长江中下游洲滩民垸是长江防洪减灾体系的重要组成,发挥扩大河道行蓄洪能力、保障重点地区防洪安全的重要作用。当前洲滩民垸在调度运用中面临启用决策难、运用时机难把握等突出问题,已成为流域防洪体系中的短板。为实现洲滩民垸的精细化调度,以长江中下游干流洲滩民垸为研究对象,构建了一个包含防洪能力、规划属性、经济社会影响3个维度的递阶层次分类指标体系,涵盖堤防欠高、城市总体规划关系、平垸行洪规划关系、常住人口、重点保护区域、耕地面积和GDP等,分河段对洲滩民垸进行运用分类,细化各河段洲滩民垸启用次序。分类结果显示:长江中下游干流洲滩民垸分为4类,其中第一类洲滩民垸人口和GDP均较低,最先启用;第二类数量最多,可提供较大的蓄洪容积;第三类蓄洪容积最大,人口最多;第四类GDP总量较高,最后启用。以城陵矶河段洲滩民垸为例,分析了该分类指标体系的合理性及分类运用的防洪效果,其分类结果与实际防洪需求和经济社会特征高度吻合,且分类调度方案整体防洪效果提升显著。结果表明,提出的洲滩民垸运用分类指标体系具有较强的科学性与实用性,创新之处在于将规划属性、经济社会影响与防洪能力系统整合,实现了从“单一防洪导向”向“防洪-发展协同”的调度理念转变,可为洪水调度方案的编制与实际防汛会商决策提供支撑。

[Objective] Floodplains and polders in the middle and lower reaches of the Yangtze River are an important part of the Yangtze River flood control system, which plays a key role in expanding the flood storage capacity of the river and ensuring the flood control safety in key areas. However, difficulties in decision-making on activation and timing of operation have become prominent issues in their operational management, making them a weak link in the basin’s flood control system. This study aims to establish a scientific and systematic classification index system for the use of floodplains and polders, in order to refine scheduling and coordinate the overall basin flood control safety with socio-economic development within floodplains and polder areas. [Methods] This study took the floodplains and polders in the middle and lower reaches of the Yangtze River as the research object, and innovatively constructed a hierarchical classification index system consisting of three dimensions: flood control capacity, planning attributes, and socio-economic impact. The index system included eight specific indicators, covering aspects such as levee height deficiency, relationship with urban master planning, relationship with floodplain operation planning, permanent population, key protected areas, cultivated land area, and GDP. Based on the principle of sectional classification, the middle and lower reaches of the Yangtze River were divided into six river sections: Jingjiang, Chenglingji, Wuhan, Hukou, Hukou-Datong, and downstream of Datong. Differentiated weights were assigned to the upstream and downstream sections of Datong. By constructing a decision matrix and combining standardization of qualitative indicators based on classification with linear normalization of quantitative indicators, the comprehensive scores of floodplains and polders were obtained and divided into four categories (from Class I to Class IV), clarifying their order of activation. [Results] A total of 243 floodplains and polders (excluding those that had been completely decommissioned) along the main stream of the middle and lower reaches of the Yangtze River were evaluated. The classification results showed that there were seven Class I floodplains and polders with a total flood storage capacity of 20 million m³ and relatively low population and GDP; Class II had the largest number, with 154 floodplains and polders providing a total flood storage capacity of 3.81 billion m³; Class III included 65 floodplains and polders, featuring the largest flood storage capacity (4.87 billion m³) and the highest population (about 450 000 people); and Class IV comprised 17 floodplains and polders, with a total GDP of 10.83 billion CNY. Correlation analysis indicated that “levee height deficiency” had the greatest impact on classification (correlation coefficient =-0.7), followed by “permanent population” and “GDP” (both=-0.6), while “cultivated land area” had the least influence. Taking the Chenglingji section as an example, the classification results were highly consistent with the actual flood control requirements and the socio-economic characteristics of the area. Further verification through a 1954-type flood regulation simulation showed that, compared with the baseline scheme, the classified regulation scheme reduced excess flood volume by approximately 0.55 billion m³ in the vicinity of Chenglingji, and significantly improved the overall flood control effectiveness. [Conclusion] The classification index system for the use of floodplains and polders proposed in this study has strong scientific and practical value. Its innovation lies in the systematic integration of planning attributes, socio-economic impacts, and flood control capacity, achieving a conceptual shift from a “single flood-control orientation” to a “flood control-development coordination” approach. The proposed index system provides a scientific basis for the “sectional control and hierarchical scheduling” of floodplains and polders in the middle and lower reaches of the Yangtze River. It supports the optimization of flood regulation schemes and real-time decision-making during flood control consultations, offering important practical significance for improving the overall flood regulation and scheduling capacity of the Yangtze River Basin.