The effects of rainfall and underlying surface conditions on flood recession processes are a critical issue for flood risk reduction and water use in a region. In this article, we examined and clarified the issue in the upper Huaihe River Basin where flood disasters frequently occur. Data on 58 rainstorms and flooding events at eight watersheds during 2006–2015 were collected. An exponential equation (with a key flood recession coefficient) was used to fit the flood recession processes, and their correlations with six potential causal factors—decrease rate of rainfall intensity, distance from the storm center to the outlet of the basin, basin area, basin shape coefficient, basin average slope, and basin relief amplitude—were analyzed by the Spearman correlation test and the Kendall tau test. Our results show that 95% of the total flood recession events could be well fitted with the coefficient of determination (R²) values higher than 0.75. When the decrease rate of rainfall intensity (Vi) is smaller than 0.2 mm/h², rainfall conditions more significantly control the flood recession process; when Vi is greater than 0.2 mm/h², underlying surface conditions dominate. The result of backward elimination shows that when Vi takes the values of 0.2–0.5 mm/h² and is greater than 0.5 mm/h², the flood recession process is primarily influenced by the basin’s average slope and basin area, respectively. The other three factors, however, indicate weak effects in the study area.

降雨和潜在地表条件对洪水衰退过程的影响是减少区域洪水风险和用水的关键问题。在本文中，我们检查并澄清了淮河上游流域经常发生洪灾的问题。收集了2006-2015年间八个流域的58次暴雨和洪水事件的数据。使用了一个指数方程式（具有关键的洪水衰退系数）来拟合洪水衰退过程，并将其与六个潜在的因果关系（降雨强度的降低速率，从风暴中心到流域出口的距离，流域面积，盆地形状系数，盆地平均斜率和盆地起伏幅度-通过Spearman相关检验和Kendall tau检验进行了分析。R ²）的值高于0.75。当降雨强度的下降率（Vi）小于0.2 mm / h ^2时，降雨条件会更明显地控制洪水的衰退过程；当Vi大于0.2 mm / h ^2时，主要的表面条件占主导地位。向后消除的结果表明，当Vi的取值为0.2-0.5 mm / h ²且大于0.5 mm / h ^2时，洪水衰退过程主要受盆地平均坡度和盆地面积的影响。然而，其他三个因素表明研究区域的影响较弱。