考虑径流非一致性的水库分期旱限水位优化研究

Optimization of water level of reservoir stage drought limit considering runoff inconsistency

【目的】分析变化环境下水文序列的非一致性,为龙羊峡水库分期旱限水位优化调度模型的建立提供参考。【方法】采用Mann-Kendall检验法、有序聚类分析法和水文序列振动中心重构法,对龙羊峡水库年径流序列进行一致性分析及修正,然后利用水库旱限水位分级和Fisher最优分割法,对径流序列修正前后不同干旱等级下的水库分期旱限水位进行确定,最后通过耦合分期旱限水位建立以缺水指数最小为目标函数的龙羊峡水库优化调度模型,对径流序列修正前后两种情况下的分期旱限水位进行对比研究。【结果】一致性检验发现,龙羊峡水库径流序列具有明显下降的趋势,并在1989年发生突变。经一致性修正后计算龙羊峡水库7-10月、11-12月、1-4月、5-6月4个分期的旱限水位,在轻旱条件下分别为2530.00,2534.91,2539.10和2535.13 m,中旱条件下分别为2530.00,2535.44,2539.80和2536.70 m,重旱条件下分别为2530.00,2535.87,2540.35和2537.89 m;特旱条件下分别为2530.00,2536.06,2540.58和2538.12 m。采用不同调度模型对龙羊峡水库进行优化调度,结果显示修正后的调度效果较好,其总缺水量、缺水指数相比修正前分别降低5.37%和6.03%,其中枯水时段平均缺水量降低了10.71%,缺水程度改善明显。【结论】非一致性径流对龙羊峡水库旱限水位的确定有一定影响,一致性修正后的径流使水库旱限水位的确定更加可靠,水库的抗旱能力得以提升,可为水库供水、抗旱应急管理决策提供参考。

【Objective】The non-consistent changes of hydrological sequence under changing environment were analyzed to provide reference for the optimization of stage drought limit water level and the establishment of optimal operation model for the Longyangxia Reservoir.【Method】The Mann-Kendall test method,ordered cluster analysis method and vibration center reconstruction method of hydrological sequence were used to conduct consistent analysis and correction of annual runoff sequence of the Longyang-xia Reservoir.Then,drought limit water level classification and Fisher optimal segmentation method were used to determine the drought limit water levels of different stages of the reservoir under different drought levels before and after the revision of runoff sequence.Finally,the optimal operation model with minimum water shortage index as objective function was established by coupling staged drought limit water level,and the staged drought limit water levels before and after runoff sequence modification were compared.【Result】The consistency test showed that the runoff sequence of the Longyangxia Reservoir had an obvious downward trend with mutation in 1989.After consistency correction,the water levels of mild,moderate,severe and extreme droughts in July-October,November-December,January-April and May-June were 2530.00,2534.91,2539.10 and 2535.13 m;2530.00,2535.44,2539.80 and 2536.70 m;2530.00,2535.87,2540.35 and 2537.89 m;and 2530.00,2536.06,2540.58 and 2538.12 m,respectively.Different dispatching models were used to optimize the operation,and the results showed that the revised dispatching effect was the best and the total water shortage and water shortage index were decreased by 5.37%and 6.03%,respectively.The average water shortage in dry period was decrease by 10.71%with more significant improvement.【Conclusion】The non-consistent runoff had certain influences on the determination of drought limit water level of the Longyangxia Reservoir.The consistence corrected runoff provided more reliable determination of the drought limit water level and improved the drought resistant capacity.This study can provide reference for the decision-making of water supply and drought emergency management.