Author(s): Y. C. Chen; J. Fu; Z. W. Liu
Linked Author(s): Zhaowei Liu
Keywords: Three Gorges Dam; Dissolved oxygen; Super-saturation; Predictionmethod
Abstract: The variety of dissolved oxygen (DO) concentration is investigated based on the measured water quality data at the upstream and downstream sections near Three Gorges Dam. It is shown that tremendous mount of oxygen dissolves into water with releasing flood through spillways and the super-saturation phenomenon of DO is observed downstream of the dam. However, the downstream DO concentration is hardly changed in the water released through Three Gorges Hydropower Stations. An easy-used prediction method for DO percent saturation downstream of hydroprojects is developed. The percent saturation downstream of spillways is calculated by assuming that the gas transfer between water and air is so rapid as to dissolve sufficient amount of gas into water in bubble swarm area, which is reasonable when water re-aerated intensively in still basin. Then the percent saturation is further averaged by mixing hydropower station flow and spillway flow. Several cases including four different hydroprojects along Columbia River and Three Gorges Project are predicted for calibration and validation, and the calculated DO percent saturation is well agreed with the original monitoring data. The method is also used to predict the DO percent saturation of Huanglingmiao section about 12km downstream from Three Gorges Dam at different typical reservoir water levels, which shows that the DO percent saturation will be as much as 140% if there is a flood with 1 in 100 year's frequency.
Year: 2009