| In recent years, extreme rainstorms have shown a trend of sudden and frequent occurrences, making the early risk assessment of such events a crucial task for flood control departments at all levels. This study transplants the "23.7" rainstorm from the Haihe River Basin to the Miyun Reservoir Basin. The transplantation process considers various spatial distribution characteristics of rainfall that might occur under different moisture conditions in the basin. The EasyDHM model is used to simulate the possible flood responses at typical sections of the basin and at Miyun Reservoir after the rainstorm transplantation, and scheduling exercises are conducted. The research results indicate that: (1) Under the rainfall conditions of different events in 2012, 2016, and 2023, the areal rainfall of Miyun Reservoir after transplantation was amplified by 2 to 3 times, while maintaining the characteristic of the rainstorm center being located in the mid-lower reaches of the Chao River Basin, with the rainfall isohyet map showing a decrease from south to north; (2) The peak discharge of Miyun Reservoir after simulating the transplanted rainstorm flood was amplified by 5.69 times and 8.12 times in 2012 and 2016, respectively, reaching the level of a once-in-a-century flood, and by 7.39 times in 2023, reaching the level of a once-in-ten-thousand-years flood; (3) The flood scheduling simulation results of the 2023 transplanted rainstorm at Miyun Reservoir showed that the reservoir retained a total of 1.197 billion cubic meters of floodwater, with the reservoir level reaching a maximum of 158.98 meters, surpassing the design flood level for 27 hours. After reducing the initial water level through pre-release scheduling, the flood control pressure on the reservoir can be effectively alleviated. The research results can provide support for flood control scheduling at Miyun Reservoir under extreme rainfall scenarios. |
