The Symposium about Building a Dam in Poyang Lake: Jiangxi Has Never Been Short of Water. The Impoundment of the Three Gorges and the Forested Dams in the Upper Reaches are the Main Reasons for the Drought in Poyang Lake
2021/1/18 13:47:00 本站

On January 14-15, the technical discussion meeting of the special report on environmental impact of the Poyang Lake Water Control Project in Jiangxi Province at the feasibility study stage is being held. Whether or not a dam (floodgate) should be built on Poyang Lake has once again aroused widespread social concern.


Recently, a civil volunteer has been concerned about the Poyang Lake’s ecology for a long time called the Research Department of China Biodiversity Conservation and Green Development Foundation (CBCGDF). He believes that the main reason why Poyang Lake has been drought and frequent low water in winter is mainly due to the impoundment of the Three Gorges and the dams of the five major water systems in the upper reaches of Poyang Lake.


The volunteer said: "Jiangxi has never been short of water, and the problem of low water in autumn and winter can be solved by regulating storage." "The earlier low water period of Poyang Lake and the low water level in winter were also caused by man-made reasons."


This civil volunteer has a good knowledge of the Poyang Lake Basin. According to his observations, before the completion of the Three Gorges Reservoir, Poyang Lake did not experience successive winter droughts or drastically advanced dry seasons in autumn and winter. After the Three Gorges Reservoir was stored, this situation became more frequent. The reason is that as a large hydropower station, the precipitation in autumn and winter generally decreases. At this time, hydropower stations usually store water, which will inevitably lead to a decrease in water from downstream lakes and an earlier dry season in autumn and winter.


Similar to the Three Gorges Reservoir, since the 1990s, the five major tributaries of the upper Poyang Lake in Jiangxi Province have been mainly distributed in the Ganjiang, Fuhe, Xinjiang, Raohe and Xiushui basins. Large and small dams were built, mainly divided into two types: flowing dams and storage dams, all of which are used to generate electricity.


"In Jiangxi, there is a customary saying that the dam is called the Diamond Dam, which means that a dam is equivalent to a diamond, and you can collect money every year after it is completed," said the volunteer. According to their investigation, the average amount of water flowing into Poyang Lake from the five major tributaries of Poyang Lake is about 150 billion cubic meters each year. Among them, the Gan River accounts for more than half. Today, there are more than 2,000 dams on the five major tributaries. Every year after the cold and dew season, these large and small dams begin to store water, waiting for the next spring and summer to release water for power generation. In this way, superimposed with the Three Gorges Dam's autumn and winter water storage effect, the winter dry phenomenon of Poyang Lake appears.


"Although the state has asked for the rectification of small hydropower in the river basin since then, in fact, many local small hydropower projects were built by relatives of civil servants, or there are other reasons that cannot be demolished at all," the volunteer said. But in the summer of 2020, there was a big flood in Poyang Lake. The water level exceeded the 0.08m recorded in the 1998 Yangtze River flood. "If a dam is built in Poyang Lake, the pressure of summer flood control will be extended to the downstream Anqing. Please remember to consider this factor." The volunteer believes that Jiangxi is certainly willing to build a dam, because in addition to retaining clear water, it can also reduce flood losses. For example, during the floods in the summer of 2020, early rice and late rice in several counties along the lake had no harvest, resulting in considerable losses.


"The water is flowing, and the main cause of the winter drought in Poyang Lake is human factors. Without the regulation and storage effect of this natural lake, can the problem be solved by just building a dam? Please be sure to bring this issue to the symposium," the volunteer said.


Note: In order to protect this civil volunteer, his name and address are not involved.

 (Milu deer)

(Photo credit: CBCGDF volunteers of Poyang Lake)

Original Chinese article:

By / Yang Xi Modified / Maggie