Page - 233 - in Book of Full Papers - Symposium Hydro Engineering

storage in upstream reservoirs at different levels. Without reducing the design flood control standards of the Three Gorges Reservoir, a number of water storage schemes are formulated to calculate the full capacity of the Three Gorges Reservoir and seek for a better water storage scheme. 2. NEW SITUATION OF TGR IMPOUNDMENT 2.1. IMPACTS OF UPSTREAM RESERVOIRS ON WATER STORAGE As of 2017, there are 28 reservoirs in the upper and middle reaches of the Yangtze River that are jointly dispatched, with a total capacity of 57.5 billion m3 and a total flood control storage capacity of 41.5 billion m3. Including TGR, there are 21 reservoirs, with total water demand of 31.87 billion m3, to be large water storage. In the joint water storage plan approved by the state flood control department in 2017, the flood control reservoir was taken as "sub-reservoirs and gradually water storage". 7 reservoirs started to impound on August 1 ahead of schedule, and the remaining 13 reservoirs began to impound on September 1, partially overlapping the storage time of TGR, drastically reducing the amount of water infused into TGR. In the long term, four large reservoirs of Wudongde, Baihetan, Lianghekou and Shuangjiangkou will also be added on the basis of 2017, and the pressure of water storage will be further increased. In the 2017 level year, the total storage of upstream reservoirs in September and October is 9.7 billion m3, which is equivalent to 43.9% of the maximum storage capacity of TGR. In the prospective level year,assuming that all four newly added reservoirs begin to impound in September, the total water storage capacity of the upstream reservoirs from September to October is 22.2 billion m3, which is basically the same as that of the Three Gorges Reservoir.Therefore, the impoundment of large-scale upstream reservoirs has a significant impact on runoff in September and October, significantly reducing the inflow into TGR during the impoundment period.The reservoirs have been built and will be built in the upper reaches of the Yangtze River are shown in Figure 1. 233