Abstract:

The Three Gorges Project is the largest construction project in China, with tremendous economic and social benefits in flood control, power generation, navigation and other aspects. However, the use of the Three Gorges Project will inevitably have some impacts on the original hydrological situation of rivers and lakes. This research quantitatively analyzed the water level impact of the use of the Three Gorges Project on the Poyang Lake by establishing water and sediment simulation models of the middle and down stream of the Yangtze River (Yichang to Datong segment). The results showed that, during the impoundment of the Three Gorges Reservoir (mid to late September to November), the discharge flow reduced 3 000-6 000 m3/s than before. The biggest drop of water level around the Poyang Lake was between 07 m and 19 m, and the average was between 04 m and 09 m. On this basis, the impacts of the impoundment of the Three Gorges Reservoir on farmland irrigation and urban water supply of the Poyang Lake area were analyzed through the typical investigation and analysis. For farmland irrigation impact, the loss around the Poyang Lake area by the impoundment of the Three Gorges Reservoir was estimated to 01 billion Yuan per year. For urban water supply, about 15 million urban populations were affected by the impoundment of the Three Gorges Reservoir, and about 270 million m3 water supplies was affected, affecting time was about 30 days. The countermeasures to eliminate or reduce the impacts were also proposed in this paper. The results can provide scientific basis and technical support for economic and social sustainable development of the middle and down stream regions of the Yangtze River and integrated management of the Poyang Lake