十三围防洪保护区位于珠江河网区域的西江和北江交汇后的西江右岸,西江洪水峰高量大,洪水威胁严重,进行洪水风险分析十分必要。考虑到珠江河网区域水流运动复杂,基于一维水动力学模型构建了珠江河网一维模型,并根据历史洪水资料验证了模型的可靠性。为了反映保护区内的河道、堤防、道路等对洪水传播的影响,采用精细化的非结构网格构建了十三围保护区二维水动力学模型进行洪水演进模拟。通过一、二维耦合模型,分别对江根段、西头窦段溃口进行了西江50,100,200 a一遇设计洪水下的洪水淹没方案计算,并对计算成果进行了合理性分析,包括水量平衡分析、局部流场分析、溃口流量水位过程分析等。结合社会经济数据进行了受淹面积、受影响人口、淹没损失等方面的洪水影响分析,可为防汛抢险、避洪转移等提供重要信息参考。

Flood risk analysis for the Shisan dyke flood protection zone is very imperative as the zone is located in the Pearl River network area with high flood peak and severe flood threat. Since the water flow in the Pearl River network is complicated, we first of all built a one-dimensional model of the Pearl River network and verified the reliability of the model based on historical flood data. Furthermore, we built a two-dimensional hydrodynamic model of the flood protection zone using a refined unstructured grid to simulate the flood evolution in the purpose of reflecting the impact of rivers, dikes and roads in the protected area on flood propagation. Assuming that dike breach occurred in the Jianggen segment and the Xitoudou segment, we simulated the flood inundation in the Xijiang River under design flood of 50-year event flood, 100-year event flood, and 200-year event flood by coupling the 1D model and 2D model. The rationality of computation results was examined in terms of water balance analysis, local flow field analysis, and water level process at the breach. In association with socio-economic data, the impacts of flood were also investigated from aspects of inundated area, affected population, and inundation losses. Combined with socio-economic data, the flood impact analysis is finished, such as flooded area, affected population, and inundation loss.