降雨移动对河道洪峰影响研究——以深圳为例

全球气候变化和快速城镇化加剧了城市降雨过程的不稳定性，进而影响城市河道洪水过程，加剧了城市洪涝防治难度。本文以深圳市河湾片区为研究区，利用数值模拟方法研究了降雨移动方向对城市河道洪峰的影响。基于雨强和移动方向的不同组合构建了 1300 个降雨方案，并利用城市洪涝模型分别模拟了各降雨方案条件下的河道洪水过程，从模拟结果中提取河道断面的洪峰流量以构建评价指标，在全区、河道、断面等不同尺度进行了统计和对比分析。结果表明：随着雨强增加，降雨移动方向对河道洪峰的影响会减小；河道下游断面受影响程度明显高于上游断面；单个断面的洪峰受影响程度与降雨过程的移动方向呈现出较强相关性。研究结果可为城市洪涝防治和洪水风险评估提供参考。

Influence of rainfall movement direction on flood peak in urban river with Hewan district in Shenzhen as a case study

Global climate change and rapid urbanization lead to the increasing spatial-temporal heterogeneity of urban rainfall process, which further affects the urban river flood process and aggravates the difficulty in urban flood control. In this paper, the influence of rainfall heterogeneity on river flood in Hewan district of Shenzhen is studied. Firstly, 1300 rainfall processes reflecting the heterogeneity of rainfall processes are designed, and the urban flood model is applied to simulate the flood process of each river. Then, the flood peak discharge of each cross-section is extracted to construct the impact index. The analysis is carried out from different scales, including Hewan district, each river and each cross-section. Finally, suggestions are put forward about river flood risk assessment. The results show that:under the condition of the same rainfall intensity, the heterogeneity of rainfall process has a reducing effect on the river flood peak discharge at the regional scale and the influence of the heterogeneity of rainfall process on the river flood peak discharge will decrease with the increase of rainfall intensity;the influence on the downstream cross-sections of the river is significantly higher than that on the upstream cross-sections;the influence on the flood peak discharge of a cross-section has a strong correlation with the moving direction of the rainfall process. It is suggested that the impact of rainfall heterogeneity should be considered in river risk assessment.