Impact Of Three Gorges Reservoir Operation On The Change Of Area And Volume Of The Dongting Lake

The Dongting Lake, which takes in and sends out water from the Yangtze River and Xiang-zi-yuan-li rivers, is a typical passing lake. Flow regime in Dongting would change greatly under the influence of Three Gorges operation. The investigation of morphology change of the Dongting Lake after operation of Three Gorges has great significance for ecology, flood control, economy and so on. On the basis of 33 time phases TM/ETM imagines from 1993 to 2006-corresponding to the water level at Chengiingji from 19.10 meters to 31.69 meters; the influence of Three Gorges operation on the change of area and volume of the Dongting Lake is studied in this paper, adopting a dynamic analysis method of multi-temporal remote sensing and least squares method. And the mathematical model between discharge change of Three Gorges and area (volume) change in Dongting has been built. The research shows that, there is the most significant influence on the lake outlet region, and the effect gradually decreases with the increase in distance from the outlet; when discharge of the Yangtze River is over a certain critical value, the effect on the area and volume of Dongting is more obviously with the increase of discharge change value of the Yangtze River