Page - 235 - in Book of Full Papers - Symposium Hydro Engineering

3. ANALYSIS OF THE INFLUENCE OF UPSTREAM RESERVOIRS ON THE RUNOFF OF TGR DURING THE IMPOUNDMENT PERIOD 3.1 HORIZONTAL YEAR DIVISION In 2017 level year, 13 reservoirs were selected from the reservoir that has been incorporated into the joint operation,including Guanyinyan, Xiluodu, Xiangjiaba, Zipingpu, Pubugou, Goupi Beach, Silin, Shatuo, Pengshui, Bikou, Baozhusi, Tingzikou and Caojie that impound in Septerber or October. In the long-term horizon year, 4 large-scale reservoirs, including Wudong, Baihetan, Lianghekou and Shuangjiangkou, will be added on the basis of the 2017 level year, for a total of 17 reservoirs. 3.2 RUNOFF CALCULATION According to the water storage scheme which has been built and proposed in the upper reaches of the Yangtze River, the amount of water storage needed to be allocated in every ten days is calculated.The long series runoff data of 110 years (1881-1990 years) were calculated by 2017 level year and long-term level year respectively, and the runoff data of Three Gorges dam site under the operation conditions of upstream cascade reservoirs were obtained.Based on the calculated data of long series of runoff, the accumulating rate of TGR and the influence on the downstream are analyzed and compared under different schemes. The average runoff of the 110-year-long series (1881-1990) of the Three Gorges Dam site in September and October was 122.5 billion m3. The runoff series for the 110-year (1881-1990) Three Gorges Dam site were calculated considering the upstream reservoir construction conditions .In 2017 level year, there are 13 reservoirs operating above TGR, reducing the total runoff of 9.7 billion in September and October. In the prospective level year,there are 17 reservoirs operating above the Three Gorges to reduce the total runoff of 22.2 billion m3.The simulation results show that 75 years is less than the multi-year average of the preliminary design in the 2017 level year, accounting for 68.2%.,and 90 years in the prospective level year, accounting for 81.8%. 4. CALCULATION OF THE FULL STORAGE RATE OF TGR 4.1 CALCULATION SCHEME AND CONTROL CONDITION 235