Retrospective simulation on the Haihe “23· 7” basin-wide extreme flood

To support the decision-making and forecasting work for the catastrophic flood in the Haihe River Basin, the Zijingguan and Manshuihe sub-basins, located in the Daqing River where a catastrophic flood occurred in July 2023, were selected for the flood simulation and prediction with the Xin’anjiang-Haihe model based on measured rainfall and discharge data. For the Zijingguan sub-basin, 5 floods from 1996 to 2020 were chosen for the parameter calibration, while for the Manshuihe sub-basin, 8 floods from 1953 to 2016 were used. The simulation was validated against the Haihe “23· 7” basin-wide extreme flood event. The results showed that the relative errors of peak discharge and flood volume in both sub-basins were within 20%, with a peak timing error of 0 hours. The high accuracy of the hydrological model constructed in this study, along with the good agreement between simulation and measured results, demonstrates its ability to reflect the actual flood process. A comparison between different models revealed that the Xin’anjiang-Haihe model performed better in the Manshuihe sub-basin, which is more affected by human activities, compared to the Zijingguan sub-basin with lesser human influence.