基于GIS的漳河上游城市非点源污染负荷估算

为了解漳河上游水污染成因,2017年对长治市城区典型功能区不同下垫面进行了11场降雨监测,分析了次降雨径流污染物平均浓度(EMC),采用平均浓度模型法估算了2017年漳河上游各城市非点源污染年负荷,并结合ArcGIS技术分析了各市县污染程度。结果表明:2017年,长治市城区降雨径流非点源污染较为严重;各功能区路面径流污染物的EMC值大于屋面,主要污染源为SS、CODCr、TN和重金属Cd;商业区路面SS的EMC值高达666.87 mg/L,工业区屋面Cd的EMC值是44.27μg/L,居民区路面CODCr、TN的EMC值分别为148.69 mg/L、6.273 mg/L。长治市城区非点源TN、TP、SS、CODCr、Cd、Cu、Zn和Pb年负荷入河总量分别为5.301 t/a、0.464 t/a、267.310 t/a、177.890 t/a、0.075 t/a、0.150 t/a、0.384 t/a和0.023 t/a;3种下垫面非点源污染年负荷入河贡献率顺序为屋面、路面、绿地。从空间分布方面来看,长治市城区污染的产出最多,武乡县产出最少。

Estimation of urban non-point source pollution load in upper reaches of Zhanghe River based on GIS

In order to understand the causes of water pollution in the upper reaches of Zhanghe River,11 rainfall monitoring were conducted on different underlying surfaces of typical functional areas in Changzhi City in 2017,and the event mean concentration(EMC)of pollutants in the runoff of each rainfall was analyzed.The annual non-point source pollution load of each city in the upper reaches of Zhanghe River in 2017 was estimated by the average concentration model method,and the pollution degree of each city and county was analyzed by using ArcGIS technology.The results show that in 2017,the non-point source pollution of rainfall runoff in Changzhi City is more serious.The EMC value of pavement runoff pollutants in each functional area is greater than that of roof,and the main pollution sources are SS,CODCr,TN and heavy metal Cd.The EMC value of SS of commercial area pavement is 666.87 mg/L,that of Cd of industrial area roof is 44.27μg/L,and that of CODCr and TN of residential area pavement is 148.69 mg/L and 6.273 mg/L,respectively.The total annual load of non-point source TN,TP,SS,CODCr,CD,Cu,Zn and Pb in the urban area of Changzhi City is 5.301 t/a,0.464 t/a,267.310 t/a,177.890 t/a,0.075 t/a,0.150 t/a,0.384 t/a and 0.023 t/a,respectively.The contribution rate of non-point source pollution annual load on three kinds of underlying surface to the river is in the order from large to small of roof,pavement and green space.In terms of spatial distribution,Changzhi City has the most pollution output and Wuxiang County has the least.