北京城市洪涝模型建设与典型示范

Construction and demonstration of urban flood modeling in Beijing

伴随城市快速发展,城市不透水面积持续增加,使得在同等降雨条件下流域内洪峰流量增加、峰现时间缩短,洪涝灾害威胁扩大。城市水利工程众多,虽然城市排水管网和河道都经过全面整治,但随着城区面积增加,城区防洪排涝河道和管网的服务范围、下垫面状况、排水单元和沟渠、支流发生了显著改变,河网的产汇流过程也发生了较大变化。针对城市洪涝灾害发生的复杂性和不确定性特点,提出北京市洪涝模型构建技术框架,并以清河流域为典型流域构建洪涝模型,分别从不同下垫面和降雨条件下河网排洪能力复核、河道防洪预警指标细化、城市洪涝风险量化等方面构建基于洪涝模拟的城市防汛安全调度技术体系。

With the rapid urbanization, the ratio of impervious area in river basins has increased greatly. It resulted in the increase of peak flood discharges, reduction of time of concentrations, and expanding threat of flood disasters. Especially, under the unified planning and overall management of channels and drainage systems for urban rivers, the rainfall-runoff relationship is changed greatly at urban river basin scale. Considering the complex and uncertainty of urban flood disasters, this paper proposes a technical framework of urban flood model, and taking Qinghe River as an example to construct the model. The river flood diversion capacity is rechecked. The indicator levels of early warning of river flood are refined with quantified the relationship between flood peak and rainfall depth. The watershed flood risk characteristics are also addressed based on the model. This study would provide a guide to flood control and storm water utilization assessment in the watershed of urban area.