沂沭河流域"8·14"洪水模拟及下排调度方案比较OA

The Yishu River basin has steep upstream topography and rapid concentration,making them particularly vulnerable to severe flash floods during extreme storm events.Although an engineering system encompassing upstream reservoirs and downstream floodways has been established,determining the best discharge dispatching scheme remains a critical challenge,exacerbated by the conflict between river conveyance capacities and reservoir storage risks.During long-distance routing,traditional integrated hydrological-hydrodynamic models frequently experience continuous error accumulation,which significantly distorts downstream boundary conditions and misleads collaborative dispatching evaluations.Therefore,a high-precision modeling approach is crucial to remove simulation distortions and assess the advantages of intricate downstream operational strategies in a scientific manner. This study developed a chained hydrological-hydrodynamic coupled model that combines the three-source Xin'anjiang model with the integrated flood management system 1D hydrodynamic module to simulate the typical"8•14"extreme flood in 2020.To address the critical issue of error accumulation,an innovative chained mechanism was implemented.The basin was segmented into upper and lower sections anchored by the Linyi and Chonggou key stations.The observed flow discharges from these two stations were specifically included as transitional boundaries just before downstream diversion calculations,rather than full-process simulations.Four scenarios were developed to compare water level evolution and overtopping risks under various downstream strategies:no dispatching,actual dispatching,full eastward diversion,and rule-based dispatch. Validation results demonstrated that the chained approach successfully eliminated upstream cumulative errors,providing highly reliable hydrodynamic inputs for downstream sections.The chained model significantly decreased flood volume errors prior to diversion at the Linyi and Chonggou sections from 54.93%and 72.96%to 5.73%and 14.29%,respectively,when compared to full-process hydrological simulation.Significant differences in hydraulic control were found between the four schemes.Under the no-dispatching scenario,the downstream channels faced extreme pressure,causing an overtopping height of 1.18 m at a Shuhe section.The full eastward diversion scheme relieved the Yihe River but forced multiple sections of the Yi-to-Shu Floodway to overflow while generating a severe peak inflow of 6,844.39 m3/s at Shilianghe Reservoir,approaching its regulatory limit.The rule-based scheme provided balanced water level control but lacked flexibility against extreme peaks.In contrast,the actual dispatching scheme successfully mitigated overtopping risks across all backbone channels by dynamically coordinating rule-based and southward policies. The suggested chained hydrological-hydrodynamic coupled model provides a reliable tool for simulating intricate hydraulic interactions and gate dispatching in interconnected river systems by successfully removing the negative effects of long-distance routing errors.Comparative analysis indicates that the actual integrated dispatching strategy achieves the optimal flood control outcome for the Yishu River basin.The actual scheme restricted the peak inflows of Luoma Lake and Shilianghe Reservoir to safe levels of 6,380.19 m3/s and 6,102.23 m3/s,respectively,by prioritizing the southward discharge for the Yihe River and utilizing both the eastward and southward potentials for the Shuhe River.This approach effectively accomplishes cooperative peak shaving and refined risk allocation,offering crucial scientific references for upcoming flood control planning and intelligent dispatching choices.