Research On Reservoir Operation By Stages A Case Study Of Chengbihe Reservoir In Guangxi

Aimed at the problems—the accuracy and rationality of flood season staging, the relationship between seasonal and annual flood control standard, the risk estimation of reservoir operation by stages—in reservoir operation by stages, thesis took Chengbihe Reservoir in Guangxi province for example, discussed the following aspects:flood season reasonable staging, sampling of seasonal design flood, determination of seasonal flood control standard, stochastic simulation of reservoir control, and risk estimation of reservoir control by stages.Based on the analysis of randomness, fuzziness, and grey features of flood season, the methods of mathematical statistics, fuzzy sets analysis, and grey fixed weight clustering were adopted to divide the flood season of Chengbihe Reservoir into three stages: pre-flood-season(4-1～5-31), main flood season(6-1-8-31), post-flood season(9-1～10-31).The conclusion, that the seasonal design flood frequency equals to the reciprocal of flood control standard only under the condition of maximum sampling by stages, was obtained by comparative analysis of annual maximum sampling by stages and maximum sampling by stages. Thesis pointed out that it’s unreasonable to adopt the same flood control standard to reservoir regulation, the reasonable reservoir regulation style is by adopting stage flood control standard. Thesis also pointed out that, as long as the seasonal flood control standard equals to the designed annual flood control standard, the flood control standard of reservoir shall not be lessened after operated by stages. The seasonal design flood of Chengbihe Reservoir was calculated by currently method of seasonal design flood, based on the theory put forward above.20×104hydrographs of the main-flood-season and post-flood-season respectively was generated by stochastic simulation. The feasible regions of flood control level of Chengbihe Reservoir were:main flood season185.00m, post-flood-season185.00m～188.63m, and main flood season185.25m, post-flood-season185.00m～188.50m, based on the currently seasonal design flood method and stochastic simulation respectively. The final feasible region of flood control level of Chengbihe Reservoir is:main flood season185.00m, post-flood-season185.00m～188.50m.