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[摘要]
以大兴机场海绵系统为例,根据降雨径流资料,建立暴雨雨水管理模型 (storm?water?management?model, SWMM),模拟不同海绵设施组合情景下的水文过程。结果表明:在不同设计暴雨条件下,绿色基础设施、景观湖 以及组合方案均能削减洪峰流量、延迟洪峰时刻;组合方案的雨水控制效果最为显著,5a 重现期下,出口处洪峰 流量削减率和雨水总量控制率分别达 41.5% 和 79.9%;景观湖的蓄滞作用在不同的重现期下对出口流量的影响时 段不同,景观湖在低重现期下蓄积降雨过程中的雨水,削减降雨初期外排出口的流量,而在高重现期下蓄积空间 主要用于降雨后期的雨水汇流的收集,在出口段明渠退水过程中减少外排雨水;绿色基础设施在上游区域的溢流 量削减率达到 10.6%,在洪峰削减、延迟峰值时刻上表现明显;上游连接景观湖后造成的回流会导致退水时长增 加,在高重现期下回流雨水占用明渠蓄水空间,可能增加上游管网的溢流风险。
[Key word]
[Abstract]
Urban floods have become more and more frequent in a changing environment. Continue climate change and rapid urbanization pose great challenges to traditional stormwater management systems, resulting in frequent flooding in urban areas. Traditional flood control mainly relies on traditional gray infrastructure, because the burden of drainage increases, the method of simply increasing gray infrastructure is not sustainable for stormwater management. As an alternative to traditional gray infrastructure, Green Infrastructure is applied to alleviate urban flood.The sponge system of Daxing Airport is taken as an example. A storm water management model was established to simulate the hydrological process under different combinations of sponge facilities, on the basis of rainfall-runoff data, and the historical rainfall and flood flow data were used for calibration and verification. The different return period of design rainfall (5 a, 10 a, 50 a), according to the current construction situation, three kinds of sponge facilities laid schemes were designed, and compared with the simulation results without any sponge facilities, and the impacts of sponge facilities on flood peak flow, overflow volume were analyzed. The result can provide scientific and technical support for flood control and disaster reduction in the study area.The simulation results indicate: (1) Under different design rainstorm events, Green Infrastructure, landscape lakes, and combined solutions could reduce peak flow and delay peak times of the hydrograph. The rainwater control effect of the combined scheme is the most significant, comparing to the separate solutions. Under the 5-year return period, the reduction rate of the flood peak flow at the outlet and the control rate of the total rainwater amounted to 41.5% and 79.9%, respectively; (2) The storage and stagnation effect of the landscape lake was analyzed under different return periods. The landscape lake accumulates the rainwater during the rainfall under the low return period, reducing the flow of the outlet at the early stage of the rainfall, while the storage space is mainly used for the rainwater confluence in the later period of the rainfall under the high return period. (3) The overflow reduction rate of Green Infrastructure in the upstream area reaches 10.6%, which is obvious in the reduction of flood peaks. The backflow caused by the upstream connection to the landscape lake will lead to an increase in the duration of the backwater. Under the high return period, the backflow rainwater will occupy the water storage space of the open channel, which may increase the overflow risk of the upstream pipe network.Green Infrastructure and landscape lakes have a significant impact on the rainwater control effect in the study area, and the current combination of sponge facilities in the study area can effectively alleviate urban waterloggin. The storage and stagnation effect of the landscape lake is significant for the open channel system, especially for the control of the discharge flow at the outlet; the effect of the Green Infrastructure is reflected in the concentrated construction area, and the adjustment effect is obvious under low rainfall intensity. The Green Infrastructure of the airport and the flood control effect of the landscape lake were initially discussed in order to provide a reference for future research and engineering construction. In future research, the combined dispatch of reservoirs and pumping stations and the combination of sponge facilities can be combined to study the effect of stormwater control under collaborative management.
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