Flood control schemes and the scale of drainage facilities are closely related to the occurrence of rainstorms and the tide level of an outer river, so it is necessary to study the probability of the occurrence of rainstorms and the tide levels. Based on the daily rainfall and tide level data of Jiangyin station from 1956 to 2018 in the Wuchengxiyu region of Taihu Lake basin, copula functions were used to establish the joint distribution function of annual 1-day, 3-day, 7-day, and 15-day maximum rainfall and the highest tide level of the Yangtze River for different return periods. Based on this information, a risk probability model was constructed to evaluate the flood and tidal risks.

It was found that when the design criteria of rainfall and tide level were similar, the probability of the simultaneous occurrence of rainfall and tide level greater than their respective magnitudes was significantly less than their respective design frequencies. The encounter combination analysis method proposed in this study has a wide application prospect for flood control and drainage design.

防洪方案和排水设施的规模与暴雨的发生和外河的潮位密切相关，因此有必要研究暴雨发生的概率和潮位。以太湖流域五城西峪地区江阴站1956—2018年的日降水和潮位数据为基础，利用Copula函数建立年1天、3天、7天、不同重现期长江15天最大降雨量和最高潮位. 基于这些信息，构建了风险概率模型来评估洪水和潮汐风险。

研究发现，当降雨和潮位设计准则相近时，大于各自量级的降雨和潮位同时发生的概率明显小于各自的设计频率。本研究提出的遭遇组合分析方法在防洪排涝设计中具有广泛的应用前景。