植草沟滞蓄城市道路雨水的试验及模拟

Experiment and simulation of the vegetative swale to control road stormwater

为定量分析植草沟的水文性能,优化其设计参数取值,通过植草沟滞蓄城市道路雨水的试验设施开展模拟径流试验,验证了SWMM(storm water management model)模型模拟植草沟滞蓄效果的可行性,通过模型情景分析提出了设施的优化设计参数,评估了设施对提高道路排水标准和长期径流削减的影响。研究结果表明:SWMM模型对模拟植草沟水文性能具有较好的精度,对较小的降雨重现期和边坡比,较大的滞蓄深度、植被覆盖率和面积负荷比,植草沟的滞蓄能力更强,建议其设计降雨重现期不超过10年,滞蓄深度为10 cm以上,边坡比至少为3,植被覆盖率为0. 5以上,面积负荷比为5%以上。模拟北京某城市道路采用植草沟设施后,可将3年、5年、10年的排水标准分别提高到15年、20年、30年,在长达64年的运行中,植草沟几乎可消纳自身及汇水区域内所有径流,可为道路植草沟的设计和应用提供参考。

In order to quantitatively analyze the hydrological performance of vegetative swale facilities and optimize the value of their design parameters,the feasibility of SWMM model to simulate the effects of vegetative swale facilities on rainwater storage in urban roads was verified through simulated runoff experiments conducted by the experimental vegetative swale.The optimized design parameters of facilities were put forward through model scenario analysis,and the influence of facilities on improving road drainage standards and long-term runoff reduction was evaluated.The research results show that SWMM model has good accuracy in simulating the hydrological performance of vegetative swale facilities.For smaller rainfall return period and slope ratio,larger storage depth,vegetation coverage rate and area load ratio,vegetative swale facilities have stronger storage capacity.It is suggested that the design rainfall return period should not exceed 10 a,storage depth should be above 10 cm,slope ratio should be at least 3,vegetation coverage rate should be above 0.5,and area load ratio should be above 5 %.The drainage standards of 3 a,5 a,and10 a can be raised to 15 a,20 a,and 30 a respectively after simulating the use of the vegetative swale in an urban road in Beijing,and in 64 years of operation,the vegetative swale can remove almost all runoff in itself and catchment area,which can provide reference for the design and application of vegetative swale facilities on roads.