子汇水区划分精度对SWMM模拟城市非点源的影响

Impact of Sub-catchment Size Delineation on Urban Non-point Source Pollution Simulation Using SWMM

SWMM作为动态模拟的城市非点源污染模型,被广泛应用于城市非点源负荷估算研究,并在很多小尺度研究中取得了很好的效果。随着中国城市发展不断加快,城市非点源污染研究的空间尺度也随之变大,如何科学合理选择建模时子汇水区划分精度成为研究中一个重要问题。文章主要分析SWMM应用于城市区域非点源污染模拟时,不同子汇水区划分精度对水质模拟结果的影响,并在此基础上,以降低SWMM建模工作量并保证模拟结果的准确度为原则,对如何选择子汇水区的精度进行了深入的探讨。结果表明事件降雨为降雨输入时,子汇水区划分精度对水质模拟结果影响较大,宜采用高精度或高中精度模型;单月份和雨季连续降雨为降雨输入时,子汇水区划分精度对水质模拟结果影响较小,可以使用低精度模型。

As a dynamic urban non-point source pollution model,SWMM is widely used in the estimation of urban nonpoint source load. With the increasing scale of the study area,how to choose a scientific and rational sub-catchment division precision has become a problem in the study. The effects on water quality modeling results of different sub-catchment division precision were analyzed,when SWMM applied to urban non-point source pollution modeling. Results indicated that with event rainfall as the rainfall input,the precision of the sub-catchment division has greater impact on water quality simulation results;while with single month or rainy season as the rainfall input,the precision of sub-catchment division has less impact on water quality simulation results.