomkyo River (Jiao-Muzu in Chinese) and Chuchen county’s Trokyab River (Chuosi-Jia in Chinese) merge into a single river. Shuangjiangkou is “confluence of two rivers” in Chinese. The dam will serve as an upstream regulatory dam for a series of dams downstream on the Dadu River (Gyalrong Gyamo Ngulchu in Tibetan). Several of these dams will be built in Tibetan areas of Trokyab, Tsodun, Drakpar, Kyomkyo, and Dampa in Chuchen and Barkham counties.
Here are some photos of the site posted by Kou Lihang on Google Earth. The first photo shows construction work on the project.
Here is James' full report:
At present the Shuangjiangkou dam is under construction and the local people have to move out of the area of the future reservoir. The only descriptions of the project I could find on the internet written in English is an article by Tashi Tsering from 2004, see pages 9 and 10. He has also reported about the dam in this short news release:
At that time in 2004 and 2005 it was just a plan for another dam. While there were concerns concerning “local Tibetans who have been ordered to move away” and “historical Buddhist shrines in the area … likely to be submerged… ” no details were available. Using various sources published since then and the internet I was able to get a much more detailed view of what happens in Gyarong in 2010. On Google Earth a photo of construction activity at the construction site has been posted by Kou Lihang at position 31° 47´ 54” N and 101° 54´ 50” E [posted above]. This is more or less where the dam is built. The exact position is 2 kilometers downstream from where the two rivers meet.
Shuangjiangkou Dam Impact Data
Technical project description
The dam is 314m high. The reservoir storage capacity is 2.732 billion cubic meters of water. Installed generating capacity is 2000 MW with four turbines rated at 500 MW each. The average water flow at the dam site was measured at 524 cubic meters per second as the year round average. The average generated electricity is expected at 8.128 billion kw/h per year. The minimum expected generated electricity is 4.86 billion kw/h per year. The dam is expected to be filled with water by November 2014 and the first turbine is to run in 2015. The building cost is estimated to be 20 billion RMB or 3 billion US Dollars.
By regulating the water flow of the Dadu River with such a big reservoir the generating capacity of the dams planed or in operation further downstream will also increase by an estimated 1782 MW per year. The reservoir is also intended to hold back as much as possible of the sand that currently flows down the Dadu. Each cubic meter of water contains at present on average of between 225 grams to 298 grams of sand and silt. The total amount expected to arrive at the reservoir per year is around 4 million tons. Holding back such a large amount of sand has a positive effect on all dams downstream, as all dam reservoirs remain working at full capacity for longer and turbines are not damaged by sand. The foundation of the dam is at 2196 m above sea level and the top of the dam at 2510 m. The water level is planned to reach a maximum level of 2500 m or 10 meters below the top of the dam. At the top the dam will be 16 meters wide.
Impact on nature, population and culture
The reservoir size, once the level of 2500 meters above sea level is achieved, is from the dam about 33 kilometers along the river in direction west or Guanyin. In direction east the water will reach just below the town of Songgang which is 35 kilometers from the dam. Travelling for example from east to west with a visit to the dam it is a 68 kilometers long trip.
Impact on population
A total of 5925 persons have to move out of the flooded area. Nearly all of them are Gyarong Tibetans. The areas to be flooded are part of Ma’erkang (Barkham) and Jinchuan (Chuchen) county. Only one small township (Xiang) named Baiwan (Pagbar, meaning “White Bend”) with a population of 2390 persons is inside the reservoir area. The main village of Baiwan Xiang is called Jiada (Kyodag) with a population of 300 persons. All other people are from other small villages along the rivers. The dam is designed to fill up to a level of a maximum of 2500 meters above sea level as the towns of Songgang (Zonggag) and Guanyin would be under water too, if a higher level would have been decided. It looks like the reservoir size is designed to minimize the impact on the local population. Any other site along the Dadu River for a similar sized dam would result in much more people resettled.
Impact on culture
The two counties have a total of 82 Tibetan Buddhist monasteries and temples with 2252 monks in 2009. There are 7 monasteries or village temples which will be under water. The number of monks in the 7 monasteries is 137 in 2009. The 7 monasteries have 1787 followers (persons supporting and visiting frequently) in the surrounding villages which are 4.8% of the population of the two counties. This means the majority of the 5925 persons who will be resettled will be able to visit their traditional monastery. The resettlement as planed in 2009 is to move people in the same township to higher ground and not far away to new locations. An archeological survey of the reservoir area was completed during 20 days in June 2005. The archeologists from Chengdu were searching for new underground sites. Indeed 12 sites, mostly from the New Stone Age, were discovered in such a short time. The details are published in “Sichuan Wenwu” (Sichuan Cultural Relics) 6 / 2005 pages 17 to 20.
The main source for the data: Journal of the Southwest Minority University, Vol. 2009 / 07, pages 16 to 19. Chengdu, China. No abstract in English. For the technical data the most up to date sources from the internet were used. Older articles are still available but the most recent figures were used for this update.
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