惠济河洪水成因变化及重现期计算研究

Study on Variation of Flood Causes and Calculation of Return Period in Huiji River

2021年7月以来,开封市出现了历史罕见的极端暴雨天气,然而在降雨量创历史极值的情况下,惠济河大王庙水文站实测最大洪峰只有112 m^(3)/s,在历年最大洪峰流量中仅处于中等水平。文章通过分析惠济河洪水成因,解释了年径流量及汛期洪水不断减少的原因。以惠济河流域大王庙水文站1964-2021年年最大流量系列为研究实例,根据皮尔逊Ⅲ型曲线的重现期计算方法与原理,进行洪水重现期的时空演变实证分析。结果表明:惠济河流域洪水重现期随时空演变而发生变化,洪水重现期的水位流量随之发生变化,洪水重现期的流量演变趋势随时空减少。

Since July 2021,extreme rainstorm weather,which is rare in history,has occurred in Kaifeng City.However,under the circumstance that the rainfall has reached the historical extreme value,the largest flood peak measured by the Dawangmiao Hydrological Station of Huiji River is only 112 m^(3)/s,which is considered moderate compared to the historical maximum peak flows.By analyzing the causes of floods in Huiji River,this paper explains the reasons for the continuous reduction of annual runoff and floods in flood seasons.Taking the maximum flow series from 1964 to 2021 at the Dawangmiao Hydrological Station in the Huiji River Basin as a research example,according to the return period calculation method and principle of the Pearson type III curve,an empirical analysis of the temporal and spatial evolution of the flood return period is carried out.The results show that the flood return period of the Huiji River Basin changes with time and space,the water level and flow during the flood return period change accordingly,and the evolution trend of the flood return period decreases with time and space.