China News Service Nanchang, July 17 (Wu Pengquan) A reporter from China News Service learned from the Jiangxi Provincial Flood Control and Drought Relief Headquarters that the total amount of water that the Yangtze River poured into Poyang Lake in 53 years was 146.2 billion cubic meters, an average of 2.76 billion cubic meters per year.
Since July, Jiangxi Province, a province in the middle and lower reaches of the Yangtze River, has been hit by continuous heavy rainfall. Several rivers and Poyang Lake have suffered numbered floods and super-alarm floods. The water levels at multiple sites have even exceeded guarantees, exceeded 1998, and exceeded history. In addition, the main stream of the Yangtze River has also formed a top-down irrigation for Poyang Lake, causing the water level to continue to rise.
The director of the Hydrology Department of Jiangxi Provincial Hydrological Bureau, Fangfang Fang, said on the 17th that Poyang Lake, China's largest freshwater lake, has a unique form of "high water is a lake, low water is like a river", "a flood, a dry line". The dual impact of the Yangtze River main stream and the Jiangxi Wuhe flood.
Since July, Jiangxi, a province in the middle and lower reaches of the Yangtze River, has been hit by continuous heavy rainfall. The water level of the river has risen rapidly, and the water level of Poyang Lake has exceeded the historical extreme of 1998. Photo by Han Junxuan
From 23 o'clock on July 6 to 15 o'clock on the 8th, the Yangtze River flooding and backfilling occurred at Poyang Lake. The water level of Hukou Station rose from 19.82 meters to 20.66 meters. The amount of backfilling water was 300 million cubic meters, and the maximum backflow was 3160 seconds.
According to a total of 70 years of data from Hukou Station from 1950 to 2019, 53 years of backflow occurred. The total amount of water flowing back into the Poyang Lake from the Yangtze River was 146.2 billion cubic meters, with an average of 2.76 billion cubic meters per year. Among them, the maximum reverse irrigation flow was 13600 seconds cubic meters on July 11, 1991, when the water level of Hukou Station was 18.56m; the annual maximum reverse irrigation flow was 11.4 billion cubic meters in 1991; the highest level of reverse irrigation occurred at 10:00 on July 7, 2016 By 10 o'clock on the 8th, the water level at Hukou Station rose from 21.03 meters to 21.22 meters.
In Fangfangfang's view, the Yangtze River backflow is a normal phenomenon of the changes in the hydrological situation of the Yangtze River and Poyang Lake, and is the basic feature of the interaction between the Yangtze River and Poyang Lake. "According to the statistical analysis, the operation of the Three Gorges Reservoir has effectively reduced the frequency and amount of backfilling of the Yangtze River to Poyang Lake, and reduced the flood resistance pressure of Poyang Lake." (End)