水库分级分期旱限水位设计与控制研究

Research on the design and control of grading and staged drought-limited water level for reservoir

水库旱限水位的合理设置与科学运用对实现水资源安全高效利用、减轻旱灾损失具有重要意义。针对现有方法确定旱限水位时未全面考虑用户对供水保证率、破坏深度的要求,借助优化方法计算而在推广应用时有较高的技术门槛与难度等问题,本文明确了水库分级分期旱限水位定义,以各用户供水保证率最大、最大供水破坏深度最小为目标,构建了旱限水位优化计算模型,提出了旱限水位的多目标优化计算方法;在此基础上,通过分析旱限水位年内变化规律,识别影响供水效果的旱限水位关键时期,提出了一种快速、便捷、适于工程推广应用的旱限水位简便计算方法。结果表明:旱限水位年内变化规律与用水量年内分布规律一致,且高用水时期的旱警水位、枯水期的旱保水位对系统供水目标影响大,为简便计算方法中初步确定旱限水位的反馈调整提供了依据。不设置旱限水位以及按现有方法设置旱限水位,供水系统均发生严重缺水事件,而按本文提出的优化计算方法及简便方法设置旱限水位后,水库可通过提前恰当限制供水,有效避免后续严重缺水事件的发生,使得系统缺水事件发生的几率及严重程度满足设计要求,有效提升了抗旱能力。本文研究为水利部门制定水库旱限水位,指导水库抗旱调度提供了一套优化计算方法及一套科学便捷的方法。

The reasonable setting and scientific application of the drought-limited water level(DLWL)of reservoir is of great importance for the safe and efficient use of water resources.Existing researches does not fully consider water supply guarantee rate and shortage ratio requirements when determining the DLWL,and the use of optimization methods makes it difficult to apply.To conquer these problems,firstly grading and staged DLWL is defined.Then a multi-objective optimization method that maximize water supply guarantee rate and minimize water supply shortage ratio of all water users is proposed.Based on the optimization results,the annual variation law of DLWL is analyzed and the critical period in which DLWL has the greatest influence on water supply is explored.Finally,a simple method to calculate DLWL is proposed,which is fast,convenient and suitable for engineering application.The results show that the annual variation of the DLWL is consistent with the distribution of water consumption during the year,and the drought warning water level during the high water use season and the drought preservation water level during the dry season have a great impact on water supply,which helps to adjust originally determined DLWL in the simple method.If the DLWL is not set or set according to the existing optimization method,serious water shortages occur.When the DLWL is set by the optimization method and simple method proposed in this article,the reservoir water supply system properly limits water supply in advance and avoid the occurrence of subsequent serious water shortage events.It makes both probability and severity of system water shortage events meet requirements,and improves drought resistance.This study provides an optimization method and a scientific and convenient method for the water conservancy department to formulate reservoir DLWL and guide reservoir drought resistant operation.