Scientific assessment of the hydrodynamic conditions of water system connection is of great significance and value in guiding the ecological construction of urban water system connection and building healthy river–lake relationship. Based on the advantages of SWMM in effectively simulating urban rainfall and surface runoff, a hydrological and hydrodynamic model was constructed before and after the implementation of urban water system connection project, and the model was applied to the analysis of rainfall and flooding processes in two recurrence periods of 5a and 10a after the implementation of urban water system connection in Pingyu County. The results show that the initial flow rate and velocity of river cross-section increased in the same recurrence period after the water system connection, the maximum increase of water exchange capacity was 115.56%, the peak flow rate and velocity were weakened and the peak time was lagged, and the hydrodynamic conditions were improved significantly.

科学评价水系连通水动力条件，对指导城市水系连通生态建设、构建健康河湖关系具有重要意义和价值。基于 SWMMH 在有效模拟城市降雨和地表径流方面的优势，构建了城市水系连通工程实施前后的水文水动力模型，并将该模型应用于两次循环降雨和洪水过程的分析。平榆县城市水系统接入实施后的5a和10a时期。结果表明，水系接通后，河流断面初始流速和流速在同一重现期内增加，