中文摘要：

人海河口闸下河道淤积会带来防洪排涝安全问题、影响上游的排灌环境、恶化下游的通航条件、威胁水闸的正常运行等，本文主要针对其增大防洪排涝灾害风险进行探讨。首先介绍了海河流域主要入海河口和苏北里下四港闸下河道的淤积情况和排水能力的变化，然后根据闸下淤积影响因子、洪涝灾害发生频率和抗灾能力等指数建立了风险评估体系，以海河流域和江苏里下四河为例，划分闸下淤积危害为五级，分别为极轻危害、轻危害、中危害、较重危害和重危害。计算分析表明：海河流域的海河闸和永定河闸闸下河道淤积为较重危害，泥沙淤积为严重淤积；独流减河闸下淤积为中危害，泥沙淤积为相对严重淤积。江苏里下四河的射阳河闸和黄沙港闸闸下淤积为较重危害，泥沙淤积为严重淤积；新洋港闸和斗龙港闸闸下淤积为中危害，泥沙淤积为相对严重淤积。

英文摘要：

Sediment deposition downstream of the sluice in estuary causes a series of bad effects on flood control, drainage security, up- stream irrigation and drainage, downstream navigation condition and sluice normal running. This article mainly discusses the increasing disaster risk in flood control and drainage. Firstly, deposition and drainage capacity changes of main estuaries in Haihe River basin and four rivers downstream of the sluices in Northern Jiangsu are introduced. Then a risk assessment system is established based on the impact factor of the deposition downstream of the sluice, flood disaster frequency and anti-disaster ability index. Taking Haihe River basin and four rivers in Lixiahe Area as examples, the sediment deposition hazard downstream of the sluice is divided into five levels including very light hazard, light hazard, medium hazard, slight heavy hazard and heavy hazard. Calculation and analysis show that sediment deposition downstream of the Haihe Sluice and Yongdinghe Sluice belongs to heavy hazard, sediment deposition downstream of the Duliujianhe Sluice belongs to medium hazard, sediment deposition downstream of the Sheyanghe Sluice and Huangshagang Sluice belongs to slight heavy haz- ard, sediment deposition downstream of the Xinyanggang Sluice and Doulonggang Sluice belongs to medium hazard.