淮河淮南段聚集了大量的人口、工厂、农田、建筑物等，一旦发生较大规模的洪水，将对人民生命财产安全造成严重威胁。运用 HEC-RAS 软件和 HEC-GeoRAS 模块，在 GIS 环境中，模拟现有防洪工程条件下淮河淮南段在40年、60年及100年一遇洪水周期下的洪水漫顶淹没情况，得到不同横断面的设计水位线、漫顶淹没的范围、淹没水深等数据。洪水漫顶模拟结果表明 : 淮河淮南段的防洪堤坝能够抵御 40 年、 60 年一遇的洪水，基本能抵抗100年一遇的洪水；模拟水位与设计水位吻合度高，基于 HEC-RAS 的洪水漫顶模拟合理可信，可为防洪预警、制定人员疏散方案及洪水灾害风险分析等方面提供依据。

There are a large number of people, factories, farmlands and buildings in Huainan area, the south part of Huai River. Big floods will severely endanger people ' s life and property. In this paper, HEC---RAS software and HEC-GeoRAS module are employed in GIS to simulate the flood overtopping inundation in Huainan reach of Huai River under the existing flood protection works during floods once in 40, 60, and 100 years respectively. The designed water level of different cross-sections, the overtopping inundation area, and the inundation depth data are obtained. The simulation manifested that the flood protection works in this reach are capable of handling floods once in 40 and 60 years, and can generally withstand floods once in 100 years. The simulated water level is consistent with the designed level. Therefore it is concluded that it is reasonable and credible to use HEC-RAS to simulate flood overtopping, and thereby providing reference for the early warning, the population evacuation planning, as well as flood disaster risk analysis.