西安市对渭河水质的影响分析

Impact Analysis of Xi'an to the Water Quality of Weihe River

根据渭河西安段各代表断面的水质监测结果和该流域不同代表年径流量,通过平均浓度法计算各污染物负荷量,得出渭河干流以点源污染为主,支流非点源污染较干流严重.基于2009～2011年实测污染物浓度数据,由物料衡算法计算得到咸阳至临潼断面间西安地区对渭河干流的污染物输入量,分析西安段各项污染负荷占下游监测断面临潼的比例,量化西安对渭河水质所造成的影响程度.计算结果显示,渭河临潼断面污染负荷主要来自于咸阳断面上游,TN、COD及NH4+-N输出入量均占下游断面的40%以上.其次来源于西安地区,除TP占下游断面53%外,其余污染物占30%以上,且西安地区非点源污染比其上、下游断面严重,点源负荷约占总负荷63%.

Based on the water quality inspection results of Weihe River in the Xi＇an section and the runoff at the watershed in different representative years,it was found through the pollution load calculated from the mean concentration method that Weihe River＇s main stream was dominated by point source pollution and non-point source pollution was more serious in tributaries.The input amount of pollutant to Weihe River＇ main stream from Xi＇an which is located within the Xianyang and Lintong section was calculated from the material balance algorithm based on the pollutant concentrations measured in 2009 and 2011.The percentage of the pollution load of Xi＇an area on Lower reaches＇ monitoring section of Lintong was analysed and the impact of Xi＇an area on the water quality of Weihe River was quantified.The computational results showed that the upstream of the Xianyang section was the main source of the pollution load of the Lintong section in Weihe River,followed by Xi＇an area.More than 40% of TN,COD and NH＋4-N of the Lintong section came from the upstream of the Xianyang section and more than 30% came from Xi＇an area,in addition,53% of TP came from Xi＇an area.The non-point source pollution in Xi＇an was more serious than in its upstream and downstream areas while point source pollution load accounted for 63% of the total.