小浪底水库拦沙期应急保滩能力研究

Study on Emergency Beach Protection Capacity of Xiaolangdi Reservoir in Sediment Storage Period

黄河下游滩区防洪是当前中下游洪水调度的难点,研究利用小浪底水库拦沙期较大的库容兼顾滩区防洪安全十分必要。通过实测资料分析、数学模型计算,分析了黄河中游洪水分期特点及近期变化,提出了适宜的保滩流量和分期分级洪水保滩库容需求量,研究以小浪底水库为主的中游水库群应急保滩运用方式,分析了水库应急保滩能力。结果表明:扣除大洪水防洪所需库容,前汛期小浪底水库现状汛限水位235 m以上库容可保证5 a一遇“上大洪水”下游不漫滩,“下大洪水”因小花间无控制区来水量较大,故难以保证下游滩区洪水不漫滩;后汛期现状汛限水位248 m以上库容可保证10 a一遇洪水下游不漫滩。实时调度中结合预报小浪底水库提前预泄腾库,保滩能力可进一步提升。但随着小浪底水库拦沙库容逐渐淤满,水库兼顾下游滩区防洪的能力将逐渐降低。

The flood control of the beach area in the lower Yellow River is the focus of the current flood dispatching in the middle and lower reaches,and the large storage capacity of Xiaolangdi Reservoir in sediment storage period is studied to take into account the flood control safety of the beach area.Through the analysis of measured data and mathematical model calculation,the characteristics and recent changes of flood staging in the middle reaches were analyzed,and the appropriate beach protection flow and the demand for beach protection capacity of staging and grading flood were proposed.The emergency beach protection operation mode of the middle reaches reservoir group dominated by Xiaolangdi Reservoir was studied and the emergency beach protection capacity of the reservoir was analyzed.The results show that for floods from the area above Sanmenxia,the storage capacity of Xiaolangdi reservoir above flood limit level of 235 m in the pre⁃flood season can guarantee no flooding in the floodplain in 5⁃year frequency.Due to the large inflow of water in the uncontrolled reach of Xiaolangdi⁃Huayuankou,it is difficult to ensure no flooding in the downstream beach area.The storage capacity above the flood limit level of 248 m in the post⁃flood season can guarantee no flooding in the floodplain in 10⁃year frequency.In the real⁃time operation,the reservoir combines with the forecast to release the reservoir in advance,and the beach protection ability can be further improved.However,as the sediment storage capacity of Xiaolangdi Reservoir gradually becomes full,the flood control capacity of the reservoir considering the downstream beach area will gradually decrease.