低影响开发模式下城市雨洪控制效果模拟研究

由于贵安新区作为国家第一批海绵城市试点,对我国西南地区的其他城市有非常好的借鉴作用。本文以贵安新区示范区为研究对象,构建暴雨洪水管理模型(SWMM),并根据贵安新区海绵城市建设相关规划,结合研究区下垫面特征,在不同重现期降水情景下设计7种LID措施组合情景并进行相应的模拟与分析,评估不同LID措施组合对雨洪控制的效果,寻求最优LID措施组合。结果表明:LID措施组合方案的雨洪控制效果均优于单一LID措施,其中下凹式绿地+透水铺装组合措施对高频暴雨和低频暴雨的洪峰流量削减率高达67.2%和44.5%,延缓洪水峰现时间,可以很好地发挥雨洪控制作用,增加雨洪资源的利用量。结合径流系数控制效果,下凹式绿地+透水铺装组合的造价可以降低60.3%,综合考虑水文效应与经济效应,得到贵安新区LID措施的最优配置为:下凹式绿地+透水铺装。以上结果可为贵安新区的城市雨洪管理及海绵城市建设提供相应的理论支撑。

Simulative study on effect of urban rain-flood control under low-impact development mode

As one of the first batch of sponge city pilots in China,Gui an New District plays a better referential role for the other cities in the Southwest China.By taking Gui an New District as the study object,a storm water management model(SWMM)is established herein,and then 7 combined scenarios of LID(low-impact development)under the scenarios of the precipitation with different return periods are designed and then correspondingly simulated and analyzed in combination with the characteristics of the underlying surface of the study area according to the relevant planning of the sponge city construction of the district,while the effects from different combinations of the LID measures on the rain-flood control are evaluated for seeking the optimal combination of the LID measures.The result shows that the rain-flood control effects of all the schemes of the combined LID measures are better than that from the single LID measure,in which the flood peak-flow clipping rate of the combined measures of concave-down green space+permeable pavementis as high as 67.2%and 44.5%for high-frequency and low-frequency rainstorms respectively,and then delays the occurrence of flood peak,which can better play the role of rain-flood control and increase the utilization of rain-flood resources.Combined with the runoff coefficient control effect,the construction cost of the combination of concave-down green space+permeable pavement can be reduced by 60.3%,thus the optimal layout of the LID measures for Gui an New District is obtained,i.e.concave-down green space+permeable pavement,under the comprehensive consideration of both the hydrological effect and economic effect.The result mentioned above can provide the relevant theoretical support for both the urban rain-flood management and the sponge city construction of Gui an New District.