SWMM模拟植草沟功能的参数敏感性分析

Parameter Sensitivity Analysis of SWMM Model for Simulation of Grass Swales

SWMM在中国城市雨洪管理研究中的应用日益广泛,但关于模型参数设置及其对模型运算结果的影响研究尚有不足。以植草沟为研究对象,采用实测数据,对SWMM中最大入渗率、最小入渗率、入渗衰减系数、表面糙率等4个参数的敏感性进行了研究,并对比分析了根据文献设置模型参数值和应用实测参数值进行模拟的结果。结果表明,采用实测参数的模拟结果要优于采用手册中建议的参数值的模拟结果,前者更接近实测值;4个参数中,土壤最大入渗率为最敏感参数,表面糙率为不敏感参数;有关土壤入渗的模型参数敏感度受到降雨强度的影响。因此,在应用SWMM模拟植草沟功能时需要考虑参数如何取值,对具有敏感性的参数应尽可能采用实测值。

The use of stormwater management model （SWMM） in studying urban stormwater man- agement has increased dramatically in China. However, ways to set up model parameters and the effects on the final results are still not adequately studied. The data measured from a constructed grass swale under simulated rain events were used to investigate the sensitivities of four parameters including maximum infiltration rate, minimum infiltration rate, infiltration attenuation coefficient and surface roughness in SWMM. The simulation results based separately on recommended values and measured values of the four parameters were compared. The results showed that： ① simulations based on measured values of parameters achieved better results than simulations based on recommended values. The results simulated by the former were closer to the measured values than those by the later; ② among the four tested parameters, the maximum infiltration rate of soil was a sensitive parameter, the surface roughness was not sensitive; and ③ the sensitivity of parameters was affected by intensities of rain events. Therefore, care should be taken in assigning values for parameters when applying SWMM to simulate the function of grass swales. For sensitive parameters, it is better to use the measured values of parameters in simulations.