溪洛渡-向家坝梯级水库汛末蓄水时间与目标决策研究

Impounding Time and Objective Decision of SiluoduXiangjiaba Cascade Reservoirs in the Flood Recession Period

针对梯级水库运用过程中蓄水与排沙之间矛盾,本文以溪洛渡-向家坝梯级水库为例,考虑上游修建白鹤滩水库条件,对两座水库汛末蓄水时间进行了优化研究.首先讨论两库蓄水时间调整对梯级水库发电、航运以及泥沙淤积的影响;然后构建梯级水库水沙联调多目标决策模型对两库蓄水时间进行优化决策,得到溪洛渡—向家坝梯级水库蓄水时间与多年平均发电量和库容淤损率之间的非劣解集;最后应用加权理想点评价模型对非劣解进行评价,给出不同目标权重下满足发电和减淤要求的梯级水库最佳蓄水方案.结果表明,(1)增加梯级水库发电量,势必要提前水库汛末蓄水时间,这必以增加库容淤损率为代价;(2)各目标权重不同,最优方案不同.当泥沙目标权重较大时,溪洛渡水库9月21日蓄水比9月11日蓄水好,且泥沙目标权重越大,最优方案对应的向家坝水库蓄水时间越晚;当发电目标权重较大时,溪洛渡水库9月11日比9月21日蓄水好,且发电目标权重越大,最优方案对应的向家坝水库蓄水时间越早.研究成果可为溪洛渡—向家坝梯级水库正式建成后制定合理的调度运用方案提供科学的依据.

Aimed to the contradictions between impounding and desilting in cascade reservoirs operation,optimize research on the impounding time of Siluodu-Xiangjiaba cascade reservoirs in the flood recession period considering that Baihetan reservoir is operated. Firstly,the sediment deposition and the benefit of generation and shipping of Siluodu-Xiangjiaba cascade reservoirs in different impounding schemes were studied; Secondly,a multi-objective optimization model for the coordinated regulation of flow and sediment in cascade reservoirs was established to study the optimum impounding time of Siluodu-Xiangjiaba cascade reservoirs; and then noninferior solutions for impounding time,power generation and siltation-loss rate of capacity were obtained with catfish effect particle swarm optimization algorithm; Finally,a weighted ideal point method was applied to decide an optimum impounding scheme. The results shows that an increasing power generation required advancing the impounding time in the flood recession period,which resulted in an increase in siltation-loss rate. The optimal scheme differs with different weights of targets. If the weight of sediment was greater than that of generation,the schemes that Xiluodu reservoir began to impound on Sep. 21 were better than those on Sep. 11,and a bigger weight of siltation-loss rate required a postponed impounding time of Xiangjiaba reservoir. If the weight of generation was greater than that of sediment,the schemes that Xiluodu reservoir began to impound on Sep. 11 is better than those on Sep. 21,and a bigger weight of power generation requires an advanced impounding time of Xiangjiaba reservoir. The results can be used for Siluodu-Xiangjiaba cascade reservoirs operation.