基于暴雨管理模型的长江流域丘陵城镇面源污染控制方案效果评估

Evaluation of the effectiveness of urban non-point source pollution control schemes in hilly areas of the Yangtze River Basin based on Storm Water Management Model

  • 摘要: 随着我国长江流域城镇工业源和生活源污染控制的持续加强,面源污染贡献率明显增加,利用相关技术组合有效控制城镇面源负荷,已经成为长江流域城镇控制污染负荷和提升水体生态环境质量的主要内容。为探讨面源污染控制技术设施对长江流域丘陵地区城镇降雨径流降污减量的效果,以重庆市永川区新城区内某区域作为研究对象进行汇水区概化,并对其构建暴雨管理模型(SWMM)和进行参数确定及验证,采用该模型模拟透水铺装、绿色屋顶、雨水花园和下凹式绿地4种单项技术设施方案及其9种组合设施方案对研究区域降雨径流总量及污染物(包括SS、COD、TN、NH3-N和TP)负荷削减情况;并采用基于群决策的层次分析法,从效益-经济-技术3个角度综合评估各种组合控制方案对降雨径流水量水质控制效果。结果表明:所构建的研究区SWMM模型的水文、水力参数率定结果误差小于1%,水质参数率定结果纳什效率系数均在0.7以上且误差平方均值(B%MSSE指数)接近于0,实现了模型参数本土化;在各降雨重现期下,4种单项技术设施方案中透水铺装对径流量和污染物负荷控制效果最优;基于效益-经济-技术3个角度综合评估组合方案,确定方案P7为研究区域面源污染削减最佳组合方案,即布设面积比例为35%透水铺装、30%绿色屋顶、7%雨水花园和30%下凹式绿地,其径流总量削减率达到29.4%,SS、COD、TN、NH3-N和TP负荷削减率分别达到36.2%、35.1%、35.1%、30.6%和32.2%。

     

    Abstract: With the continuous strengthening of industrial and domestic pollution control in urban areas of the Yangtze River Basin in China, the contribution rate of non-point source (NPS) pollution has significantly increased. Utilizing relevant technology combinations to effectively control urban NPS load and improve water ecological environment quality has been the main content in urban areas of the Yangtze River Basin. In order to explore the effectiveness of NPS pollution control technology and facilities in reducing pollution and urban runoff in hilly areas of the Yangtze River Basin, this article took certain part of the New City Area of Yongchuan District, Chongqing as the research object to generate a catchment area. The Storm Water Management Model (SWMM) was constructed, and the parameters were determined and verified. The model was used to simulate four types of single Low Impact Development (LID) facilities, including permeable pavement, green roofs, rainwater gardens, and sunken green space, and nine combination schemes to reduce rainfall runoff and pollutant loads (including SS, COD, TN, NH3-N, and TP) in the study area. From the perspectives of benefits, economy, and technology, the Analytic Hierarchy Process (AHP) based on cluster analysis was adopted to evaluate the effectiveness of various combination control schemes on the rainfall-runoff water process. The results showed that: the error of the hydrological and hydraulic parameter calibration results of the SWMM model in the research area was less than 1%, the Nash-Sutcliffe efficiency coefficients of the water quality parameters calibration results were all above 0.7, and B% MSSE index was close to 0, achieving the localization of model parameters. Under different designed rainfall scenarios, permeable pavement had the best control effect on runoff volume and runoff pollution load among the four single facility schemes. Based on a comprehensive evaluation from the perspectives of benefits, economy, and technology, plan P7 had been determined as the optimal combination plan for reducing NPS pollution in the study area. P7 had a layout area ratio of 35% permeable pavement, 30% green roof, 7% rain garden, and 30% sunken green space. The total runoff reduction rate reached 29.4%, and the reduction rates of SS, COD, TN, NH3-N, and TP loads reached 36.2%, 35.1%, 35.1%, 30.6%, and 32.2%, respectively.

     

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