渭河中下游与黄河潼关段2021年洪水特征及预报分析

Flood characteristics and forecasting analysis of 2021 in the middle and lower reaches of the Wei river and the Tongguan section of the yellow river

受强秋淋影响,2021年渭河中下游、黄河潼关段形成多次编号洪水,洪水在演进中洪峰量级及传播时间异常。为分析洪水演进规律,根据实测与整编洪水资料,采用对比分析、数值模拟等方法分析研究了洪水来源与组成、河段过流能力、洪水演进规律及预报误差影响因素。结果表明:(1)渭河2、3号洪水在下游全面漫滩临堤,洪水传播时间滞后、洪峰出现衰减,且2号洪水衰减程度明显大于3号洪水;潼关3号洪水对渭河3号洪水华县以下河段洪水形成顶托,吊桥站峰现时间早于华县站。(2)渭河中下游及黄河潼关段预报误差产生的主要因素:渭河2号洪水咸阳以下河段由局部漫滩向全面漫滩发展,临潼、华县站洪峰滞时和衰减程度异常偏多,黄河1号洪水中华县&龙门~潼关未控区间来水对潼关洪水贡献较常规偏大。

Under the influence of strong autumn showers,multiple numbered floods were formed in the middle and lower reaches of the Wei river and the Tongguan section of the yellow river in 2021,with anomalies in flood magnitude and propagation time during the evolution of the floods.In order to analyze the flood evolution rules,based on the measured and compiled flood data,comparative analysis,numerical simulation and other methods were used to analyze and study the source and composition of the flood,the overflow capacity of the river section,the flood evolution rules and the influencing factors of the forecast error.The results show:(1)flood No.2 and No.3 of the Wei river are fully flooded in the lower reaches of the embankment,the flood propagation time lags,the flood peak appears to be attenuated,and the degree of attenuation of flood No.2 is significantly greater than that of flood No.3;flood No.3 in Tongguan formed a top support for the flood in the section of the Wei river below Huaxian of flood No.3,and the peak of Hangqiao station appeared earlier than that of Huaxian station.(2)The main factors of forecast errors in the middle and lower reaches of the Wei river and the Tongguan section of the yellow river:The river section below Xianyang of the Wei river flood No.2 developed from local flooding to full flooding,the flood peak lag time and attenuation degree of Lintong and Huaxian stations were abnormally high,and the incoming water from the uncontrolled interval of the yellow river flood No.1,Zhonghua county&Longmen~Tongguan,made a larger contribution to the flooding in Tongguan than the conventional one.