应对不同等级干旱的水库分期旱限水位及抗旱调度研究

Drought is a kind of major natural disaster in the world, and making preparedness plans for drought resistance has gradually become a hot topic in scientific research. In order to solve the problems of water shortage and frequent drought in the Weihe River Basin , the comprehensive drought index system and evaluation model, which are coupled the information of precipitation and soil moisture, are established to study the mechanism and evolution law of drought disaster. Based on the VIC hydrological model, the response relations between climate scenarios and drought grades are analyzed. Then, the processes of water requirements for all drought grades are investigate by applying the method such as neural networks, and based on the aim of minimum water shortage of the basin, the optimal scheduling model is established to fight drought, and the PGA algorithm is used to solve the model. The reservoir inflow runoff is simulated by driving the VIC model under different climate scenarios, and the reservoir limited water levels in different periods for corresponding drought grades are calculated through scheduling model solution. According to the results of scheduling model, the reservoir operation charts for each drought grade are draw. The limited water levels and operation charts in the main reservoirs (e.g., Fengjiashan, Yangmaowan, Shitouhe and Jinpeng) in each period (e.g., spring, autumn, and winter) for each drought grade are finally obtained by emending limited water levels and dispatching lines constantly with historical data. The research will be of great significance for drought resistance and disaster reduction as well as the establishment of drought pre-emergency plans.

干旱是困扰人类的重大自然灾害，干旱应对及抗旱预案逐渐成为科学研究热点。项目针对渭河流域水资源短缺、旱灾频发等问题，将大气降水、土壤墒情等水源信息耦合，构建流域综合干旱指标体系及干旱评估模型，探讨干旱致灾机理及演变规律；通过建立渭河流域VIC分布式水文模型，分析气候情景与干旱等级的响应关系；应用神经网络等方法，研究不同干旱等级下的需水过程，并建立应对干旱的流域缺水量最小优化模型，采用并行遗传算法(PGA)求解；以不同等级干旱下的气候情景驱动VIC模型，模拟水库入库径流，通过模型求解，研究相应等级干旱的水库分期优化旱限水位；根据调度结果，绘制各等级干旱下水库综合抗旱调度图，通过修正最终获得不同等级干旱下渭河流域主要水库（冯家山水库、羊毛湾水库、石头河水库、金盆水库）各分期 (春季、秋季、冬季) 旱限水位以及抗旱综合调度图。其成果对于应用有限的水资源抗旱减灾，制定干旱应急预案具有重要意义。

干旱是世界上分布最广且造成经济损失最严重的自然灾害之一，即使在科技快速发展的今天，因旱致灾的后果仍无法避免。因此，亟需开展干旱事件与合理抗旱的科学研究。本研究以黄河流域为例，系统地提出了一套集干旱“评估-传播-驱动-预测”于一体的理论体系。选取干旱指标，识别气象、农业、水文干旱演变规律及驱动因素，剖析干旱驱动机制，揭示不同干旱类型之间内在关联及传播机理，量化气象、农业、水文干旱归因作用大小及方向，预测未来气候和土地利用变化情景下的流域气象、农业和水文干旱发展态势及发生概率。运用熵权法和综合模糊评价法构建黄河流域综合干旱指标(MIDI)，并分析了不同等级干旱下的时空演变规律。在此基础上，基于水文气候因子和水库蓄水条件采用Fisher最优分割法来识别旱限水位的季节性，并基于旱限水位建立水库群抗旱调度模型。结果表明，旱限水位在处理多水库抗旱调度问题时，具有明显的优势。实施抗旱调度后，流域缺水时段、缺水量、最大缺水深度和平均缺水深度的改善程度分别为8.14%、16.49%、14.07%和16.49%；流域平均修复程度为0.23；无旱等级月份增加了6.67%，严重干旱情况有所减少；枯水年（1969年）和偏枯水年（1974年）流域内干旱持续时间平均减少了68.06%和45.30%；连续枯水年（1990-1999年）干旱等级由特旱和重旱转向轻旱的比例为14.19%。抗旱措施促使流域干旱风险下降，其成果对于应用有限的水资源抗旱减灾，制定干旱应急预案具有重要意义。