Research on Stage-Divided Flood-Limited Water Level Under Pre-Release Rules During Flood Season

Flood Limited Water Level (FLWL) serves as the core control parameter for the synergistic optimization of flood control operation and beneficial water utilization efficiency in reservoirs during the flood season. Addressing the critical issue of insufficient adaptability in static control schemes, this study innovatively proposes a staged dynamic FLWL regulation model based on pre-release rules. This methodology combines hydrometeorological division theory with frequent flood control mechanisms and establishes a dual-threshold control equation with safe pre-release discharge (qpre) and effective pre-release duration (tpre) as sensitive factors. The dynamic FLWL scheme is designed to ensure that no additional risk is imposed on the reservoir and its upstream/downstream regions, and it incorporates a set of hierarchical rules for the strategic pre-release and standard safety modes. Taking the Wuxikou Reservoir in Jiangxi Province as a case study, the safe pre-release discharge value under regular flood conditions and the effective pre-release duration are determined. Additionally, a dynamic FLWL control model is developed according to the reservoir’s characteristics. The verification results demonstrate the significant benefits of the dynamic FLWL model in reducing peak water levels and shortening flood duration. Compared with the original operation plan, the proposed model effectively lowers the maximum water level of the reservoir by 10% and simultaneously shortens the duration of high water levels by nearly 24 h. The research results provide a reference for the efficient utilization of water resources in reservoir basins in monsoon humid areas.