Page - 237 - in Book of Full Papers - Symposium Hydro Engineering

4.2 THE INFLUENCE OF RAISING INITIAL WATER LEVEL ON THE FULL STORAGE RATE OF TGR. Since 2008, TGR started for the first time to carry out 175m experimental water storage,according to the principle of “ safety, science, reliable and Gradualism”.In view of the runoff reduction in the impoundment period, the simultaneous storage of the upstream reservoir and the increase of the water demand in the lower reaches, the contradiction between the water storage and the discharge is outstanding.After fully demonstrating the flood control safety and sedimentation of pre-impoundment, the impounding mode of the Three Gorges reservoir has been further studied, and a water storage way to undertake the flood control stage and raise the water level has been put forward.TGR have achieved 175m water target for 8 consecutive years from 2010 to 2017 after further optimizing the storage scheme, and the discharge standard increased from about 5500m3/s to 8000m3/s during October. Practice in recent years has also shown that storing flood resources and raising the initial water level TGR, were effective measures to improve the full storage rate. Based on the simulated runoff of Three Gorges dam site after the operation of cascade reservoirs in different levels, the storage rate of TGR under different storage levels was calculated. In the prospective level year, TGR began to store water in September 10th and when the initial water level reached 152m, the full storage rate could reach over 90%. If the water storage started in early September 1st, the storage level from 148m to 152 had little effect on the full storage rate of TGR.The influence of different initial water level on the full storage rate of TGR is shown in table 2. Table 2 The influence of different initial water level on the full storage rate of TGR Date Initial water level Year of non-full Full storage rate 2017 prospective 2017 prospective Sep.10 148 6 13 94.5% 88.2% 150 6 12 94.5% 89.1% 152 4 10 96.4% 90.9% 155 4 7 96.4% 93.6% Sep.1st 148 4 11 96.4% 90.0% 150 3 11 97.3% 90.0% 152 3 10 97.3% 90.9% 155 2 6 98.2% 94.5% 237