Influence of flood control regulation of Three Gorges Reservoir on flood of upper Yangtze River in August,2009

The large flood of upper Yangtze River occurred in August,2009,in order to mitigate flood control pressure of Jingjiang River and 4 outflow channels in the south of Jingjiang River,the flood discharge of Three Gorges Reservoir is controlled to cut down flood peak discharge.Through retduction calculation,we analyze the influence of flood control regulation by Three Gorges Reservoir on flood control of Jingjiang River and Chenglingji reach.The results show that the peak water level of Three Gorges Reservoir during this flood detention reached to 152.89 m;the water levels at Shashi and Chenglingji are below defense level,and high water level of Jingjiang reach was avoided and flood control response grade was lowered.Three Gorges Reservoir regulation reduced flood control cost of mid-lower Yangtze River and increased power generation of 5.3×10 8 kW·h.It is the first large-scale flood control regulation since the completion of Three Gorges Reservoir and flood control and generation benefits have been gained.