Research On The Lethal Effect Of The Dissolved Gas Super-saturation Resulted From Three Gorges Project To Fish

The world-famous Three Gorges Project is apart from Gezhouba Dam riverway 43 kilometers, rested on between upper reaches of Gezhouba Dam and lower Xiling Gorges of the Yangtze River. In June of 2003, Sluice water level rise to 13S meters, towering above downstream of The Gorges Dam 60 meters. On 22nd June, Dam strobe opened, dissolved gas super-saturation may be caused by the entrainment of air in water released over dam sluice ways, which brings threat to the living of aquatic in water. To discuss the efifects of the way of dam operation and reason of the fish death, this paper mainly studies the variance of water-quality indexes at the downstream from Zhicheng to Jingzhou reach of the Yangtze River in 2002, 2004, 2005 and the experiment of biology domino effect on fish, The primary results are as follows:(1) The variance of water-quality at Zhicheng and Jingzhou riverway in 2002, 2004, 2005 Firstly, this experiment monitors water-quality at the downstream from Zhicheng to Jingzhou reach of the Yangtze River, and estimates Single index of water-quality respectively, also discusses the variance of water-quality after the Three Gorges reservoir formation. The results indicate that all indexes of water quality change little except for Cu, SPM, DO and water temperature. The water-quality parameters exceeding the standard are Hg, TCu,, TPb, Oil and TP at the monitor sites from Zhicheng to Jingzhou reach of the Yangtze River in 2002,2004,2005. Thus, it is predicted that the fish death was not caused by contamination. Water temperature as near as makes no difference in these years and research is short-timed, so it is not clear whether it has any relation to fish death. The content of Cu and SPM decreases obviously, which indicates that water-quality is meliorated and makes no difference to fish. The dissolved oxygen was increased significantly, and should be caused by the water spilling by the Three Gorges Dam. In a word, the gas super-saturation resulting in Three Gorges Dam brings threat to fish and has directly relation to the fish death.