基于小量级降雨预报的水库汛限水位动态控制风险分析

摘要

建立基于降雨预报的汛限水位动态控制风险模型,以定量评估动态控制给水库防洪管理带来的风险.统计分析了"无雨"或"小雨"预报的精准性,建立了考虑"无雨"或"小雨"漏报、校核洪水发生的频率、汛限水位控制值域、洪水调度方式等条件下的汛限水位动态控制风险模型,并以近似的频率分布曲线族替代概率分布函数进行模型求解.以汉中市石门水库为例,分析了石门水库的蓄泄能力,提出了流域24小时预报"无雨"时抬高汛限水位至617.5m,预报"小雨"时抬高至617.0m,且"无雨"或"小雨"漏报时采用动态控制的调度方式,其最高洪水位超过水库设计洪水位的理论风险均在可接受范围内.汛限水位动态控制可有效提高雨洪资源的利用率,建立基于降雨概率的调度风险分析模型可定量估计可能发生的风险,为决策者提供参考依据.%The risk control model for the dynamic control of flood limited level based on rainfall forecast is established to quantitatively evaluate the risks brought by dynamic control by which to reservoir flood control management.The paper analyzes the precision of"no rain"or"light rain"forecast, and establishes the risk model for the dynamic control of flood limited level under the conditions of considering the missing report of"no rain"or"light rain", checking the frequency of flood, flood control level range, flood regulation mode and so on, with the model solved by using the approximate frequency distribution curve instead of the probability distribution function.Taking the Shimen Reservoir in Hanzhong City as an example, this paper analyzes the storing and discharging capacity of Shimen reservoir, suggesting that according to the dispatching mode watershed 24hours forecast"no rain"can raise the flood limited water level to 617.5m, that forecast"light rain"can be raised to 617.0m, that"no rain"or"light rain"omission when using dynamic control, and that the risk of the maximum flood level exceeding the reservoir design flood level is acceptable.The dynamic control of flood limited level can effectively improve the utilization rate of rainwater resources, establishing a dispatching risk analysis model based on rainfall probability can quantitatively estimate the possible risks and provide reference for decision makers.