沁河下游洪水还原模拟分析——以2021年7月暴雨洪水为例

Simulation analysis of flooding in lower Qinhe River——A case study of July 2021 flood

2021年7月,沁河下游受2106号台风“烟花”影响普降大到暴雨,出现了自1982年以来最大洪水,河口村水库在洪水调节中发挥了巨大的作用。采用MIKE21模型对2021年7月沁河下游洪水过程进行了无河口村水库条件下的还原模拟分析。结果表明,河口村水库的调蓄削峰作用明显,武陟水文站洪峰次数由3次降低为2次,洪峰流量也由1727 m^(3)/s、1773 m^(3)/s和1615 m^(3)/s减小到368 m^(3)/s和1510 m^(3)/s;在无河口村水库条件下,洪水流量高于1200 m^(3)/s和1500 m^(3)/s的时长分别为49 h和25 h,经河口村水库调蓄削峰后,洪水流量高于1200 m^(3)/s的时长降低至24 h,高于1500 m^(3)/s的时长几乎降为0,河口村水库有效削减了大流量洪水持续时间;河口村水库还改善了沁河下游的漫滩情况,沁北自然溢滞洪区和沁河下游滩区的淹没面积分别减少了1575.33 hm2和473.73 hm2。研究成果可为沁河下游的防汛工作提供技术支撑。

In July 2021,the lower Qinhe River was affected by the severe typhoon In-Fa,which caused heavy rainfall and the largest flood occurred since 1982,the Hekou village reservoir played a huge role in the flood regulation process.In order to simulate and analyze the flood process of the lower Qinhe River in July 2021 without the Hekou village reservoir,a twodimensional hydrodynamic model was established using the MIKE21.The results showed that the peak-cutting effect of the Hekou village reservoir was significant.Compare with no Hekou village reservoir,the number of peak flood events at Wuzhi hydrological station decreased from 3 times to 2 times and the magnitude of flood peaks also decreased significantly,and the peak flow rates also decreased from 1 727 m^(3)/s,1 773 m^(3)/s,and 1615 m^(3)/s to 368 m^(3)/s and 1 510 m^(3)/s.The duration of high flow during the flood process was also influenced by the reservoir′s peak-cutting effect,the duration of flow above 1 200 m^(3)/s decreased from 49 h to 24 h,and the duration of flow above 1 500 m^(3)/s even decreased from 25 h to 0.The Hekou village reservoir has also improved the situation of flood-sustained areas in the lower Qinhe River.The inundation areas in the natural overflow area of the north qinyang and the lower Qinhe River have been decreased by 1 575.33 hectares and 473.73 hectares respectively.The research results can provide technical support for flood prevention work in the lower Qinhe River.